Add commands for switching modes

Make mode simple int instead of enum for simplify using in other subsystems
Bring back handling old message for motor outputs in pyflix
2026-01-12 05:57:52 +00:00 · 2025-08-11 22:35:38 +03:00 · 2025-07-31 12:35:59 +03:00 · 2025-07-31 12:35:41 +03:00 · 2025-07-31 12:32:43 +03:00 · 2025-07-31 12:23:26 +03:00
73 changed files with 1204 additions and 1561 deletions
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -23,9 +23,7 @@ jobs:
      with:
        name: firmware-binary
        path: flix/build
-    - name: Build firmware for ESP32-S3
+    - name: Build firmware without Wi-Fi
      run: make BOARD=esp32:esp32:esp32s3
    - name: Build firmware with WiFi disabled
      run: sed -i 's/^#define WIFI_ENABLED 1$/#define WIFI_ENABLED 0/' flix/flix.ino && make
    - name: Check c_cpp_properties.json
      run: tools/check_c_cpp_properties.py
@@ -55,25 +53,15 @@ jobs:
      run: python3 tools/check_c_cpp_properties.py
  build_simulator:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
    container:
      image: ubuntu:20.04
    steps:
    - name: Install dependencies
      run: |
        apt-get update
        DEBIAN_FRONTEND=noninteractive apt-get install -y curl wget build-essential cmake g++ pkg-config gnupg2 lsb-release sudo
    - name: Install Arduino CLI
      uses: arduino/setup-arduino-cli@v1.1.1
    - uses: actions/checkout@v4
    - name: Install Gazebo
-      run: |
+      run: curl -sSL http://get.gazebosim.org | sh
        sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu-stable `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-stable.list'
        wget https://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -
        sudo apt-get update
        sudo apt-get install -y gazebo11 libgazebo11-dev
    - name: Install SDL2
-      run: sudo apt-get install -y libsdl2-dev
+      run: sudo apt-get install libsdl2-dev
    - name: Build simulator
      run: make build_simulator
    - uses: actions/upload-artifact@v4
--- a/.vscode/c_cpp_properties.json
+++ b/.vscode/c_cpp_properties.json
@@ -5,15 +5,13 @@
 			"includePath": [
 				"${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",
 				"~/Arduino/libraries/**",
-				"/usr/include/gazebo-11/",
+				"/usr/include/**"
 				"/usr/include/ignition/math6/"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
@@ -53,14 +51,14 @@
 			"name": "Mac",
 			"includePath": [
 				"${workspaceFolder}/flix",
 				// "${workspaceFolder}/gazebo",
 				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/cores/esp32",
 				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/libraries/**",
 				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.2.0/variants/d1_mini32",
 				"~/Library/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/include/**",
 				"~/Library/Arduino15/packages/esp32/tools/esp32-arduino-libs/idf-release_v5.4-2f7dcd86-v1/esp32/dio_qspi/include",
 				"~/Documents/Arduino/libraries/**",
-				"/opt/homebrew/include/gazebo-11/",
+				"/opt/homebrew/include/**"
 				"/opt/homebrew/include/ignition/math6/"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
@@ -102,7 +100,6 @@
 			"includePath": [
 				"${workspaceFolder}/flix",
 				"${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",
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,6 +1,5 @@
 {
 	"C_Cpp.intelliSenseEngineFallback": "enabled",
 	"C_Cpp.errorSquiggles": "disabled",
 	"files.associations": {
 		"*.sdf": "xml",
 		"*.ino": "cpp",
--- a/2
+++ b/2
@@ -32,7 +32,7 @@ simulator: build_simulator
 	gazebo --verbose ${CURDIR}/gazebo/flix.world
 log:
-	tools/log.py
+	PORT=$(PORT) tools/grab_log.py
 plot:
 	plotjuggler -d $(shell ls -t tools/log/*.csv | head -n1)
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Flix
-**Flix** (*flight + X*) — open source ESP32-based quadcopter made from scratch.
+**Flix** (*flight + X*) — making an open source ESP32-based quadcopter from scratch.
 <table>
  <tr>
@@ -17,11 +17,11 @@
 * Dedicated for education and research.
 * Made from general-purpose components.
-* Simple and clean source code in Arduino (<2k lines firmware).
+* Simple and clean source code in Arduino.
-* Control using USB gamepad, remote control or smartphone.
+* Control using remote control or smartphone.
 * Precise simulation with Gazebo.
 * Wi-Fi and MAVLink support.
 * Wireless command line interface and analyzing.
 * Precise simulation with Gazebo.
 * Python library.
 * Textbook on flight control theory and practice ([in development](https://quadcopter.dev)).
 * *Position control (using external camera) and autonomous flights¹*.
@@ -38,11 +38,7 @@ Version 0 demo video: https://youtu.be/8GzzIQ3C6DQ.
 <a href="https://youtu.be/8GzzIQ3C6DQ"><img width=500 src="https://i3.ytimg.com/vi/8GzzIQ3C6DQ/maxresdefault.jpg"></a>
-Usage in education (RoboCamp): https://youtu.be/Wd3yaorjTx0.
+See the [user builds gallery](docs/user.md).
 <a href="https://youtu.be/Wd3yaorjTx0"><img width=500 src="https://i3.ytimg.com/vi/Wd3yaorjTx0/sddefault.jpg"></a>
 See the [user builds gallery](docs/user.md):
 <a href="docs/user.md"><img src="docs/img/user/user.jpg" width=500></a>
@@ -52,29 +48,25 @@ The simulator is implemented using Gazebo and runs the original Arduino code:
 <img src="docs/img/simulator1.png" width=500 alt="Flix simulator">
-## Documentation
+## Articles
-1. [Assembly instructions](docs/assembly.md).
+* [Assembly instructions](docs/assembly.md).
-2. [Usage: build, setup and flight](docs/usage.md).
+* [Building and running the code](docs/build.md).
 3. [Simulation](gazebo/README.md).
 4. [Python library](tools/pyflix/README.md).
 Additional articles:
 * [User builds gallery](docs/user.md).
 * [Firmware architectural overview](docs/firmware.md).
 * [Troubleshooting](docs/troubleshooting.md).
 * [Firmware architecture overview](docs/firmware.md).
 * [Python library tutorial](tools/pyflix/README.md).
 * [Log analysis](docs/log.md).
 * [User builds gallery](docs/user.md).
 ## Components
 |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|
+|IMU (and barometer²) board|GY‑91, MPU-9265 (or other MPU‑9250/MPU‑6500 board)<br>ICM‑20948³<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|
+|<span style="background:yellow">(Recommended) Buck-boost converter</span>|To be determined, output 5V or 3.3V, see [user-contributed schematics](https://miro.com/app/board/uXjVN-dTjoo=/?moveToWidget=3458764612179508274&cot=14)|<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|
+|Motor|8520 3.7V brushed motor (shaft 0.8mm).<br>Motor with exact 3.7V voltage is needed, not ranged working voltage (3.7V — 6V).|<img src="docs/img/motor.jpeg" width=100>|4|
-|Propeller|55 mm (alternatively 65 mm)|<img src="docs/img/prop.jpg" width=100>|4|
+|Propeller|Hubsan 55 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|
@@ -82,17 +74,19 @@ Additional articles:
 |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|
 |Screws for frame assembly|M1.4x5|<img src="docs/img/screw-m1.4.jpg" height=30 align=center>|4|
-|Frame main part|3D printed²: [`stl`](docs/assets/flix-frame-1.1.stl) [`step`](docs/assets/flix-frame-1.1.step)<br>Recommended settings: layer 0.2 mm, line 0.4 mm, infill 100%.|<img src="docs/img/frame1.jpg" width=100>|1|
+|Frame main part|3D printed⁴:<br>[`flix-frame-1.1.stl`](docs/assets/flix-frame-1.1.stl) [`flix-frame-1.1.step`](docs/assets/flix-frame-1.1.step)<br>Recommended settings: layer 0.2 mm, line 0.4 mm, infill 100%.|<img src="docs/img/frame1.jpg" width=100>|1|
-|Frame top part|3D printed: [`stl`](docs/assets/esp32-holder.stl) [`step`](docs/assets/esp32-holder.step)|<img src="docs/img/esp32-holder.jpg" width=100>|1|
+|Frame top part|3D printed:<br>[`esp32-holder.stl`](docs/assets/esp32-holder.stl) [`esp32-holder.step`](docs/assets/esp32-holder.step)|<img src="docs/img/esp32-holder.jpg" width=100>|1|
-|Washer for IMU board mounting|3D printed: [`stl`](docs/assets/washer-m3.stl) [`step`](docs/assets/washer-m3.step)|<img src="docs/img/washer-m3.jpg" width=100>|2|
+|Washer for IMU board mounting|3D printed:<br>[`washer-m3.stl`](docs/assets/washer-m3.stl) [`washer-m3.step`](docs/assets/washer-m3.step)|<img src="docs/img/washer-m3.jpg" width=100>|2|
-|Controller (recommended)|CC2500 transmitter, like BetaFPV LiteRadio CC2500 (RC receiver/Wi-Fi).<br>Two-sticks gamepad (Wi-Fi only) — see [recommended gamepads](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/setup_view/joystick.html#supported-joysticks).<br>Other⁵|<img src="docs/img/betafpv.jpg" width=100><img src="docs/img/logitech.jpg" width=80>|1|
+|*RC transmitter (optional)*|*KINGKONG TINY X8 (warning: lacks USB support) or other⁵*|<img src="docs/img/tx.jpg" width=100>|1|
-|*RC receiver (optional)*|*DF500 or other³*|<img src="docs/img/rx.jpg" width=100>|1|
+|*RC receiver (optional)*|*DF500 or other⁵*|<img src="docs/img/rx.jpg" width=100>|1|
 |Wires|28 AWG recommended|<img src="docs/img/wire-28awg.jpg" width=100>||
 |Tape, double-sided tape||||
-*¹ — barometer is not used for now.*<br>
+*² — barometer is not used for now.*<br>
-*² — this frame is optimized for GY-91 board, if using other, the board mount holes positions should be modified.*<br>
+*³ — change `MPU9250` to `ICM20948` in `imu.ino` file if using ICM-20948 board.*<br>
-*³ — you also may use any transmitter-receiver pair with SBUS interface.*
+*³⁻¹ — MPU-6050 supports I²C interface only (not recommended). To use it change IMU declaration to `MPU6050 IMU(Wire)`.*<br>
 *⁴ — this frame is optimized for GY-91 board, if using other, the board mount holes positions should be modified.*<br>
 *⁵ — you may use any transmitter-receiver pair with SBUS interface.*
 Tools required for assembly:
@@ -102,15 +96,13 @@ Tools required for assembly:
 * Screwdrivers.
