Position control draft

(Setting alpha = 1 efficiently disables the filter.)
Filtering does more harm than good in voltage monitoring.

.github/workflows/build.yml

@@ -23,10 +23,12 @@ jobs:
       with:
         name: firmware-binary
         path: flix/build
+    - name: Build firmware for ESP32-C3
+      run: make BOARD=esp32:esp32:esp32c3
     - name: Build firmware for ESP32-S3
       run: make BOARD=esp32:esp32:esp32s3
-    - name: Build firmware with WiFi disabled
-      run: sed -i 's/^#define WIFI_ENABLED 1$/#define WIFI_ENABLED 0/' flix/flix.ino && make
+    - name: Build espnow-proxy
+      run: arduino-cli compile --fqbn esp32:esp32:esp32 tools/espnow-proxy
     - name: Check c_cpp_properties.json
       run: tools/check_c_cpp_properties.py
 

.gitignore

@@ -4,9 +4,10 @@ build/
 tools/log/
 tools/dist/
 *.egg-info/
-.dependencies
+.core
+.libs
 .vscode/*
-!.vscode/settings.json
+!.vscode/settings.default.json
 !.vscode/c_cpp_properties.json
 !.vscode/tasks.json
 !.vscode/launch.json

.markdownlint.json

@@ -7,6 +7,7 @@
 	"MD024": false,
 	"MD033": false,
 	"MD034": false,
+	"MD040": false,
 	"MD059": false,
 	"MD044": {
 		"html_elements": false,

.vscode/c_cpp_properties.json

@@ -6,19 +6,18 @@
 				"${workspaceFolder}/flix",
 				"${workspaceFolder}/gazebo",
 				"${workspaceFolder}/tools/**",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/libraries/**",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32",
-				"~/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/**",
-				"~/.arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/dio_qspi/include",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/libraries/**",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32",
+				"~/.arduino15/packages/esp32/tools/esp32-libs/3.3.10/include/**",
 				"~/Arduino/libraries/**",
 				"/usr/include/gazebo-11/",
 				"/usr/include/ignition/math6/"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32/Arduino.h",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32/pins_arduino.h",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32/Arduino.h",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
 				"${workspaceFolder}/flix/estimate.ino",
@@ -31,9 +30,10 @@
 				"${workspaceFolder}/flix/rc.ino",
 				"${workspaceFolder}/flix/time.ino",
 				"${workspaceFolder}/flix/wifi.ino",
-				"${workspaceFolder}/flix/parameters.ino"
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/.arduino15/packages/esp32/tools/esp-x32/2411/bin/xtensa-esp32-elf-g++",
+			"compilerPath": "~/.arduino15/packages/esp32/tools/esp-x32/2601/bin/xtensa-esp32-elf-g++",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [
@@ -53,19 +53,18 @@
 			"name": "Mac",
 			"includePath": [
 				"${workspaceFolder}/flix",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/libraries/**",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32",
-				"~/Library/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/include/**",
-				"~/Library/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/dio_qspi/include",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/libraries/**",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32",
+				"~/Library/Arduino15/packages/esp32/tools/esp32-libs/3.3.10/include/**",
 				"~/Documents/Arduino/libraries/**",
 				"/opt/homebrew/include/gazebo-11/",
 				"/opt/homebrew/include/ignition/math6/"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32/Arduino.h",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32/pins_arduino.h",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32/Arduino.h",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/flix.ino",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
@@ -78,9 +77,10 @@
 				"${workspaceFolder}/flix/rc.ino",
 				"${workspaceFolder}/flix/time.ino",
 				"${workspaceFolder}/flix/wifi.ino",
-				"${workspaceFolder}/flix/parameters.ino"
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/Library/Arduino15/packages/esp32/tools/esp-x32/2411/bin/xtensa-esp32-elf-g++",
+			"compilerPath": "~/Library/Arduino15/packages/esp32/tools/esp-x32/2601/bin/xtensa-esp32-elf-g++",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [
@@ -103,17 +103,16 @@
 				"${workspaceFolder}/flix",
 				"${workspaceFolder}/gazebo",
 				"${workspaceFolder}/tools/**",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/libraries/**",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32",
-				"~/AppData/Local/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/**",
-				"~/AppData/Local/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/dio_qspi/include",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/libraries/**",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32",
+				"~/AppData/Local/Arduino15/packages/esp32/tools/esp32-libs/3.3.10/include/**",
 				"~/Documents/Arduino/libraries/**"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32/Arduino.h",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32/pins_arduino.h",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32/Arduino.h",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
 				"${workspaceFolder}/flix/estimate.ino",
@@ -126,9 +125,10 @@
 				"${workspaceFolder}/flix/rc.ino",
 				"${workspaceFolder}/flix/time.ino",
 				"${workspaceFolder}/flix/wifi.ino",
-				"${workspaceFolder}/flix/parameters.ino"
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2411/bin/xtensa-esp32-elf-g++.exe",
+			"compilerPath": "~/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2601/bin/xtensa-esp32-elf-g++.exe",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [

.vscode/extensions.json

@@ -1,6 +1,7 @@
 {
 	// See https://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
 	"recommendations": [
+		"dangmai.workspace-default-settings",
 		"ms-vscode.cpptools",
 		"ms-vscode.cmake-tools",
 		"ms-python.python"

Makefile

@@ -1,29 +1,40 @@
 BOARD = esp32:esp32:d1_mini32
-PORT := $(wildcard /dev/serial/by-id/usb-Silicon_Labs_CP21* /dev/serial/by-id/usb-1a86_USB_Single_Serial_* /dev/cu.usbserial-*)
-PORT := $(strip $(PORT))
+PORT := $(strip $(wildcard /dev/serial/by-id/usb-Silicon_Labs_CP21* /dev/serial/by-id/usb-1a86_USB_Single_Serial_* /dev/cu.usbserial-* /dev/cu.usbmodem*))
 
-build: .dependencies
-	arduino-cli compile --fqbn $(BOARD) flix
+export ARDUINO_NETWORK_CONNECTION_TIMEOUT := 1h
+
+build: .core .libs
+	arduino-cli compile --fqbn $(BOARD) --build-property "build.core_debug_level=1" flix
 
 upload: build
 	arduino-cli upload --fqbn $(BOARD) -p "$(PORT)" flix
 
+erase:
+	arduino-cli burn-bootloader --fqbn $(BOARD) -p "$(PORT)" -P esptool
+
 monitor:
 	arduino-cli monitor -p "$(PORT)" -c baudrate=115200
 
-dependencies .dependencies:
-	arduino-cli core update-index --config-file arduino-cli.yaml
-	arduino-cli core install esp32:esp32@3.2.0 --config-file arduino-cli.yaml
+core .core:
+	arduino-cli core update-index --additional-urls https://espressif.github.io/arduino-esp32/package_esp32_index.json
+	arduino-cli core install esp32:esp32@3.3.10 --additional-urls https://espressif.github.io/arduino-esp32/package_esp32_index.json
+	touch .core
+
+libs .libs:
 	arduino-cli lib update-index
 	arduino-cli lib install "FlixPeriph"
-	arduino-cli lib install "MAVLink"@2.0.16
-	touch .dependencies
+	arduino-cli lib install "MAVLink"@2.0.25
+	touch .libs
+
+upload_proxy: .core .libs
+	arduino-cli compile --fqbn $(BOARD) tools/espnow-proxy
+	arduino-cli upload --fqbn $(BOARD) -p "$(PORT)" tools/espnow-proxy
 
 gazebo/build cmake: gazebo/CMakeLists.txt
 	mkdir -p gazebo/build
 	cd gazebo/build && cmake ..
 
-build_simulator: .dependencies gazebo/build
+build_simulator: .libs gazebo/build
 	make -C gazebo/build
 
 simulator: build_simulator
@@ -38,6 +49,6 @@ plot:
 	plotjuggler -d $(shell ls -t tools/log/*.csv | head -n1)
 
 clean:
-	rm -rf gazebo/build flix/build flix/cache .dependencies
+	rm -rf gazebo/build flix/build flix/cache .core .libs
 
-.PHONY: build upload monitor dependencies cmake build_simulator simulator log clean
+.PHONY: build upload monitor core libs cmake build_simulator simulator log clean

README.md

@@ -1,6 +1,9 @@
-# Flix
+<!-- markdownlint-disable MD041 -->
 
-**Flix** (*flight + X*) — open source ESP32-based quadcopter made from scratch.
+<p align="center">
+  <img src="docs/img/flix.svg" width=180 alt="Flix logo"><br>
+  <b>Flix</b> (<i>flight + X</i>) — open source ESP32-based quadcopter made from scratch.
+</p>
 
 <table>
   <tr>
@@ -18,15 +21,13 @@
 * Dedicated for education and research.
 * Made from general-purpose components.
 * Simple and clean source code in Arduino (<2k lines firmware).
-* Control using USB gamepad, remote control or smartphone.
-* Wi-Fi and MAVLink support.
+* Communication using MAVLink protocol over Wi-Fi or ESP-NOW.
+* Control with USB gamepad, remote control or smartphone.
 * Wireless command line interface and analyzing.
 * Precise simulation with Gazebo.
-* Python library.
+* Python library for scripting and automatic flights.
 * Textbook on flight control theory and practice ([in development](https://quadcopter.dev)).
-* *Position control (using external camera) and autonomous flights¹*.
-
-*¹ — planned.*
+* *Position control (planned)*.
 
 ## It actually flies
 
@@ -46,13 +47,21 @@ See the [user builds gallery](docs/user.md):
 
 <a href="docs/user.md"><img src="docs/img/user/user.jpg" width=500></a>
 
+### PCB
+
+The official PCB *(Flix2)* is in development now. Follow the [project's channel](https://t.me/opensourcequadcopter) to track the progress.
+
+Outdoor flights demo video of the current prototype:
+
+<a href="https://youtu.be/KXlNmvUTi4g"><img width=300 src="https://i3.ytimg.com/vi/KXlNmvUTi4g/maxresdefault.jpg"></a>
+
 ## Simulation
 
 The simulator is implemented using Gazebo and runs the original Arduino code:
 
 <img src="docs/img/simulator1.png" width=500 alt="Flix simulator">
 
-## Documentation
+## Documentation articles
 
 1. [Assembly instructions](docs/assembly.md).
 2. [Usage: build, setup and flight](docs/usage.md).
@@ -70,14 +79,14 @@ Additional articles:
 
 |Type|Part|Image|Quantity|
 |-|-|:-:|:-:|
-|Microcontroller board|ESP32 Mini|<img src="docs/img/esp32.jpg" width=100>|1|
-|IMU (and barometer¹) board|GY‑91, MPU-9265 (or other MPU‑9250/MPU‑6500 board)<br>ICM20948V2 (ICM‑20948)³<br>GY-521 (MPU-6050)³⁻¹|<img src="docs/img/gy-91.jpg" width=90 align=center><br><img src="docs/img/icm-20948.jpg" width=100><br><img src="docs/img/gy-521.jpg" width=100>|1|
-|Boost converter (optional, for more stable power supply)|5V output|<img src="docs/img/buck-boost.jpg" width=100>|1|
+|Microcontroller board|ESP32 Mini.<br>ESP32-S3/ESP32-C3 boards are also supported.|<img src="docs/img/esp32.jpg" width=100>|1|
+|IMU (and barometer¹) board|GY‑91, MPU-9265 (or other MPU‑9250/MPU‑6500 board)<br>ICM20948V2 (ICM‑20948)<br>GY-521 (MPU-6050)|<img src="docs/img/gy-91.jpg" width=90 align=center><br><img src="docs/img/icm-20948.jpg" width=100><br><img src="docs/img/gy-521.jpg" width=100>|1|
+|*Boost converter (optional, for more stable power supply)*|*5V output*|<img src="docs/img/buck-boost.jpg" width=100>|1|
 |Motor|8520 3.7V brushed motor.<br>Motor with exact 3.7V voltage is needed, not ranged working voltage (3.7V — 6V).<br>Make sure the motor shaft diameter and propeller hole diameter match!|<img src="docs/img/motor.jpeg" width=100>|4|
-|Propeller|55 mm (alternatively 65 mm)|<img src="docs/img/prop.jpg" width=100>|4|
-|MOSFET (transistor)|100N03A or [analog](https://t.me/opensourcequadcopter/33)|<img src="docs/img/100n03a.jpg" width=100>|4|
-|Pull-down resistor|10 kΩ|<img src="docs/img/resistor10k.jpg" width=100>|4|
-|3.7V Li-Po battery|LW 952540 (or any compatible by the size)|<img src="docs/img/battery.jpg" width=100>|1|
+|Propeller|55 mm or 65 mm|<img src="docs/img/prop.jpg" width=100>|4|
+|MOSFET (transistor)|UMW 100N03A or [analog](https://t.me/opensourcequadcopter/33).<br>Warning: don't use KIA 100N03A or other manufacturers, they might not work!|<img src="docs/img/100n03a.jpg" width=100>|4|
+|Pull-down resistor<br>Voltage measurement resistor|10 kΩ|<img src="docs/img/resistor10k.jpg" width=100>|6|
+|3.7V Li-Po battery|LW 952540 (or any compatible by the size).<br>Make sure the battery has enough discharge rate — 25C or more!|<img src="docs/img/battery.jpg" width=100>|1|
 |Battery connector cable|MX2.0 2P female|<img src="docs/img/mx.png" width=100>|1|
 |Li-Po Battery charger|Any|<img src="docs/img/charger.jpg" width=100>|1|
 |Screws for IMU board mounting|M3x5|<img src="docs/img/screw-m3.jpg" width=100>|2|
@@ -137,10 +146,10 @@ You can see a user-contributed [variant of complete circuit diagram](https://mir
 
   |Motor|Position|Direction|Prop type|Motor wires|GPIO|
   |-|-|-|-|-|-|
-  |Motor 0|Rear left|Counter-clockwise|B|Black & White|GPIO12 (*TDI*)|
-  |Motor 1|Rear right|Clockwise|A|Blue & Red|GPIO13 (*TCK*)|
-  |Motor 2|Front right|Counter-clockwise|B|Black & White|GPIO14 (*TMS*)|
-  |Motor 3|Front left|Clockwise|A|Blue & Red|GPIO15 (*TD0*)|
+  |Motor 0|Rear left|Counter-clockwise|B|Black & White|GPIO12 *(TDI)*|
+  |Motor 1|Rear right|Clockwise|A|Blue & Red|GPIO13 *(TCK)*|
+  |Motor 2|Front right|Counter-clockwise|B|Black & White|GPIO14 *(TMS)*|
+  |Motor 3|Front left|Clockwise|A|Blue & Red|GPIO15 *(TD0)*|
 
   Clockwise motors have blue & red wires and correspond to propeller type A (marked on the propeller).
   Counter-clockwise motors have black & white wires correspond to propeller type B.
@@ -151,14 +160,16 @@ You can see a user-contributed [variant of complete circuit diagram](https://mir
   |-|-|
   |GND|GND|
   |VIN|VCC (or 3.3V depending on the receiver)|
-  |Signal (TX)|GPIO4¹|
+  |Signal (TX)|GPIO4|
 
-*¹ — UART2 RX pin was [changed](https://docs.espressif.com/projects/arduino-esp32/en/latest/migration_guides/2.x_to_3.0.html#id14) to GPIO4 in Arduino ESP32 core 3.0.*
+* Optionally connect the battery voltage divider for voltage monitoring to any ADC1 pin (e. g. *GPIO32* on ESP32, *GPIO3* on ESP32-S3).
+
+  ESP32 and ESP32-S3 [can measure](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/adc.html#analogsetattenuation) up to 3.1 V and ESP32-S3/ESP32-C3 can measure up to 2.5 V, so choose the voltage divider resistors accordingly.
 
 ## Resources
 
 * Telegram channel on developing the drone and the flight controller (in Russian): https://t.me/opensourcequadcopter.
-* Official Telegram chat: https://t.me/opensourcequadcopterchat.
+* Official Telegram chat: https://t.me/opensourcequadcopterchat (English / Russian).
 * Detailed article on Habr.com about the development of the drone (in Russian): https://habr.com/ru/articles/814127/.
 
 ## Disclaimer

arduino-cli.yaml

@@ -1,5 +0,0 @@
-board_manager:
-  additional_urls:
-    - https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
-network:
-  connection_timeout: 1h

docs/assembly.md

@@ -28,6 +28,8 @@ Soldered components ([schematics variant](https://miro.com/app/board/uXjVN-dTjoo
 
 <img src="img/assembly/7.jpg" width=600>
 
+See an alternative assembly process photos here: https://drive.google.com/drive/folders/1FG5BH9RCzdf1XmJcC70PymiRMXcz6Fx7?usp=sharing.
+
 ## Motor directions
 
 > [!WARNING]
@@ -41,10 +43,10 @@ Motors connection table:
 
 |Motor|Position|Direction|Prop type|Motor wires|GPIO|
 |-|-|-|-|-|-|
-|Motor 0|Rear left|Counter-clockwise|B|Black & White|GPIO12 (*TDI*)|
-|Motor 1|Rear right|Clockwise|A|Blue & Red|GPIO13 (*TCK*)|
-|Motor 2|Front right|Counter-clockwise|B|Black & White|GPIO14 (*TMS*)|
-|Motor 3|Front left|Clockwise|A|Blue & Red|GPIO15 (*TD0*)|
+|Motor 0|Rear left|Counter-clockwise|B|Black & White|GPIO12 *(TDI)*|
+|Motor 1|Rear right|Clockwise|A|Blue & Red|GPIO13 *(TCK)*|
+|Motor 2|Front right|Counter-clockwise|B|Black & White|GPIO14 *(TMS)*|
+|Motor 3|Front left|Clockwise|A|Blue & Red|GPIO15 *(TD0)*|
 
 ## Motors tightening
 

docs/book/firmware.md

@@ -35,7 +35,7 @@
 
 ### Подсистема управления
 
-Состояние органов управления обрабатывается в функции `interpretControls()` и преобразуется в *команду управления*, которая включает следующее:
+Состояние органов управления обрабатывается в функции `interpretControls()` и преобразуется в **команду управления**, которая включает следующее:
 
 * `attitudeTarget` *(Quaternion)* — целевая ориентация дрона.
 * `ratesTarget` *(Vector)* — целевые угловые скорости, *рад/с*.

docs/book/geometry.md

@@ -110,7 +110,7 @@ float angle = Vector::angleBetween(a, b); // 1.57 (90 градусов)
 
 #### Скалярное произведение
 
-Скалярное произведение векторов (*dot product*) — это произведение длин двух векторов на косинус угла между ними. В математике оно обозначается знаком `·` или слитным написанием векторов. Интуитивно, результат скалярного произведения показывает, насколько два вектора *сонаправлены*.
+Скалярное произведение векторов *(dot product)* — это произведение длин двух векторов на косинус угла между ними. В математике оно обозначается знаком `·` или слитным написанием векторов. Интуитивно, результат скалярного произведения показывает, насколько два вектора *сонаправлены*.
 
 В Flix используется статический метод `Vector::dot()`:
 
@@ -124,7 +124,7 @@ float dotProduct = Vector::dot(a, b); // 32
 
 #### Векторное произведение
 
-Векторное произведение (*cross product*) позволяет найти вектор, перпендикулярный двум другим векторам. В математике оно обозначается знаком `×`, а в прошивке используется статический метод `Vector::cross()`:
+Векторное произведение *(cross product)* позволяет найти вектор, перпендикулярный двум другим векторам. В математике оно обозначается знаком `×`, а в прошивке используется статический метод `Vector::cross()`:
 
 ```cpp
 Vector a(1, 2, 3);
@@ -144,9 +144,9 @@ Vector crossProduct = Vector::cross(a, b); // -3, 6, -3
 
 В прошивке углы Эйлера сохраняются в обычный объект `Vector` (хоть и, строго говоря, не являются вектором):
 
-* Угол по крену (*roll*) — `vector.x`.
-* Угол по тангажу (*pitch*) — `vector.y`.
-* Угол по рысканию (*yaw*) — `vector.z`.
+* Угол по крену *(roll)* — `vector.x`.
+* Угол по тангажу *(pitch)* — `vector.y`.
+* Угол по рысканию *(yaw)* — `vector.z`.
 
 Особенности углов Эйлера:
 
@@ -162,8 +162,8 @@ Vector crossProduct = Vector::cross(a, b); // -3, 6, -3
 
 Помимо углов Эйлера, любую ориентацию в трехмерном пространстве можно представить в виде вращения вокруг некоторой оси на некоторый угол. В геометрии это доказывается, как **теорема вращения Эйлера**. В таком представлении ориентация задается двумя величинами:
 
-* **Ось вращения** (*axis*) — единичный вектор, определяющий ось вращения.
-* **Угол поворота** (*angle* или *θ*) — угол, на который нужно повернуть объект вокруг этой оси.
+* **Ось вращения** *(axis)* — единичный вектор, определяющий ось вращения.
+* **Угол поворота** *(angle* или *θ)* — угол, на который нужно повернуть объект вокруг этой оси.
 
 В Flix ось вращения задается объектом `Vector`, а угол поворота — числом типа `float` в радианах:
 
@@ -177,7 +177,7 @@ float angle = radians(45);
 
 ### Вектор вращения
 
-Если умножить вектор *axis* на угол поворота *θ*, то получится **вектор вращения** (*rotation vector*). Этот вектор играет важную роль в алгоритмах управления ориентацией летательного аппарата.
+Если умножить вектор *axis* на угол поворота *θ*, то получится **вектор вращения** *(rotation vector)*. Этот вектор играет важную роль в алгоритмах управления ориентацией летательного аппарата.
 
 Вектор вращения обладает замечательным свойством: если угловые скорости объекта (в собственной системе координат) в каждый момент времени совпадают с компонентами этого вектора, то за единичное время объект придет к заданной этим вектором ориентации. Это свойство позволяет использовать вектор вращения для управления ориентацией объекта посредством управления угловыми скоростями.
 
@@ -198,7 +198,7 @@ Vector rotation = radians(45) * Vector(1, 2, 3);
 	<a href="https://github.com/okalachev/flix/blob/master/flix/quaternion.h"><code>quaternion.h</code></a>.<br>
 </div>
 
-Вектор вращения удобен, но еще удобнее использовать **кватернион**. В Flix кватернионы задаются объектами `Quaternion` из библиотеки `quaternion.h`. Кватернион состоит из четырех значений: *w*, *x*, *y*, *z* и рассчитывается из вектора оси вращения (*axis*) и угла поворота (*θ*) по формуле:
+Вектор вращения удобен, но еще удобнее использовать **кватернион**. В Flix кватернионы задаются объектами `Quaternion` из библиотеки `quaternion.h`. Кватернион состоит из четырех значений: *w*, *x*, *y*, *z* и рассчитывается из вектора оси вращения *(axis)* и угла поворота *(θ)* по формуле:
 
 \\[ q = \left( \begin{array}{c} w \\\\ x \\\\ y \\\\ z \end{array} \right) = \left( \begin{array}{c} \cos\left(\frac{\theta}{2}\right) \\\\ axis\_x \cdot \sin\left(\frac{\theta}{2}\right) \\\\ axis\_y \cdot \sin\left(\frac{\theta}{2}\right) \\\\ axis\_z \cdot \sin\left(\frac{\theta}{2}\right) \end{array} \right) \\]
 

docs/book/gyro.md

@@ -87,13 +87,13 @@ Flix поддерживает следующие модели IMU:
 #include <FlixPeriph.h>
 #include <SPI.h>
 
-MPU9250 IMU(SPI);
+MPU9250 imu(SPI);
 
 void setup() {
 	Serial.begin(115200);
-	bool success = IMU.begin();
+	bool success = imu.begin();
 	if (!success) {
-		Serial.println("Failed to initialize IMU");
+		Serial.println("Failed to initialize the IMU");
 	}
 }
 ```
@@ -108,21 +108,21 @@ void setup() {
 #include <FlixPeriph.h>
 #include <SPI.h>
 
-MPU9250 IMU(SPI);
+MPU9250 imu(SPI);
 
 void setup() {
 	Serial.begin(115200);
-	bool success = IMU.begin();
+	bool success = imu.begin();
 	if (!success) {
-		Serial.println("Failed to initialize IMU");
+		Serial.println("Failed to initialize the IMU");
 	}
 }
 
 void loop() {
-	IMU.waitForData();
+	imu.waitForData();
 
 	float gx, gy, gz;
-	IMU.getGyro(gx, gy, gz);
+	imu.getGyro(gx, gy, gz);
 
 	Serial.printf("gx:%f gy:%f gz:%f\n", gx, gy, gz);
 	delay(50); // замедление вывода
@@ -135,36 +135,36 @@ void loop() {
 
 ## Конфигурация гироскопа
 
-В коде Flix настройка IMU происходит в функции `configureIMU`. В этой функции настраиваются три основных параметра гироскопа: диапазон измерений, частота сэмплов и частота LPF-фильтра.
+В коде Flix настройка IMU происходит в функции `configureIMU`. В этой функции настраиваются три основных параметра гироскопа: диапазон измерений, частота сэмплирования и частота LPF-фильтра.
 