 * Multimeter.
-Feel free to modify the design and or code, and create your own improved versions. Send your results to the [official Telegram chat](https://t.me/opensourcequadcopterchat), or directly to the author ([E-mail](mailto:okalachev@gmail.com), [Telegram](https://t.me/okalachev)).
+Feel free to modify the design and or code, and create your own improved versions of Flix! Send your results to the [official Telegram chat](https://t.me/opensourcequadcopterchat), or directly to the author ([E-mail](mailto:okalachev@gmail.com), [Telegram](https://t.me/okalachev)).
 ## Schematics
 ### Simplified connection diagram
-<img src="docs/img/schematics1.svg" width=700 alt="Flix version 1 schematics">
+<img src="docs/img/schematics1.svg" width=800 alt="Flix version 1 schematics">
 *(Dashed elements are optional).*
 Motor connection scheme:
@@ -118,6 +110,8 @@ Motor connection scheme:
 You can see a user-contributed [variant of complete circuit diagram](https://miro.com/app/board/uXjVN-dTjoo=/?moveToWidget=3458764612338222067&cot=14) of the drone.
 See [assembly guide](docs/assembly.md) for instructions on assembling the drone.
 ### Notes
 * Power ESP32 Mini with Li-Po battery using VCC (+) and GND (-) pins.
@@ -135,15 +129,14 @@ You can see a user-contributed [variant of complete circuit diagram](https://mir
 * Solder pull-down resistors to the MOSFETs.
 * Connect the motors to the ESP32 Mini using MOSFETs, by following scheme:
-  |Motor|Position|Direction|Prop type|Motor wires|GPIO|
+  |Motor|Position|Direction|Wires|GPIO|
-  |-|-|-|-|-|-|
+  |-|-|-|-|-|
-  |Motor 0|Rear left|Counter-clockwise|B|Black & White|GPIO12 (*TDI*)|
+  |Motor 0|Rear left|Counter-clockwise|Black & White|GPIO12 (*TDI*)|
-  |Motor 1|Rear right|Clockwise|A|Blue & Red|GPIO13 (*TCK*)|
+  |Motor 1|Rear right|Clockwise|Blue & Red|GPIO13 (*TCK*)|
-  |Motor 2|Front right|Counter-clockwise|B|Black & White|GPIO14 (*TMS*)|
+  |Motor 2|Front right|Counter-clockwise|Black & White|GPIO14 (*TMS*)|
-  |Motor 3|Front left|Clockwise|A|Blue & Red|GPIO15 (*TD0*)|
+  |Motor 3|Front left|Clockwise|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 and white wires and clockwise motors have blue and red wires.
  Counter-clockwise motors have black & white wires correspond to propeller type B.
 * Optionally connect the RC receiver to the ESP32's UART2:
@@ -151,18 +144,32 @@ 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)|GPIO4⁶|
-*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.*
+*⁶ — 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.*
-## Resources
+### IMU placement
-* Telegram channel on developing the drone and the flight controller (in Russian): https://t.me/opensourcequadcopter.
+Default IMU orientation in the code is **LFD** (Left-Forward-Down):
-* Official Telegram chat: https://t.me/opensourcequadcopterchat.
+
-* Detailed article on Habr.com about the development of the drone (in Russian): https://habr.com/ru/articles/814127/.
+<img src="docs/img/gy91-lfd.svg" width=400 alt="GY-91 axes">
 In case of using other IMU orientation, modify the `rotateIMU` function in the `imu.ino` file.
 See [FlixPeriph documentation](https://github.com/okalachev/flixperiph?tab=readme-ov-file#imu-axes-orientation) to learn axis orientation of other IMU boards.
 ## Materials
 Subscribe to the Telegram channel on developing the drone and the flight controller (in Russian): https://t.me/opensourcequadcopter.
 Join the official Telegram chat: https://t.me/opensourcequadcopterchat.
 Detailed article on Habr.com about the development of the drone (in Russian): https://habr.com/ru/articles/814127/.
 See the information on the obsolete version 0 in the [corresponding article](docs/version0.md).
 ## Disclaimer
-This is a DIY project, and I hope you find it interesting and useful. However, it's not easy to assemble and set up, and it's provided "as is" without any warranties. There's no guarantee that it will work perfectly, or even work at all.
+This is a fun DIY project, and I hope you find it interesting and useful. However, it's not easy to assemble and set up, and it's provided "as is" without any warranties. There’s no guarantee that it will work perfectly — or even work at all.
 ⚠️ The author is not responsible for any damage, injury, or loss resulting from the use of this project. Use at your own risk!
--- a/docs/assembly.md
+++ b/docs/assembly.md
@@ -27,27 +27,3 @@ Soldered components ([schematics variant](https://miro.com/app/board/uXjVN-dTjoo
 <br>Assembled drone:
 <img src="img/assembly/7.jpg" width=600>
 ## Motor directions
 > [!WARNING]
 > The drone above is an early build, and it has **inversed** motor directions scheme. The photos only illustrate the assembly process in general.
 Use standard motor directions scheme:
 <img src="img/motors.svg" width=200>
 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*)|
 ## Motors tightening
 Motors should be installed very tightly — any vibration may lead to bad attitude estimation and unstable flight. If motors are loose, use tiny tape pieces to fix them tightly as shown below:
 <img src="img/motor-tape.jpg" width=600>
--- a/docs/book/firmware.md
+++ b/docs/book/firmware.md
@@ -1,10 +1,8 @@
 # Архитектура прошивки
-Прошивка Flix это обычный скетч Arduino, реализованный в однопоточном стиле. Код инициализации находится в функции `setup()`, а главный цикл — в функции `loop()`. Скетч состоит из нескольких файлов, каждый из которых отвечает за определенную подсистему.
+<img src="img/dataflow.svg" width=800 alt="Firmware dataflow diagram">
-<img src="img/dataflow.svg" width=600 alt="Firmware dataflow diagram">
+Главный цикл работает на частоте 1000 Гц. Передача данных между подсистемами происходит через глобальные переменные:
 Главный цикл `loop()` работает на частоте 1000 Гц. Передача данных между подсистемами происходит через глобальные переменные:
 * `t` *(float)* — текущее время шага, *с*.
 * `dt` *(float)* — дельта времени между текущим и предыдущим шагами, *с*.
@@ -12,39 +10,23 @@
 * `acc` *(Vector)* — данные с акселерометра, *м/с<sup>2</sup>*.
 * `rates` *(Vector)* — отфильтрованные угловые скорости, *рад/с*.
 * `attitude` *(Quaternion)* — оценка ориентации (положения) дрона.
-* `controlRoll`, `controlPitch`, `controlYaw`, `controlThrottle`, `controlMode` *(float)* — команды управления от пилота, в диапазоне [-1, 1].
+* `controlRoll`, `controlPitch`, ... *(float[])* — команды управления от пилота, в диапазоне [-1, 1].
-* `motors` *(float[4])* — выходные сигналы на моторы, в диапазоне [0, 1].
+* `motors` *(float[])* — выходные сигналы на моторы, в диапазоне [0, 1].
 ## Исходные файлы
-Исходные файлы прошивки находятся в директории `flix`. Основные файлы:
+Исходные файлы прошивки находятся в директории `flix`. Ключевые файлы:
-* [`flix.ino`](https://github.com/okalachev/flix/blob/master/flix/flix.ino) — основной файл Arduino-скетча. Определяет некоторые глобальные переменные и главный цикл.
+* [`flix.ino`](https://github.com/okalachev/flix/blob/canonical/flix/flix.ino) — основной входной файл, скетч Arduino. Включает определение глобальных переменных и главный цикл.
-* [`imu.ino`](https://github.com/okalachev/flix/blob/master/flix/imu.ino) — чтение данных с датчика IMU (гироскоп и акселерометр), калибровка IMU.
+* [`imu.ino`](https://github.com/okalachev/flix/blob/canonical/flix/imu.ino) — чтение данных с датчика IMU (гироскоп и акселерометр), калибровка IMU.
-* [`rc.ino`](https://github.com/okalachev/flix/blob/master/flix/rc.ino) — чтение данных с RC-приемника, калибровка RC.
+* [`rc.ino`](https://github.com/okalachev/flix/blob/canonical/flix/rc.ino) — чтение данных с RC-приемника, калибровка RC.
-* [`estimate.ino`](https://github.com/okalachev/flix/blob/master/flix/estimate.ino) — оценка ориентации дрона, комплементарный фильтр.
+* [`mavlink.ino`](https://github.com/okalachev/flix/blob/canonical/flix/mavlink.ino) — взаимодействие с QGroundControl через MAVLink.
-* [`control.ino`](https://github.com/okalachev/flix/blob/master/flix/control.ino) — подсистема управления, трехмерный двухуровневый каскадный ПИД-регулятор.
+* [`estimate.ino`](https://github.com/okalachev/flix/blob/canonical/flix/estimate.ino) — оценка ориентации дрона, комплементарный фильтр.
-* [`motors.ino`](https://github.com/okalachev/flix/blob/master/flix/motors.ino) — выход PWM на моторы.
+* [`control.ino`](https://github.com/okalachev/flix/blob/canonical/flix/control.ino) — управление ориентацией и угловыми скоростями дрона, трехмерный двухуровневый каскадный PID-регулятор.
-* [`mavlink.ino`](https://github.com/okalachev/flix/blob/master/flix/mavlink.ino) — взаимодействие с QGroundControl или [pyflix](https://github.com/okalachev/flix/tree/master/tools/pyflix) через протокол MAVLink.
+* [`motors.ino`](https://github.com/okalachev/flix/blob/canonical/flix/motors.ino) — управление выходными сигналами на моторы через ШИМ.
-Вспомогательные файлы:
+Вспомогательные файлы включают:
-* [`vector.h`](https://github.com/okalachev/flix/blob/master/flix/vector.h), [`quaternion.h`](https://github.com/okalachev/flix/blob/master/flix/quaternion.h) — библиотеки векторов и кватернионов.
+* [`vector.h`](https://github.com/okalachev/flix/blob/canonical/flix/vector.h), [`quaternion.h`](https://github.com/okalachev/flix/blob/canonical/flix/quaternion.h) — реализация библиотек векторов и кватернионов проекта.
-* [`pid.h`](https://github.com/okalachev/flix/blob/master/flix/pid.h) — ПИД-регулятор.
+* [`pid.h`](https://github.com/okalachev/flix/blob/canonical/flix/pid.h) — реализация общего ПИД-регулятора.
-* [`lpf.h`](https://github.com/okalachev/flix/blob/master/flix/lpf.h) — фильтр нижних частот.
+* [`lpf.h`](https://github.com/okalachev/flix/blob/canonical/flix/lpf.h) — реализация общего фильтра нижних частот.
 ### Подсистема управления
 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*.
 * `ratesExtra` *(Vector)* — дополнительные (feed-forward) угловые скорости, для управления рысканием в режиме STAB, *рад/с*.
 * `torqueTarget` *(Vector)* — целевой крутящий момент, диапазон [-1, 1].
 * `thrustTarget` *(float)* — целевая общая тяга, диапазон [0, 1].
 Команда управления обрабатывается в функциях `controlAttitude()`, `controlRates()`, `controlTorque()`. Если значение одной из переменных установлено в `NAN`, то соответствующая функция пропускается.
 <img src="img/control.svg" width=300 alt="Control subsystem diagram">
 Состояние *armed* хранится в переменной `armed`, а текущий режим — в переменной `mode`.
--- a/docs/build.md
+++ b/docs/build.md
@@ -1,2 +1,205 @@
-<!-- markdownlint-disable MD041 -->
+# Building and running
-Build instructions are moved to [usage article](usage.md).
+
 To build the firmware or the simulator, you need to clone the repository using git:
 ```bash
 git clone https://github.com/okalachev/flix.git
 cd flix
 ```
 ## Simulation
 ### Ubuntu
 The latest version of Ubuntu supported by Gazebo 11 simulator is 22.04. If you have a newer version, consider using a virtual machine.
 1. Install Arduino CLI:
   ```bash
   curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=~/.local/bin sh
   ```
 2. Install Gazebo 11:
   ```bash
   curl -sSL http://get.gazebosim.org | sh
   ```
   Set up your Gazebo environment variables:
   ```bash
   echo "source /usr/share/gazebo/setup.sh" >> ~/.bashrc
   source ~/.bashrc
   ```
 3. Install SDL2 and other dependencies:
   ```bash
   sudo apt-get update && sudo apt-get install build-essential libsdl2-dev
   ```
 4. Add your user to the `input` group to enable joystick support (you need to re-login after this command):
   ```bash
   sudo usermod -a -G input $USER
   ```
 5. Run the simulation:
   ```bash
   make simulator
   ```
 ### macOS
 1. Install Homebrew package manager, if you don't have it installed:
   ```bash
   /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
   ```
 2. Install Arduino CLI, Gazebo 11 and SDL2:
   ```bash
   brew tap osrf/simulation
   brew install arduino-cli
   brew install gazebo11
   brew install sdl2
   ```
   Set up your Gazebo environment variables:
   ```bash
   echo "source /opt/homebrew/share/gazebo/setup.sh" >> ~/.zshrc
   source ~/.zshrc
   ```
 3. Run the simulation:
   ```bash
   make simulator
   ```
 ### Setup and flight
 #### Control with smartphone
 1. Install [QGroundControl mobile app](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/getting_started/download_and_install.html#android) on your smartphone. For **iOS**, use [QGroundControl build from TAJISOFT](https://apps.apple.com/ru/app/qgc-from-tajisoft/id1618653051).
 2. Connect your smartphone to the same Wi-Fi network as the machine running the simulator.
 3. If you're using a virtual machine, make sure that its network is set to the **bridged** mode with Wi-Fi adapter selected.
 4. Run the simulation.
 5. Open QGroundControl app. It should connect and begin showing the virtual drone's telemetry automatically.
 6. Go to the settings and enable *Virtual Joystick*. *Auto-Center Throttle* setting **should be disabled**.
 7. Use the virtual joystick to fly the drone!
 #### Control with USB remote control
 1. Connect your USB remote control to the machine running the simulator.
 2. Run the simulation.
 3. Calibrate the RC using `cr` command in the command line interface.
 4. Run the simulation again.
 5. Use the USB remote control to fly the drone!
 ## Firmware
 ### Arduino IDE (Windows, Linux, macOS)
 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.
 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.
 5. Clone the project using git or [download the source code as a ZIP archive](https://codeload.github.com/okalachev/flix/zip/refs/heads/master).
 6. Open the downloaded Arduino sketch `flix/flix.ino` in Arduino IDE.
 7. 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.
 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)
 1. [Install Arduino CLI](https://arduino.github.io/arduino-cli/installation/).
   On Linux, use:
   ```bash
   curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=~/.local/bin sh
   ```
 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. Compile the firmware using `make`. Arduino dependencies will be installed automatically:
   ```bash
   make
   ```
   You can flash the firmware to the board using command:
   ```bash
   make upload
   ```
   You can also compile the firmware, upload it and start serial port monitoring using command:
   ```bash
   make upload monitor
   ```
 See other available Make commands in the [Makefile](../Makefile).
 > [!TIP]
 > You can test the firmware on a bare ESP32 board without connecting IMU and other peripherals. The Wi-Fi network `flix` should appear and all the basic functionality including CLI and QGroundControl connection should work.
 ### Setup and flight
 Before flight you need to calibrate the accelerometer:
 1. Open Serial Monitor in Arduino IDE (or use `make monitor` command in the command line).
 2. Type `ca` command there and follow the instructions.
 #### Control with smartphone
 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.
 3. Connect your smartphone to the appeared `flix` Wi-Fi network (password: `flixwifi`).
 4. Open QGroundControl app. It should connect and begin showing the drone's telemetry automatically.
 5. Go to the settings and enable *Virtual Joystick*. *Auto-Center Throttle* setting **should be disabled**.
 6. Use the virtual joystick to fly the drone!
 #### Control with remote control
 Before flight using remote control, you need to calibrate it:
 1. Open Serial Monitor in Arduino IDE (or use `make monitor` command in the command line).
 2. Type `cr` command there and follow the instructions.
 3. Use the remote control to fly the drone!
 #### Control with USB remote control
 If your drone doesn't have RC receiver installed, you can use USB remote control and QGroundControl app to fly it.
 1. Install [QGroundControl](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/getting_started/download_and_install.html) app on your computer.
 2. Connect your USB remote control to the computer.
 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.
 7. Use the USB remote control to fly the drone!
 #### Adjusting parameters
 You can adjust some of the drone's parameters (include PID coefficients) in QGroundControl app. In order to do that, go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Parameters*.
 <img src="img/parameters.png" width="400">
 #### CLI access
 In addition to accessing the drone's command line interface (CLI) using the serial port, you can also access it with QGroundControl using Wi-Fi connection. To do that, go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*.
 <img src="img/cli.png" width="400">
 > [!NOTE]
 > If something goes wrong, go to the [Troubleshooting](troubleshooting.md) article.
 ### Firmware code structure
 See [firmware overview](firmware.md) for more details.
--- a/docs/firmware.md
+++ b/docs/firmware.md
@@ -1,67 +1,39 @@
 # Firmware overview
-The firmware is a regular Arduino sketch, and it follows the classic Arduino one-threaded design. The initialization code is in the `setup()` function, and the main loop is in the `loop()` function. The sketch includes several files, each responsible for a specific subsystem.
+The firmware is a regular Arduino sketch, and follows the classic Arduino one-threaded design. The initialization code is in the `setup()` function, and the main loop is in the `loop()` function. The sketch includes multiple files, each responsible for a specific part of the system.
 ## Dataflow
-<img src="img/dataflow.svg" width=600 alt="Firmware dataflow diagram">
+<img src="img/dataflow.svg" width=800 alt="Firmware dataflow diagram">
-The main loop is running at 1000 Hz. The dataflow goes through global variables, including:
+The main loop is running at 1000 Hz. All the dataflow is happening through global variables (for simplicity):
-* `t` *(float)* — current step time, *s*.
+* `t` *(double)* — current step time, *s*.
 * `dt` *(float)* — time delta between the current and previous steps, *s*.
 * `gyro` *(Vector)* — data from the gyroscope, *rad/s*.
 * `acc` *(Vector)* — acceleration data from the accelerometer, *m/s<sup>2</sup>*.
 * `rates` *(Vector)* — filtered angular rates, *rad/s*.
 * `attitude` *(Quaternion)* — estimated attitude (orientation) of drone.
-* `controlRoll`, `controlPitch`, `controlYaw`, `controlThrottle`, `controlMode` *(float)* — pilot control inputs, range [-1, 1].
+* `controlRoll`, `controlPitch`, ... *(float[])* — pilot's control inputs, range [-1, 1].
-* `motors` *(float[4])* — motor outputs, range [0, 1].
+* `motors` *(float[])* — motor outputs, range [0, 1].
 ## Source files
-Firmware source files are located in `flix` directory.
+Firmware source files are located in `flix` directory. The key files are:
-* [`flix.ino`](../flix/flix.ino) — Arduino sketch main file, entry point.Includes some global variable definitions and the main loop.
+* [`flix.ino`](../flix/flix.ino) — main entry point, Arduino sketch. Includes global variables definition and the main loop.
 * [`imu.ino`](../flix/imu.ino) — reading data from the IMU sensor (gyroscope and accelerometer), IMU calibration.
 * [`rc.ino`](../flix/rc.ino) — reading data from the RC receiver, RC calibration.
-* [`estimate.ino`](../flix/estimate.ino) — attitude estimation, complementary filter.
+* [`estimate.ino`](../flix/estimate.ino) — drone's attitude estimation, complementary filter.
-* [`control.ino`](../flix/control.ino) — control subsystem, three-dimensional two-level cascade PID controller.
+* [`control.ino`](../flix/control.ino) — drone's attitude and rates control, three-dimensional two-level cascade PID controller.
-* [`motors.ino`](../flix/motors.ino) — PWM motor output control.
+* [`motors.ino`](../flix/motors.ino) — PWM motor outputs control.
 * [`mavlink.ino`](../flix/mavlink.ino) — interaction with QGroundControl or [pyflix](../tools/pyflix) via MAVLink protocol.
 * [`cli.ino`](../flix/cli.ino) — serial and MAVLink console.
-Utility files:
+Utility files include:
-* [`vector.h`](../flix/vector.h), [`quaternion.h`](../flix/quaternion.h) — vector and quaternion libraries.
+* [`vector.h`](../flix/vector.h), [`quaternion.h`](../flix/quaternion.h) — project's vector and quaternion libraries implementation.
-* [`pid.h`](../flix/pid.h) — generic PID controller.