-### Частота сэмплов
+### Частота сэмплирования
 
-Большинство IMU могут обновлять данные с разной частотой. В полетных контроллерах обычно используется частота обновления от 500 Гц до 8 кГц. Чем выше частота сэмплов, тем выше точность управления полетом, но и больше нагрузка на микроконтроллер.
+Большинство IMU могут обновлять данные с разной частотой. В полетных контроллерах обычно используется частота обновления от 500 Гц до 8 кГц. Чем выше частота, тем выше точность управления полетом, но и тем больше нагрузка на микроконтроллер.
 
-Частота сэмплов устанавливается методом `setSampleRate()`. В Flix используется частота 1 кГц:
+Частота сэмплирования устанавливается методом `setSampleRate()`. В Flix используется частота 1 кГц:
 
 ```cpp
 IMU.setRate(IMU.RATE_1KHZ_APPROX);
 ```
 
-Поскольку не все поддерживаемые IMU могут работать строго на частоте 1 кГц, в библиотеке FlixPeriph существует возможность приближенной настройки частоты сэмплов. Например, у IMU ICM-20948 при такой настройке реальная частота сэмплирования будет равна 1125 Гц.
+Поскольку не все поддерживаемые IMU могут работать строго на частоте 1 кГц, в библиотеке FlixPeriph существует возможность приближенной настройки частоты сэмплирования. Например, у IMU ICM-20948 при такой настройке реальная частота сэмплирования будет равна 1125 Гц.
 
 Другие доступные для установки в библиотеке FlixPeriph частоты сэмплирования:
 
-* `RATE_MIN` — минимальная частота сэмплов для конкретного IMU.
+* `RATE_MIN` — минимальная частота для конкретного IMU.
 * `RATE_50HZ_APPROX` — значение, близкое к 50 Гц.
 * `RATE_1KHZ_APPROX` — значение, близкое к 1 кГц.
 * `RATE_8KHZ_APPROX` — значение, близкое к 8 кГц.
-* `RATE_MAX` — максимальная частота сэмплов для конкретного IMU.
+* `RATE_MAX` — максимальная частота для конкретного IMU.
 
 #### Диапазон измерений
 
-Большинство MEMS-гироскопов поддерживают несколько диапазонов измерений угловой скорости. Главное преимущество выбора меньшего диапазона — бо́льшая чувствительность. В полетных контроллерах обычно выбирается максимальный диапазон измерений от –2000 до 2000 градусов в секунду, чтобы обеспечить возможность динамичных маневров.
+Большинство MEMS-гироскопов поддерживают несколько диапазонов измерений угловой скорости. Главное преимущество выбора меньшего диапазона — бо́льшая чувствительность. В полетных контроллерах обычно выбирается максимальный диапазон измерений от –2000 до 2000 градусов в секунду, чтобы обеспечить возможность быстрых маневров.
 
 В библиотеке FlixPeriph диапазон измерений гироскопа устанавливается методом `setGyroRange()`:
 
 ```cpp
-IMU.setGyroRange(IMU.GYRO_RANGE_2000DPS);
+imu.setGyroRange(imu.GYRO_RANGE_2000DPS);
 ```
 
 ### LPF-фильтр
@@ -172,16 +172,16 @@ IMU.setGyroRange(IMU.GYRO_RANGE_2000DPS);
 IMU InvenSense могут фильтровать измерения на аппаратном уровне при помощи фильтра нижних частот (LPF). Flix реализует собственный фильтр для гироскопа, чтобы иметь больше гибкости при поддержке разных IMU. Поэтому для встроенного LPF устанавливается максимальная частота среза:
 
 ```cpp
-IMU.setDLPF(IMU.DLPF_MAX);
+imu.setDLPF(imu.DLPF_MAX);
 ```
 
 ## Калибровка гироскопа
 
-Как и любое измерительное устройство, гироскоп вносит искажения в измерения. Наиболее простая модель этих искажений делит их на статические смещения (*bias*) и случайный шум (*noise*):
+Как и любое измерительное устройство, гироскоп вносит искажения в измерения. Наиболее простая модель этих искажений делит их на статические смещения *(bias)* и случайный шум *(noise)*:
 
 \\[ gyro_{xyz}=rates_{xyz}+bias_{xyz}+noise \\]
 
-Для качественной работы подсистемы оценки ориентации и управления дроном необходимо оценить *bias* гироскопа и учесть его в вычислениях. Для этого при запуске программы производится калибровка гироскопа, которая реализована в функции `calibrateGyro()`. Эта функция считывает данные с гироскопа в состоянии покоя 1000 раз и усредняет их. Полученные значения считаются *bias* гироскопа и в дальнейшем вычитаются из измерений.
+Для точной работы подсистемы оценки ориентации и управления дроном необходимо оценить *bias* гироскопа и учесть его в вычислениях. Для этого при запуске программы производится калибровка гироскопа, которая реализована в функции `calibrateGyro()`. Эта функция считывает данные с гироскопа в состоянии покоя 1000 раз и усредняет их. Полученные значения считаются *bias* гироскопа и в дальнейшем вычитаются из измерений.
 
 Программа для вывода данных с гироскопа с калибровкой:
 
@@ -189,23 +189,23 @@ IMU.setDLPF(IMU.DLPF_MAX);
 #include <FlixPeriph.h>
 #include <SPI.h>
 
-MPU9250 IMU(SPI);
+MPU9250 imu(SPI);
 
 float gyroBiasX, gyroBiasY, gyroBiasZ; // bias гироскопа
 
 void setup() {
 	Serial.begin(115200);
-	bool success = IMU.begin();
+	bool success = imu.begin();
 	if (!success) {
-		Serial.println("Failed to initialize IMU");
+		Serial.println("Failed to initialize the IMU");
 	}
 	calibrateGyro();
 }
 
 void loop() {
 	float gx, gy, gz;
-	IMU.waitForData();
-	IMU.getGyro(gx, gy, gz);
+	imu.waitForData();
+	imu.getGyro(gx, gy, gz);
 
 	// Устранение bias гироскопа
 	gx -= gyroBiasX;
@@ -226,9 +226,9 @@ void calibrateGyro() {
 
 	// Получение 1000 измерений гироскопа
 	for (int i = 0; i < samples; i++) {
-		IMU.waitForData();
+		imu.waitForData();
 		float gx, gy, gz;
-		IMU.getGyro(gx, gy, gz);
+		imu.getGyro(gx, gy, gz);
 		gyroBiasX += gx;
 		gyroBiasY += gy;
 		gyroBiasZ += gz;

docs/firmware.md

@@ -38,13 +38,13 @@ Utility files:
 
 ### Control subsystem
 
-Pilot inputs are interpreted in `interpretControls()`, and then converted to the *control command*, which consists of the following:
+Pilot inputs are interpreted in `interpretControls()`, and then converted to the **control command**, which consists of the following:
 
 * `attitudeTarget` *(Quaternion)* — target attitude of the drone.
 * `ratesTarget` *(Vector)* — target angular rates, *rad/s*.
-* `ratesExtra` *(Vector)* — additional (feed-forward) angular rates , used for yaw rate control in STAB mode, *rad/s*.
+* `ratesExtra` *(Vector)* — additional (feed-forward) angular rates, used for yaw rate control in STAB mode, *rad/s*.
 * `torqueTarget` *(Vector)* — target torque, range [-1, 1].
-* `thrustTarget` *(float)* — collective thrust target, range [0, 1].
+* `thrustTarget` *(float)* — collective motor thrust target, range [0, 1].
 
 Control command is handled in `controlAttitude()`, `controlRates()`, `controlTorque()` functions. Each function may be skipped if the corresponding control target is set to `NAN`.
 
@@ -62,6 +62,43 @@ print("Test value: %.2f\n", testValue);
 
 In order to add a console command, modify the `doCommand()` function in `cli.ino` file.
 
+> [!IMPORTANT]
+> Avoid using delays in in-flight commands, it will **crash** the drone! (The design is one-threaded.)
+>
+> For on-the-ground commands, use `pause()` function, instead of `delay()`. This function allows to pause in a way that MAVLink connection will continue working.
+
+### Parameter subsystem
+
+Parameters subsystem (`parameters.ino`) uses standard [Preferences.h](https://docs.espressif.com/projects/arduino-esp32/en/latest/tutorials/preferences.html) ESP32 library to store parameters in non-volatile memory. Each parameter is a regular global variable, which is registered in the `parameters` array.
+
+To add a new parameter:
+
+1. Define a global variable for the parameter, two types are supported: `float` and `int`.
+2. Add an entry to the `parameters` array, with the parameter name, a pointer to the variable, and optionally a callback function to call when the parameter is changed.
+3. Everything else will be handled automatically.
+
+See examples of adding new parameters in commits: [c434107](https://github.com/okalachev/flix/commit/c434107), [a687303](https://github.com/okalachev/flix/commit/a687303).
+
+> [!NOTE]
+> Since all the parameters are internally stored and passed as floats, the safe range for `int` parameters is -16777216 to 16777215.
+
+## Adding a subsystem
+
+To add a new subsystem:
+
+1. Create a new `*.ino` file for your subsystem.
+2. Define setup and loop functions for the subsystem, for example `setupMySubsystem()` and `loopMySubsystem()`.
+3. Use `Rate` class if you need to limit the loop frequency, for example:
+
+    ```cpp
+    Rate mySubsystemRate(100); // 100 Hz
+
+    void loopMySubsystem() {
+    	if (!mySubsystemRate) return;
+    	// Do something...
+    }
+4. Add setup and loop calls in to `setup()` and `loop()` functions in `flix.ino`.
+
 ## Building the firmware
 
 See build instructions in [usage.md](usage.md).

docs/img/flix.svg

@@ -0,0 +1,38 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 734.86 378.46">
+  <defs>
+    <style>
+      .a {
+        fill: none;
+        stroke: #d5d5d5;
+        stroke-miterlimit: 10;
+        stroke-width: 31px;
+      }
+
+      .b {
+        fill: #c1c1c1;
+      }
+
+      .c {
+        fill: #ff9400;
+      }
+
+      .d {
+        fill: #d5d5d5;
+      }
+    </style>
+  </defs>
+  <g>
+    <g>
+      <line class="a" x1="448.78" y1="294.23" x2="648.77" y2="93.24"/>
+      <line class="a" x1="449.78" y1="94.24" x2="649.77" y2="295.23"/>
+      <circle class="b" cx="549.27" cy="193.73" r="41.5"/>
+      <circle class="c" cx="449.35" cy="93.74" r="77.95"/>
+      <circle class="c" cx="648.89" cy="93.53" r="77.95"/>
+      <circle class="c" cx="647.89" cy="294.51" r="77.95"/>
+      <circle class="c" cx="448.9" cy="294.51" r="77.95"/>
+    </g>
+    <path class="d" d="M8,161.93q0-17.85,22.36-17.85h4.81V100.57Q35.17,8.49,131.23,8h1q36.87,0,47.31,7.48L181,17.41l1,2.41V50q0,12.32-5.82,12.31-2.43,0-7.4-4.64t-14.19-9a48.63,48.63,0,0,0-21.22-4.41q-12,0-19.17,3.5a18.85,18.85,0,0,0-9.82,10.62,67.35,67.35,0,0,0-3.52,12.06,82.52,82.52,0,0,0-.85,13.39v60.32h27.28q10.86,0,16.05,5.43a17.52,17.52,0,0,1,5.19,12.42,22.5,22.5,0,0,1-1.21,7.36q-1.22,3.51-6.64,7.24t-14.36,3.74H101.64V344.82a56,56,0,0,1-.61,9.65,37.8,37.8,0,0,1-2.56,7.6,11.83,11.83,0,0,1-6.94,6.4q-5,1.93-13.51,1.93H57.08q-10.47,0-15.7-4.71t-5.73-8.44a77.31,77.31,0,0,1-.48-9.53V180.27H29.4Q8,180.27,8,161.93Z"/>
+    <path class="d" d="M201.21,348.2V37q0-23.16,20.86-23.4h22.81q22.8,0,22.8,22.44V346.27a68.92,68.92,0,0,1-.49,9.41,22.59,22.59,0,0,1-2.42,7.12,11.48,11.48,0,0,1-6.67,5.43,47.78,47.78,0,0,1-12.74,2.17H225q-11.4,0-17.58-4.47T201.21,348.2Z"/>
+    <path class="d" d="M284.9,61.08V36.47a40.39,40.39,0,0,1,1.7-12.91,11.36,11.36,0,0,1,6.18-7,25.27,25.27,0,0,1,6.68-2.3c1.45-.15,4-.4,7.76-.72h25.23q10.43,0,16.73,4.7t6.31,18.22V62.05a27.94,27.94,0,0,1-.85,7.11,23,23,0,0,1-2.06,5.43,20,20,0,0,1-2.91,4,10,10,0,0,1-3.52,2.54c-1.21.48-2.54,1-4,1.44a11.53,11.53,0,0,1-3.4.73,13.71,13.71,0,0,0-3.15.48H307.7q-10.43,0-16.61-4.7T284.9,61.08Zm1.94,284.71V166.28q0-22.2,21.83-22.2h20.38q10.92,0,16.62,4t6.67,8.45a60.47,60.47,0,0,1,1,12.18V348.2q0,22.2-21.83,22.2H308.67q-10.43,0-15.64-4.95t-5.7-8.81A90.93,90.93,0,0,1,286.84,345.79Z"/>
+  </g>
+</svg>

docs/troubleshooting.md

@@ -4,28 +4,33 @@
 
 Do the following:
 
-* **Check ESP32 core is installed**. Check if the version matches the one used in the [tutorial](usage.md#firmware).
-* **Check libraries**. Install all the required libraries from the tutorial. Make sure there are no MPU9250 or other peripherals libraries that may conflict with the ones used in the tutorial.
+* **Check ESP32 core is installed**. Check if the version matches the one used in the [tutorial](usage.md#building-the-firmware).
+* **Check libraries**. Install all the required libraries from the tutorial. Make sure there are no MPU-9250 or other peripherals libraries that may conflict with the ones used in the tutorial.
 * **Check the chosen board**. The correct board to choose in Arduino IDE for ESP32 Mini is *WEMOS D1 MINI ESP32*.
 
 ## The drone doesn't fly
 
 Do the following:
 
-* **Check the battery voltage**. Use a multimeter to measure the battery voltage. It should be in range of 3.7-4.2 V.
-* **Check if there are some startup errors**. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button to make sure you see the whole ESP32 output.
+* **Check the battery voltage**. Use a multimeter to measure the battery voltage. The fully charged battery should have about 4.2V.
+* **Check the battery you use has enough discharge current**. The battery should be able to provide 15A of current. So the C-rating for a 1000 mAh battery should be at least 15C (higher is better).
+* **Check if there are some startup errors**. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button or `reboot` command to see the whole startup output.
 * **Check the baudrate is correct**. If you see garbage characters in the Serial Monitor, make sure the baudrate is set to 115200.
-* **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
-* **Check if the CLI is working**. Perform `help` command in Serial Monitor. You should see the list of available commands. You can also access the CLI using QGroundControl (*Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*).
+* **Check if the console is working**. Perform `help` command in Serial Monitor. You should see the list of available commands. You can also access the console using QGroundControl *(Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console)*.
 * **Configure QGroundControl correctly before connecting to the drone** if you use it to control the drone. Go to the settings and enable *Virtual Joystick*. *Auto-Center Throttle* setting **should be disabled**.
 * **If QGroundControl doesn't connect**, you might need to disable the firewall and/or VPN on your computer.
+* **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
 * **Check the IMU is working**. Perform `imu` command and check its output:
   * The `status` field should be `OK`.
   * The `rate` field should be about 1000 (Hz).
   * The `accel` and `gyro` fields should change as you move the drone.
+* **Check the IMU orientation is set correctly**. If the attitude estimation is rotated, set the correct IMU orientation as described in the [tutorial](usage.md#define-imu-orientation).
 * **Calibrate the accelerometer.** if is wasn't done before. Type `ca` command in Serial Monitor and follow the instructions.
-* **Check the attitude estimation**. Connect to the drone using QGroundControl. Rotate the drone in different orientations and check if the attitude estimation shown in QGroundControl is correct.
-* **Check the IMU orientation is set correctly**. If the attitude estimation is rotated, make sure `rotateIMU` function is defined correctly in `imu.ino` file.
+* **Check the attitude estimation**. Connect to the drone using QGroundControl. Rotate the drone in different orientations and check if the attitude estimation is shown exactly as on the video below:
+
+  <a href="https://youtu.be/yVRN23-GISU"><img width=200 src="https://i3.ytimg.com/vi/yVRN23-GISU/maxresdefault.jpg"></a>
+
+* **Check the IMU output**. Connect to the drone using QGroundControl on your computer. Go to the *Analyze* tab, *MAVLINK Inspector*. Plot the data from the `SCALED_IMU` message. The gyroscope and accelerometer data should change according to the drone movement.
 * **Check the motors type**. Motors with exact 3.7V voltage are needed, not ranged working voltage (3.7V — 6V).
 * **Check the motors**. Perform the following commands using Serial Monitor:
   * `mfr` — should rotate front right motor (counter-clockwise).
@@ -33,7 +38,10 @@ Do the following:
   * `mrl` — should rotate rear left motor (counter-clockwise).
   * `mrr` — should rotate rear right motor (clockwise).
 * **Check the propeller directions are correct**. Make sure your propeller types (A or B) are installed as on the picture:
+
   <img src="img/user/peter_ukhov-2/1.jpg" width="200">
-* **Check the remote control**. Using `rc` command, check the control values reflect your sticks movement. All the controls should change between -1 and 1, and throttle between 0 and 1.
-* If using SBUS receiver, **calibrate the RC**. Type `cr` command in Serial Monitor and follow the instructions.
-* **Check the IMU output using QGroundControl**. Connect to the drone using QGroundControl on your computer. Go to the *Analyze* tab, *MAVLINK Inspector*. Plot the data from the `SCALED_IMU` message. The gyroscope and accelerometer data should change according to the drone movement.
+
+* **If using an SBUS receiver**:
+  * **Define the used GPIO pin** in `RC_RX_PIN` parameter.
+  * **Calibrate the RC** using `cr` command in the console.
+  * **Check the controls** using `rc` command. All the controls should change between -1 and 1, and the throttle between 0 and 1.

docs/usage.md

@@ -20,13 +20,14 @@ You can build and upload the firmware using either **Arduino IDE** (easier for b
 
 1. Install [Arduino IDE](https://www.arduino.cc/en/software) (version 2 is recommended).
 2. *Windows users might need to install [USB to UART bridge driver from Silicon Labs](https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers).*
-3. Install ESP32 core, version 3.2.0. See the [official Espressif's instructions](https://docs.espressif.com/projects/arduino-esp32/en/latest/installing.html#installing-using-arduino-ide) on installing ESP32 Core in Arduino IDE.
+3. Install ESP32 core, version 3.3.10. See the [official Espressif's instructions](https://docs.espressif.com/projects/arduino-esp32/en/latest/installing.html#installing-using-arduino-ide) on installing ESP32 Core in Arduino IDE.
 4. Install the following libraries using [Library Manager](https://docs.arduino.cc/software/ide-v2/tutorials/ide-v2-installing-a-library):
    * `FlixPeriph`, the latest version.
-   * `MAVLink`, version 2.0.16.
+   * `MAVLink`, version 2.0.25.
 5. Open the `flix/flix.ino` sketch from downloaded firmware sources in Arduino IDE.
-6. Connect your ESP32 board to the computer and choose correct board type in Arduino IDE (*WEMOS D1 MINI ESP32* for ESP32 Mini) and the port.
-7. [Build and upload](https://docs.arduino.cc/software/ide-v2/tutorials/getting-started/ide-v2-uploading-a-sketch) the firmware using Arduino IDE.
+6. Connect your ESP32 board to the computer and choose correct board type in Arduino IDE (*WEMOS D1 MINI ESP32* for ESP32 Mini, *ESP32S3 Dev Module* for ESP32-S3 Super Mini) and the port.
+7. Set *Tools* ⇒ *Core Debug Level* to *Error* to see the errors in the serial console. Set *Tools* ⇒ *USB CDC on Boot* to *Enabled* for ESP32-S3/ESP32-C3 boards.
+8. [Build and upload](https://docs.arduino.cc/software/ide-v2/tutorials/getting-started/ide-v2-uploading-a-sketch) the firmware using Arduino IDE.
 
 ### Command line (Windows, Linux, macOS)
 
@@ -57,6 +58,12 @@ You can build and upload the firmware using either **Arduino IDE** (easier for b
    make upload monitor
    ```
 
+   For ESP32-S3/ESP32-C3 boards, set the appropriate [FQBN](https://docs.arduino.cc/arduino-cli/FAQ/#whats-the-fqbn-string) using `BOARD` parameter:
+
+   ```bash
+   make BOARD=esp32:esp32:esp32s3:FlashSize=4M,CDCOnBoot=cdc upload
+   ```
+
 See other available Make commands in [Makefile](../Makefile).
 
 > [!TIP]
@@ -69,8 +76,25 @@ See other available Make commands in [Makefile](../Makefile).
 In case if using different IMU model than MPU9250, change `imu` variable declaration in the `imu.ino`:
 