+* [`pid.h`](../flix/pid.h) — generic PID controller implementation.
-* [`lpf.h`](../flix/lpf.h) — generic low-pass filter.
+* [`lpf.h`](../flix/lpf.h) — generic low-pass filter implementation.
-### Control subsystem
+## Building
-Pilot inputs are interpreted in `interpretControls()`, and then converted to the *control command*, which consists of the following:
+See build instructions in [build.md](build.md).
 * `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*.
 * `torqueTarget` *(Vector)* — target torque, range [-1, 1].
 * `thrustTarget` *(float)* — collective 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`.
 <img src="img/control.svg" width=300 alt="Control subsystem diagram">
 Armed state is stored in `armed` variable, and current mode is stored in `mode` variable.
 ### Console
 To write into the console, `print()` function is used. This function sends data both to the Serial console and to the MAVLink console (which can be accessed wirelessly in QGroundControl). The function supports formatting:
 ```cpp
 print("Test value: %.2f\n", testValue);
 ```
 In order to add a console command, modify the `doCommand()` function in `cli.ino` file.
 ## Building the firmware
 See build instructions in [usage.md](usage.md).
--- a/docs/img/arduino-ide.png
+++ b/docs/img/arduino-ide.png
--- a/docs/img/arming.svg
+++ b/docs/img/arming.svg
@@ -1,22 +0,0 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 340.21 211.28">
  <defs>
    <style>
      .a {
        fill: #d5d5d5;
      }
      .b {
        fill: #fff;
      }
      .c {
        fill: #636363;
      }
    </style>
  </defs>
  <path class="a" d="M340,159.31c-4.74-86-35.9-128.7-35.9-128.7C288.3,9.53,269.17,2.91,251.87.39s-22.31,7.87-22.31,7.87C201.7,4,170.11,4.19,170.11,4.19S138.51,4,110.65,8.26c0,0-5-10.38-22.3-7.87S51.91,9.53,36.14,30.61c0,0-31.16,42.67-35.9,128.7-2.82,51.08,19.68,55.36,38.43,50.4a60.08,60.08,0,0,0,30.55-19.66c7.51-9,19.64-25.32,34-28,17.28-3.26,33.14-4.77,45.09-4.78l21.82,0,21.81,0c12,0,27.82,1.52,45.09,4.78,14.34,2.71,26.47,19,34,28a60.06,60.06,0,0,0,30.56,19.66C320.29,214.67,342.79,210.39,340,159.31Z"/>
  <circle class="b" cx="88.54" cy="85.75" r="45.22"/>
  <circle class="b" cx="251.67" cy="85.75" r="45.22"/>
  <circle class="c" cx="251.67" cy="85.75" r="13.8"/>
  <circle class="c" cx="103.8" cy="112.12" r="13.8"/>
 </svg>
--- a/docs/img/betafpv.jpg
+++ b/docs/img/betafpv.jpg
--- a/docs/img/control.svg
+++ b/docs/img/control.svg
--- a/docs/img/controls.svg
+++ b/docs/img/controls.svg
@@ -1,123 +0,0 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 464.2 249.05">
  <defs>
    <style>
      .a {
        fill: #d5d5d5;
      }
      .b {
        fill: #fff;
      }
      .c {
        fill: #636363;
      }
      .d {
        opacity: 0.7;
      }
      .e {
        fill: none;
        stroke: #0076ba;
        stroke-linecap: round;
        stroke-miterlimit: 10;
        stroke-width: 13px;
      }
      .f {
        fill: #0076ba;
      }
      .g {
        font-size: 30px;
        font-family: Tahoma;
      }
      .h {
        letter-spacing: 0em;
      }
      .i {
        letter-spacing: -0.01em;
      }
      .j {
        letter-spacing: -0.06em;
      }
      .k {
        letter-spacing: 0em;
      }
      .l {
        letter-spacing: -0.02em;
      }
      .m {
        letter-spacing: 0em;
      }
      .n {
        opacity: 0.6;
      }
    </style>
  </defs>
  <path class="a" d="M408.84,197.08c-4.74-86-35.9-128.7-35.9-128.7C357.17,47.3,338,40.68,320.73,38.17S298.43,46,298.43,46C270.57,41.81,239,42,239,42s-31.59-.15-59.45,4.07c0,0-5-10.38-22.31-7.86S120.78,47.3,105,68.38c0,0-31.16,42.68-35.9,128.7-2.82,51.08,19.68,55.36,38.42,50.4a60.06,60.06,0,0,0,30.56-19.66c7.51-9,19.64-25.32,34-28,17.27-3.26,33.14-4.77,45.09-4.78L239,195l21.82,0c11.95,0,27.81,1.52,45.09,4.78,14.34,2.71,26.47,19,34,28a60.08,60.08,0,0,0,30.55,19.66C389.16,252.44,411.66,248.16,408.84,197.08Z"/>
  <circle class="b" cx="157.41" cy="123.52" r="45.22"/>
  <circle class="b" cx="320.54" cy="123.52" r="45.22"/>
  <circle class="c" cx="320.54" cy="123.52" r="13.8"/>
  <circle class="c" cx="157.41" cy="149.89" r="13.8"/>
  <g class="d">
    <g>
      <line class="e" x1="157.41" y1="149.89" x2="157.41" y2="49.87"/>
      <polygon class="f" points="180.74 56.7 157.41 16.29 134.07 56.7 180.74 56.7"/>
    </g>
  </g>
  <text class="g" transform="translate(38.38 25.91)">Th<tspan class="h" x="34.25" y="0">r</tspan><tspan x="44.91" y="0">o</tspan><tspan class="i" x="61.2" y="0">t</tspan><tspan x="71" y="0">tle</tspan></text>
  <g class="d">
    <g>
      <line class="e" x1="157.41" y1="149.89" x2="82.41" y2="149.89"/>
      <polygon class="f" points="89.24 126.56 48.82 149.89 89.24 173.23 89.24 126.56"/>
    </g>
  </g>
  <text class="g" transform="translate(0.18 176.36)"><tspan class="j">Y</tspan><tspan class="h" x="15.37" y="0">a</tspan><tspan x="30.97" y="0">w</tspan></text>
  <g class="d">
    <g>
      <line class="e" x1="320.54" y1="123.52" x2="320.54" y2="50.32"/>
      <polygon class="f" points="343.88 57.15 320.54 16.74 297.2 57.15 343.88 57.15"/>
    </g>
  </g>
  <text class="g" transform="translate(336.56 26.36)">P<tspan class="k" x="16.54" y="0">i</tspan><tspan x="23.45" y="0">tch</tspan></text>
  <g class="d">
    <g>
      <line class="e" x1="320.54" y1="123.52" x2="395.54" y2="123.52"/>
      <polygon class="f" points="388.71 146.86 429.12 123.52 388.71 100.19 388.71 146.86"/>
    </g>
  </g>
  <text class="g" transform="translate(416.03 160.01)"><tspan class="l">R</tspan><tspan x="18.08" y="0">o</tspan><tspan class="m" x="34.37" y="0">l</tspan><tspan x="41.31" y="0">l</tspan></text>
  <g class="d">
    <g>
      <line class="e" x1="157.41" y1="149.89" x2="213.73" y2="149.89"/>
      <polygon class="f" points="206.9 173.23 247.32 149.89 206.9 126.56 206.9 173.23"/>
    </g>
  </g>
  <g class="d">
    <g>
      <line class="e" x1="320.54" y1="124.52" x2="320.54" y2="197.73"/>
      <polygon class="f" points="297.2 190.9 320.54 231.31 343.88 190.9 297.2 190.9"/>
    </g>
  </g>
  <g class="n">
    <g>
      <line class="e" x1="318.03" y1="123.52" x2="262.32" y2="123.52"/>
      <polygon class="f" points="269.14 100.19 228.73 123.52 269.14 146.86 269.14 100.19"/>
    </g>
  </g>
  <g class="d">
    <g>
      <line class="e" x1="157.41" y1="151.66" x2="157.41" y2="197.73"/>
      <polygon class="f" points="134.07 190.9 157.41 231.31 180.74 190.9 134.07 190.9"/>
    </g>
  </g>
 </svg>
--- a/docs/img/dataflow.svg
+++ b/docs/img/dataflow.svg
--- a/docs/img/disarming.svg
+++ b/docs/img/disarming.svg
@@ -1,22 +0,0 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 340.21 211.28">
  <defs>
    <style>
      .a {
        fill: #d5d5d5;
      }
      .b {
        fill: #fff;
      }
      .c {
        fill: #636363;
      }
    </style>
  </defs>
  <path class="a" d="M340,159.31c-4.74-86-35.9-128.7-35.9-128.7C288.3,9.53,269.17,2.91,251.87.39s-22.31,7.87-22.31,7.87C201.7,4,170.11,4.19,170.11,4.19S138.51,4,110.65,8.26c0,0-5-10.38-22.3-7.87S51.91,9.53,36.14,30.61c0,0-31.16,42.67-35.9,128.7-2.82,51.08,19.68,55.36,38.43,50.4a60.08,60.08,0,0,0,30.55-19.66c7.51-9,19.64-25.32,34-28,17.28-3.26,33.14-4.77,45.09-4.78l21.82,0,21.81,0c12,0,27.82,1.52,45.09,4.78,14.34,2.71,26.47,19,34,28a60.06,60.06,0,0,0,30.56,19.66C320.29,214.67,342.79,210.39,340,159.31Z"/>
  <circle class="b" cx="88.54" cy="85.75" r="45.22"/>
  <circle class="b" cx="251.67" cy="85.75" r="45.22"/>
  <circle class="c" cx="251.67" cy="85.75" r="13.8"/>
  <circle class="c" cx="73.28" cy="112.12" r="13.8"/>
 </svg>
--- a/docs/img/drone-axes-rotate.svg
+++ b/docs/img/drone-axes-rotate.svg
@@ -1,136 +0,0 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 813.79 508.65">
  <defs>
    <style>
      .a, .d, .f, .j, .p {
        fill: none;
      }
      .a {
        stroke: #d5d5d5;
        stroke-width: 31px;
      }
      .a, .p {
        stroke-miterlimit: 10;
      }
      .b {
        fill: #ff9400;
      }
      .c {
        opacity: 0.8;
      }
      .d {
        stroke: #d80100;
      }
      .d, .f, .j {
        stroke-linejoin: bevel;
        stroke-width: 13px;
      }
      .e {
        fill: #d80100;
      }
      .f {
        stroke: #57ed00;
      }
      .g {
        fill: #57ed00;
      }
      .h {
        fill: #c1c1c1;
      }
      .i {
        opacity: 0.12;
      }
      .j {
        stroke: #0076ba;
      }
      .k {
        fill: #0076ba;
      }
      .l {
        font-size: 50px;
        font-family: Tahoma;
      }
      .m {
        letter-spacing: -0.01em;
      }
      .n {
        letter-spacing: -0.01em;
      }
      .o {
        letter-spacing: 0em;
      }
      .p {
        stroke: #000;
        stroke-width: 10px;
      }
    </style>
  </defs>
  <g>
    <g>
      <line class="a" x1="259.14" y1="432.84" x2="532.46" y2="340.23"/>
      <line class="a" x1="311.69" y1="313.16" x2="481.62" y2="461.39"/>
      <ellipse class="b" cx="311.35" cy="312.8" rx="88.68" ry="47.94"/>
      <ellipse class="b" cx="532.53" cy="340.42" rx="88.68" ry="47.94"/>
      <ellipse class="b" cx="479.72" cy="460.7" rx="88.68" ry="47.94"/>
      <ellipse class="b" cx="259.21" cy="433.03" rx="88.68" ry="47.94"/>
    </g>
    <g class="c">
      <g>
        <line class="d" x1="396.65" y1="386.83" x2="564.66" y2="35.72"/>
        <polygon class="e" points="582.76 51.95 579.15 5.42 540.66 31.8 582.76 51.95"/>