 ```cpp
-ICM20948 imu(SPI);  // For ICM-20948
-MPU6050 imu(Wire);  // For MPU-6050
+ICM20948 imu(SPI);  // For ICM-20948 via SPI
+// or
+MPU6050 imu(Wire);  // For MPU-6050 via I2C
+```
+
+If using non-default SPI pins, pass SCK, MISO, and MOSI pin numbers to `SPI.begin` call and SS pin to `imu` constructor like that:
+
+```cpp
+ICM20948(SPI, <SS>);
+// ...
+SPI.begin(<SCK>, <MISO>, <MOSI>);
+imu.begin();
+```
+
+If using non-default I2C pins, pass SDA and SCL pin numbers to `Wire.setPins` call like that:
+
+```cpp
+Wire.begin(<SDA>, <SCL>);
+imu.begin();
 ```
 
 ### Connect using QGroundControl
@@ -80,7 +104,10 @@ QGroundControl is a ground control station software that can be used to monitor
 1. Install mobile or desktop version of [QGroundControl](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/getting_started/download_and_install.html).
 2. Power up the drone.
 3. Connect your computer or smartphone to the appeared `flix` Wi-Fi network (password: `flixwifi`).
-4. Launch QGroundControl app. It should connect and begin showing the drone's telemetry automatically
+4. Launch QGroundControl app. It should connect and begin showing the drone's telemetry automatically.
+
+> [!TIP]
+> If QGroundControl doesn't connect, try to disable the firewall and/or VPN on your computer, as they may block the connection.
 
 ### Access console
 
@@ -95,7 +122,7 @@ To access the console using serial port:
 To access the console using QGroundControl:
 
 1. Connect to the drone using QGroundControl app.
-2. Go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*.
+2. Go to the QGroundControl menu ⇒ *Analyze Tools* ⇒ *MAVLink Console*.
 
 <img src="img/cli.png" width="400">
 
@@ -108,11 +135,13 @@ The drone is configured using parameters. To access and modify them, go to the Q
 
 <img src="img/parameters.png" width="400">
 
+You can also work with parameters using `p` command in the console. Parameter names are case-insensitive.
+
 ### Define IMU orientation
 
-Use parameters, to define the IMU board axes orientation relative to the drone's axes: `IMU_ROT_ROLL`, `IMU_ROT_PITCH`, and `IMU_ROT_YAW`.
+The IMU orientation (relative to the drone's axes) is defined using the parameters: `IMU_ROT_ROLL`, `IMU_ROT_PITCH`, and `IMU_ROT_YAW`.
 
-The drone has *X* axis pointing forward, *Y* axis pointing left, and *Z* axis pointing up, and the supported IMU boards have *X* axis pointing to the pins side and *Z* axis pointing up from the side with the components:
+The drone has *X* axis pointing forward, *Y* axis pointing left, and *Z* axis pointing up, and the supported IMU boards have *X* axis pointing to the mounting holes side and *Z* axis pointing up from the component side:
 
 <img src="img/imu-axes.png" width="200">
 
@@ -120,10 +149,10 @@ Use the following table to set the parameters for common IMU orientations:
 
 |Orientation|Parameters|Orientation|Parameters|
 |:-:|-|-|-|
-|<img src="img/imu-rot-1.png" width="200">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0    |<img src="img/imu-rot-5.png" width="200">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0|
-|<img src="img/imu-rot-2.png" width="200">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|<img src="img/imu-rot-6.png" width="200">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|
-|<img src="img/imu-rot-3.png" width="200">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|<img src="img/imu-rot-7.png" width="200">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|
-|<img src="img/imu-rot-4.png" width="200"><br>☑️ **Default**|<br>`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|<img src="img/imu-rot-8.png" width="200">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|
+|<img src="img/imu-rot-3.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0    |<img src="img/imu-rot-7.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0|
+|<img src="img/imu-rot-2.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|<img src="img/imu-rot-6.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|
+|<img src="img/imu-rot-1.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|<img src="img/imu-rot-5.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|
+|<img src="img/imu-rot-4.png" width="180"><br>☑️ **Default**|<br>`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|<img src="img/imu-rot-8.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|
 
 ### Calibrate accelerometer
 
@@ -132,34 +161,75 @@ Before flight you need to calibrate the accelerometer:
 1. Access the console using QGroundControl (recommended) or Serial Monitor.
 2. Type `ca` command there and follow the instructions.
 
-### Check everything works
+### Setup motors
 
-1. Check the IMU is working: perform `imu` command and check its output:
+If using non-default motor pins, set the pin numbers using the parameters: `MOTOR_PIN_FL`, `MOTOR_PIN_FR`, `MOTOR_PIN_RL`, `MOTOR_PIN_RR` (front-left, front-right, rear-left, rear-right respectively).
+
+Certain ESP32 models (such as ESP32-S3 and ESP32-C3) support a lower maximum PWM frequency; on these boards the parameter `MOT_PWM_FREQ` should be set to 38000 Hz.
+
+If using brushless motors and ESCs:
+
+1. Set the appropriate PWM using the parameters: `MOT_PWM_STOP`, `MOT_PWM_MIN`, and `MOT_PWM_MAX` (1000, 1000, and 2000 is typical).
+2. Decrease the PWM frequency using the `MOT_PWM_FREQ` parameter (400 is typical).
+
+> [!CAUTION]
+> **Remove the props when configuring the motors!** If improperly configured, you may not be able to stop them.
+
+### Battery voltage monitoring
+
+ESP32 ADC can measure only up to 3.3 V, so you need to use a voltage divider to monitor the battery voltage. To enable voltage measurement, set the following parameters:
+
+1. `PWR_VOLT_PIN` — GPIO pin number where the voltage divider is connected (*-1* to disable).
+2. `PWR_VOLT_SCALE` — voltage divider coefficient (*2* for two equal resistors).
+
+After this setup, you should see the battery voltage in QGroundControl top panel or using `pw` command in the console.
+
+### Important: check everything works
+
+1. Check the IMU is working: perform `imu` command in the console and check the output:
 
    * The `status` field should be `OK`.
    * The `rate` field should be about 1000 (Hz).
    * The `accel` and `gyro` fields should change as you move the drone.
+   * The `accel bias` and `accel scale` fields should contain calibration parameters (not zeros and ones).
+   * The `gyro bias` field should contain estimated gyro bias (not zeros).
    * The `landed` field should be `1` when the drone is still on the ground and `0` when you lift it up.
 
-2. Check the attitude estimation: connect to the drone using QGroundControl, rotate the drone in different orientations and check if the attitude estimation shown in QGroundControl is correct. Attitude indicator in QGroundControl is shown below:
+2. Check the attitude estimation: connect to the drone using QGroundControl, rotate the drone in different orientations and check if the attitude estimation shown in QGroundControl is correct. Compare your attitude indicator (in the *large vertical* mode) to the video:
 
-   <img src="img/qgc-attitude.png" height="200">
+   <a href="https://youtu.be/yVRN23-GISU"><img width=300 src="https://i3.ytimg.com/vi/yVRN23-GISU/maxresdefault.jpg"></a>
 
-3. Perform motor tests in the console. Use the following commands **— remove the propellers before running the tests!**
+3. Perform motor tests. Use the following commands **— remove the propellers before running the tests!**
 
-   * `mfr` — should rotate front right motor (counter-clockwise).
-   * `mfl` — should rotate front left motor (clockwise).
-   * `mrl` — should rotate rear left motor (counter-clockwise).
-   * `mrr` — should rotate rear right motor (clockwise).
+   * `mfr` — rotate front right motor (counter-clockwise).
+   * `mfl` — rotate front left motor (clockwise).
+   * `mrl` — rotate rear left motor (counter-clockwise).
+   * `mrr` — rotate rear right motor (clockwise).
+
+   Make sure rotation directions and propeller types match the following diagram:
+
+   <img src="img/motors.svg" width=200>
 
 > [!WARNING]
 > Never run the motors when powering the drone from USB, always use the battery for that.
 
 ## Setup remote control
 
-There are several ways to control the drone's flight: using **smartphone** (Wi-Fi), using **SBUS remote control**, or using **USB remote control** (Wi-Fi).
+There are several ways to control the drone's flight: using **smartphone** (Wi-Fi), using **SBUS remote control**, or using **USB remote control** (Wi-Fi/ESP-NOW).
 
-### Control with smartphone
+### Control with a smartphone
+
+#### Using Mavlink Joystick app (Android)
+
+<img src="https://github.com/goldarte/mavlink-joystick/blob/master/app_screen.png?raw=true" width="400">
+
+1. Download and install [Mavlink Joystick app](https://github.com/goldarte/mavlink-joystick/releases/latest).
+2. Power the drone using the battery.
+3. Connect your smartphone to the appeared `flix` Wi-Fi network (password: `flixwifi`).
+4. Open Mavlink Joystick app. It should connect and begin showing the drone's telemetry automatically.
+5. Use the virtual joystick to fly the drone!
+
+#### Using QGroundControl app
 
 1. Install [QGroundControl mobile app](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/getting_started/download_and_install.html#android) on your smartphone.
 2. Power the drone using the battery.
@@ -171,15 +241,17 @@ There are several ways to control the drone's flight: using **smartphone** (Wi-F
 > [!TIP]
 > Decrease `CTL_TILT_MAX` parameter when flying using the smartphone to make the controls less sensitive.
 
-### Control with remote control
+### Control with a remote control
 
-Before using remote SBUS-connected remote control, you need to calibrate it:
+If using SBUS-connected remote control you need to enable SBUS and calibrate it:
 
-1. Access the console using QGroundControl (recommended) or Serial Monitor.
-2. Type `cr` command and follow the instructions.
-3. Use the remote control to fly the drone!
+1. Connect to the drone using QGroundControl.
+2. In parameters, set the `RC_RX_PIN` parameter to the GPIO pin number where the SBUS signal is connected, for example: 4. Negative value disables SBUS.
+3. Check if the receiver is working using `rc` command in the console.
+4. Open the console, type `cr` command and follow the instructions to calibrate the remote control.
+5. Use the remote control to fly the drone!
 
-### Control with USB remote control
+### Control with a USB remote control
 
 If your drone doesn't have RC receiver installed, you can use USB remote control and QGroundControl app to fly it.
 
@@ -188,7 +260,7 @@ If your drone doesn't have RC receiver installed, you can use USB remote control
 3. Power up the drone.
 4. Connect your computer to the appeared `flix` Wi-Fi network (password: `flixwifi`).
 5. Launch QGroundControl app. It should connect and begin showing the drone's telemetry automatically.
-6. Go the the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Joystick*. Calibrate you USB remote control there.
+6. Go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Joystick*. Calibrate your USB remote control there.
 7. Use the USB remote control to fly the drone!
 
 ## Flight
@@ -214,11 +286,11 @@ When finished flying, **disarm** the drone, moving the left stick to the bottom
 
 ### Flight modes
 
-Flight mode is changed using mode switch on the remote control or using the command line.
+Flight mode is changed using mode switch on the remote control (if configured) or using the console commands. The main flight mode is *STAB*. In order to change modes using SBUS remote control, set the parameters: `CTL_FLT_MODE_0`, `CTL_FLT_MODE_1`, and `CTL_FLT_MODE_2` to required mode numbers (0 for *RAW*, 1 for *ACRO*, 2 for *STAB*, 3 for *AUTO*).
 
 #### STAB
 
-The default mode is *STAB*. In this mode, the drone stabilizes its attitude (orientation). The left stick controls throttle and yaw rate, the right stick controls pitch and roll angles.
+In this mode, the drone stabilizes its attitude (orientation). The left stick controls throttle and yaw rate, the right stick controls pitch and roll angles.
 
 > [!IMPORTANT]
 > The drone doesn't stabilize its position, so slight drift is possible. The pilot should compensate it manually.
@@ -233,15 +305,78 @@ In this mode, the pilot controls the angular rates. This control method is diffi
 
 #### AUTO
 
-In this mode, the pilot inputs are ignored (except the mode switch, if configured). The drone can be controlled using [pyflix](../tools/pyflix/) Python library, or by modifying the firmware to implement the needed autonomous behavior.
+In this mode, the pilot inputs are ignored (except the mode switch). The drone can be controlled using [pyflix](../tools/pyflix/) Python library, or by modifying the firmware to implement the needed behavior.
 
-If the pilot moves the control sticks, the drone will switch back to *STAB* mode.
+If the pilot moves the control sticks and mode switch is not configured, the drone will switch back to *STAB* mode.
 
-<img src="img/parameters.png" width="400">
+## Wi-Fi configuration
+
+You can configure the Wi-Fi using parameters and console commands.
+
+The Wi-Fi mode is chosen using `WIFI_MODE` parameter in QGroundControl or in the console:
+
+* `0` — Wi-Fi is disabled.
+* `1` — Access Point mode *(AP)* — the drone creates a Wi-Fi network.
+* `2` — Client mode *(STA)* — the drone connects to an existing Wi-Fi network (may cause additional delays, so generally not recommended).
+* `3` — ESP-NOW mode — the drone uses ESP-NOW protocol for communication.
+
+The SSID and password are configured using the `ap` and `sta` console commands:
+
+```
+ap <ssid> <password>
+sta <ssid> <password>
+```
+
+Example of configuring the Access Point mode:
+
+```
+ap my-flix-ssid mypassword123
+p WIFI_MODE 1
+```
+
+Disabling Wi-Fi:
+
+```
+p WIFI_MODE 0
+```
+
+### Using ESP-NOW
+
+[ESP-NOW](https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/network/esp_now.html) is a low level wireless communication protocol. It can provide lower latency, better reliability, and longer range than Wi-Fi. However, it requires a second ESP32 board to be used as a proxy for the computer.
+
+<img src="img/espnow-connection.jpg" width="600">
+
+To setup ESP-NOW communication:
+
+1. Flash the second ESP32 board with ESP-NOW proxy sketch: [`tools/espnow-proxy/espnow-proxy.ino`](../tools/espnow-proxy/espnow-proxy.ino). Use Arduino IDE or command line: `make upload_proxy`.
+
+2. Open Serial Monitor in Arduino IDE or use `make monitor` command. The ESP32 will print its MAC address and generated encryption key, for example:
+
+   ```
+   espnow 7a:c8:e3:eb:bf:e9 &PiuSysxP9+$L&5E
+   ```
+
+   Run this line as a console command on each drone you want to bind to this proxy board. [The maximum number](https://github.com/espressif/esp-idf/blob/e95cab4be8fd293e3f3323181e7a2280874da6f7/components/esp_wifi/include/esp_now.h#L32-L33) of simultaneously connected drones is 20 (unencrypted) or 6 (encrypted).
+
+3. Set the `WIFI_MODE` parameter to `3` on the drone:
+
+   ```
+   p WIFI_MODE 3
+   ```
+
+4. Go to the QGroundControl menu ⇒ *Application Settings* ⇒ *Comm Links*, add new link with the following settings:
+   * Name: ESP32.
+   * Type: Serial.
+   * Serial Port: choose the port of the proxy ESP32 board, e. g. `/dev/cu.usbserial-0001`.
+   * Baud Rate: 115200.
+5. Click *Save*, click *Connect*. QGroundControl should connect to the drone using ESP-NOW and begin showing the telemetry.
+
+> [!TIP]
+> Make sure Arduino IDE is not running when using ESP-NOW proxy board, as it may block it.
 
 ## Flight log
 
-After the flight, you can download the flight log for analysis wirelessly. Use the following for that:
+After the flight, you can download the flight log wirelessly for analysis. Use the following command on your computer for that:
 
 ```bash
 make log

docs/user.md

@@ -4,6 +4,89 @@ This page contains user-built drones based on the Flix project. Publish your pro
 
 ---
 
+Author: Alican Erüst.<br>
+Description: QX95 mm frame, 55 mm propellers, 3.7 V 25C 1050 mAh LiPo battery, MPU6050 IMU, Logitech F310 gamepad controller, with a total quadcopter weight of 66 g.
+
+<img src="img/user/alicanerus/1.jpg" height=200> <img src="img/user/alicanerus/2.jpg" height=200> <img src="img/user/alicanerus/3.jpg" height=200>
+
+[Flight video](https://drive.google.com/file/d/1k0WeWTKnCAfaugkX7LcmNxsUuq79RL8Z/view?usp=sharing).
+
+---
+
+Author: [Неруш Михаил](https://t.me/NerushMV).<br>
+Description: custom frame made of 4 mm plywood, 8520 brushed motors, 75 mm propellers, MPU-6500. FlySky FS-i6X with ESP32-based adapter for ESP-NOW communication (using PPM output).<br>
+Sources and materials: [link](https://drive.google.com/drive/folders/1uWiDcuorLrtVs_IIR7Y13omij-7Q1nx8).
+
+<img src="img/user/nerush/1.jpg" height=200> <img src="img/user/nerush/2.jpg" height=200>
+
+[Flight video](https://drive.google.com/file/d/1jRXeGx34lJpUfw0GKLQeIzkWZvooQJSE/view?usp=sharing).
+
+---
+
+Author: [Konstantinos Paraskevas](https://github.com/Frapais).<br>
+Description: drone with a custom single-boarded airframe, extending the [Sprig-C3 module](https://github.com/Frapais/Sprig-C3).
+ESP32-C3 microcontroller, ICM-20948 IMU, on-board fuel-gauge, status LED indicator.<br>
+Repository with all the code and PCB sources: https://github.com/Frapais/Sprig-Drone.
+
+<img src="img/user/kostas/1.jpg" height=150> <img src="img/user/kostas/2.jpg" height=150>
+
+Detailed video about making the drone:
+
+<a href="https://youtu.be/82Q-uBq6s48"><img width=400 src="https://i3.ytimg.com/vi/82Q-uBq6s48/maxresdefault.jpg"></a>
+
+---
+
+Author: [Awab Anas](http://t.me/AW_VENOM).<br>
+Description: ESP32 D1 Mini, MPU-6050, 8520 3.7V brushed motors, 55 mm propellers, battery li-po 1200 mAh, controlling via [Mavlink Joystick app](https://github.com/goldarte/mavlink-joystick/releases/latest).<br>
+[Flight validation](https://drive.google.com/file/d/12z0jfctZDBA6b5UKCG0Uje5rAxj6DhF-/view?usp=sharing).
+
+<img src="img/user/aw_venom/1.jpg" height=200>
+
+---
+
+Author: [Ina Tix](https://t.me/ina_tix).<br>
+Description: XR2981 based DC-DC converter, ELRS MINI 2.4GHz RX SX1280 receiver (SBUS interface), Radiomaster TX12 remote control.<br>
+[Flight validation](https://drive.google.com/file/d/1yqkKNuz4R_yxGqUNQxVpixJbXqEEcUSj/view?usp=share_link).
+
+<img src="img/user/ina_tix/1.jpg" height=200> <img src="img/user/ina_tix/2.jpg" height=200> <img src="img/user/ina_tix/3.jpg" height=200>
+
+---
+
+Author: Oleg Kalachev.<br>
+Description: the first attempt on making an official PCB based Flix drone (Flix2 board). The IMU is not working on this version, so an external MPU-6050 board was used, therefore considered as **Flix version 1.5**.<br>
+[Flight video](https://drive.google.com/file/d/1R7tuUsFmPY0CGcOCFfMFaCp9kR49K3bl/view?usp=sharing).
+
+<img src="img/flix1.5.jpg" width=300>
+
+---
+
+Author: [FanBy0ru](https://https://github.com/FanBy0ru).<br>
+Description: custom 3D-printed frame.<br>
+Frame STLs and flight validation: https://cults3d.com/en/3d-model/gadget/armature-pour-flix-drone.
+
+<img src="img/user/fanby0ru/1.jpg" height=200> <img src="img/user/fanby0ru/2.jpg" height=200>
+
+---
+
+Author: Ivan44 Phalko.<br>
+Description: custom PCB, cusom test bench.<br>
+[Flight validation](https://drive.google.com/file/d/17DNDJ1gPmCmDRAwjedCbJ9RXAyqMqqcX/view?usp=sharing).
+
+<img src="img/user/phalko/1.jpg" height=200> <img src="img/user/phalko/2.jpg" height=200> <img src="img/user/phalko/3.jpg" height=200>
+
+---
+
+Author: **Arkadiy "Arky" Matsekh**, Foucault Dynamics, Gold Coast, Australia.<br>
+The drone was built for the University of Queensland industry-led Master's capstone project.
+
+**Flight video:**
+
+<a href="https://drive.google.com/file/d/1NNYSVXBY-w0JjCo07D8-PgnVq3ca9plj/view?usp=sharing"><img height=300 src="img/user/arkymatsekh/video.jpg"></a>
+
+<img src="img/user/arkymatsekh/1.jpg" height=150> <img src="img/user/arkymatsekh/2.jpg" height=150> <img src="img/user/arkymatsekh/3.jpg" height=150>
+
+---
+
 Author: [goldarte](https://t.me/goldarte).<br>
 
 <img src="img/user/goldarte/1.jpg" height=150> <img src="img/user/goldarte/2.jpg" height=150>
@@ -14,9 +97,20 @@ Author: [goldarte](https://t.me/goldarte).<br>
 
 ---
 
+Author: [malagis](https://oshwhub.com/malagis).<br>
+
+A Chinese custom PCB version of Flix with a big community of users, lots of materials and modifications.
+
+Main project's page: https://oshwhub.com/malagis/esp32-mini-plane.<br>
+Video about the project: https://www.bilibili.com/video/BV14vyqBFEJn/.
+
+<img src="img/user/malagis/1.jpg" height=200> <img src="img/user/malagis/2.jpg" height=200> <img src="img/user/malagis/3.jpg" height=200>
+
+---
+
 ## School 548 course
 
-Special quadcopter design and engineering course took place in october-november 2025 in School 548, Moscow. Course included UAV control theory, electronics, and practical drone assembly and setup using the Flix project.
+Special course on quadcopter design and engineering took place in october-november 2025 in School 548, Moscow. The course included UAV control theory, electronics, drone assembly and setup practice, using the Flix project.
 
 <img height=200 src="img/user/school548/1.jpg"> <img height=200 src="img/user/school548/2.jpg"> <img height=200 src="img/user/school548/3.jpg">
 
@@ -25,7 +119,7 @@ STL files and other materials: see [here](https://drive.google.com/drive/folders
 ### Selected works
 
 Author: [KiraFlux](https://t.me/@kiraflux_0XC0000005).<br>
-Description: **custom ESPNOW remote control** is implemented, firmware modified to support ESPNOW protocol.<br>
+Description: **custom ESPNOW remote control** was implemented, modified firmware to support ESPNOW protocol.<br>
 Telegram posts: [1](https://t.me/opensourcequadcopter/106), [2](https://t.me/opensourcequadcopter/114).<br>
 Modified Flix firmware: https://github.com/KiraFlux/flix/tree/klyax.<br>
 Remote control project: https://github.com/KiraFlux/ESP32-DJC.<br>

flix/cli.ino

@@ -6,58 +6,70 @@
 #include "pid.h"
 #include "vector.h"
 #include "util.h"
+#include "filter.h"
 
 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
-extern const int RAW, ACRO, STAB, AUTO;
+extern const int RAW, ACRO, STAB, AUTO, POS;
+extern const int W_AP, W_STA, W_ESPNOW;
 extern float t, dt, loopRate;
 extern uint16_t channels[16];
-extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlMode;
+extern float controlTime;
 extern int mode;
 extern bool armed;
+extern LowPassFilter<Vector> gyroBiasFilter;
+extern float voltage;
 
 const char* motd =
-"\nWelcome to\n"
 " _______  __       __  ___   ___\n"
 "|   ____||  |     |  | \\  \\ /  /\n"
 "|  |__   |  |     |  |  \\  V  /\n"
 "|   __|  |  |     |  |   >   <\n"
 "|  |     |  `----.|  |  /  .  \\\n"
 "|__|     |_______||__| /__/ \\__\\\n\n"
+"(C) Oleg Kalachev\n"
+"https://github.com/okalachev/flix\n\n"
 "Commands:\n\n"
 "help - show help\n"
 "p - show all parameters\n"
-"p <name> - show parameter\n"
+"p <str> - show parameters starting with str\n"
 "p <name> <value> - set parameter\n"
 "preset - reset parameters\n"
 "time - show time info\n"
-"ps - show pitch/roll/yaw\n"
-"psq - show attitude quaternion\n"
 "imu - show IMU data\n"
+"ca - calibrate accel\n"
+"st - show state estimation\n"
 "arm - arm the drone\n"
 "disarm - disarm the drone\n"
 "raw/stab/acro/auto - set mode\n"
 "rc - show RC data\n"
-"wifi - show Wi-Fi info\n"
-"mot - show motor output\n"
-"log [dump] - print log header [and data]\n"
 "cr - calibrate RC\n"
-"ca - calibrate accel\n"
-"cl - calibrate level\n"
-"mfr, mfl, mrr, mrl - test motor (remove props)\n"
+"pw - show power info\n"
+"wifi - show Wi-Fi info\n"
+"wifi ap/sta/espnow/off - set Wi-Fi mode\n"
+"ap <ssid> <password> - configure Wi-Fi access point\n"
+"sta <ssid> <password> - configure Wi-Fi client mode\n"
+"espnow <mac> [<key>] - configure ESP-NOW peer\n"
+"mot - show motor output\n"
+"mfr/mfl/mrr/mrl [<thrust>] - test motor (remove props)\n"
+"log [dump] - print log header [and data]\n"
+"log - show log info\n"
+"log header - show log header\n"
+"log reset - reset log\n"
+"log <name> <rate> - setup log topic rate\n"
+"l <str> - show log values starting with str\n"
+"l expose <name> - expose log value to telemetry\n"
 "sys - show system info\n"
 "reset - reset drone's state\n"
 "reboot - reboot the drone\n";
 
 void print(const char* format, ...) {
-	char buf[1000];
+	char buf[3000];
 	va_list args;
 	va_start(args, format);
 	vsnprintf(buf, sizeof(buf), format, args);
 	va_end(args);
 	Serial.print(buf);
-#if WIFI_ENABLED
 	mavlinkPrint(buf);
-#endif
 }
 