      </g>
    </g>
    <g class="c">
      <g>
        <line class="f" x1="396.77" y1="387.06" x2="69.41" y2="341.09"/>
        <polygon class="g" points="79.42 318.93 36.15 336.42 72.93 365.15 79.42 318.93"/>
      </g>
    </g>
    <ellipse class="h" cx="396.36" cy="386.61" rx="47.21" ry="25.52"/>
    <path class="i" d="M398,375.67l-14.42,12.95a4.32,4.32,0,0,0,2.35,7.5l16.81,2.11a4.33,4.33,0,0,0,4.8-5l-2.39-15.06A4.32,4.32,0,0,0,398,375.67Z"/>
    <g class="c">
      <g>
        <line class="j" x1="396.77" y1="385.56" x2="396.77" y2="92.64"/>
        <polygon class="k" points="420.1 99.47 396.77 59.06 373.43 99.47 420.1 99.47"/>
      </g>
    </g>
    <text class="l" transform="translate(0 292.27)">y/left</text>
    <text class="l" transform="translate(268.4 81.58)">z/up</text>
    <text class="l" transform="translate(600.99 43.18)">x/<tspan class="m" x="43.87" y="0">f</tspan><tspan x="59.3" y="0">or</tspan><tspan class="n" x="104.47" y="0">w</tspan><tspan x="141.14" y="0">a</tspan><tspan class="o" x="167.38" y="0">r</tspan><tspan x="185.16" y="0">d</tspan></text>
    <g class="c">
      <g>
        <path class="p" d="M470.35,114a52.71,52.71,0,0,1,103.57-2.31,51.67,51.67,0,0,1-1.33,25.92"/>
        <polygon points="562.15 128.29 563.93 154.16 585.44 139.69 562.15 128.29"/>
      </g>
    </g>
    <g class="c">
      <g>
        <path class="p" d="M344.16,164.77a52.66,52.66,0,1,0,103.78,16.31"/>
        <polygon points="460.61 184.04 446.18 162.5 434.74 185.76 460.61 184.04"/>
      </g>
    </g>
    <g class="c">
      <g>
        <path class="p" d="M138.4,411.11a52.71,52.71,0,0,1,18.43-101.94A51.68,51.68,0,0,1,182,315.65"/>
        <polygon points="170.73 324.01 196.43 327.44 186.55 303.47 170.73 324.01"/>
      </g>
    </g>
  </g>
 </svg>
--- a/docs/img/drone-axes.svg
+++ b/docs/img/drone-axes.svg
@@ -1,110 +0,0 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 664.49 478.47">
  <defs>
    <style>
      .a, .d, .f, .j {
        fill: none;
      }
      .a {
        stroke: #d5d5d5;
        stroke-miterlimit: 10;
        stroke-width: 31px;
      }
      .b {
        fill: #ff9400;
      }
      .c {
        opacity: 0.8;
      }
      .d {
        stroke: #d80100;
      }
      .d, .f, .j {
        stroke-linejoin: bevel;
        stroke-width: 13px;
      }
      .e {
        fill: #d80100;
      }
      .f {
        stroke: #57ed00;
      }
      .g {
        fill: #57ed00;
      }
      .h {
        fill: #c1c1c1;
      }
      .i {
        opacity: 0.12;
      }
      .j {
        stroke: #0076ba;
      }
      .k {
        fill: #0076ba;
      }
      .l {
        font-size: 50px;
        font-family: Tahoma;
      }
      .m {
        letter-spacing: -0.01em;
      }
      .n {
        letter-spacing: -0.01em;
      }
      .o {
        letter-spacing: 0em;
      }
    </style>
  </defs>
  <g>
    <g>
      <line class="a" x1="207.39" y1="402.28" x2="480.71" y2="309.67"/>
      <line class="a" x1="259.93" y1="282.6" x2="429.86" y2="430.83"/>
      <ellipse class="b" cx="259.59" cy="282.24" rx="88.68" ry="47.94"/>
      <ellipse class="b" cx="480.77" cy="309.86" rx="88.68" ry="47.94"/>
      <ellipse class="b" cx="427.96" cy="430.14" rx="88.68" ry="47.94"/>
      <ellipse class="b" cx="207.45" cy="402.47" rx="88.68" ry="47.94"/>
    </g>
    <g class="c">
      <g>
        <line class="d" x1="344.89" y1="356.27" x2="422.02" y2="172.47"/>
        <polygon class="e" points="440.89 187.79 435.01 141.5 397.86 169.74 440.89 187.79"/>
      </g>
    </g>
    <g class="c">
      <g>
        <line class="f" x1="345.01" y1="356.5" x2="79.27" y2="319.17"/>
        <polygon class="g" points="89.28 297.01 46.01 314.5 82.78 343.23 89.28 297.01"/>
      </g>
    </g>
    <ellipse class="h" cx="344.6" cy="356.05" rx="47.21" ry="25.52"/>
    <path class="i" d="M346.25,345.11l-14.41,12.95a4.32,4.32,0,0,0,2.34,7.5L351,367.67a4.33,4.33,0,0,0,4.8-5l-2.39-15.06A4.31,4.31,0,0,0,346.25,345.11Z"/>
    <g class="c">
      <g>
        <line class="j" x1="345.01" y1="355" x2="345.01" y2="62.08"/>
        <polygon class="k" points="368.35 68.91 345.01 28.5 321.67 68.91 368.35 68.91"/>
      </g>
    </g>
    <text class="l" transform="translate(-0.76 281.71)">y/left</text>
    <text class="l" transform="translate(371.65 38.02)">z/up</text>
    <text class="l" transform="translate(455.23 152.62)">x/<tspan class="m" x="43.87" y="0">f</tspan><tspan x="59.3" y="0">or</tspan><tspan class="n" x="104.47" y="0">w</tspan><tspan x="141.14" y="0">a</tspan><tspan class="o" x="167.38" y="0">r</tspan><tspan x="185.16" y="0">d</tspan></text>
  </g>
 </svg>
--- a/docs/img/logitech.jpg
+++ b/docs/img/logitech.jpg
--- a/docs/img/mosfet-connection.png
+++ b/docs/img/mosfet-connection.png
--- a/docs/img/motor-tape.jpg
+++ b/docs/img/motor-tape.jpg
--- a/docs/img/motors.svg
+++ b/docs/img/motors.svg
@@ -1,89 +0,0 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 356.79 357.11">
  <defs>
    <style>
      .a, .e {
        fill: none;
        stroke-miterlimit: 10;
      }
      .a {
        stroke: #d5d5d5;
        stroke-width: 31px;
      }
      .b {
        fill: #c1c1c1;
      }
      .c {
        fill: #ff9400;
      }
      .d {
        opacity: 0.12;
      }
      .e {
        stroke: #cc5200;
        stroke-width: 8px;
      }
      .f {
        fill: #cc5200;
      }
      .g {
        font-size: 50px;
        fill: #fff;
      }
      .g, .h {
        font-family: Tahoma;
      }
      .h {
        font-size: 20px;
      }
      .i {
        letter-spacing: 0em;
      }
    </style>
  </defs>
  <g>
    <g>
      <line class="a" x1="77.4" y1="278.67" x2="277.4" y2="77.67"/>
      <line class="a" x1="78.4" y1="78.67" x2="278.4" y2="279.67"/>
      <circle class="b" cx="177.9" cy="178.17" r="41.5"/>
      <circle class="c" cx="77.97" cy="78.17" r="77.95"/>
      <circle class="c" cx="277.52" cy="77.95" r="77.95"/>
    </g>
    <path class="d" d="M174.29,163.6l-8.45,26.05A4.32,4.32,0,0,0,170,195.3h16.9a4.32,4.32,0,0,0,4.11-5.65l-8.45-26.05A4.32,4.32,0,0,0,174.29,163.6Z"/>
    <g>
      <path class="e" d="M307.47,122.53a52.66,52.66,0,1,0-72.08-76"/>
      <polygon class="f" points="228.68 38.51 227.44 59.21 245.99 49.94 228.68 38.51"/>
    </g>
    <g>
      <path class="e" d="M48.11,122.22a52.66,52.66,0,1,1,72.08-75.95"/>
      <polygon class="f" points="109.59 49.63 128.14 58.91 126.9 38.2 109.59 49.63"/>
    </g>
    <text class="g" transform="translate(64.89 98.77)">3</text>
    <text class="g" transform="translate(260.92 98.8)">2</text>
    <text class="h" transform="translate(66.06 129.25)">p<tspan class="i" x="11.05" y="0">r</tspan><tspan x="18.16" y="0">op A</tspan></text>
    <text class="h" transform="translate(232.55 128.95)">p<tspan class="i" x="11.05" y="0">r</tspan><tspan x="18.16" y="0">op B</tspan></text>
    <circle class="c" cx="278.83" cy="277.92" r="77.95"/>
    <g>
      <path class="e" d="M249,322a52.66,52.66,0,1,1,72.09-76"/>
      <polygon class="f" points="310.45 249.38 329 258.66 327.76 237.95 310.45 249.38"/>
    </g>
    <text class="g" transform="translate(265.76 298.52)">1</text>
    <text class="h" transform="translate(266.92 329.01)">p<tspan class="i" x="11.05" y="0">r</tspan><tspan x="18.16" y="0">op A</tspan></text>
    <circle class="c" cx="77.95" cy="277.92" r="77.95"/>
    <g>
      <path class="e" d="M107.9,322.49a52.66,52.66,0,1,0-72.08-76"/>
      <polygon class="f" points="29.11 238.47 27.87 259.18 46.42 249.91 29.11 238.47"/>
    </g>
    <text class="g" transform="translate(61.35 298.76)">0</text>
    <text class="h" transform="translate(32.98 328.92)">p<tspan class="i" x="11.05" y="0">r</tspan><tspan x="18.16" y="0">op B</tspan></text>
  </g>
 </svg>
--- a/docs/img/qgc-attitude.png
+++ b/docs/img/qgc-attitude.png
--- a/docs/img/qgc-proxy.png
+++ b/docs/img/qgc-proxy.png
--- a/docs/img/schematics1.svg
+++ b/docs/img/schematics1.svg
--- a/docs/img/kingkong.jpg
+++ b/docs/img/kingkong.jpg
--- a/docs/img/user/goldarte/1.jpg
+++ b/docs/img/user/goldarte/1.jpg
--- a/docs/img/user/goldarte/2.jpg
+++ b/docs/img/user/goldarte/2.jpg
--- a/docs/img/user/goldarte/video.jpg
+++ b/docs/img/user/goldarte/video.jpg
--- a/docs/img/user/robocamp/1.jpg
+++ b/docs/img/user/robocamp/1.jpg
--- a/docs/img/user/school548/1.jpg
+++ b/docs/img/user/school548/1.jpg
--- a/docs/img/user/school548/2.jpg
+++ b/docs/img/user/school548/2.jpg
--- a/docs/img/user/school548/3.jpg
+++ b/docs/img/user/school548/3.jpg
--- a/docs/img/user/school548/kiraflux-video.jpg
+++ b/docs/img/user/school548/kiraflux-video.jpg
--- a/docs/img/user/school548/kiraflux1.jpg
+++ b/docs/img/user/school548/kiraflux1.jpg
--- a/docs/img/user/school548/kiraflux2.jpg
+++ b/docs/img/user/school548/kiraflux2.jpg
--- a/docs/img/user/school548/tolyan4krut-video.jpg
+++ b/docs/img/user/school548/tolyan4krut-video.jpg
--- a/docs/img/user/school548/tolyan4krut.jpg
+++ b/docs/img/user/school548/tolyan4krut.jpg
--- a/docs/img/user/school548/vlad_tolshinov1.jpg
+++ b/docs/img/user/school548/vlad_tolshinov1.jpg
--- a/docs/img/user/school548/vlad_tolshinov2.jpg
+++ b/docs/img/user/school548/vlad_tolshinov2.jpg
--- a/docs/log.md
+++ b/docs/log.md
@@ -2,7 +2,11 @@
 Flix quadcopter uses RAM to store flight log data. The default log capacity is 10 seconds at 100 Hz. This configuration can be adjusted in the `log.ino` file.