 void pause(float duration) {
@@ -65,9 +77,7 @@ void pause(float duration) {
 	while (t - start < duration) {
 		step();
 		handleInput();
-#if WIFI_ENABLED
 		processMavlink();
-#endif
 		delay(50);
 	}
 }
@@ -88,14 +98,12 @@ void doCommand(String str, bool echo = false) {
 	// execute command
 	if (command == "help" || command == "motd") {
 		print("%s\n", motd);
-	} else if (command == "p" && arg0 == "") {
-		printParameters();
-	} else if (command == "p" && arg0 != "" && arg1 == "") {
-		print("%s = %g\n", arg0.c_str(), getParameter(arg0.c_str()));
+	} else if (command == "p" && arg1 == "") {
+		printParameters(arg0.c_str());
 	} else if (command == "p") {
 		bool success = setParameter(arg0.c_str(), arg1.toFloat());
 		if (success) {
-			print("%s = %g\n", arg0.c_str(), arg1.toFloat());
+			print("%s = %g\n", arg0.c_str(), getParameter(arg0.c_str()));
 		} else {
 			print("Parameter not found: %s\n", arg0.c_str());
 		}
@@ -105,15 +113,15 @@ void doCommand(String str, bool echo = false) {
 		print("Time: %f\n", t);
 		print("Loop rate: %.0f\n", loopRate);
 		print("dt: %f\n", dt);
-	} else if (command == "ps") {
-		Vector a = attitude.toEuler();
-		print("roll: %f pitch: %f yaw: %f\n", degrees(a.x), degrees(a.y), degrees(a.z));
-	} else if (command == "psq") {
-		print("qw: %f qx: %f qy: %f qz: %f\n", attitude.w, attitude.x, attitude.y, attitude.z);
 	} else if (command == "imu") {
 		printIMUInfo();
 		printIMUCalibration();
 		print("landed: %d\n", landed);
+	} else if (command == "st") {
+		print("rates: %g %g %g\n", rates.x, rates.y, rates.z);
+		print("attitude: %g %g %g %g\n", attitude.w, attitude.x, attitude.y, attitude.z);
+		print("roll: %g° pitch: %g° yaw: %g°\n", degrees(attitude.getRoll()), degrees(attitude.getPitch()), degrees(attitude.getYaw()));
+		print("landed: %d\n", landed);
 	} else if (command == "arm") {
 		armed = true;
 	} else if (command == "disarm") {
@@ -126,6 +134,8 @@ void doCommand(String str, bool echo = false) {
 		mode = ACRO;
 	} else if (command == "auto") {
 		mode = AUTO;
+	} else if (command == "pos") {
+		mode = POS;
 	} else if (command == "rc") {
 		print("channels: ");
 		for (int i = 0; i < 16; i++) {
@@ -133,39 +143,59 @@ void doCommand(String str, bool echo = false) {
 		}
 		print("\nroll: %g pitch: %g yaw: %g throttle: %g mode: %g\n",
 			controlRoll, controlPitch, controlYaw, controlThrottle, controlMode);
+		print("time: %.1f\n", controlTime);
 		print("mode: %s\n", getModeName());
 		print("armed: %d\n", armed);
-	} else if (command == "wifi") {
-#if WIFI_ENABLED
+	} else if (command == "pw") {
+		print("Voltage: %.1f V\n", voltage);
+	} else if (command == "wifi" && arg0 == "") {
 		printWiFiInfo();
-#endif
+	} else if (command == "wifi") {
+		setWiFiMode(arg0);
+	} else if (command == "ap") {
+		configWiFi(W_AP, arg0.c_str(), arg1.c_str());
+	} else if (command == "sta") {
+		configWiFi(W_STA, arg0.c_str(), arg1.c_str());
+	} else if (command == "espnow") {
+		configWiFi(W_ESPNOW, arg0.c_str(), arg1.c_str());
 	} else if (command == "mot") {
 		print("front-right %g front-left %g rear-right %g rear-left %g\n",
 			motors[MOTOR_FRONT_RIGHT], motors[MOTOR_FRONT_LEFT], motors[MOTOR_REAR_RIGHT], motors[MOTOR_REAR_LEFT]);
-	} else if (command == "log") {
+	} else if (command == "log" && arg0 == "") {
+		printLogInfo();
+	} else if (command == "log" && arg1 != "") {
+		configLogThrottle(arg0.c_str(), arg1.toFloat());
+	} else if (command == "log" && arg0 == "header") {
 		printLogHeader();
-		if (arg0 == "dump") printLogData();
+	} else if (command == "log" && arg0 == "reset") {
+		resetLog();
+	} else if (command == "l" && arg0 == "expose" && arg1 != "") {
+		exposeLogValue(arg1.c_str());
+	} else if (command == "l") {
+		printLogValues(arg0.c_str());
 	} else if (command == "cr") {
 		calibrateRC();
 	} else if (command == "ca") {
 		calibrateAccel();
-	} else if (command == "cl") {
-		calibrateLevel();
 	} else if (command == "mfr") {
-		testMotor(MOTOR_FRONT_RIGHT);
+		testMotor(MOTOR_FRONT_RIGHT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
 	} else if (command == "mfl") {
-		testMotor(MOTOR_FRONT_LEFT);
+		testMotor(MOTOR_FRONT_LEFT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
 	} else if (command == "mrr") {
-		testMotor(MOTOR_REAR_RIGHT);
+		testMotor(MOTOR_REAR_RIGHT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
 	} else if (command == "mrl") {
-		testMotor(MOTOR_REAR_LEFT);
+		testMotor(MOTOR_REAR_LEFT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
 	} else if (command == "sys") {
 #ifdef ESP32
 		print("Chip: %s\n", ESP.getChipModel());
 		print("Temperature: %.1f °C\n", temperatureRead());
-		print("Free heap: %d\n", ESP.getFreeHeap());
+		print("Total RAM: %d KB\n", ESP.getHeapSize() / 1024);
+		print("Free heap: %d KB\n", ESP.getFreeHeap() / 1024);
+		print("PSRAM: %d KB\n", ESP.getPsramSize() / 1024);
+		print("Free PSRAM: %d KB\n", ESP.getFreePsram() / 1024);
+		print("Firmware: " __DATE__ " " __TIME__ "\n");
 		// Print tasks table
-		print("Num  Task                Stack  Prio  Core  CPU%%\n");
+		print("Num  Task                MinSt  Prio  Core  CPU%%\n");
 		int taskCount = uxTaskGetNumberOfTasks();
 		TaskStatus_t *systemState = new TaskStatus_t[taskCount];
 		uint32_t totalRunTime;
@@ -174,12 +204,13 @@ void doCommand(String str, bool echo = false) {
 			String core = systemState[i].xCoreID == tskNO_AFFINITY ? "*" : String(systemState[i].xCoreID);
 			int cpuPercentage = systemState[i].ulRunTimeCounter / (totalRunTime / 100);
 			print("%-5d%-20s%-7d%-6d%-6s%d\n",systemState[i].xTaskNumber, systemState[i].pcTaskName,
-				systemState[i].usStackHighWaterMark, systemState[i].uxCurrentPriority, core, cpuPercentage);
+				systemState[i].usStackHighWaterMark, systemState[i].uxCurrentPriority, core.c_str(), cpuPercentage);
 		}
 		delete[] systemState;
 #endif
 	} else if (command == "reset") {
 		attitude = Quaternion();
+		gyroBiasFilter.reset();
 	} else if (command == "reboot") {
 		ESP.restart();
 	} else {
@@ -198,7 +229,7 @@ void handleInput() {
 
 	while (Serial.available()) {
 		char c = Serial.read();
-		if (c == '\n') {
+		if (c == '\n' || c == '\r') {
 			doCommand(input);
 			input.clear();
 		} else {

flix/control.ino

@@ -6,7 +6,7 @@
 #include "vector.h"
 #include "quaternion.h"
 #include "pid.h"
-#include "lpf.h"
+#include "filter.h"
 #include "util.h"
 
 #define PITCHRATE_P 0.05
@@ -34,10 +34,16 @@
 #define TILT_MAX radians(30)
 #define RATES_D_LPF_ALPHA 0.2 // cutoff frequency ~ 40 Hz
 
-const int RAW = 0, ACRO = 1, STAB = 2, AUTO = 3; // flight modes
+const int RAW = 0, ACRO = 1, STAB = 2, AUTO = 3, POS = 4;
 int mode = STAB;
 bool armed = false;
 
+Quaternion attitudeTarget;
+Vector ratesTarget;
+Vector ratesExtra; // feedforward rates
+Vector torqueTarget;
+float thrustTarget;
+
 PID rollRatePID(ROLLRATE_P, ROLLRATE_I, ROLLRATE_D, ROLLRATE_I_LIM, RATES_D_LPF_ALPHA);
 PID pitchRatePID(PITCHRATE_P, PITCHRATE_I, PITCHRATE_D, PITCHRATE_I_LIM, RATES_D_LPF_ALPHA);
 PID yawRatePID(YAWRATE_P, YAWRATE_I, YAWRATE_D);
@@ -46,15 +52,11 @@ PID pitchPID(PITCH_P, PITCH_I, PITCH_D);
 PID yawPID(YAW_P, 0, 0);
 Vector maxRate(ROLLRATE_MAX, PITCHRATE_MAX, YAWRATE_MAX);
 float tiltMax = TILT_MAX;
-
-Quaternion attitudeTarget;
-Vector ratesTarget;
-Vector ratesExtra; // feedforward rates
-Vector torqueTarget;
-float thrustTarget;
+int flightModes[] = {STAB, STAB, STAB}; // map for rc mode switch
 
 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
 extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlMode;
+extern Vector position, positionTarget;
 
 void control() {
 	interpretControls();
@@ -65,9 +67,9 @@ void control() {
 }
 
 void interpretControls() {
-	if (controlMode < 0.25) mode = STAB;
-	if (controlMode < 0.75) mode = STAB;
-	if (controlMode > 0.75) mode = STAB;
+	if (controlMode < 0.25) mode = flightModes[0];
+	else if (controlMode <= 0.75) mode = flightModes[1];
+	else if (controlMode > 0.75) mode = flightModes[2];
 
 	if (mode == AUTO) return; // pilot is not effective in AUTO mode
 
@@ -78,7 +80,18 @@ void interpretControls() {
 
 	thrustTarget = controlThrottle;
 
-	if (mode == STAB) {
+	if (mode == POS) {
+		if (controlRoll != 0 || controlPitch != 0) {
+			positionTarget.x = NAN;
+			positionTarget.y = NAN;
+		} else if (invalid(positionTarget.x) || invalid(positionTarget.y)) {
+			// reset position target
+			positionTarget.x = position.x;
+			positionTarget.y = position.y;
+		}
+	}
+
+	if (mode == STAB || (mode == POS && invalid(positionTarget.x))) {
 		float yawTarget = attitudeTarget.getYaw();
 		if (!armed || invalid(yawTarget) || controlYaw != 0) yawTarget = attitude.getYaw(); // reset yaw target
 		attitudeTarget = Quaternion::fromEuler(Vector(controlRoll * tiltMax, controlPitch * tiltMax, yawTarget));
@@ -148,12 +161,26 @@ void controlTorque() {
 	motors[MOTOR_REAR_LEFT] = thrustTarget + torqueTarget.x + torqueTarget.y - torqueTarget.z;
 	motors[MOTOR_REAR_RIGHT] = thrustTarget - torqueTarget.x + torqueTarget.y + torqueTarget.z;
 
+	// Prioritize angle control over thrust control
+	desaturate(motors[MOTOR_FRONT_LEFT], motors[MOTOR_FRONT_RIGHT], motors[MOTOR_REAR_LEFT], motors[MOTOR_REAR_RIGHT]);
+
 	motors[0] = constrain(motors[0], 0, 1);
 	motors[1] = constrain(motors[1], 0, 1);
 	motors[2] = constrain(motors[2], 0, 1);
 	motors[3] = constrain(motors[3], 0, 1);
 }
 
+void desaturate(float& a, float& b, float& c, float& d) {
+	float maxThrust = max(max(a, b), max(c, d));
+	if (maxThrust > 1) {
+		float diff = maxThrust - 1;
+		a -= diff;
+		b -= diff;
+		c -= diff;
+		d -= diff;
+	}
+}
+
 const char* getModeName() {
 	switch (mode) {
 		case RAW: return "RAW";

flix/estimate.ino

@@ -1,24 +1,38 @@
 // Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
 // Repository: https://github.com/okalachev/flix
 
-// Attitude estimation from gyro and accelerometer
+// Attitude estimation using gyro and accelerometer
 
 #include "quaternion.h"
 #include "vector.h"
-#include "lpf.h"
+#include "filter.h"
 #include "util.h"
 
+Vector rates; // estimated angular rates, rad/s
+Quaternion attitude; // estimated attitude
+bool landed;
+
 float accWeight = 0.003;
+float levelWeight = 0.0002;
 LowPassFilter<Vector> ratesFilter(0.2); // cutoff frequency ~ 40 Hz
+NotchFilter<Vector> ratesNotch(382, 0);
+
+void setupEstimate() {
+	print("Setup estimation\n");
+	ratesNotch.reset();
+}
 
 void estimate() {
 	applyGyro();
 	applyAcc();
+	applyLevel();
+	estimatePosition();
 }
 
 void applyGyro() {
 	// filter gyro to get angular rates
 	rates = ratesFilter.update(gyro);
+	rates = ratesNotch.update(rates);
 
 	// apply rates to attitude
 	attitude = Quaternion::rotate(attitude, Quaternion::fromRotationVector(rates * dt));
@@ -26,8 +40,7 @@ void applyGyro() {
 
 void applyAcc() {
 	// test should we apply accelerometer gravity correction
-	float accNorm = acc.norm();
-	landed = !motorsActive() && abs(accNorm - ONE_G) < ONE_G * 0.1f;
+	landed = !motorsActive() && abs(acc.norm() - ONE_G) < ONE_G * 0.1f;
 
 	if (!landed) return;
 
@@ -38,3 +51,13 @@ void applyAcc() {
 	// apply correction
 	attitude = Quaternion::rotate(attitude, Quaternion::fromRotationVector(correction));
 }
+
+void applyLevel() {
+	if (landed) return;
+	if (thrustTarget < 0.1) return; // skip at idle thrust
+
+	// assume the pilot keeps the drone more or less level in flight
+	Vector up = Quaternion::rotateVector(Vector(0, 0, 1), attitude);
+	Vector correction = Vector::rotationVectorBetween(Vector(0, 0, 1), up) * levelWeight;
+	attitude = Quaternion::rotate(attitude, Quaternion::fromRotationVector(correction));
+}

flix/filter.h

@@ -0,0 +1,98 @@
+// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// Low pass and notch filters
+
+#pragma once
+
+template <typename T> // Using template to make the filter usable for scalar and vector values
+class LowPassFilter {
+public:
+	float alpha; // smoothing constant, 1 means filter disabled
+	T output;
+
+	LowPassFilter(float alpha): alpha(alpha) {};
+
+	T update(const T input) {
+		if (!init) {
+			init = true;
+			return output = input;
+		}
+		return output += alpha * (input - output);
+	}
+
+	void setCutOffFrequency(float cutOffFreq, float dt) {
+		alpha = 1 - exp(-2 * PI * cutOffFreq * dt);
+	}
+
+	void reset() {
+		init = false;
+	}
+
+private:
+	bool init = false;
+};
+
+template <typename T>
+class NotchFilter {
+public:
+	float frequency;
+	float bandwidth;
+	T output;
+
+	NotchFilter(float frequency, float bandwidth): frequency(frequency), bandwidth(bandwidth) {
+		reset();
+	};
+
+	T update(const T input) {
+		if (frequency <= 0 || bandwidth <= 0) return input;
+
+		if (!init) {
+			init = true;
+			x1 = x2 = input;
+			y1 = y2 = input;
+			return output = input;
+		}
+
+		output = b0 * input + b1 * x1 + b2 * x2 - a1 * y1 - a2 * y2;
+
+		x2 = x1;
+		x1 = input;
+		y2 = y1;
+		y1 = output;
+
+		return output;
+	}
+
+	void reset() {
+		const float dt = 0.001f;
+		float f = frequency;
+		float bw = bandwidth;
+		if (f < 0) f = 0;
+		if (bw < 1e-6f) bw = 1e-6f;
+
+		float q = f / bw;
+		if (q < 1e-3f) q = 1e-3f;
+
+		const float w0 = 2.0f * PI * f * dt;
+		const float c = cos(w0);
+		const float s = sin(w0);
+		const float alpha = s / (2.0f * q);
+
+		const float a0 = 1.0f + alpha;
+		const float invA0 = 1.0f / a0;
+
+		b0 = 1.0f * invA0;
+		b1 = -2.0f * c * invA0;
+		b2 = 1.0f * invA0;
+		a1 = -2.0f * c * invA0;
+		a2 = (1.0f - alpha) * invA0;
+
+		init = false;
+	}
+
+private:
+	float b0, b1, b2, a1, a2;
+	T x1, x2, y1, y2;
+	bool init = false;
+};

flix/flix.ino

@@ -7,32 +7,27 @@
 #include "quaternion.h"
 #include "util.h"
 
-#define WIFI_ENABLED 1
-
-float t = NAN; // current step time, s
-float dt; // time delta from previous step, s
-float controlRoll, controlPitch, controlYaw, controlThrottle; // pilot's inputs, range [-1, 1]
-float controlMode = NAN;
-Vector gyro; // gyroscope data
-Vector acc; // accelerometer data, m/s/s
-Vector rates; // filtered angular rates, rad/s
-Quaternion attitude; // estimated attitude
-bool landed; // are we landed and stationary
-float motors[4]; // normalized motors thrust in range [0..1]
+extern float t, dt;
+extern float controlRoll, controlPitch, controlYaw, controlThrottle, controlMode;
+extern Vector gyro, acc;
+extern Vector rates;
+extern Quaternion attitude;
+extern bool landed;
+extern float motors[4];
 
 void setup() {
 	Serial.begin(115200);
-	print("Initializing flix\n");
-	disableBrownOut();
+	print("Initializing Flix\n");
 	setupParameters();
+	setupPower();
 	setupLED();
-	setupMotors();
 	setLED(true);
-#if WIFI_ENABLED
+	setupMotors();
 	setupWiFi();
-#endif
 	setupIMU();
 	setupRC();
+	setupEstimate();
+	setupLog();
 	setLED(false);
 	print("Initializing complete\n");
 }
@@ -45,9 +40,8 @@ void loop() {
 	control();
 	sendMotors();
 	handleInput();
-#if WIFI_ENABLED
 	processMavlink();
-#endif
-	logData();
+	readVoltage();
+	loopLog();
 	syncParameters();
 }

flix/imu.ino

@@ -6,15 +6,20 @@
 #include <SPI.h>
 #include <FlixPeriph.h>
 #include "vector.h"
-#include "lpf.h"
+#include "filter.h"
 #include "util.h"
 
 MPU9250 imu(SPI);
-Vector imuRotation(0, 0, -PI / 2); // imu orientation as Euler angles
+Vector imuRotation(0, 0, PI / 2); // imu orientation as Euler angles
 
+Vector gyro; // gyroscope output, rad/s
+Vector gyroBias;
+
+Vector acc; // accelerometer output, m/s/s
 Vector accBias;
 Vector accScale(1, 1, 1);
-Vector gyroBias;
+
+LowPassFilter<Vector> gyroBiasFilter(0.001);
 
 void setupIMU() {
 	print("Setup IMU\n");
@@ -35,10 +40,12 @@ void readIMU() {
 	imu.getGyro(gyro.x, gyro.y, gyro.z);
 	imu.getAccel(acc.x, acc.y, acc.z);
 	calibrateGyroOnce();
-	// apply scale and bias
+
+	// Apply scale and bias
 	acc = (acc - accBias) / accScale;
 	gyro = gyro - gyroBias;
-	// rotate to body frame
+
+	// Rotate to body frame
 	Quaternion rotation = Quaternion::fromEuler(imuRotation);
 	acc = Quaternion::rotateVector(acc, rotation.inversed());
 	gyro = Quaternion::rotateVector(gyro, rotation.inversed());
@@ -48,7 +55,6 @@ void calibrateGyroOnce() {
 	static Delay landedDelay(2);
 	if (!landedDelay.update(landed)) return; // calibrate only if definitely stationary
 
-	static LowPassFilter<Vector> gyroBiasFilter(0.001);
 	gyroBias = gyroBiasFilter.update(gyro);
 }
 
@@ -102,19 +108,12 @@ void calibrateAccelOnce() {
 	if (acc.x < accMin.x) accMin.x = acc.x;
 	if (acc.y < accMin.y) accMin.y = acc.y;
 	if (acc.z < accMin.z) accMin.z = acc.z;
+
 	// Compute scale and bias
 	accScale = (accMax - accMin) / 2 / ONE_G;
 	accBias = (accMax + accMin) / 2;
 }
 
-void calibrateLevel() {
-	print("Place perfectly level [1 sec]\n");
-	pause(1);
-	Quaternion correction = Quaternion::fromBetweenVectors(Quaternion::rotateVector(Vector(0, 0, 1), attitude), Vector(0, 0, 1));
-	imuRotation = Quaternion::rotate(correction, Quaternion::fromEuler(imuRotation)).toEuler();
-	print("✓ Done: %.3f %.3f %.3f\n", degrees(imuRotation.x), degrees(imuRotation.y), degrees(imuRotation.z));
-}
-
 void printIMUCalibration() {
 	print("gyro bias: %f %f %f\n", gyroBias.x, gyroBias.y, gyroBias.z);
 	print("accel bias: %f %f %f\n", accBias.x, accBias.y, accBias.z);
@@ -126,7 +125,8 @@ void printIMUInfo() {
 	print("model: %s\n", imu.getModel());
 	print("who am I: 0x%02X\n", imu.whoAmI());
 	print("rate: %.0f\n", loopRate);
-	print("gyro: %f %f %f\n", rates.x, rates.y, rates.z);
+	print("temperature: %.1f °C\n", imu.getTemp());
+	print("gyro: %f %f %f\n", gyro.x, gyro.y, gyro.z);
 	print("acc: %f %f %f\n", acc.x, acc.y, acc.z);
 	imu.waitForData();
 	Vector rawGyro, rawAcc;

flix/log.ino

@@ -1,77 +1,277 @@
 // Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
 // Repository: https://github.com/okalachev/flix
 
-// In-RAM logging
+// Logging subsystem
 
 #include "vector.h"
 #include "util.h"
 
-#define LOG_RATE 100
-#define LOG_DURATION 10
-#define LOG_SIZE LOG_DURATION * LOG_RATE
+int logMemory = -1; // 0 - RAM, 1 - PSRAM, -1 - disabled
+float logUsage = 0.5; // fraction of free memory to use for log
 
-Vector attitudeEuler;
-Vector attitudeTargetEuler;
-
-struct LogEntry {
+struct LogValue {
 	const char *name;
-	float *value;
+	Value value;
+	float lastValue = NAN;
+	bool logged = true; // if false, use only for triggering log update
+	LogValue() : name(nullptr), value() {}; // empty value constructor
+	template <typename T>
+	LogValue(const char *name, T value, bool logged = true) : name(name), value(value), logged(logged) {};
 };
 
-LogEntry logEntries[] = {
-	{"t", &t},
-	{"rates.x", &rates.x},
-	{"rates.y", &rates.y},
-	{"rates.z", &rates.z},
-	{"ratesTarget.x", &ratesTarget.x},
-	{"ratesTarget.y", &ratesTarget.y},
-	{"ratesTarget.z", &ratesTarget.z},
-	{"attitude.x", &attitudeEuler.x},
-	{"attitude.y", &attitudeEuler.y},
-	{"attitude.z", &attitudeEuler.z},
-	{"attitudeTarget.x", &attitudeTargetEuler.x},
-	{"attitudeTarget.y", &attitudeTargetEuler.y},
-	{"attitudeTarget.z", &attitudeTargetEuler.z},
-	{"thrustTarget", &thrustTarget}
+struct LogTopic {
+	LogValue values[10];
+	int length = 0; // number of logged values
+	float throttle; // max update rate, Hz
+	float lastUpdate = -INFINITY;
+
+	LogTopic(float throttle, LogValue v0, LogValue v1 = {}, LogValue v2 = {}, LogValue v3 = {}, LogValue v4 = {}, LogValue v5 = {}, LogValue v6 = {}, LogValue v7 = {}, LogValue v8 = {}, LogValue v9 = {}) :
+		throttle(throttle), values{v0, v1, v2, v3, v4, v5, v6, v7, v8, v9} {
+			// Count logged values
+			for (auto& v : values) {
+				if (v.name == nullptr) break;
+				if (v.logged) length++;
+			}
+		};
+
+	LogTopic(LogValue v0, LogValue v1 = {}, LogValue v2 = {}, LogValue v3 = {}, LogValue v4 = {}, LogValue v5 = {}, LogValue v6 = {}, LogValue v7 = {}, LogValue v8 = {}, LogValue v9 = {}) :
+		LogTopic(INFINITY, v0, v1, v2, v3, v4, v5, v6, v7, v8, v9) {};
 };
 
-const int logColumns = sizeof(logEntries) / sizeof(logEntries[0]);
-float logBuffer[LOG_SIZE][logColumns];
+LogTopic logTopics[] = {
+	// time
+	LogTopic({"t", &t}), // must be the first topic
+	LogTopic(1, {"loopRate", &loopRate}),
 
-void prepareLogData() {
-	attitudeEuler = attitude.toEuler();
-	attitudeTargetEuler = attitudeTarget.toEuler();
-}
+	// imu
+	LogTopic(
+		{"gyro.x", &gyro.x},
+		{"gyro.y", &gyro.y},
+		{"gyro.z", &gyro.z}),
 
-void logData() {
-	if (!armed) return;
-	static int logPointer = 0;
-	static Rate period(LOG_RATE);
-	if (!period) return;
+	LogTopic(50,
+		{"acc.x", &acc.x},
+		{"acc.y", &acc.y},
+		{"acc.z", &acc.z}),
 
-	prepareLogData();
+	LogTopic(10,
+		{"gyroBias.x", &gyroBias.x},
+		{"gyroBias.y", &gyroBias.y},
+		{"gyroBias.z", &gyroBias.z}),
 
-	for (int i = 0; i < logColumns; i++) {
-		logBuffer[logPointer][i] = *logEntries[i].value;
-	}
+	// estimation
+	LogTopic(50,
+		{"rates.x", &rates.x},
+		{"rates.y", &rates.y},
+		{"rates.z", &rates.z},
+		{"attitude.roll", []() { return attitude.getRoll(); }},
+		{"attitude.pitch", []() { return attitude.getPitch(); }},
+		{"attitude.yaw", []() { return attitude.getYaw(); }}),
 
-	logPointer++;
-	if (logPointer >= LOG_SIZE) {
-		logPointer = 0;
+	LogTopic(50,
+		{"position.x", &position.x},
+		{"position.y", &position.y},
+		{"position.z", &position.z}),
+
+	// rc
+	LogTopic(10,
+		{"controlTime", &controlTime, false}, // trigger value
+		{"controlRoll", &controlRoll},
+		{"controlPitch", &controlPitch},
+		{"controlYaw", &controlYaw},
+		{"controlThrottle", &controlThrottle}),
+
+	// control
+	LogTopic({"armed", &armed}),
+	LogTopic({"mode", &mode}),
+
+	LogTopic(10,
+		{"ratesTarget.x", &ratesTarget.x},
+		{"ratesTarget.y", &ratesTarget.y},
+		{"ratesTarget.z", &ratesTarget.z},
+		{"attitudeTarget.roll", []() { return attitudeTarget.getRoll(); }},
+		{"attitudeTarget.pitch", []() { return attitudeTarget.getPitch(); }},
+		{"attitudeTarget.yaw", []() { return attitudeTarget.getYaw(); }},
+		{"thrustTarget", &thrustTarget}),
+
+	// motors
+	LogTopic(
+		{"motors[0]", &motors[0]},
+		{"motors[1]", &motors[1]},
+		{"motors[2]", &motors[2]},
+		{"motors[3]", &motors[3]}),
+
+	// misc
+	LogTopic(5,
+		{"voltage", &voltage},
+		{"temp", &temperatureRead},
+		{"imuTemp", []() { return imu.getTemp(); }}),
+};
+
+void *logBuffer; // buffer for log data
+size_t logCapacity;
+size_t logCursor = 0;
+size_t logLength = 0;
+LogValue *logExposed = nullptr; // log values exposed to telemetry
+
+void setupLog() {
+	print("Setup log\n");
+
+	free(logBuffer); // when reconfiguring
+	logBuffer = nullptr;
+	logCursor = 0;
+	logLength = 0;
+
+	if (logMemory == 0) {
+		logCapacity = ESP.getFreeHeap() * logUsage;
+		logBuffer = (uint8_t *)calloc(logCapacity, 1);
+	} else if (logMemory == 1) {
+		logCapacity = ESP.getFreePsram() * logUsage;
+		logBuffer = (uint8_t *)heap_caps_calloc(logCapacity, 1, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
 	}
 }
 
-void printLogHeader() {
-	for (int i = 0; i < logColumns; i++) {
-		print("%s%s", logEntries[i].name, i < logColumns - 1 ? "," : "\n");
-	}
-}
+void loopLog() {
+	if (logBuffer == nullptr || !armed) return;
 
-void printLogData() {
-	for (int i = 0; i < LOG_SIZE; i++) {
-		if (logBuffer[i][0] == 0) continue; // skip empty records
-		for (int j = 0; j < logColumns; j++) {
-			print("%g%s", logBuffer[i][j], j < logColumns - 1 ? "," : "\n");
+	if (!logLength) resetLog(); // reset state on first log write
+
+	static Rate sync(2);
+	if (sync) {
+		const uint8_t marker[] = {0x1A, 0x91, 0x4F, 0xF6, 0x7F};
+		writeLog(&marker, sizeof(marker)); // write sync marker
+	}
+
+	for (uint8_t i = 0; i < sizeof(logTopics) / sizeof(logTopics[0]); i++) {
+		LogTopic& topic = logTopics[i];
+		if (t - topic.lastUpdate < 1 / topic.throttle) continue; // throttle topic
+		if (!isTopicUpdated(i)) continue; // skip if topic was't updated
+
+		topic.lastUpdate = t;
+		writeLog(&i, sizeof(i)); // write topic index
+
+		for (auto& value : topic.values) {
+			if (value.name == nullptr) break;
+			if (!value.logged) continue;
+			value.lastValue = value.value.get();
+			writeLog(&value.lastValue, sizeof(float)); // write value
 		}
 	}
 }
+
+void resetLog() {
+	for (auto& topic : logTopics) {
+		topic.lastUpdate = -INFINITY;
+		for (auto& value : topic.values) {
+			value.lastValue = NAN;
+		}
+	}
+	logCursor = 0;
+	logLength = 0;
+}
+
+void writeLog(const void *data, size_t size) {
+	size_t first = min(size, logCapacity - logCursor);
+	size_t second = size - first;
+	memcpy(logBuffer + logCursor, data, first);
+	logCursor = (logCursor + first) % logCapacity;
+	if (second > 0) {
+		memcpy(logBuffer + logCursor, data + first, second);
+		logCursor = (logCursor + second) % logCapacity;
+	}
+	logLength = min(logLength + size, logCapacity);
+}
+
+void readLog(void *data, size_t position, size_t size) {
+	if (logLength == logCapacity) {
+		position = (logCursor + position) % logCapacity;
+	}
+	size_t first = min(size, logCapacity - position);
+	size_t second = size - first;
+	memcpy(data, logBuffer + position, first);
+	if (second > 0) {
+		memcpy(data + first, logBuffer, second);
+	}
+}
+
+bool isTopicUpdated(const uint8_t topic) {
+	LogTopic& logTopic = logTopics[topic];
+	bool updated = false;
+
+	for (auto& value : logTopic.values) {
+		if (value.name == nullptr) break;
+		float v = value.value.get();
+		if (!floatEquals(value.lastValue, v)) {
+			value.lastValue = v;
+			updated = true;
+		}
+	}
+	return updated;
+}
+
+void printLogInfo() {
+	if (logMemory == -1) return print("Log: disabled\n");
+
+	print("Memory: %s\n", logMemory == 0 ? "RAM" : "PSRAM");
+	print("Usage: %.f%%\n", logUsage * 100);
+	print("Capacity: %u bytes\n", (unsigned)logCapacity);
+	print("Used: %u bytes\n", (unsigned)logLength);
+	print("Estimated duration: %d seconds\n", estimateLogDuration());
+}
+
+int estimateLogDuration() {
+	float bandwidth = 0;
+	for (LogTopic& topic : logTopics) {
+		float rate = isinf(topic.throttle) ? loopRate : topic.throttle;
+		bandwidth += rate * topic.length * sizeof(float);
+	}
+	return logCapacity / bandwidth;
+}
+
+void printLogHeader() {
+	int i = 0;
+	for (auto& topic : logTopics) {
+		print("Topic #%d (%g Hz):\n", i++, topic.throttle);
+		for (auto& value : topic.values) {
+			if (value.name == nullptr) break;
+			print("  %s%s\n", value.name, value.logged ?"" : " (not logged)");
+		}
+	}
+}
+
+void printLogValues(const char *filter) {
+	for (LogTopic& topic : logTopics) {
+		for (LogValue& value : topic.values) {
+			if (value.name == nullptr) break;
+			if (strncasecmp(value.name, filter, strlen(filter))) continue;
+			print("%s = %g\n", value.name, value.value.get());
+		}
+	}
+}
+
+void configLogThrottle(const char *name, float throttle) {
+	for (LogTopic& topic : logTopics) {
+		for (LogValue& value : topic.values) {
+			if (value.name == nullptr) break;
+			if (strcasecmp(value.name, name) != 0) continue;
+			topic.throttle = throttle;
+			print("Log throttle for %s set to %.1f Hz\n", name, throttle);
+			return;
+		}
+	}
+	print("Log value not found: %s\n", name);
+}
+
+void exposeLogValue(const char *name) {
+	for (int i = 0; i < sizeof(logTopics) / sizeof(logTopics[0]); i++) {
+		LogTopic& topic = logTopics[i];
+		for (LogValue& value : topic.values) {
+			if (value.name == nullptr) break;
+			if (strcasecmp(value.name, name) != 0) continue;
+			logExposed = &value;
+			print("Log value %s exposed\n", name);
+			return;
+		}
+	}
+	print("Log value not found: %s\n", name);
+}

flix/lpf.h

@@ -1,39 +0,0 @@
-// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
-// Repository: https://github.com/okalachev/flix
-
-// Low pass filter implementation
-
-#pragma once
-
-template <typename T> // Using template to make the filter usable for scalar and vector values
-class LowPassFilter {
-public:
-	float alpha; // smoothing constant, 1 means filter disabled
-	T output;
-
-	LowPassFilter(float alpha): alpha(alpha) {};
-
-	T update(const T input) {
-		if (alpha == 1) { // filter disabled
-			return input;
-		}
-
-		if (!initialized) {
-			output = input;
-			initialized = true;
-		}
-
-		return output += alpha * (input - output);
-	}
-
-	void setCutOffFrequency(float cutOffFreq, float dt) {
-		alpha = 1 - exp(-2 * PI * cutOffFreq * dt);
-	}
-
-	void reset() {
-		initialized = false;
-	}
-
-private:
-	bool initialized = false;
-};

flix/mavlink.ino

@@ -3,21 +3,24 @@
 
 // MAVLink communication
 
-#if WIFI_ENABLED
-
 #include <MAVLink.h>
 #include "util.h"
 
-#define SYSTEM_ID 1
-#define MAVLINK_RATE_SLOW 1
-#define MAVLINK_RATE_FAST 10
+extern float controlTime;
+extern float voltage;
+
+int mavlinkSysId = 1;
+
+Rate telemetrySlow(2);
+Rate telemetryAttitude(20);
+Rate telemetryRC(10);
+Rate telemetryMotors(10);
+Rate telemetryIMU(15);
+Rate telemetryTopic(10);
 
 bool mavlinkConnected = false;
 String mavlinkPrintBuffer;
 
-extern float controlTime;
-extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlMode;
-
 void processMavlink() {
 	sendMavlink();
 	receiveMavlink();
@@ -29,44 +32,65 @@ void sendMavlink() {
 	mavlink_message_t msg;
 	uint32_t time = t * 1000;
 
-	static Rate slow(MAVLINK_RATE_SLOW), fast(MAVLINK_RATE_FAST);
-
-	if (slow) {
-		mavlink_msg_heartbeat_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, MAV_TYPE_QUADROTOR, MAV_AUTOPILOT_GENERIC,
+	if (telemetrySlow) {
+		mavlink_msg_heartbeat_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, MAV_TYPE_QUADROTOR, MAV_AUTOPILOT_GENERIC,
 			(armed ? MAV_MODE_FLAG_SAFETY_ARMED : 0) |
 			((mode == STAB) ? MAV_MODE_FLAG_STABILIZE_ENABLED : 0) |
 			((mode == AUTO) ? MAV_MODE_FLAG_AUTO_ENABLED : MAV_MODE_FLAG_MANUAL_INPUT_ENABLED),
 			mode, MAV_STATE_STANDBY);
 		sendMessage(&msg);
+	}
 
-		if (!mavlinkConnected) return; // send only heartbeat until connected
+	if (!mavlinkConnected) return; // send only heartbeat until connected
 
-		mavlink_msg_extended_sys_state_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+	if (telemetrySlow) {
+		mavlink_msg_extended_sys_state_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			MAV_VTOL_STATE_UNDEFINED, landed ? MAV_LANDED_STATE_ON_GROUND : MAV_LANDED_STATE_IN_AIR);
 		sendMessage(&msg);
 	}
 
-	if (fast && mavlinkConnected) {
-		const float zeroQuat[] = {0, 0, 0, 0};
-		mavlink_msg_attitude_quaternion_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
-			time, attitude.w, attitude.x, -attitude.y, -attitude.z, rates.x, -rates.y, -rates.z, zeroQuat); // convert to frd
+	if (telemetrySlow && valid(voltage)) {
+		uint16_t voltages[] = {(uint16_t)(voltage * 1000), UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX};
+		uint16_t voltagesExt[] = {0, 0, 0, 0};
+		float remaining = constrain(mapf(voltage, 3.4, 4.2, 0, 1), 0, 1);
+		mavlink_msg_battery_status_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, 0, MAV_BATTERY_FUNCTION_ALL,
+			MAV_BATTERY_TYPE_LIPO, INT16_MAX, voltages, -1, -1, -1, remaining * 100, 0, MAV_BATTERY_CHARGE_STATE_OK, voltagesExt, 0, 0);
 		sendMessage(&msg);
+	}
 
-		mavlink_msg_rc_channels_raw_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, controlTime * 1000, 0,
+	if (telemetryAttitude) {
+		const float offset[] = {0, 0, 0, 0};
+		mavlink_msg_attitude_quaternion_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
+			time, attitude.w, attitude.x, -attitude.y, -attitude.z, rates.x, -rates.y, -rates.z, offset); // convert to frd
+		sendMessage(&msg);
+	}
+
+	if (telemetryRC && channels[0]) { // 0 means no RC input
+		mavlink_msg_rc_channels_raw_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, controlTime * 1000, 0,
 			channels[0], channels[1], channels[2], channels[3], channels[4], channels[5], channels[6], channels[7], UINT8_MAX);
-		if (channels[0] != 0) sendMessage(&msg); // 0 means no RC input
+		sendMessage(&msg);
+	}
 
+	if (telemetryMotors) {
 		float controls[8];
 		memcpy(controls, motors, sizeof(motors));
-		mavlink_msg_actuator_control_target_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, time, 0, controls);
+		mavlink_msg_actuator_control_target_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, time, 0, controls);
 		sendMessage(&msg);
+	}
 
-		mavlink_msg_scaled_imu_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, time,
-			acc.x * 1000, -acc.y * 1000, -acc.z * 1000, // convert to frd
+	if (telemetryIMU) {
+		mavlink_msg_scaled_imu_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, time,
+			acc.x / ONE_G * 1000, -acc.y / ONE_G * 1000, -acc.z / ONE_G * 1000, // convert to frd
 			gyro.x * 1000, -gyro.y * 1000, -gyro.z * 1000,
 			0, 0, 0, 0);
 		sendMessage(&msg);
 	}
+
+	if (telemetryTopic && logExposed != nullptr) {
+		mavlink_msg_named_value_float_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
+			time, logExposed->name, logExposed->value.get());
+		sendMessage(&msg);
+	}
 }
 
 void sendMessage(const void *msg) {
@@ -75,16 +99,36 @@ void sendMessage(const void *msg) {
 	sendWiFi(buf, len);
 }
 
+static uint8_t mavlinkBatch[ESP_NOW_MAX_DATA_LEN_V2];
+static int mavlinkBatchSize = 0;
+
+void batchMessage(const void *msg) {
+	uint8_t buf[MAVLINK_MAX_PACKET_LEN];
+	int len = mavlink_msg_to_send_buffer(buf, (mavlink_message_t *)msg);
+
+	if (mavlinkBatchSize + len > sizeof(mavlinkBatch)) {
+		sendWiFi(mavlinkBatch, mavlinkBatchSize);
+		mavlinkBatchSize = 0;
+	}
+	memcpy(mavlinkBatch + mavlinkBatchSize, buf, len);
+	mavlinkBatchSize += len;
+}
+
+void flushBatchMessages() {
+	sendWiFi(mavlinkBatch, mavlinkBatchSize);
+	mavlinkBatchSize = 0;
+}
+
 void receiveMavlink() {
 	uint8_t buf[MAVLINK_MAX_PACKET_LEN];
 	int len = receiveWiFi(buf, MAVLINK_MAX_PACKET_LEN);
-	if (len) mavlinkConnected = true;
 
 	// New packet, parse it
 	mavlink_message_t msg;
 	mavlink_status_t status;
 	for (int i = 0; i < len; i++) {
 		if (mavlink_parse_char(MAVLINK_COMM_0, buf[i], &msg, &status)) {
+			mavlinkConnected = true;
 			handleMavlink(&msg);
 		}
 	}
@@ -96,7 +140,7 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_MANUAL_CONTROL) {
 		mavlink_manual_control_t m;
 		mavlink_msg_manual_control_decode(&msg, &m);
-		if (m.target && m.target != SYSTEM_ID) return; // 0 is broadcast
+		if (m.target && m.target != mavlinkSysId) return; // 0 is broadcast
 
 		controlThrottle = m.z / 1000.0f;
 		controlPitch = m.x / 1000.0f;
@@ -109,11 +153,11 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_PARAM_REQUEST_LIST) {
 		mavlink_param_request_list_t m;
 		mavlink_msg_param_request_list_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 
 		mavlink_message_t msg;
 		for (int i = 0; i < parametersCount(); i++) {
-			mavlink_msg_param_value_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+			mavlink_msg_param_value_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 				getParameterName(i), getParameter(i), MAV_PARAM_TYPE_REAL32, parametersCount(), i);
 			sendMessage(&msg);
 		}
@@ -122,7 +166,7 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_PARAM_REQUEST_READ) {
 		mavlink_param_request_read_t m;
 		mavlink_msg_param_request_read_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 
 		char name[MAVLINK_MSG_PARAM_REQUEST_READ_FIELD_PARAM_ID_LEN + 1];
 		strlcpy(name, m.param_id, sizeof(name)); // param_id might be not null-terminated
@@ -131,7 +175,7 @@ void handleMavlink(const void *_msg) {
 			memcpy(name, getParameterName(m.param_index), 16);
 		}
 		mavlink_message_t msg;
-		mavlink_msg_param_value_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+		mavlink_msg_param_value_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			name, value, MAV_PARAM_TYPE_REAL32, parametersCount(), m.param_index);
 		sendMessage(&msg);
 	}
@@ -139,32 +183,40 @@ void handleMavlink(const void *_msg) {
 	if (msg.msgid == MAVLINK_MSG_ID_PARAM_SET) {
 		mavlink_param_set_t m;
 		mavlink_msg_param_set_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 
 		char name[MAVLINK_MSG_PARAM_SET_FIELD_PARAM_ID_LEN + 1];
 		strlcpy(name, m.param_id, sizeof(name)); // param_id might be not null-terminated
-		setParameter(name, m.param_value);
+		bool success = setParameter(name, m.param_value);
+		if (!success) return;
 		// send ack
 		mavlink_message_t msg;
-		mavlink_msg_param_value_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
-			m.param_id, m.param_value, MAV_PARAM_TYPE_REAL32, parametersCount(), 0); // index is unknown
+		mavlink_msg_param_value_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
+			m.param_id, getParameter(name), MAV_PARAM_TYPE_REAL32, parametersCount(), 0); // index is unknown
 		sendMessage(&msg);
 	}
 
+	if (msg.msgid == MAVLINK_MSG_ID_VISION_POSITION_ESTIMATE) {
+		mavlink_vision_position_estimate_t m;
+		mavlink_msg_vision_position_estimate_decode(&msg, &m);
+		Vector pos(m.x, m.y, m.z);
+		correctPosition(pos);
+	}
+
 	if (msg.msgid == MAVLINK_MSG_ID_MISSION_REQUEST_LIST) { // handle to make qgc happy
 		mavlink_mission_request_list_t m;
 		mavlink_msg_mission_request_list_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 
 		mavlink_message_t msg;
-		mavlink_msg_mission_count_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, 0, 0, 0, MAV_MISSION_TYPE_MISSION, 0);
+		mavlink_msg_mission_count_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, 0, 0, 0, MAV_MISSION_TYPE_MISSION, 0);
 		sendMessage(&msg);
 	}
 
 	if (msg.msgid == MAVLINK_MSG_ID_SERIAL_CONTROL) {
 		mavlink_serial_control_t m;
 		mavlink_msg_serial_control_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 
 		char data[MAVLINK_MSG_SERIAL_CONTROL_FIELD_DATA_LEN + 1];
 		strlcpy(data, (const char *)m.data, m.count); // data might be not null-terminated
@@ -176,20 +228,26 @@ void handleMavlink(const void *_msg) {
 
 		mavlink_set_attitude_target_t m;
 		mavlink_msg_set_attitude_target_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 
-		// copy attitude, rates and thrust targets
-		ratesTarget.x = m.body_roll_rate;
-		ratesTarget.y = -m.body_pitch_rate; // convert to flu
-		ratesTarget.z = -m.body_yaw_rate;
-		attitudeTarget.w = m.q[0];
-		attitudeTarget.x = m.q[1];
-		attitudeTarget.y = -m.q[2];
-		attitudeTarget.z = -m.q[3];
-		thrustTarget = m.thrust;
-		ratesExtra = Vector(0, 0, 0);
+		if (!(m.type_mask & ATTITUDE_TARGET_TYPEMASK_ATTITUDE_IGNORE)) {
+			// Attitude control
+			attitudeTarget.w = m.q[0];
+			attitudeTarget.x = m.q[1];
+			attitudeTarget.y = -m.q[2];
+			attitudeTarget.z = -m.q[3];
+			ratesExtra.x = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_ROLL_RATE_IGNORE ? 0 : m.body_roll_rate;
+			ratesExtra.y = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_PITCH_RATE_IGNORE ? 0 : -m.body_pitch_rate; // convert to flu
+			ratesExtra.z = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_YAW_RATE_IGNORE ? 0 : -m.body_yaw_rate;
+		} else {
+			// Rates control
+			attitudeTarget.invalidate();
+			ratesTarget.x = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_ROLL_RATE_IGNORE ? ratesTarget.x : m.body_roll_rate;
+			ratesTarget.y = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_PITCH_RATE_IGNORE ? ratesTarget.y : -m.body_pitch_rate;
+			ratesTarget.z = m.type_mask & ATTITUDE_TARGET_TYPEMASK_BODY_YAW_RATE_IGNORE ? ratesTarget.z : -m.body_yaw_rate;
+		}
 
-		if (m.type_mask & ATTITUDE_TARGET_TYPEMASK_ATTITUDE_IGNORE) attitudeTarget.invalidate();
+		thrustTarget = valid(m.thrust) ? m.thrust : thrustTarget;
 		armed = m.thrust > 0;
 	}
 
@@ -198,7 +256,7 @@ void handleMavlink(const void *_msg) {
 
 		mavlink_set_actuator_control_target_t m;
 		mavlink_msg_set_actuator_control_target_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 
 		attitudeTarget.invalidate();
 		ratesTarget.invalidate();
@@ -207,37 +265,48 @@ void handleMavlink(const void *_msg) {
 		armed = motors[0] > 0 || motors[1] > 0 || motors[2] > 0 || motors[3] > 0;
 	}
 
+	if (msg.msgid == MAVLINK_MSG_ID_LOG_REQUEST_LIST) {
+		const uint32_t qgcEpoch = 1262304000; // qgc accepts only timestamps after 2010-01-01
+		mavlink_message_t response;
+		mavlink_msg_log_entry_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &response,
+			0, 1, 0, qgcEpoch + t * 60, logLength); // put fake unique date to make qgc happy with saving logs
+		sendMessage(&response);
+	}
+
 	if (msg.msgid == MAVLINK_MSG_ID_LOG_REQUEST_DATA) {
 		mavlink_log_request_data_t m;
 		mavlink_msg_log_request_data_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 
-		// Send all log records
-		for (int i = 0; i < sizeof(logBuffer) / sizeof(logBuffer[0]); i++) {
-			mavlink_message_t msg;
-			mavlink_msg_log_data_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, 0, i,
-				sizeof(logBuffer[0]), (uint8_t *)logBuffer[i]);
-			sendMessage(&msg);
+		for (int i = 0; i < m.count; i += MAVLINK_MSG_LOG_DATA_FIELD_DATA_LEN) {
+			int chunkSize = min(MAVLINK_MSG_LOG_DATA_FIELD_DATA_LEN, (int)(m.count - i));
+			mavlink_message_t response;
+			uint8_t data[MAVLINK_MSG_LOG_DATA_FIELD_DATA_LEN];
+			readLog(data, m.ofs + i, chunkSize);
+			mavlink_msg_log_data_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &response,
+				m.id, m.ofs + i, chunkSize, data);
+			batchMessage(&response);
 		}
+		flushBatchMessages();
 	}
 
 	// Handle commands
 	if (msg.msgid == MAVLINK_MSG_ID_COMMAND_LONG) {
 		mavlink_command_long_t m;
 		mavlink_msg_command_long_decode(&msg, &m);
-		if (m.target_system && m.target_system != SYSTEM_ID) return;
+		if (m.target_system && m.target_system != mavlinkSysId) return;
 		mavlink_message_t response;
 		bool accepted = false;
 
 		if (m.command == MAV_CMD_REQUEST_MESSAGE && m.param1 == MAVLINK_MSG_ID_AUTOPILOT_VERSION) {
 			accepted = true;
-			mavlink_msg_autopilot_version_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &response,
+			mavlink_msg_autopilot_version_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &response,
 				MAV_PROTOCOL_CAPABILITY_PARAM_FLOAT | MAV_PROTOCOL_CAPABILITY_MAVLINK2, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0);
 			sendMessage(&response);
 		}
 
 		if (m.command == MAV_CMD_COMPONENT_ARM_DISARM) {
-			if (m.param1 && controlThrottle > 0.05) return; // don't arm if throttle is not low
+			if (m.param1 == 1 && controlThrottle > 0.05) return; // don't arm if throttle is not low
 			accepted = true;
 			armed = m.param1 == 1;
 		}
@@ -250,7 +319,7 @@ void handleMavlink(const void *_msg) {
 