-To perform log analysis, you need to download the flight log. To to that, ensure you're connected to the drone using Wi-Fi and run the following command:
+To perform log analysis, you need to download the log right after the flight without powering off the drone. Then you can use several tools to analyze the log data.
 ## Log download
 To download the log, connect the ESP32 using USB right after the flight and run the following command:
 ```bash
 make log
--- a/docs/troubleshooting.md
+++ b/docs/troubleshooting.md
@@ -4,9 +4,8 @@
 Do the following:
-* **Check ESP32 core is installed**. Check if the version matches the one used in the [tutorial](usage.md#firmware).
+* **Check ESP32 core is installed**. Check if the version matches the one used in the [tutorial](build.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 the chosen board**. The correct board to choose in Arduino IDE for ESP32 Mini is *WEMOS D1 MINI ESP32*.
 ## The drone doesn't fly
@@ -15,7 +14,7 @@ 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 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.
+* **Make sure correct IMU model is chosen**. If using ICM-20948 board, change `MPU9250` to `ICM20948` everywhere 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*).
 * **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.
@@ -32,8 +31,7 @@ Do the following:
  * `mfl` — should rotate front left motor (clockwise).
  * `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:
+* **Calibrate the RC** if you use it. Type `cr` command in Serial Monitor and follow the instructions.
-  <img src="img/user/peter_ukhov-2/1.jpg" width="200">
+* **Check the RC data** if you use it. Use `rc` command, `Control` should show correct values between -1 and 1, and between 0 and 1 for the throttle.
 * **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.
 * **Check the gyroscope only attitude estimation**. Comment out `applyAcc();` line in `estimate.ino` and check if the attitude estimation in QGroundControl. It should be stable, but only drift very slowly.
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -1,238 +0,0 @@
 # Usage: build, setup and flight
 To fly Flix quadcopter, you need to build the firmware, upload it to the ESP32 board, and set up the drone for flight.
 To get the firmware sources, clone the repository using git:
 ```bash
 git clone https://github.com/okalachev/flix.git && cd flix
 ```
 Beginners can [download the source code as a ZIP archive](https://github.com/okalachev/flix/archive/refs/heads/master.zip).
 ## Building the firmware
 You can build and upload the firmware using either **Arduino IDE** (easier for beginners) or **command line**.
 ### Arduino IDE (Windows, Linux, macOS)
 <img src="img/arduino-ide.png" width="400" alt="Flix firmware open in Arduino IDE">
 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.
 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.
 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.
 ### Command line (Windows, Linux, macOS)
 1. [Install Arduino CLI](https://arduino.github.io/arduino-cli/installation/).
   On Linux, install it like this:
   ```bash
   curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=~/.local/bin sh
   ```
 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. Compile the firmware using `make`. Arduino dependencies will be installed automatically:
   ```bash
   make
   ```
   You can flash the firmware to the board using command:
   ```bash
   make upload
   ```
   You can also compile the firmware, upload it and start serial port monitoring using command:
   ```bash
   make upload monitor
   ```
 See other available Make commands in [Makefile](../Makefile).
 > [!TIP]
 > You can test the firmware on a bare ESP32 board without connecting IMU and other peripherals. The Wi-Fi network `flix` should appear and all the basic functionality including console and QGroundControl connection should work.
 ## Before first flight
 ### Choose the IMU model
 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
 ```
 ### Setup the IMU orientation
 The IMU orientation is defined in `rotateIMU` function in the `imu.ino` file. Change it so it converts the IMU axes to the drone's axes correctly. **Drone axes are X forward, Y left, Z up**:
 <img src="img/drone-axes.svg" width="200">
 See various [IMU boards axes orientations table](https://github.com/okalachev/flixperiph/?tab=readme-ov-file#imu-axes-orientation) to help you set up the correct orientation.
 ### Connect using QGroundControl
 QGroundControl is a ground control station software that can be used to monitor and control the drone.
 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
 ### Access console
 The console is a command line interface (CLI) that allows to interact with the drone, change parameters, and perform various actions. There are two ways of accessing the console: using **serial port** or using **QGroundControl (wirelessly)**.
 To access the console using serial port:
 1. Connect the ESP32 board to the computer using USB cable.
 2. Open Serial Monitor in Arduino IDE (or use `make monitor` in the command line).
 3. In Arduino IDE, make sure the baudrate is set to 115200.
 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*.
   <img src="img/cli.png" width="400">
 > [!TIP]
 > Use `help` command to see the list of available commands.
 ### Calibrate accelerometer
 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
 1. 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.
   * 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:
   <img src="img/qgc-attitude.png" height="200">
 3. Perform motor tests in the console. 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).
 > [!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).
 ### Control with smartphone
 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.
 3. Connect your smartphone to the appeared `flix` Wi-Fi network (password: `flixwifi`).
 4. Open QGroundControl app. It should connect and begin showing the drone's telemetry automatically.
 5. Go to the settings and enable *Virtual Joystick*. *Auto-Center Throttle* setting **should be disabled**.
 6. Use the virtual joystick to fly the drone!
 > [!TIP]
 > Decrease `CTL_TILT_MAX` parameter when flying using the smartphone to make the controls less sensitive.
 ### Control with remote control
 Before using remote SBUS-connected remote control, you need to 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!
 ### Control with USB remote control
 If your drone doesn't have RC receiver installed, you can use USB remote control and QGroundControl app to fly it.
 1. Install [QGroundControl](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/getting_started/download_and_install.html) app on your computer.
 2. Connect your USB remote control to the computer.
 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.
 7. Use the USB remote control to fly the drone!
 ## Flight
 For both virtual sticks and a physical joystick, the default control scheme is left stick for throttle and yaw and right stick for pitch and roll:
 <img src="img/controls.svg" width="300">
 ### Arming and disarming
 To start the motors, you should **arm** the drone. To do that, move the left stick to the bottom right corner:
 <img src="img/arming.svg" width="150">
 After that, the motors **will start spinning** at low speed, indicating that the drone is armed and ready to fly.
 When finished flying, **disarm** the drone, moving the left stick to the bottom left corner:
 <img src="img/disarming.svg" width="150">
 > [!NOTE]
 > If something goes wrong, go to the [Troubleshooting](troubleshooting.md) article.
 ### Flight modes
 Flight mode is changed using mode switch on the remote control or using the command line.
 #### 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.
 > [!IMPORTANT]
 > The drone doesn't stabilize its position, so slight drift is possible. The pilot should compensate it manually.
 #### ACRO
 In this mode, the pilot controls the angular rates. This control method is difficult to fly and mostly used in FPV racing.
 #### RAW
 *RAW* mode disables all the stabilization, and the pilot inputs are mixed directly to the motors. The IMU sensor is not involved. This mode is intended for testing and demonstration purposes only, and basically the drone **cannot fly in this mode**.
 #### 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.
 If the pilot moves the control sticks, the drone will switch back to *STAB* mode.
 ## Adjusting parameters
 You can adjust some of the drone's parameters (include PID coefficients) in QGroundControl. In order to do that, go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Parameters*.
 <img src="img/parameters.png" width="400">
 ## Flight log
 After the flight, you can download the flight log for analysis wirelessly. Use the following for that:
 ```bash
 make log
 ```
 See more details about log analysis in the [log analysis](log.md) article.