 		// send command ack
 		mavlink_message_t ack;
-		mavlink_msg_command_ack_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &ack, m.command, accepted ? MAV_RESULT_ACCEPTED : MAV_RESULT_UNSUPPORTED, UINT8_MAX, 0, msg.sysid, msg.compid);
+		mavlink_msg_command_ack_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &ack, m.command, accepted ? MAV_RESULT_ACCEPTED : MAV_RESULT_UNSUPPORTED, UINT8_MAX, 0, msg.sysid, msg.compid);
 		sendMessage(&ack);
 	}
 }
@@ -267,7 +336,7 @@ void sendMavlinkPrint() {
 		char data[MAVLINK_MSG_SERIAL_CONTROL_FIELD_DATA_LEN + 1];
 		strlcpy(data, str + i, sizeof(data));
 		mavlink_message_t msg;
-		mavlink_msg_serial_control_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg,
+		mavlink_msg_serial_control_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			SERIAL_CONTROL_DEV_SHELL,
 			i + MAVLINK_MSG_SERIAL_CONTROL_FIELD_DATA_LEN < strlen(str) ? SERIAL_CONTROL_FLAG_MULTI : 0, // more chunks to go
 			0, 0, strlen(data), (uint8_t *)data, 0, 0);
@@ -275,5 +344,3 @@ void sendMavlinkPrint() {
 	}
 	mavlinkPrintBuffer.clear();
 }
-
-#endif

flix/motors.ino

@@ -1,63 +1,59 @@
 // Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
 // Repository: https://github.com/okalachev/flix
 
-// Motors output control using MOSFETs
-// In case of using ESCs, change PWM_STOP, PWM_MIN and PWM_MAX to appropriate values in μs, decrease PWM_FREQUENCY (to 400)
+// PWM control for motors
 
 #include "util.h"
 
-#define MOTOR_0_PIN 12 // rear left
-#define MOTOR_1_PIN 13 // rear right
-#define MOTOR_2_PIN 14 // front right
-#define MOTOR_3_PIN 15 // front left
+float motors[4]; // normalized motor thrusts in range [0..1]
 
-#define PWM_FREQUENCY 78000
-#define PWM_RESOLUTION 10
-#define PWM_STOP 0
-#define PWM_MIN 0
-#define PWM_MAX 1000000 / PWM_FREQUENCY
+int motorPins[4] = {-1, -1, -1, -1}; // default pin numbers
+int pwmFrequency = 78000;
+int pwmResolution = 10;
+int pwmStop = 0;
+int pwmMin = 0;
+int pwmMax = -1; // -1 means duty cycle mode
 
-// Motors array indexes:
-const int MOTOR_REAR_LEFT = 0;
-const int MOTOR_REAR_RIGHT = 1;
-const int MOTOR_FRONT_RIGHT = 2;
-const int MOTOR_FRONT_LEFT = 3;
+const int MOTOR_REAR_LEFT = 0, MOTOR_REAR_RIGHT = 1, MOTOR_FRONT_RIGHT = 2, MOTOR_FRONT_LEFT = 3;
 
 void setupMotors() {
-	print("Setup Motors\n");
-
-	// configure pins
-	ledcAttach(MOTOR_0_PIN, PWM_FREQUENCY, PWM_RESOLUTION);
-	ledcAttach(MOTOR_1_PIN, PWM_FREQUENCY, PWM_RESOLUTION);
-	ledcAttach(MOTOR_2_PIN, PWM_FREQUENCY, PWM_RESOLUTION);
-	ledcAttach(MOTOR_3_PIN, PWM_FREQUENCY, PWM_RESOLUTION);
-
+	print("Setup motors\n");
+	// Configure pins
+	for (int i = 0; i < 4; i++) {
+		if (motorPins[i] < 0) continue; // skip unassigned motors
+		ledcAttach(motorPins[i], pwmFrequency, pwmResolution);
+		pwmFrequency = ledcChangeFrequency(motorPins[i], pwmFrequency, pwmResolution); // when reconfiguring
+	}
 	sendMotors();
-	print("Motors initialized\n");
+}
+
+void sendMotors() {
+	for (int i = 0; i < 4; i++) {
+		if (motorPins[i] < 0) continue; // skip unassigned motors
+		ledcWrite(motorPins[i], getDutyCycle(motors[i]));
+	}
 }
 
 int getDutyCycle(float value) {
 	value = constrain(value, 0, 1);
-	float pwm = mapf(value, 0, 1, PWM_MIN, PWM_MAX);
-	if (value == 0) pwm = PWM_STOP;
-	float duty = mapf(pwm, 0, 1000000 / PWM_FREQUENCY, 0, (1 << PWM_RESOLUTION) - 1);
-	return round(duty);
-}
 
-void sendMotors() {
-	ledcWrite(MOTOR_0_PIN, getDutyCycle(motors[0]));
-	ledcWrite(MOTOR_1_PIN, getDutyCycle(motors[1]));
-	ledcWrite(MOTOR_2_PIN, getDutyCycle(motors[2]));
-	ledcWrite(MOTOR_3_PIN, getDutyCycle(motors[3]));
+	if (pwmMax >= 0) { // pwm mode
+		float pwm = mapf(value, 0, 1, pwmMin, pwmMax);
+		if (value == 0) pwm = pwmStop;
+		float duty = mapf(pwm, 0, 1000000 / pwmFrequency, 0, (1 << pwmResolution) - 1);
+		return round(duty);
+	} else { // duty cycle mode
+		return round(value * ((1 << pwmResolution) - 1));
+	}
 }
 
 bool motorsActive() {
 	return motors[0] != 0 || motors[1] != 0 || motors[2] != 0 || motors[3] != 0;
 }
 
-void testMotor(int n) {
+void testMotor(int n, float thrust) {
 	print("Testing motor %d\n", n);
-	motors[n] = 1;
+	motors[n] = thrust;
 	delay(50); // ESP32 may need to wait until the end of the current cycle to change duty https://github.com/espressif/arduino-esp32/issues/5306
 	sendMotors();
 	pause(3);

flix/parameters.ino

@@ -5,17 +5,30 @@
 
 #include <Preferences.h>
 #include "util.h"
+#include "pid.h"
 
-extern float channelZero[16];
-extern float channelMax[16];
-extern float rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
+extern int channelZero[16], channelMax[16];
+extern int rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
+extern int rcRxPin, voltagePin;
+extern int wifiMode, wifiLongRange, udpLocalPort, udpRemotePort, espnowChannel;
+extern float rcLossTimeout, descendTime, disarmTilt;
+extern float voltageScale;
+extern LowPassFilter<float> voltageFilter;
+extern PID posX_PID, posY_PID;
 
 Preferences storage;
 
 struct Parameter {
-	const char *name; // max length is 15 (Preferences key limit)
-	float *variable;
-	float value; // cache
+	const char *name; // max length is 15
+	bool integer;
+	union { float *f; int *i; }; // pointer to the variable
+	float inital; // default value
+	float cache; // what's stored in flash
+	void (*callback)(); // called after parameter change
+	Parameter(const char *name, float *variable, void (*callback)() = nullptr) : name(name), integer(false), f(variable), callback(callback) {};
+	Parameter(const char *name, int *variable, void (*callback)() = nullptr) : name(name), integer(true), i(variable), callback(callback) {};
+	float getValue() const { return integer ? *i : *f; };
+	void setValue(const float value) { if (integer) *i = value; else *f = value; };
 };
 
 Parameter parameters[] = {
@@ -24,13 +37,16 @@ Parameter parameters[] = {
 	{"CTL_R_RATE_I", &rollRatePID.i},
 	{"CTL_R_RATE_D", &rollRatePID.d},
 	{"CTL_R_RATE_WU", &rollRatePID.windup},
+	{"CTL_R_RATE_D_A", &rollRatePID.lpf.alpha},
 	{"CTL_P_RATE_P", &pitchRatePID.p},
 	{"CTL_P_RATE_I", &pitchRatePID.i},
 	{"CTL_P_RATE_D", &pitchRatePID.d},
 	{"CTL_P_RATE_WU", &pitchRatePID.windup},
+	{"CTL_P_RATE_D_A", &pitchRatePID.lpf.alpha},
 	{"CTL_Y_RATE_P", &yawRatePID.p},
 	{"CTL_Y_RATE_I", &yawRatePID.i},
 	{"CTL_Y_RATE_D", &yawRatePID.d},
+	{"CTL_Y_RATE_D_A", &yawRatePID.lpf.alpha},
 	{"CTL_R_P", &rollPID.p},
 	{"CTL_R_I", &rollPID.i},
 	{"CTL_R_D", &rollPID.d},
@@ -42,6 +58,15 @@ Parameter parameters[] = {
 	{"CTL_R_RATE_MAX", &maxRate.x},
 	{"CTL_Y_RATE_MAX", &maxRate.z},
 	{"CTL_TILT_MAX", &tiltMax},
+	{"CTL_FLT_MODE_0", &flightModes[0]},
+	{"CTL_FLT_MODE_1", &flightModes[1]},
+	{"CTL_FLT_MODE_2", &flightModes[2]},
+	// position
+	{"POS_XY_P", &posX_PID.p, setupPosition},
+	{"POS_XY_I", &posX_PID.i, setupPosition},
+	{"POS_XY_D", &posX_PID.d, setupPosition},
+	{"POS_XY_WU", &posX_PID.windup, setupPosition},
+	{"POS_XY_D_A", &posX_PID.lpf.alpha, setupPosition},
 	// imu
 	{"IMU_ROT_ROLL", &imuRotation.x},
 	{"IMU_ROT_PITCH", &imuRotation.y},
@@ -52,10 +77,25 @@ Parameter parameters[] = {
 	{"IMU_ACC_SCALE_X", &accScale.x},
 	{"IMU_ACC_SCALE_Y", &accScale.y},
 	{"IMU_ACC_SCALE_Z", &accScale.z},
+	{"IMU_GYRO_BIAS_A", &gyroBiasFilter.alpha},
 	// estimate
 	{"EST_ACC_WEIGHT", &accWeight},
+	{"EST_LVL_WEIGHT", &levelWeight},
 	{"EST_RATES_LPF_A", &ratesFilter.alpha},
+	{"EST_RATES_NF_F", &ratesNotch.frequency, setupEstimate},
+	{"EST_RATES_NF_BW", &ratesNotch.bandwidth, setupEstimate},
+	// motors
+	{"MOT_PIN_FL", &motorPins[MOTOR_FRONT_LEFT], setupMotors},
+	{"MOT_PIN_FR", &motorPins[MOTOR_FRONT_RIGHT], setupMotors},
+	{"MOT_PIN_RL", &motorPins[MOTOR_REAR_LEFT], setupMotors},
+	{"MOT_PIN_RR", &motorPins[MOTOR_REAR_RIGHT], setupMotors},
+	{"MOT_PWM_FREQ", &pwmFrequency, setupMotors},
+	{"MOT_PWM_RES", &pwmResolution, setupMotors},
+	{"MOT_PWM_STOP", &pwmStop},
+	{"MOT_PWM_MIN", &pwmMin},
+	{"MOT_PWM_MAX", &pwmMax},
 	// rc
+	{"RC_RX_PIN", &rcRxPin, setupRC},
 	{"RC_ZERO_0", &channelZero[0]},
 	{"RC_ZERO_1", &channelZero[1]},
 	{"RC_ZERO_2", &channelZero[2]},
@@ -77,17 +117,56 @@ Parameter parameters[] = {
 	{"RC_THROTTLE", &throttleChannel},
 	{"RC_YAW", &yawChannel},
 	{"RC_MODE", &modeChannel},
+	// wifi
+	{"WIFI_MODE", &wifiMode},
+	{"WIFI_PORT_LOC", &udpLocalPort},
+	{"WIFI_PORT_REM", &udpRemotePort},
+	{"WIFI_LONG_RANGE", &wifiLongRange},
+	// espnow
+	{"ESPNOW_CHANNEL", &espnowChannel},
+	// mavlink
+	{"MAV_SYS_ID", &mavlinkSysId},
+	{"MAV_RATE_SLOW", &telemetrySlow.rate},
+	{"MAV_RATE_ATT", &telemetryAttitude.rate},
+	{"MAV_RATE_RC", &telemetryRC.rate},
+	{"MAV_RATE_MOT", &telemetryMotors.rate},
+	{"MAV_RATE_IMU", &telemetryIMU.rate},
+	{"MAV_RATE_TOPIC", &telemetryTopic.rate},
+	// log
+	{"LOG_MEMORY", &logMemory, setupLog},
+	{"LOG_USAGE", &logUsage, setupLog},
+	{"LOG_RATE_000", &logTopics[0].throttle},
+	{"LOG_RATE_001", &logTopics[1].throttle},
+	{"LOG_RATE_002", &logTopics[2].throttle},
+	{"LOG_RATE_003", &logTopics[3].throttle},
+	{"LOG_RATE_004", &logTopics[4].throttle},
+	{"LOG_RATE_005", &logTopics[5].throttle},
+	{"LOG_RATE_006", &logTopics[6].throttle},
+	{"LOG_RATE_007", &logTopics[7].throttle},
+	{"LOG_RATE_008", &logTopics[8].throttle},
+	{"LOG_RATE_009", &logTopics[9].throttle},
+	{"LOG_RATE_010", &logTopics[10].throttle},
+	{"LOG_RATE_011", &logTopics[11].throttle},
+	// power
+	{"PWR_VOLT_PIN", &voltagePin, setupPower},
+	{"PWR_VOLT_SCALE", &voltageScale},
+	{"PWR_VOLT_LPF_A", &voltageFilter.alpha},
+	// safety
+	{"SF_RC_LOSS_TIME", &rcLossTimeout},
+	{"SF_DESCEND_TIME", &descendTime},
+	{"SF_DISARM_TILT", &disarmTilt}
 };
 
 void setupParameters() {
-	storage.begin("flix", false);
+	print("Setup parameters\n");
+	storage.begin("flix");
 	// Read parameters from storage
 	for (auto &parameter : parameters) {
-		if (!storage.isKey(parameter.name)) {
-			storage.putFloat(parameter.name, *parameter.variable);
+		parameter.inital = parameter.getValue();
+		if (storage.isKey(parameter.name)) {
+			parameter.setValue(storage.getFloat(parameter.name));
 		}
-		*parameter.variable = storage.getFloat(parameter.name, *parameter.variable);
-		parameter.value = *parameter.variable;
+		parameter.cache = parameter.getValue();
 	}
 }
 
@@ -102,13 +181,13 @@ const char *getParameterName(int index) {
 
 float getParameter(int index) {
 	if (index < 0 || index >= parametersCount()) return NAN;
-	return *parameters[index].variable;
+	return parameters[index].getValue();
 }
 
 float getParameter(const char *name) {
 	for (auto &parameter : parameters) {
-		if (strcmp(parameter.name, name) == 0) {
-			return *parameter.variable;
+		if (strcasecmp(parameter.name, name) == 0) {
+			return parameter.getValue();
 		}
 	}
 	return NAN;
@@ -116,8 +195,10 @@ float getParameter(const char *name) {
 
 bool setParameter(const char *name, const float value) {
 	for (auto &parameter : parameters) {
-		if (strcmp(parameter.name, name) == 0) {
-			*parameter.variable = value;
+		if (strcasecmp(parameter.name, name) == 0) {
+			if (parameter.integer && !isfinite(value)) return false; // can't set integer to NaN or Inf
+			parameter.setValue(value);
+			if (parameter.callback) parameter.callback();
 			return true;
 		}
 	}
@@ -130,16 +211,23 @@ void syncParameters() {
 	if (motorsActive()) return; // don't use flash while flying, it may cause a delay
 
 	for (auto &parameter : parameters) {
-		if (parameter.value == *parameter.variable) continue;
-		if (isnan(parameter.value) && isnan(*parameter.variable)) continue; // handle NAN != NAN
-		storage.putFloat(parameter.name, *parameter.variable);
-		parameter.value = *parameter.variable;
+		if (floatEquals(parameter.getValue(), parameter.cache)) continue; // no change
+
+		storage.putFloat(parameter.name, parameter.getValue());
+		parameter.cache = parameter.getValue(); // update cache
 	}
 }
 
-void printParameters() {
+void printParameters(const char *filter) {
+	print("Name             Value          [Default]\n");
 	for (auto &parameter : parameters) {
-		print("%s = %g\n", parameter.name, *parameter.variable);
+		if (strncasecmp(parameter.name, filter, strlen(filter))) continue;
+
+		if (floatEquals(parameter.getValue(), parameter.inital)) { // parameter changed
+			print("%-15s  %-13g\n", parameter.name, parameter.getValue());
+		} else {
+			print("%-15s  %-13g  [%g]\n", parameter.name, parameter.getValue(), parameter.inital);
+		}
 	}
 }
 

flix/pid.h

@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "lpf.h"
+#include "filter.h"
 
 class PID {
 public:

flix/position.ino

@@ -0,0 +1,95 @@
+#include "vector.h"
+#include "quaternion.h"
+#include "pid.h"
+#include "util.h"
+
+float mass = 0.065;
+float motorThrust = 0.031 * ONE_G;
+float positionWeight = 0.9;
+float velocityWeight = 0.9;
+
+PID velX_PID(1.0, 0.0, 0.02);
+PID velY_PID(1.0, 0.0, 0.02);
+PID velZ_PID(1.0, 0.0, 0.02);
+
+// PID posX_PID(1.0, 0.0, 0.0);
+// PID posY_PID(1.0, 0.0, 0.0);
+// PID posZ_PID(1.0, 0.0, 0.0);
+
+PID posX_PID(0.1, 0.0, 0.0);
+PID posY_PID(0.1, 0.0, 0.0);
+PID posZ_PID(0.1, 0.0, 0.0);
+
+Vector acceleration;
+Vector velocity;
+Vector position;
+Vector velocityTarget(NAN, NAN, NAN);
+Vector positionTarget(NAN, NAN, NAN);
+
+extern Quaternion attitudeTarget;
+extern float thrustTarget;
+
+void setupPosition() {
+	// TODO: posY_PID = posX_PID;
+	// posX_PID.copy(posY_PID);
+	posY_PID.p = posX_PID.p;
+	posY_PID.i = posX_PID.i;
+	posY_PID.d = posX_PID.d;
+}
+
+void estimatePosition() {
+	acceleration = Quaternion::rotateVector(acceleration, attitude) + Vector(0, 0, -ONE_G);
+	velocity += acceleration * dt;
+	position += velocity * dt;
+}
+
+void correctPosition(Vector& pos) {
+	// position += (pos - position) * positionWeight;
+	position = pos;
+	// positionUpdated = true;
+
+	if (invalid(positionTarget.x) || invalid(positionTarget.y)) return;
+
+	attitudeTarget.setPitch(posX_PID.update(positionTarget.x - position.x));
+	attitudeTarget.setRoll(posY_PID.update(positionTarget.y - position.y));
+}
+
+void correctVelocity(Vector& vel) {
+	velocity += (vel - velocity) * velocityWeight;
+}
+
+void controlVelocity() {
+	Vector accelerationTarget(
+		velX_PID.update(velocityTarget.x - velocity.x),
+		velY_PID.update(velocityTarget.y - velocity.y),
+		velZ_PID.update(velocityTarget.z - velocity.z)
+	);
+
+	Vector thrustVector = (accelerationTarget + Vector(0, 0, ONE_G)) * mass;
+
+	const Vector up(0, 0, 1);
+
+	attitudeTarget = Quaternion::fromBetweenVectors(up, thrustVector);
+	float maxThrust = motorThrust * 4; // 4 motors
+	thrustTarget = thrustVector.norm() / maxThrust;
+}
+
+void controlPosition() {
+	if (positionTarget.invalid()) return;
+
+	velocityTarget = Vector(
+		posX_PID.update(positionTarget.x - position.x),
+		posY_PID.update(positionTarget.y - position.y),
+		posZ_PID.update(positionTarget.z - position.z)
+	);
+
+	controlVelocity();
+}
+
+void controlPositionSimple() {
+	if (positionTarget.invalid()) return;
+
+	// straight attitude target control
+	attitudeTarget.setPitch(posX_PID.update(positionTarget.x - position.x));
+	attitudeTarget.setRoll(posY_PID.update(positionTarget.y - position.y));
+}

flix/power.ino

@@ -0,0 +1,29 @@
+// Copyright (c) 2026 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// Power management
+
+#include <soc/soc.h>
+#include <soc/rtc_cntl_reg.h>
+#include "filter.h"
+#include "util.h"
+
+float voltage = NAN;
+LowPassFilter<float> voltageFilter(1);
+int voltagePin = -1;
+float voltageScale = 2;
+
+void setupPower() {
+	REG_CLR_BIT(RTC_CNTL_BROWN_OUT_REG, RTC_CNTL_BROWN_OUT_ENA); // disable reset on low voltage
+	if (digitalPinToAnalogChannel(voltagePin) == -1) voltagePin = -1; // test ADC pin
+}
+
+void readVoltage() {
+	if (voltagePin < 0) return;
+
+	static Rate rate(10);
+	if (!rate) return;
+
+	float v = analogReadMilliVolts(voltagePin) * voltageScale / 1000.0f;
+	voltage = voltageFilter.update(v);
+}

flix/rc.ino

@@ -6,30 +6,33 @@
 #include <SBUS.h>
 #include "util.h"
 
-SBUS rc(Serial2); // NOTE: Use RC(Serial2, 16, 17) if you use the old UART2 pins
+SBUS rc(Serial1);
+int rcRxPin = -1; // -1 means disabled
 
 uint16_t channels[16]; // raw rc channels
-float controlTime; // time of the last controls update
-float channelZero[16]; // calibration zero values
-float channelMax[16]; // calibration max values
+int channelZero[16]; // calibration zero values
+int channelMax[16]; // calibration max values
 
-// Channels mapping (using float to store in parameters):
-float rollChannel = NAN, pitchChannel = NAN, throttleChannel = NAN, yawChannel = NAN, modeChannel = NAN;
+float controlRoll, controlPitch, controlYaw, controlThrottle; // pilot's inputs, range [-1, 1]
+float controlMode = NAN;
+float controlTime = NAN; // time of the last controls update
+
+int rollChannel = -1, pitchChannel = -1, throttleChannel = -1, yawChannel = -1, modeChannel = -1; // channel mapping
 
 void setupRC() {
+	if (rcRxPin < 0) return;
 	print("Setup RC\n");
-	rc.begin();
+	rc.begin(rcRxPin);
 }
 
 bool readRC() {
-	if (rc.read()) {
-		SBUSData data = rc.data();
-		for (int i = 0; i < 16; i++) channels[i] = data.ch[i]; // copy channels data
-		normalizeRC();
-		controlTime = t;
-		return true;
-	}
-	return false;
+	if (rcRxPin < 0) return false;
+	if (!rc.read()) return false;
+
+	rc.getChannels(channels);
+	normalizeRC();
+	controlTime = t;
+	return true;
 }
 
 void normalizeRC() {
@@ -38,30 +41,35 @@ void normalizeRC() {
 		controls[i] = mapf(channels[i], channelZero[i], channelMax[i], 0, 1);
 	}
 	// Update control values
-	controlRoll = rollChannel >= 0 ? controls[(int)rollChannel] : NAN;
-	controlPitch = pitchChannel >= 0 ? controls[(int)pitchChannel] : NAN;
-	controlYaw = yawChannel >= 0 ? controls[(int)yawChannel] : NAN;
-	controlThrottle = throttleChannel >= 0 ? controls[(int)throttleChannel] : NAN;
-	controlMode = modeChannel >= 0 ? controls[(int)modeChannel] : NAN;
+	controlRoll = rollChannel < 0 ? 0 : controls[rollChannel];
+	controlPitch = pitchChannel < 0 ? 0 : controls[pitchChannel];
+	controlYaw = yawChannel < 0 ? 0 : controls[yawChannel];
+	controlThrottle = throttleChannel < 0 ? 0 : controls[throttleChannel];
+	controlMode = modeChannel < 0 ? NAN : controls[modeChannel]; // mode control is ineffective if not mapped
 }
 
 void calibrateRC() {
-	uint16_t zero[16];
-	uint16_t center[16];
-	uint16_t max[16];
+	if (rcRxPin < 0) {
+		print("RC_RX_PIN = %d, set the RC pin!\n", rcRxPin);
+		return;
+	}
+
+	uint16_t zero[16]; // for zero positions
+	uint16_t center[16]; // for center positions
+	uint16_t _[16]; // for unused data
 	print("1/8 Calibrating RC: put all switches to default positions [3 sec]\n");
 	pause(3);
-	calibrateRCChannel(NULL, zero, zero, "2/8 Move sticks [3 sec]\n...     ...\n...     .o.\n.o.     ...\n");
-	calibrateRCChannel(NULL, center, center, "3/8 Move sticks [3 sec]\n...     ...\n.o.     .o.\n...     ...\n");
-	calibrateRCChannel(&throttleChannel, zero, max, "4/8 Move sticks [3 sec]\n.o.     ...\n...     .o.\n...     ...\n");
-	calibrateRCChannel(&yawChannel, center, max, "5/8 Move sticks [3 sec]\n...     ...\n..o     .o.\n...     ...\n");
-	calibrateRCChannel(&pitchChannel, zero, max, "6/8 Move sticks [3 sec]\n...     .o.\n...     ...\n.o.     ...\n");
-	calibrateRCChannel(&rollChannel, zero, max, "7/8 Move sticks [3 sec]\n...     ...\n...     ..o\n.o.     ...\n");
-	calibrateRCChannel(&modeChannel, zero, max, "8/8 Put mode switch to max [3 sec]\n");
+	calibrateRCChannel(NULL, _, zero, "2/8 Move sticks [3 sec]\n...     ...\n...     .o.\n.o.     ...\n");
+	calibrateRCChannel(&throttleChannel, zero, _, "3/8 Move sticks [3 sec]\n.o.     ...\n...     .o.\n...     ...\n");
+	calibrateRCChannel(NULL, _, center, "4/8 Move sticks [3 sec]\n...     ...\n.o.     .o.\n...     ...\n");
+	calibrateRCChannel(&yawChannel, center, _, "5/8 Move sticks [3 sec]\n...     ...\n..o     .o.\n...     ...\n");
+	calibrateRCChannel(&pitchChannel, zero, _, "6/8 Move sticks [3 sec]\n...     .o.\n...     ...\n.o.     ...\n");
+	calibrateRCChannel(&rollChannel, zero, _, "7/8 Move sticks [3 sec]\n...     ...\n...     ..o\n.o.     ...\n");
+	calibrateRCChannel(&modeChannel, zero, _, "8/8 Put mode switch to max [3 sec]\n");
 	printRCCalibration();
 }
 
-void calibrateRCChannel(float *channel, uint16_t in[16], uint16_t out[16], const char *str) {
+void calibrateRCChannel(int *channel, uint16_t in[16], uint16_t out[16], const char *str) {
 	print("%s", str);
 	pause(3);
 	for (int i = 0; i < 30; i++) readRC(); // try update 30 times max
@@ -82,15 +90,15 @@ void calibrateRCChannel(float *channel, uint16_t in[16], uint16_t out[16], const
 		channelZero[ch] = in[ch];
 		channelMax[ch] = out[ch];
 	} else {
-		*channel = NAN;
+		*channel = -1;
 	}
 }
 
 void printRCCalibration() {
 	print("Control   Ch     Zero   Max\n");
-	print("Roll      %-7g%-7g%-7g\n", rollChannel, rollChannel >= 0 ? channelZero[(int)rollChannel] : NAN, rollChannel >= 0 ? channelMax[(int)rollChannel] : NAN);
-	print("Pitch     %-7g%-7g%-7g\n", pitchChannel, pitchChannel >= 0 ? channelZero[(int)pitchChannel] : NAN, pitchChannel >= 0 ? channelMax[(int)pitchChannel] : NAN);
-	print("Yaw       %-7g%-7g%-7g\n", yawChannel, yawChannel >= 0 ? channelZero[(int)yawChannel] : NAN, yawChannel >= 0 ? channelMax[(int)yawChannel] : NAN);
-	print("Throttle  %-7g%-7g%-7g\n", throttleChannel, throttleChannel >= 0 ? channelZero[(int)throttleChannel] : NAN, throttleChannel >= 0 ? channelMax[(int)throttleChannel] : NAN);
-	print("Mode      %-7g%-7g%-7g\n", modeChannel, modeChannel >= 0 ? channelZero[(int)modeChannel] : NAN, modeChannel >= 0 ? channelMax[(int)modeChannel] : NAN);
+	print("Roll      %-7d%-7d%-7d\n", rollChannel, rollChannel < 0 ? 0 : channelZero[rollChannel], rollChannel < 0 ? 0 : channelMax[rollChannel]);
+	print("Pitch     %-7d%-7d%-7d\n", pitchChannel, pitchChannel < 0 ? 0 : channelZero[pitchChannel], pitchChannel < 0 ? 0 : channelMax[pitchChannel]);
+	print("Yaw       %-7d%-7d%-7d\n", yawChannel, yawChannel < 0 ? 0 : channelZero[yawChannel], yawChannel < 0 ? 0 : channelMax[yawChannel]);
+	print("Throttle  %-7d%-7d%-7d\n", throttleChannel, throttleChannel < 0 ? 0 : channelZero[throttleChannel], throttleChannel < 0 ? 0 : channelMax[throttleChannel]);
+	print("Mode      %-7d%-7d%-7d\n", modeChannel, modeChannel < 0 ? 0 : channelZero[modeChannel], modeChannel < 0 ? 0 : channelMax[modeChannel]);
 }

flix/safety.ino

@@ -3,22 +3,23 @@
 
 // Fail-safe functions
 
-#define RC_LOSS_TIMEOUT 1
-#define DESCEND_TIME 10
-
 extern float controlTime;
 extern float controlRoll, controlPitch, controlThrottle, controlYaw;
 
+float rcLossTimeout = 1;
+float descendTime = 10;
+float disarmTilt = radians(120);
+
 void failsafe() {
 	rcLossFailsafe();
 	autoFailsafe();
+	tiltFailsafe();
 }
 
 // RC loss failsafe
 void rcLossFailsafe() {
-	if (controlTime == 0) return; // no RC at all
 	if (!armed) return;
-	if (t - controlTime > RC_LOSS_TIMEOUT) {
+	if (t - controlTime > rcLossTimeout) {
 		descend();
 	}
 }
@@ -27,7 +28,7 @@ void rcLossFailsafe() {
 void descend() {
 	mode = AUTO;
 	attitudeTarget = Quaternion();
-	thrustTarget -= dt / DESCEND_TIME;
+	thrustTarget -= dt / descendTime;
 	if (thrustTarget < 0) {
 		thrustTarget = 0;
 		armed = false;
@@ -37,12 +38,24 @@ void descend() {
 // Allow pilot to interrupt automatic flight
 void autoFailsafe() {
 	static float roll, pitch, yaw, throttle;
-	if (roll != controlRoll || pitch != controlPitch || yaw != controlYaw || abs(throttle - controlThrottle) > 0.05) {
-		// controls changed
-		if (mode == AUTO) mode = STAB; // regain control by the pilot
+	if (abs(roll - controlRoll) > 0.05 || abs(pitch - controlPitch) > 0.05 || abs(yaw - controlYaw) > 0.05 || abs(throttle - controlThrottle) > 0.05) {
+		// controls changed and mode switch is not configured
+		if (mode == AUTO && invalid(controlMode)) mode = STAB; // regain control by the pilot
 	}
 	roll = controlRoll;
 	pitch = controlPitch;
 	yaw = controlYaw;
 	throttle = controlThrottle;
 }
+
+// Disarm if tilted too much
+void tiltFailsafe() {
+	if (!armed) return;
+	if (mode != STAB) return;
+
+	Vector up = Quaternion::rotateVector(Vector(0, 0, 1), attitude);
+	float tilt = acos(up.z);
+	if (disarmTilt && tilt > disarmTilt) {
+		armed = false;
+	}
+}

flix/time.ino

@@ -3,6 +3,8 @@
 
 // Time related functions
 
+float t = NAN; // current time, s
+float dt; // time delta with the previous step, s
 float loopRate; // Hz
 
 void step() {

flix/util.h

@@ -6,8 +6,7 @@
 #pragma once
 
 #include <math.h>
-#include <soc/soc.h>
-#include <soc/rtc_cntl_reg.h>
+#include <ESP32_NOW_Serial.h>
 
 const float ONE_G = 9.80665;
 extern float t;
@@ -24,6 +23,12 @@ bool valid(float x) {
 	return isfinite(x);
 }
 
+bool floatEquals(float a, float b, float epsilon = 0) {
+	if (isnan(a) && isnan(b)) return true;
+	if (a == b) return true;
+	return fabsf(a - b) <= epsilon;
+}
+
 // Wrap angle to [-PI, PI)
 float wrapAngle(float angle) {
 	angle = fmodf(angle, 2 * PI);
@@ -35,21 +40,73 @@ float wrapAngle(float angle) {
 	return angle;
 }
 
-// Disable reset on low voltage
-void disableBrownOut() {
-	REG_CLR_BIT(RTC_CNTL_BROWN_OUT_REG, RTC_CNTL_BROWN_OUT_ENA);
-}
-
 // Trim and split string by spaces
 void splitString(String& str, String& token0, String& token1, String& token2) {
 	str.trim();
+	if (str.isEmpty()) return;
 	char chars[str.length() + 1];
 	str.toCharArray(chars, str.length() + 1);
 	token0 = strtok(chars, " ");
-	token1 = strtok(NULL, " "); // String(NULL) creates empty string
+	token1 = strtok(NULL, " ");
 	token2 = strtok(NULL, "");
+	if (token1.c_str() == NULL) token1 = "";
+	if (token2.c_str() == NULL) token2 = "";
 }
 
+// Simplified ESP-NOW Serial without resends
+class ESPNOWSerial : public ESP_NOW_Serial_Class {
+public:
+	int lost = 0;
+	using ESP_NOW_Serial_Class::ESP_NOW_Serial_Class;
+	void onSent(bool success) override {
+		if (!success) lost++;
+		ESP_NOW_Serial_Class::onSent(true); // always report success to avoid resends
+	}
+};
+
+// Simple variant type for logging and parameters
+struct Value {
+	enum { EMPTY, FLOAT, INT, BOOL, FLOAT_FN, INT_FN, BOOL_FN } type;
+	union {
+		void *pointer;
+		float *_float;
+		int *_int;
+		bool *_bool;
+		float (*floatFn)();
+		int (*intFn)();
+		bool (*boolFn)();
+	};
+
+	Value() : type(EMPTY), pointer(nullptr) {};
+	Value(float *pt) : type(FLOAT), _float(pt) {};
+	Value(int *pt) : type(INT), _int(pt) {};
+	Value(bool *pt) : type(BOOL), _bool(pt) {};
+	Value(float (*fn)()) : type(FLOAT_FN), floatFn(fn) {};
+	Value(int (*fn)()) : type(INT_FN), intFn(fn) {};
+	Value(bool (*fn)()) : type(BOOL_FN), boolFn(fn) {};
+
+	float get() const {
+		switch (type) {
+			case FLOAT: return *_float;
+			case INT: return *_int;
+			case BOOL: return *_bool ? 1 : 0;
+			case FLOAT_FN: return floatFn();
+			case INT_FN: return intFn();
+			case BOOL_FN: return boolFn() ? 1 : 0;
+			default: return NAN;
+		}
+	};
+
+	void set(float value) const {
+		switch (type) {
+			case FLOAT: *_float = value; break;
+			case INT: *_int = value; break;
+			case BOOL: *_bool = (value != 0); break;
+			default: break;
+		}
+	};
+};
+
 // Rate limiter
 class Rate {
 public:
@@ -58,6 +115,9 @@ public:
 	Rate(float rate) : rate(rate) {}
 
 	operator bool() {
+		if (t == last) {
+			return true; // the same step
+		}
 		if (t - last >= 1 / rate) {
 			last = t;
 			return true;

flix/vector.h

@@ -35,7 +35,6 @@ public:
 		z = NAN;
 	}
 
-
 	float norm() const {
 		return sqrt(x * x + y * y + z * z);
 	}
@@ -106,10 +105,23 @@ public:
 	}
 
 	static Vector rotationVectorBetween(const Vector& a, const Vector& b) {
+		float an = a.norm();
+		float bn = b.norm();
+		if (an < 1e-6 || bn < 1e-6) {
+			return Vector(0, 0, 0);
+		}
 		Vector direction = cross(a, b);
-		if (direction.zero()) {
-			// vectors are opposite, return any perpendicular vector
-			return cross(a, Vector(1, 0, 0));
+		if (direction.norm() < 1e-6) { // vectors are parallel
+			if (dot(a, b) > 0) { // same direction
+				return Vector(0, 0, 0);
+			}
+			// opposite direction
+			Vector perp = cross(a, Vector(1, 0, 0));
+			if (perp.norm() < 1e-6) {
+				perp = cross(a, Vector(0, 1, 0));
+			}
+			perp.normalize();
+			return perp * PI;
 		}
 		direction.normalize();
 		float angle = angleBetween(a, b);

flix/wifi.ino

@@ -1,49 +1,152 @@
 // Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
 // Repository: https://github.com/okalachev/flix
 
-// Wi-Fi support
-
-#if WIFI_ENABLED
+// Wi-Fi and ESP-NOW communication
 
 #include <WiFi.h>
 #include <WiFiAP.h>
 #include <WiFiUdp.h>
+#include <MacAddress.h>
+#include <ESP32_NOW_Serial.h>
+#include <Preferences.h>
+#include "util.h"
 
-#define WIFI_SSID "flix"
-#define WIFI_PASSWORD "flixwifi"
-#define WIFI_UDP_PORT 14550
-#define WIFI_UDP_REMOTE_PORT 14550
-#define WIFI_UDP_REMOTE_ADDR "255.255.255.255"
+extern Preferences storage; // use the main preferences storage
 
+const int W_DISABLED = 0, W_AP = 1, W_STA = 2, W_ESPNOW = 3;
+int wifiMode = W_AP;
+
+int wifiLongRange = 0;
+int udpLocalPort = 14550;
+int udpRemotePort = 14550;
+IPAddress udpRemoteIP = "255.255.255.255";
 WiFiUDP udp;
 
+ESPNOWSerial espnow(NULL, 0, WIFI_IF_AP);
+ESPNOWSerial espnowBroadcast(ESP_NOW.BROADCAST_ADDR, 0, WIFI_IF_AP);
+int espnowChannel = 6;
+
 void setupWiFi() {
 	print("Setup Wi-Fi\n");
-	WiFi.softAP(WIFI_SSID, WIFI_PASSWORD);
-	udp.begin(WIFI_UDP_PORT);
+	WiFi.enableLongRange(wifiLongRange);
+
+	if (wifiMode == W_AP) {
+		WiFi.softAP(storage.getString("WIFI_AP_SSID", "flix").c_str(), storage.getString("WIFI_AP_PASS", "flixwifi").c_str());
+		udp.begin(udpLocalPort);
+	}
+
+	if (wifiMode == W_STA) {
+		WiFi.begin(storage.getString("WIFI_STA_SSID", "").c_str(), storage.getString("WIFI_STA_PASS", "").c_str());
+		udp.begin(udpLocalPort);
+	}
+
+	if (wifiMode == W_ESPNOW) {
+		WiFi.mode(WIFI_AP);
+		WiFi.setChannel(espnowChannel);
+		espnow.addr(MacAddress(storage.getString("ESPNOW_PEER_MAC", "FF:FF:FF:FF:FF:FF").c_str()));
+		String key = storage.getString("ESPNOW_PEER_KEY", "");
+		espnow.setKey(key.isEmpty() ? nullptr : (const uint8_t *)key.c_str());
+		espnow.begin();
+		espnowBroadcast.begin();
+	}
+
+	WiFi.setSleep(false); // disable power save
 }
 
 void sendWiFi(const uint8_t *buf, int len) {
-	if (WiFi.softAPIP() == IPAddress(0, 0, 0, 0) && WiFi.status() != WL_CONNECTED) return;
-	udp.beginPacket(udp.remoteIP() ? udp.remoteIP() : WIFI_UDP_REMOTE_ADDR, WIFI_UDP_REMOTE_PORT);
+	if (espnow) {
+		espnow.write(buf, len);
+
+		static Rate discovery(2);
+		if (espnow.isEncrypted() && discovery) espnowBroadcast.write((const uint8_t *)"flix", 4); // broadcast message to help finding this device
+		return;
+	}
+
+	if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return;
+
+	udp.beginPacket(udpRemoteIP, udpRemotePort);
 	udp.write(buf, len);
 	udp.endPacket();
 }
 
 int receiveWiFi(uint8_t *buf, int len) {
+	if (espnow) {
+		return espnow.read(buf, len);
+	}
+
+	if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return 0;
+
 	udp.parsePacket();
+	if (udp.remoteIP()) udpRemoteIP = udp.remoteIP();
 	return udp.read(buf, len);
 }
 
 void printWiFiInfo() {
-	print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
-	print("SSID: %s\n", WiFi.softAPSSID().c_str());
-	print("Password: %s\n", WIFI_PASSWORD);
-	print("Clients: %d\n", WiFi.softAPgetStationNum());
-	print("Status: %d\n", WiFi.status());
-	print("IP: %s\n", WiFi.softAPIP().toString().c_str());
-	print("Remote IP: %s\n", udp.remoteIP().toString().c_str());
+	if (espnow) {
+		print("Mode: ESP-NOW\n");
+		print("ESP-NOW version: %d\n", ESP_NOW.getVersion());
+		print("Max packet size: %d\n", ESP_NOW.getMaxDataLen());
+		print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
+		print("Peer MAC: %s\n", MacAddress(espnow.addr()).toString().c_str());
+		print("Encrypted: %d\n", espnow.isEncrypted());
+		print("Channel: %d\n", WiFi.channel());
+		print("Lost packets: %d\n", espnow.lost);
+	} else if (WiFi.getMode() == WIFI_MODE_AP) {
+		print("Mode: Access Point (AP)\n");
+		print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
+		print("SSID: %s\n", WiFi.softAPSSID().c_str());
+		print("Password: ***\n");
+		print("Channel: %d\n", WiFi.channel());
+		print("Clients: %d\n", WiFi.softAPgetStationNum());
+		print("IP: %s\n", WiFi.softAPIP().toString().c_str());
+		print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
+	} else if (WiFi.getMode() == WIFI_MODE_STA) {
+		print("Mode: Client (STA)\n");
+		print("Connected: %d\n", WiFi.isConnected());
+		print("MAC: %s\n", WiFi.macAddress().c_str());
+		print("SSID: %s\n", WiFi.SSID().c_str());
+		print("Password: ***\n");
+		print("Channel: %d\n", WiFi.channel());
+		print("RSSI: %d dBm\n", WiFi.RSSI());
+		print("IP: %s\n", WiFi.localIP().toString().c_str());
+		print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
+	} else {
+		print("Mode: Disabled\n");
+	}
 	print("MAVLink connected: %d\n", mavlinkConnected);
 }
 
-#endif
+void configWiFi(int mode, const char *first, const char *second) {
+	MacAddress mac;
+	if (mode == W_AP && strlen(first) > 0 && strlen(second) >= 8) {
+		storage.putString("WIFI_AP_SSID", first);
+		storage.putString("WIFI_AP_PASS", second);
+	} else if (mode == W_STA && strlen(first) > 0 && strlen(second) >= 8) {
+		storage.putString("WIFI_STA_SSID", first);
+		storage.putString("WIFI_STA_PASS", second);
+	} else if (mode == W_ESPNOW && mac.fromString(first)) {
+		storage.putString("ESPNOW_PEER_MAC", first);
+		storage.putString("ESPNOW_PEER_KEY", strlen(second) == ESP_NOW_KEY_LEN ? second : "");
+	} else {
+		print("Invalid configuration\n");
+		return;
+	}
+	print("✓ Reboot to apply new settings\n");
+}
+
+void setWiFiMode(const String& mode) {
+	if (mode == "ap") {
+		wifiMode = W_AP;
+	} else if (mode == "sta") {
+		wifiMode = W_STA;
+	} else if (mode == "espnow") {
+		wifiMode = W_ESPNOW;
+	} else if (mode == "off") {
+		wifiMode = W_DISABLED;
+	} else {
+		print("Invalid Wi-Fi mode\n");
+		return;
+	}
+	static const char *modes[] = {"Disabled", "Access Point (AP)", "Client (STA)", "ESP-NOW"};
+	print("✓ Wi-Fi mode set to %s, reboot to apply\n", modes[wifiMode]);
+}

gazebo/Arduino.h

@@ -20,7 +20,13 @@
 #define radians(deg) ((deg)*DEG_TO_RAD)
 #define degrees(rad) ((rad)*RAD_TO_DEG)
 
+#define MALLOC_CAP_SPIRAM (1<<10)
+#define MALLOC_CAP_8BIT (1<<2)
+#define ESP_NOW_MAX_DATA_LEN_V2 1470
+
 #define constrain(amt,low,high) ((amt)<(low)?(low):((amt)>(high)?(high):(amt)))
+template<typename T> T max(T a, T b) { return a > b ? a : b; }
+template<typename T> T min(T a, T b) { return a < b ? a : b; }
 
 long map(long x, long in_min, long in_max, long out_min, long out_max) {
 	const long run = in_max - in_min;
@@ -149,11 +155,13 @@ public:
 	void setRxInvert(bool invert) {};
 };
 
-HardwareSerial Serial, Serial2;
+HardwareSerial Serial, Serial1, Serial2;
 
 class EspClass {
 public:
 	void restart() { Serial.println("Ignore reboot in simulation"); }
+	uint32_t getFreeHeap() { return 300 * 1024; } // assume 300 KB free heap
+	uint32_t getFreePsram() { return 8 * 1024 * 1024; } // assume 8 MB free PSRAM
 } ESP;
 
 unsigned long __delayTime = 0;
@@ -163,8 +171,16 @@ void delay(uint32_t ms) {
 	__delayTime += ms * 1000;
 }
 
+void *heap_caps_calloc(size_t n, size_t size, uint32_t caps) {
+	return calloc(n, size);
+}
+
 bool ledcAttach(uint8_t pin, uint32_t freq, uint8_t resolution) { return true; }
 bool ledcWrite(uint8_t pin, uint32_t duty) { return true; }
+uint32_t ledcChangeFrequency(uint8_t pin, uint32_t freq, uint8_t resolution) { return freq; }
+int8_t digitalPinToAnalogChannel(uint8_t pin) { return -1; }
+uint32_t analogReadMilliVolts(uint8_t pin) { return 0; }
+float temperatureRead() { return 0; }
 
 unsigned long __micros;
 unsigned long __resetTime = 0;

gazebo/ESP32_NOW_Serial.h

@@ -0,0 +1,12 @@
+// Dummy file for the simulator
+
+class ESP_NOW_Peer {
+protected:
+	size_t send(const uint8_t *data, int len) { return 0; }
+};
+
+class ESP_NOW_Serial_Class : public ESP_NOW_Peer {
+public:
+	virtual void onSent(bool success) {};
+	virtual size_t write(const uint8_t *data, size_t len) { return 0; };
+};

gazebo/SBUS.h

@@ -13,14 +13,13 @@ class SBUS {
 public:
 	SBUS(HardwareSerial& bus, const bool inv = true) {};
 	SBUS(HardwareSerial& bus, const int8_t rxpin, const int8_t txpin, const bool inv = true) {};
-	void begin() {};
+	void begin(int rxpin = -1, int txpin = -1, bool inv = true, bool fast = false) {};
 	bool read() { return joystickInit(); };
-	SBUSData data() {
-		SBUSData data;
-		joystickGet(data.ch);
+	void getChannels(uint16_t (&channels)[16]) const {
+		int16_t ch[16];
+		joystickGet(ch);
 		for (int i = 0; i < 16; i++) {
-			data.ch[i] = map(data.ch[i], -32768, 32767, 1000, 2000); // convert to pulse width style
+			channels[i] = map(ch[i], -32768, 32767, 1000, 2000); // convert to pulse width style
 		}
-		return data;
 	};
 };

gazebo/flix.h

@@ -9,45 +9,56 @@
 #include "quaternion.h"
 #include "Arduino.h"
 #include "wifi.h"
+#include "filter.h"
 
-#define WIFI_ENABLED 1
+extern float t, dt;
+extern float controlRoll, controlPitch, controlYaw, controlThrottle, controlMode;
+extern Vector rates;
+extern Quaternion attitude;
+extern bool landed;
+extern float motors[4];
 
-float t = NAN;
-float dt;
-float motors[4];
-float controlRoll, controlPitch, controlYaw, controlThrottle = NAN;
-float controlMode = NAN;
-Vector acc;
-Vector gyro;
-Vector rates;
-Quaternion attitude;
-bool landed;
-Vector imuRotation;
+Vector gyro, acc, imuRotation;
+Vector accBias, gyroBias, accScale(1, 1, 1);
+LowPassFilter<Vector> gyroBiasFilter(0);
 