--- a/docs/user.md
+++ b/docs/user.md
@@ -4,74 +4,6 @@ This page contains user-built drones based on the Flix project. Publish your pro
 ---
 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>
 **Flight video:**
 <a href="https://drive.google.com/file/d/1nQtFjEcGGLx-l4xkL5ko9ZpOTVU-WDjL/view?usp=sharing"><img height=200 src="img/user/goldarte/video.jpg"></a>
 ---
 ## 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.
 <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">
 ### Selected works
 Author: [KiraFlux](https://t.me/@kiraflux_0XC0000005).<br>
 Description: **custom ESPNOW remote control** is implemented, firmware modified to support ESPNOW protocol.<br>
 Telegram posts: https://t.me/opensourcequadcopter/106, 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>
 Drone design: https://github.com/KiraFlux/Klyax.<br>
 <img src="img/user/school548/kiraflux1.jpg" height=150> <img src="img/user/school548/kiraflux2.jpg" height=150>
 **Flight video**:
 <img height=200 src="img/user/school548/kiraflux-video.jpg"><a href="https://drive.google.com/file/d/1soHDAeHQWnm97Y4dg4nWevJuMiTdJJXW/view?usp=sharing"></a>
 Author: [tolyan4krut](https://t.me/tolyan4krut).<br>
 Description: the first drone based on ESP32-S3-CAM board **with a camera**, implementing Wi-Fi video streaming. Runs HTTP server and HTTP video stream.<br>
 Modified Flix firmware: https://github.com/CatRey/Flix-Camera-Streaming.<br>
 Telegram post: https://t.me/opensourcequadcopter/117.
 <img src="img/user/school548/tolyan4krut.jpg" height=150>
 **Flight video**:
 <a href="https://drive.google.com/file/d/1KuOBsujLsk7q8FoqKD8u7uoq4ptS5onp/view?usp=sharing"><img height=200 src="img/user/school548/tolyan4krut-video.jpg"></a>
 Author: [Vlad Tolshinov](https://t.me/Vlad_Tolshinov).<br>
 Description: custom frame with enlarged arm length, that provides very high level of stability, 65 mm props.
 <img src="img/user/school548/vlad_tolshinov1.jpg" height=150> <img src="img/user/school548/vlad_tolshinov2.jpg" height=150>
 ---
 ## RoboCamp
 Author: RoboCamp participants.<br>
 Description: 3D-printed and wooden frames, ESP32 Mini, DC-DC buck-boost converters. BetaFPV LiteRadio 3 to control the drones via Wi-Fi connection.<br>
 Features: altitude hold, obstacle avoidance, autonomous flight elements.<br>
 Some of the designed model files: https://drive.google.com/drive/folders/18YHWGquKeIevzrMH4-OUT-zKXMETTEUu?usp=share_link.
 RoboCamp took place in July 2025, Saint Petersburg, where 9 participants designed and built their own drones using the Flix project, and then modified the firmware to complete specific flight tasks.
 See the detailed video about the event:
 <a href="https://youtu.be/Wd3yaorjTx0"><img width=500 src="https://img.youtube.com/vi/Wd3yaorjTx0/sddefault.jpg"></a>
 Built drones:
 <img src="img/user/robocamp/1.jpg" width=500>
 ---
 Author: chkroko.<br>
 Description: the first Flix drone built with **brushless motors** (DShot interface).<br>
 Features: SpeedyBee BLS 35A Mini V2 ESC, ESP32-S3 board, EMAX ECO 2 2207 1700kv motors, ICM20948V2 IMU, INA226 power monitor and Bluetooth gamepad for control.<br>
--- a/docs/version0.md
+++ b/docs/version0.md
@@ -14,7 +14,7 @@ Flix version 0 (obsolete):
 |Motor|8520 3.7V brushed motor (**shaft 0.8mm!**)|<img src="img/motor.jpeg" width=100>|4|
 |Propeller|Hubsan 55 mm|<img src="img/prop.jpg" width=100>|4|
 |Motor ESC|2.7A 1S Dual Way Micro Brush ESC|<img src="img/esc.jpg" width=100>|4|
-|RC transmitter|KINGKONG TINY X8|<img src="img/kingkong.jpg" width=100>|1|
+|RC transmitter|KINGKONG TINY X8|<img src="img/tx.jpg" width=100>|1|
 |RC receiver|DF500 (SBUS)|<img src="img/rx.jpg" width=100>|1|
 |~~SBUS inverter~~*||<img src="img/inv.jpg" width=100>|~~1~~|
 |Battery|3.7 Li-Po 850 MaH 60C|||
--- a/flix/cli.ino
+++ b/flix/cli.ino
@@ -8,10 +8,11 @@
 #include "util.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 ACRO, STAB, AUTO;
-extern float t, dt, loopRate;
+extern float loopRate, dt;
 extern double t;
 extern uint16_t channels[16];
-extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlMode;
+extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlArmed, controlMode;
 extern int mode;
 extern bool armed;
@@ -33,13 +34,12 @@ const char* motd =
 "ps - show pitch/roll/yaw\n"
 "psq - show attitude quaternion\n"
 "imu - show IMU data\n"
-"arm - arm the drone\n"
+"arm - arm the drone (when no armed switch)\n"
-"disarm - disarm the drone\n"
+"disarm - disarm the drone (when no armed switch)\n"
-"raw/stab/acro/auto - set mode\n"
+"stab/acro/auto - set mode (when no mode switch)\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"
+"log - dump in-RAM log\n"
 "cr - calibrate RC\n"
 "ca - calibrate accel\n"
 "mfr, mfl, mrr, mrl - test motor (remove props)\n"
@@ -60,7 +60,7 @@ void print(const char* format, ...) {
 }
 void pause(float duration) {
-	float start = t;
+	double start = t;
 	while (t - start < duration) {
 		step();
 		handleInput();
@@ -75,10 +75,9 @@ void doCommand(String str, bool echo = false) {
 	// parse command
 	String command, arg0, arg1;
 	splitString(str, command, arg0, arg1);
 	if (command.isEmpty()) return;
 	// echo command
-	if (echo) {
+	if (echo && !command.isEmpty()) {
 		print("> %s\n", str.c_str());
 	}
@@ -108,17 +107,18 @@ void doCommand(String str, bool echo = false) {
 		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);
+		print("qx: %f qy: %f qz: %f qw: %f\n", attitude.x, attitude.y, attitude.z, attitude.w);
 	} else if (command == "imu") {
 		printIMUInfo();
 		print("gyro: %f %f %f\n", rates.x, rates.y, rates.z);
 		print("acc: %f %f %f\n", acc.x, acc.y, acc.z);
 		printIMUCalibration();
 		print("rate: %.0f\n", loopRate);
 		print("landed: %d\n", landed);
 	} else if (command == "arm") {
 		armed = true;
 	} else if (command == "disarm") {
 		armed = false;
 	} else if (command == "raw") {
 		mode = RAW;
 	} else if (command == "stab") {
 		mode = STAB;
 	} else if (command == "acro") {
@@ -130,20 +130,15 @@ void doCommand(String str, bool echo = false) {
 		for (int i = 0; i < 16; i++) {
 			print("%u ", channels[i]);
 		}
-		print("\nroll: %g pitch: %g yaw: %g throttle: %g mode: %g\n",
+		print("\nroll: %g pitch: %g yaw: %g throttle: %g armed: %g mode: %g\n",
-			controlRoll, controlPitch, controlYaw, controlThrottle, controlMode);
+			controlRoll, controlPitch, controlYaw, controlThrottle, controlArmed, controlMode);
 		print("mode: %s\n", getModeName());
 		print("armed: %d\n", armed);
 	} else if (command == "wifi") {
 #if WIFI_ENABLED
 		printWiFiInfo();
 #endif
 	} 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") {
-		printLogHeader();
+		dumpLog();
 		if (arg0 == "dump") printLogData();
 	} else if (command == "cr") {
 		calibrateRC();
 	} else if (command == "ca") {
@@ -179,6 +174,8 @@ void doCommand(String str, bool echo = false) {
 		attitude = Quaternion();
 	} else if (command == "reboot") {
 		ESP.restart();
 	} else if (command == "") {
 		// do nothing
 	} else {
 		print("Invalid command: %s\n", command.c_str());
 	}
--- a/flix/control.ino
+++ b/flix/control.ino
@@ -34,7 +34,7 @@
 #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 MANUAL = 0, ACRO = 1, STAB = 2, AUTO = 3; // flight modes
 int mode = STAB;
 bool armed = false;
@@ -54,7 +54,7 @@ Vector torqueTarget;
 float thrustTarget;
 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
-extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlMode;
+extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlArmed, controlMode;
 void control() {
 	interpretControls();
@@ -65,42 +65,47 @@ void control() {
 }
 void interpretControls() {
 	// NOTE: put ACRO or MANUAL modes there if you want to use them
 	if (controlMode < 0.25) mode = STAB;
 	if (controlMode < 0.75) mode = STAB;
-	if (controlMode > 0.75) mode = STAB;
+	if (controlMode > 0.75) mode = AUTO;
 	if (controlArmed < 0.5) armed = false;
 	if (mode == AUTO) return; // pilot is not effective in AUTO mode
-	if (controlThrottle < 0.05 && controlYaw > 0.95) armed = true; // arm gesture
+	if (landed && controlThrottle == 0 && controlYaw > 0.95) armed = true; // arm gesture
-	if (controlThrottle < 0.05 && controlYaw < -0.95) armed = false; // disarm gesture
+	if (landed && controlThrottle == 0 && controlYaw < -0.95) armed = false; // disarm gesture
 	if (abs(controlYaw) < 0.1) controlYaw = 0; // yaw dead zone
 	thrustTarget = controlThrottle;
 	if (mode == STAB) {
 		float yawTarget = attitudeTarget.getYaw();
-		if (!armed || invalid(yawTarget) || controlYaw != 0) yawTarget = attitude.getYaw(); // reset yaw target