 // declarations
 void step();
 void computeLoopRate();
 void applyGyro();
 void applyAcc();
+void applyLevel();
 void control();
 void interpretControls();
 void controlAttitude();
 void controlRates();
 void controlTorque();
+void desaturate(float& a, float& b, float& c, float& d);
 const char* getModeName();
 void sendMotors();
+int getDutyCycle(float value);
 bool motorsActive();
-void testMotor(int n);
+void testMotor(int, float);
 void print(const char* format, ...);
 void pause(float duration);
 void doCommand(String str, bool echo);
 void handleInput();
+void setupRC();
 void normalizeRC();
 void calibrateRC();
-void calibrateRCChannel(float *channel, uint16_t zero[16], uint16_t max[16], const char *str);
+void calibrateRCChannel(int*, uint16_t[16], uint16_t[16], const char*);
 void printRCCalibration();
+void loopLog();
+void resetLog();
+void writeLog(const void *data, size_t size);
+void readLog(void *data, size_t position, size_t size);
+bool isTopicUpdated(const uint8_t topic);
+void printLogInfo();
+int estimateLogDuration();
 void printLogHeader();
-void printLogData();
+void printLogValues(const char *filter);
+void configLogThrottle(const char *name, float throttle);
+void exposeLogValue(const char *name);
 void processMavlink();
 void sendMavlink();
 void sendMessage(const void *msg);
@@ -56,24 +67,30 @@ void handleMavlink(const void *_msg);
 void mavlinkPrint(const char* str);
 void sendMavlinkPrint();
 inline Quaternion fluToFrd(const Quaternion &q);
+void setupPower();
 void failsafe();
 void rcLossFailsafe();
 void descend();
 void autoFailsafe();
+void tiltFailsafe();
 int parametersCount();
 const char *getParameterName(int index);
 float getParameter(int index);
 float getParameter(const char *name);
 bool setParameter(const char *name, const float value);
-void printParameters();
+void printParameters(const char *filter);
 void resetParameters();
 
 // mocks
 void setLED(bool on) {};
-void calibrateGyro() { print("Skip gyro calibrating\n"); };
 void calibrateAccel() { print("Skip accel calibrating\n"); };
-void calibrateLevel() { print("Skip level calibrating\n"); };
 void printIMUCalibration() { print("cal: N/A\n"); };
 void printIMUInfo() {};
 void printWiFiInfo() {};
-Vector accBias, gyroBias, accScale(1, 1, 1);
+void configWiFi(bool, const char*, const char*) { print("Skip WiFi config\n"); };
+void setWiFiMode(const String& mode) { print("Skip WiFi mode set\n"); };
+
+class IMU {
+public:
+	float getTemp() { return 0; }
+} imu;

gazebo/simulator.cpp

@@ -23,10 +23,11 @@
 #include "estimate.ino"
 #include "safety.ino"
 #include "log.ino"
-#include "lpf.h"
+#include "filter.h"
 #include "mavlink.ino"
 #include "motors.ino"
 #include "parameters.ino"
+#include "power.ino"
 #include "rc.ino"
 #include "time.ino"
 
@@ -54,6 +55,8 @@ public:
 		initNode();
 		Serial.begin(0);
 		setupParameters();
+		setupLog();
+		rcRxPin = 1; // set rc pin to enable rc reading
 		gzmsg << "Flix plugin loaded" << endl;
 	}
 
@@ -72,6 +75,8 @@ public:
 		gyro = Vector(imu->AngularVelocity().X(), imu->AngularVelocity().Y(), imu->AngularVelocity().Z());
 		acc = this->accFilter.update(Vector(imu->LinearAcceleration().X(), imu->LinearAcceleration().Y(), imu->LinearAcceleration().Z()));
 
+		voltage = 4.2f; // dummy voltage value
+
 		readRC();
 		estimate();
 
@@ -84,7 +89,7 @@ public:
 
 		applyMotorForces();
 		publishTopics();
-		logData();
+		loopLog();
 		syncParameters();
 	}
 

gazebo/soc/soc.h

@@ -1,4 +1,3 @@
 // Dummy file to make it possible to compile simulator with Flix' util.h
 
-#define WRITE_PERI_REG(addr, val) {}
 #define REG_CLR_BIT(_r, _b) {}

gazebo/wifi.h

@@ -11,9 +11,15 @@
 #include <sys/poll.h>
 #include <gazebo/gazebo.hh>
 
-#define WIFI_UDP_PORT 14580
-#define WIFI_UDP_REMOTE_PORT 14550
-#define WIFI_UDP_REMOTE_ADDR "255.255.255.255"
+// Mocks
+int wifiMode = 1;
+int wifiLongRange = 0;
+int espnowChannel = 6;
+const int W_DISABLED = 0, W_AP = 1, W_STA = 2, W_ESPNOW = 3;
+
+int udpLocalPort = 14580;
+int udpRemotePort = 14550;
+const char *udpRemoteIP = "255.255.255.255";
 
 int wifiSocket;
 
@@ -22,22 +28,22 @@ void setupWiFi() {
 	sockaddr_in addr; // local address
 	addr.sin_family = AF_INET;
 	addr.sin_addr.s_addr = INADDR_ANY;
-	addr.sin_port = htons(WIFI_UDP_PORT);
+	addr.sin_port = htons(udpLocalPort);
 	if (bind(wifiSocket, (sockaddr *)&addr, sizeof(addr))) {
-		gzerr << "Failed to bind WiFi UDP socket on port " << WIFI_UDP_PORT << std::endl;
+		gzerr << "Failed to bind WiFi UDP socket on port " << udpLocalPort << std::endl;
 		return;
 	}
 	int broadcast = 1;
 	setsockopt(wifiSocket, SOL_SOCKET, SO_BROADCAST, &broadcast, sizeof(broadcast)); // enable broadcast
-	gzmsg << "WiFi UDP socket initialized on port " << WIFI_UDP_PORT << " (remote port " << WIFI_UDP_REMOTE_PORT << ")" << std::endl;
+	gzmsg << "WiFi UDP socket initialized on port " << udpLocalPort << " (remote port " << udpRemotePort << ")" << std::endl;
 }
 
 void sendWiFi(const uint8_t *buf, int len) {
 	if (wifiSocket == 0) setupWiFi();
 	sockaddr_in addr; // remote address
 	addr.sin_family = AF_INET;
-	addr.sin_addr.s_addr = inet_addr(WIFI_UDP_REMOTE_ADDR);
-	addr.sin_port = htons(WIFI_UDP_REMOTE_PORT);
+	addr.sin_addr.s_addr = inet_addr(udpRemoteIP);
+	addr.sin_port = htons(udpRemotePort);
 	sendto(wifiSocket, buf, len, 0, (sockaddr *)&addr, sizeof(addr));
 }
 

tools/csv_to_mcap.py

@@ -9,6 +9,7 @@ Usage:
 import csv
 import json
 import docopt
+import math
 from mcap.writer import Writer
 
 args = docopt.docopt(__doc__)
@@ -39,7 +40,15 @@ channel_id = writer.register_channel(
 )
 
 for row in csv_reader:
-    data = {key: float(value) for key, value in zip(header, row)}
+    if row[0] == '': continue
+    data = {}
+    for key, value in zip(header, row):
+        if value == '' or math.isnan(float(value)):
+            data[key] = None
+        else:
+            data[key] = float(value)
+
+    data = {key: float(value) if value != '' else None for key, value in zip(header, row)}
     timestamp = round(float(row[0]) * 1e9)
     writer.add_message(channel_id=channel_id, log_time=timestamp, data=json.dumps(data).encode(), publish_time=timestamp,)
 

tools/espnow-proxy/README.md

@@ -0,0 +1,3 @@
+# ESPNOW-proxy
+
+Proxy sketch for using ESP-NOW connection with Flix drone.

tools/espnow-proxy/espnow-proxy.ino

@@ -0,0 +1,108 @@
+// Copyright (c) 2026 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// Proxy for ESP-NOW connection
+
+#include <vector>
+#include <WiFi.h>
+#include <ESP32_NOW_Serial.h>
+#include <MacAddress.h>
+#include <MAVLink.h>
+#include <Preferences.h>
+#include "../../flix/util.h"
+
+const bool DISABLE_SWARM = true;
+const int CHANNEL = -1; // -1 means auto search
+char key[ESP_NOW_KEY_LEN + 1] = {0}; // with trailing null
+
+Preferences storage;
+
+std::vector<ESPNOWSerial *> peers;
+bool stop = false;
+
+void onNewPeer(const esp_now_recv_info_t *info, const uint8_t *data, int len, void *arg) {
+	if (len != 4 || memcmp(data, "flix", 4) != 0) return; // check if discovery message
+
+	if (stop) return;
+
+	Serial.printf("New peer: " MACSTR "\n", MAC2STR(info->src_addr));
+	ESPNOWSerial *link = new ESPNOWSerial(info->src_addr, WiFi.channel(), WIFI_IF_STA);
+	link->begin();
+	link->setKey((const uint8_t *)key);
+	peers.push_back(link);
+}
+
+void setup() {
+	Serial.begin(115200);
+	WiFi.mode(WIFI_STA);
+	WiFi.setSleep(false);
+
+	ESP_NOW.onNewPeer(onNewPeer, NULL);
+	ESP_NOW.begin();
+
+	storage.begin("espnow-proxy");
+	if (!storage.isKey("key")) {
+		generateRandomKey();
+		storage.putString("key", key);
+	}
+	strcpy(key, storage.getString("key").c_str());
+}
+
+void generateRandomKey() {
+	const char chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*-_+=";
+	for (int i = 0; i < ESP_NOW_KEY_LEN; i++) {
+		key[i] = chars[random(0, strlen(chars))];
+	}
+}
+
+void loop() {
+	uint8_t buf[5000];
+
+	static int channelIndex = 0;
+	static const int channels[] = {6, 11, 1, 2, 6, 11, 3, 4, 5, 6, 1, 11, 8, 6, 9, 10, 11, 6, 1, 12, 13}; // 6, 1 and 11 are most common
+
+	static unsigned long last = 0;
+	if (!stop && millis() - last > 500) {
+		// Change search channel
+		last = millis();
+		channelIndex = (channelIndex + 1) % (sizeof(channels) / sizeof(channels[0]));
+		int channel = CHANNEL < 0 ? channels[channelIndex] : CHANNEL;
+		Serial.printf("Run on Flix: espnow %s %s\n", WiFi.STA.macAddress().c_str(), key);
+		Serial.printf("Searching channel %d\n", channel);
+		WiFi.setChannel(channel);
+	}
+
+	// Send from Serial to ESP-NOW
+	while (Serial.available() > 0) {
+		int b = Serial.read();
+		if (b < 0) {
+			break;
+		}
+
+		mavlink_message_t msg;
+		mavlink_status_t status;
+		if (mavlink_parse_char(MAVLINK_COMM_0, (uint8_t)b, &msg, &status)) {
+			int len = mavlink_msg_to_send_buffer(buf, &msg);
+			for (ESPNOWSerial *link : peers) {
+				link->write(buf, len);
+			}
+		}
+	}
+
+	// Send from ESP-NOW to Serial
+	for (ESPNOWSerial *link : peers) {
+		int len = link->read(buf, sizeof(buf));
+		if (!stop) {
+			for (int i = 0; i < len; i++) {
+				if (buf[i] == MAVLINK_STX) {
+					// Got MAVLink message, stop discovery
+					Serial.printf("Received MAVLink from " MACSTR "\n", MAC2STR(link->addr()));
+					if (DISABLE_SWARM) stop = true;
+				}
+			}
+		}
+		if (len > 0) {
+			Serial.write(buf, len);
+		}
+	}
+}

tools/example.py

@@ -10,6 +10,7 @@ print('Connected:', flix.connected)
 print('Mode:', flix.mode)
 print('Armed:', flix.armed)
 print('Landed:', flix.landed)
+print('Voltage:', flix.voltage, 'V')
 print('Rates:', *[f'{math.degrees(r):.0f}°/s' for r in flix.rates])
 print('Attitude:', *[f'{math.degrees(a):.0f}°' for a in flix.attitude_euler])
 print('Motors:', flix.motors)
@@ -23,11 +24,11 @@ print('> imu')
 print(flix.cli('imu'))
 
 print('=== Get parameter...')
-pitch_p = flix.get_param('PITCH_P')
-print('PITCH_P = ', pitch_p)
+pitch_p = flix.get_param('CTL_P_P')
+print('CTL_P_P = ', pitch_p)
 
 print('=== Set parameter...')
-flix.set_param('PITCH_P', pitch_p)
+flix.set_param('CTL_P_P', pitch_p)
 
 print('=== Wait for gyro update...')
 print('Gyro: ', flix.wait('gyro'))

tools/grab_log.py

@@ -13,7 +13,7 @@ lines = []
 
 print('Downloading log...')
 count = 0
-dev.write('log\n'.encode())
+dev.write('log dump\n'.encode())
 while True:
     line = dev.readline()
     if not line:

tools/log.py

@@ -43,6 +43,7 @@ records = [record for record in records if record[0] != 0]
 
 print(f'Received records: {len(records)}')
 
+os.makedirs(f'{DIR}/log', exist_ok=True)
 log = open(f'{DIR}/log/{datetime.datetime.now().isoformat()}.csv', 'wb')
 log.write(header.encode() + b'\n')
 for record in records:

tools/log_to_csv.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+
+"""Convert flight from Flix format to CSV
+
+Usage:
+    log_to_csv.py <input_file>
+"""
+
+import os
+from pyflix import Flix
+import docopt
+import struct
+import csv
+
+DIR = os.path.dirname(os.path.realpath(__file__))
+HEADER_FILE = os.path.join(DIR, 'log/log_header.txt')
+
+# Read log header
+try:
+    # read from file
+    header = open(HEADER_FILE, 'r').read()
+except FileNotFoundError:
+    flix = Flix()
+    header = flix.cli('log header')  # receive the log schema
+    open(HEADER_FILE, 'w').write(header)  # save to file
+
+# Parse log header
+topics = []
+for line in header.splitlines():
+    if not line.startswith('  '):
+        topics.append([])
+    elif 'not logged' not in line:
+        topics[-1].append(line.strip())
+
+# Read log file
+args = docopt.docopt(__doc__)
+input_file = args['<input_file>']
+outfile_file = input_file + '.csv'
+data = open(input_file, 'rb').read()
+
+# Search for sync marker
+SYNC_MARKER = bytes.fromhex('1A 91 4F F6 7F')
+sync_offset = data.find(SYNC_MARKER)
+if sync_offset == -1:
+    raise ValueError('Sync marker not found in log file')
+data = data[sync_offset + len(SYNC_MARKER):]
+data = data.replace(SYNC_MARKER, b'')  # remove all other sync markers
+
+header_row = [f'{value}' for topic in topics for value in topic]
+rows = []
+
+offset = 0
+while offset < len(data):
+    try:
+        topic = struct.unpack_from('B', data, offset)[0]
+        offset += 1
+
+        if topic >= len(topics):
+            raise ValueError(f'Invalid topic {topic} at offset {offset}')
+
+        if topic == 0 or not rows:
+            rows.append({})
+
+        for name in topics[topic]:
+            value = struct.unpack_from('<f', data, offset)[0]
+            offset += 4
+            rows[-1][name] = value
+    except struct.error as e:
+        break
+
+# Write CSV file
+with open(outfile_file, 'w', newline='') as f:
+    writer = csv.DictWriter(f, fieldnames=header_row, extrasaction='ignore')
+    writer.writeheader()
+    rows = filter(lambda row: float(row.get('t', 0)), rows)
+    writer.writerows(rows)

tools/pyflix/README.md

@@ -24,19 +24,22 @@ pip install pyflix
 The API is accessed through the `Flix` class:
 
 ```python
-from flix import Flix
+from pyflix import Flix
 flix = Flix()  # create a Flix object and wait for connection
 ```
 
+If using ESP-NOW connection, specify the proxy device name in `FLIX_DEVICE` environment variable or pass it to the constructor: `Flix(device='/dev/cu.usbserial-0001')`.
+
 ### Telemetry
 
-Basic telemetry is available through object properties. The property names generally match the corresponding variables in the firmware itself:
+Basic telemetry is available through object properties. The property names generally match the corresponding variables in the firmware code:
 
 ```python
 print(flix.connected)       # True if connected to the drone
 print(flix.mode)            # current flight mode (str)
 print(flix.armed)           # True if the drone is armed
 print(flix.landed)          # True if the drone is landed
+print(flix.voltage)         # battery voltage (NaN - unknown, ~0 - USB powered)
 print(flix.attitude)        # attitude quaternion [w, x, y, z]
 print(flix.attitude_euler)  # attitude as Euler angles [roll, pitch, yaw]
 print(flix.rates)           # angular rates [roll_rate, pitch_rate, yaw_rate]
@@ -92,17 +95,18 @@ Full list of events:
 |-----|-----------|----------------|
 |`connected`|Connected to the drone||
 |`disconnected`|Connection is lost||
-|`armed`|Armed state update|Armed state (*bool*)|
-|`mode`|Flight mode update|Flight mode (*str*)|
-|`landed`|Landed state update|Landed state (*bool*)|
-|`print`|The drone sends text to the console|Text|
-|`attitude`|Attitude update|Attitude quaternion (*list*)|
-|`attitude_euler`|Attitude update|Euler angles (*list*)|
-|`rates`|Angular rates update|Angular rates (*list*)|
-|`channels`|Raw RC channels update|Raw RC channels (*list*)|
-|`motors`|Motor outputs update|Motor outputs (*list*)|
-|`acc`|Accelerometer update|Accelerometer output (*list*)|
-|`gyro`|Gyroscope update|Gyroscope output (*list*)|
+|`armed`|Armed state update|Armed state *(bool)*|
+|`mode`|Flight mode update|Flight mode *(str)*|
+|`landed`|Landed state update|Landed state *(bool)*|
+|`voltage`|Battery voltage update|Voltage *(float)*|
+|`print`|The drone prints text to the console|Text|
+|`attitude`|Attitude update|Attitude quaternion *(list)*|
+|`attitude_euler`|Attitude update|Euler angles *(list)*|
+|`rates`|Angular rates update|Angular rates *(list)*|
+|`channels`|Raw RC channels update|Raw RC channels *(list)*|
+|`motors`|Motor outputs update|Motor outputs *(list)*|
+|`acc`|Accelerometer update|Accelerometer output *(list)*|
+|`gyro`|Gyroscope update|Gyroscope output *(list)*|
 |`mavlink`|Received MAVLink message|Message object|
 |`mavlink.<message_name>`|Received specific MAVLink message|Message object|
 |`mavlink.<message_id>`|Received specific MAVLink message|Message object|
@@ -112,13 +116,13 @@ Full list of events:
 > [!NOTE]
 > Update events trigger on every new piece of data from the drone, and do not mean the value has changed.
 
-### Common methods
+### Basic methods
 
 Get and set firmware parameters using `get_param` and `set_param` methods:
 
 ```python
-pitch_p = flix.get_param('PITCH_P')  # get parameter value
-flix.set_param('PITCH_P', 5)         # set parameter value
+pitch_p = flix.get_param('CTL_P_P')  # get parameter value
+flix.set_param('CTL_P_P', 5)         # set parameter value
 ```
 
 Execute console commands using `cli` method. This method returns the command response:
@@ -218,6 +222,13 @@ The following scripts demonstrate how to use the library:
 * [`log.py`](../log.py) — download flight logs from the drone.
 * [`example.py`](../example.py) — a simple example, prints telemetry data and waits for events.
 
+> [!TIP]
+> Set `FLIX_DEVICE` environment variable to use these tools with ESP-NOW connection, for example:
+>
+> ```bash
+> FLIX_DEVICE=/dev/cu.usbserial-0001 tools/cli.py
+> ```
+
 ## Advanced usage
 
 ### MAVLink
@@ -277,7 +288,3 @@ logger = logging.getLogger('flix')
 logger.setLevel(logging.DEBUG)  # be more verbose
 logger.setLevel(logging.WARNING)  # be less verbose
 ```
-
-## Stability
-
-The library is in development stage. The API is not stable.

tools/pyflix/flix.py

@@ -5,6 +5,7 @@
 
 import os
 import time
+import math
 from queue import Queue, Empty
 from typing import Optional, Callable, List, Dict, Any, Union, Sequence
 import logging
@@ -26,6 +27,7 @@ class Flix:
     mode: str = ''
     armed: bool = False
     landed: bool = False
+    voltage: float = math.nan
     attitude: List[float]
     attitude_euler: List[float]  # roll, pitch, yaw
     rates: List[float]
@@ -42,22 +44,27 @@ class Flix:
     _print_buffer: str = ''
     _modes = ['RAW', 'ACRO', 'STAB', 'AUTO']
 
-    def __init__(self, system_id: int=1, wait_connection: bool=True):
+    def __init__(self, system_id: int=1, wait_connection: bool=True, device=os.getenv('FLIX_DEVICE')):
         if not (0 <= system_id < 256):
             raise ValueError('system_id must be in range [0, 255]')
         self._setup_mavlink()
         self.system_id = system_id
         self._init_state()
-        try:
-            # Direct connection
-            logger.debug('Listening on port 14550')
-            self.connection: mavutil.mavfile = mavutil.mavlink_connection('udpin:0.0.0.0:14550', source_system=255)  # type: ignore
-        except OSError as e:
-            if e.errno != errno.EADDRINUSE:
-                raise
-            # Port busy - using proxy
-            logger.debug('Listening on port 14555 (proxy)')
-            self.connection: mavutil.mavfile = mavutil.mavlink_connection('udpin:0.0.0.0:14555', source_system=254)  # type: ignore
+        if device is not None:
+            # User defined connection
+            logger.debug(f'Connecting to {device}')
+            self.connection: mavutil.mavfile = mavutil.mavlink_connection(device, source_system=255)  # type: ignore
+        else:
+            try:
+                # Direct connection
+                logger.debug('Listening on port 14550')
+                self.connection: mavutil.mavfile = mavutil.mavlink_connection('udpin:0.0.0.0:14550', source_system=255)  # type: ignore
+            except OSError as e:
+                if e.errno != errno.EADDRINUSE:
+                    raise
+                # Port busy - using proxy
+                logger.debug('Listening on port 14555 (proxy)')
+                self.connection: mavutil.mavfile = mavutil.mavlink_connection('udpin:0.0.0.0:14555', source_system=254)  # type: ignore
         self.connection.target_system = system_id
         self.mavlink: mavlink.MAVLink = self.connection.mav
         self._event_listeners: Dict[str, List[Callable[..., Any]]] = {}
@@ -68,7 +75,7 @@ class Flix:
         self._heartbeat_thread.start()
         if wait_connection:
             self.wait('mavlink.HEARTBEAT')
-            time.sleep(0.2) # give some time to receive initial state
+            time.sleep(0.6) # give some time to receive initial state
 
     def _init_state(self):
         self.attitude = [1, 0, 0, 0]
@@ -138,7 +145,7 @@ class Flix:
         while True:
             try:
                 msg: Optional[mavlink.MAVLink_message] = self.connection.recv_match(blocking=True)
-                if msg is None:
+                if msg is None or msg.get_srcSystem() != self.system_id:
                     continue
                 self._connected()
                 msg_dict = msg.to_dict()
@@ -185,11 +192,16 @@ class Flix:
             self._trigger('motors', self.motors)
 
         if isinstance(msg, mavlink.MAVLink_scaled_imu_message):
-            self.acc = self._mavlink_to_flu([msg.xacc / 1000, msg.yacc / 1000, msg.zacc / 1000])
+            ONE_G = 9.80665
+            self.acc = self._mavlink_to_flu([msg.xacc * ONE_G / 1000, msg.yacc * ONE_G / 1000, msg.zacc * ONE_G / 1000])
             self.gyro = self._mavlink_to_flu([msg.xgyro / 1000, msg.ygyro / 1000, msg.zgyro / 1000])
             self._trigger('acc', self.acc)
             self._trigger('gyro', self.gyro)
 
+        if isinstance(msg, mavlink.MAVLink_battery_status_message):
+            self.voltage = msg.voltages[0] / 1000
+            self._trigger('voltage', self.voltage)
+
         if isinstance(msg, mavlink.MAVLink_serial_control_message):
             # new chunk of data
             text = bytes(msg.data)[:msg.count].decode('utf-8', errors='ignore')

tools/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "pyflix"
-version = "0.11"
+version = "0.16"
 description = "Python API for Flix drone"
 authors = [{ name="Oleg Kalachev", email="okalachev@gmail.com" }]
 license = "MIT"