+		if (invalid(yawTarget) || controlYaw != 0) yawTarget = attitude.getYaw(); // reset yaw target if NAN or pilot commands yaw rate
 		attitudeTarget = Quaternion::fromEuler(Vector(controlRoll * tiltMax, controlPitch * tiltMax, yawTarget));
 		ratesExtra = Vector(0, 0, -controlYaw * maxRate.z); // positive yaw stick means clockwise rotation in FLU
 	}
 	if (mode == ACRO) {
-		attitudeTarget.invalidate(); // skip attitude control
+		attitudeTarget.invalidate();
 		ratesTarget.x = controlRoll * maxRate.x;
 		ratesTarget.y = controlPitch * maxRate.y;
 		ratesTarget.z = -controlYaw * maxRate.z; // positive yaw stick means clockwise rotation in FLU
 	}
-	if (mode == RAW) { // direct torque control
+	if (mode == MANUAL) { // passthrough mode
-		attitudeTarget.invalidate(); // skip attitude control
+		attitudeTarget.invalidate();
-		ratesTarget.invalidate(); // skip rate control
+		ratesTarget.invalidate();
-		torqueTarget = Vector(controlRoll, controlPitch, -controlYaw) * 0.1;
+		torqueTarget = Vector(controlRoll, controlPitch, -controlYaw) * 0.01;
 	}
 }
 void controlAttitude() {
-	if (!armed || attitudeTarget.invalid() || thrustTarget < 0.1) return; // skip attitude control
+	if (!armed || attitudeTarget.invalid()) { // skip attitude control
 		rollPID.reset();
 		pitchPID.reset();
 		yawPID.reset();
 		return;
 	}
 	const Vector up(0, 0, 1);
 	Vector upActual = Quaternion::rotateVector(up, attitude);
@@ -108,38 +113,34 @@ void controlAttitude() {
 	Vector error = Vector::rotationVectorBetween(upTarget, upActual);
-	ratesTarget.x = rollPID.update(error.x) + ratesExtra.x;
+	ratesTarget.x = rollPID.update(error.x, dt) + ratesExtra.x;
-	ratesTarget.y = pitchPID.update(error.y) + ratesExtra.y;
+	ratesTarget.y = pitchPID.update(error.y, dt) + ratesExtra.y;
 	float yawError = wrapAngle(attitudeTarget.getYaw() - attitude.getYaw());
-	ratesTarget.z = yawPID.update(yawError) + ratesExtra.z;
+	ratesTarget.z = yawPID.update(yawError, dt) + ratesExtra.z;
 }
 void controlRates() {
-	if (!armed || ratesTarget.invalid() || thrustTarget < 0.1) return; // skip rates control
+	if (!armed || ratesTarget.invalid()) { // skip rates control
 		rollRatePID.reset();
 		pitchRatePID.reset();
 		yawRatePID.reset();
 		return;
 	}
 	Vector error = ratesTarget - rates;
 	// Calculate desired torque, where 0 - no torque, 1 - maximum possible torque
-	torqueTarget.x = rollRatePID.update(error.x);
+	torqueTarget.x = rollRatePID.update(error.x, dt);
-	torqueTarget.y = pitchRatePID.update(error.y);
+	torqueTarget.y = pitchRatePID.update(error.y, dt);
-	torqueTarget.z = yawRatePID.update(error.z);
+	torqueTarget.z = yawRatePID.update(error.z, dt);
 }
 void controlTorque() {
 	if (!torqueTarget.valid()) return; // skip torque control
-	if (!armed) {
+	if (!armed || thrustTarget < 0.05) {
-		memset(motors, 0, sizeof(motors)); // stop motors if disarmed
+		memset(motors, 0, sizeof(motors)); // stop motors if no thrust
 		return;
 	}
 	if (thrustTarget < 0.1) {
 		motors[0] = 0.1; // idle thrust
 		motors[1] = 0.1;
 		motors[2] = 0.1;
 		motors[3] = 0.1;
 		return;
 	}
@@ -156,7 +157,7 @@ void controlTorque() {
 const char* getModeName() {
 	switch (mode) {
-		case RAW: return "RAW";
+		case MANUAL: return "MANUAL";
 		case ACRO: return "ACRO";
 		case STAB: return "STAB";
 		case AUTO: return "AUTO";
--- a/flix/estimate.ino
+++ b/flix/estimate.ino
@@ -11,6 +11,8 @@
 #define WEIGHT_ACC 0.003
 #define RATES_LFP_ALPHA 0.2 // cutoff frequency ~ 40 Hz
 LowPassFilter<Vector> ratesFilter(RATES_LFP_ALPHA);
 void estimate() {
 	applyGyro();
 	applyAcc();
@@ -18,7 +20,6 @@ void estimate() {
 void applyGyro() {
 	// filter gyro to get angular rates
 	static LowPassFilter<Vector> ratesFilter(RATES_LFP_ALPHA);
 	rates = ratesFilter.update(gyro);
 	// apply rates to attitude
--- a/flix/failsafe.ino
+++ b/flix/failsafe.ino
@@ -3,10 +3,12 @@
 // Fail-safe functions
-#define RC_LOSS_TIMEOUT 1
+#include "util.h"
 #define DESCEND_TIME 10
-extern float controlTime;
+#define RC_LOSS_TIMEOUT 0.5
 #define DESCEND_TIME 3.0 // time to descend from full throttle to zero
 extern double controlTime;
 extern float controlRoll, controlPitch, controlThrottle, controlYaw;
 void failsafe() {
@@ -16,33 +18,33 @@ void failsafe() {
 // RC loss failsafe
 void rcLossFailsafe() {
-	if (controlTime == 0) return; // no RC at all
+	if (mode == AUTO) return;
 	if (!armed) return;
 	if (t - controlTime > RC_LOSS_TIMEOUT) {
 		descend();
 	}
 }
 // Smooth descend on RC lost
 void descend() {
 	mode = AUTO;
 	attitudeTarget = Quaternion();
 	thrustTarget -= dt / DESCEND_TIME;
 	if (thrustTarget < 0) {
 		thrustTarget = 0;
 		armed = false;
 	}
 }
 // 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 && invalid(controlMode)) {
-		if (mode == AUTO) mode = STAB; // regain control by the pilot
+			mode = STAB; // regain control to the pilot
 		}
 	}
 	roll = controlRoll;
 	pitch = controlPitch;
 	yaw = controlYaw;
 	throttle = controlThrottle;
 }
 // Smooth descend on RC lost
 void descend() {
 	mode = AUTO;
 	thrustTarget -= dt / DESCEND_TIME;
 	if (thrustTarget < 0) thrustTarget = 0;
 	if (thrustTarget == 0) armed = false;
 }
--- a/flix/flix.ino
+++ b/flix/flix.ino
@@ -7,12 +7,13 @@
 #include "quaternion.h"
 #include "util.h"
 #define SERIAL_BAUDRATE 115200
 #define WIFI_ENABLED 1
-float t = NAN; // current step time, s
+double 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;
+float controlArmed = NAN, controlMode = NAN;
 Vector gyro; // gyroscope data
 Vector acc; // accelerometer data, m/s/s
 Vector rates; // filtered angular rates, rad/s
@@ -21,7 +22,7 @@ bool landed; // are we landed and stationary
 float motors[4]; // normalized motors thrust in range [0..1]
 void setup() {
-	Serial.begin(115200);
+	Serial.begin(SERIAL_BAUDRATE);
 	print("Initializing flix\n");
 	disableBrownOut();
 	setupParameters();
--- a/flix/imu.ino
+++ b/flix/imu.ino
@@ -4,12 +4,11 @@
 // Work with the IMU sensor
 #include <SPI.h>
-#include <FlixPeriph.h>
+#include <MPU9250.h>
 #include "vector.h"
 #include "lpf.h"
 #include "util.h"
-MPU9250 imu(SPI);
+MPU9250 IMU(SPI);
 Vector accBias;
 Vector accScale(1, 1, 1);
@@ -17,22 +16,22 @@ Vector gyroBias;
 void setupIMU() {
 	print("Setup IMU\n");
-	imu.begin();
+	IMU.begin();
 	configureIMU();
 }
 void configureIMU() {
-	imu.setAccelRange(imu.ACCEL_RANGE_4G);
+	IMU.setAccelRange(IMU.ACCEL_RANGE_4G);
-	imu.setGyroRange(imu.GYRO_RANGE_2000DPS);
+	IMU.setGyroRange(IMU.GYRO_RANGE_2000DPS);
-	imu.setDLPF(imu.DLPF_MAX);
+	IMU.setDLPF(IMU.DLPF_MAX);
-	imu.setRate(imu.RATE_1KHZ_APPROX);
+	IMU.setRate(IMU.RATE_1KHZ_APPROX);
-	imu.setupInterrupt();
+	IMU.setupInterrupt();
 }
 void readIMU() {
-	imu.waitForData();
+	IMU.waitForData();
-	imu.getGyro(gyro.x, gyro.y, gyro.z);
+	IMU.getGyro(gyro.x, gyro.y, gyro.z);
-	imu.getAccel(acc.x, acc.y, acc.z);
+	IMU.getAccel(acc.x, acc.y, acc.z);
 	calibrateGyroOnce();
 	// apply scale and bias
 	acc = (acc - accBias) / accScale;
@@ -50,8 +49,9 @@ void rotateIMU(Vector& data) {
 }
 void calibrateGyroOnce() {
-	static Delay landedDelay(2);
+	static float landedTime = 0;
-	if (!landedDelay.update(landed)) return; // calibrate only if definitely stationary
+	landedTime = landed ? landedTime + dt : 0;
 	if (landedTime < 2) return; // calibrate only if definitely stationary
 	static LowPassFilter<Vector> gyroCalibrationFilter(0.001);
 	gyroBias = gyroCalibrationFilter.update(gyro);
@@ -59,7 +59,7 @@ void calibrateGyroOnce() {
 void calibrateAccel() {
 	print("Calibrating accelerometer\n");
-	imu.setAccelRange(imu.ACCEL_RANGE_2G); // the most sensitive mode
+	IMU.setAccelRange(IMU.ACCEL_RANGE_2G); // the most sensitive mode
 	print("1/6 Place level [8 sec]\n");
 	pause(8);
@@ -93,9 +93,9 @@ void calibrateAccelOnce() {
 	// Compute the average of the accelerometer readings
 	acc = Vector(0, 0, 0);
 	for (int i = 0; i < samples; i++) {
-		imu.waitForData();
+		IMU.waitForData();
 		Vector sample;
-		imu.getAccel(sample.x, sample.y, sample.z);
+		IMU.getAccel(sample.x, sample.y, sample.z);
 		acc = acc + sample;
 	}
 	acc = acc / samples;
@@ -119,16 +119,7 @@ void printIMUCalibration() {
 }
 void printIMUInfo() {
-	imu.status() ? print("status: ERROR %d\n", imu.status()) : print("status: OK\n");
+	IMU.status() ? print("status: ERROR %d\n", IMU.status()) : print("status: OK\n");
-	print("model: %s\n", imu.getModel());
+	print("model: %s\n", IMU.getModel());
-	print("who am I: 0x%02X\n", imu.whoAmI());
+	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("acc: %f %f %f\n", acc.x, acc.y, acc.z);
 	imu.waitForData();
 	Vector rawGyro, rawAcc;
 	imu.getGyro(rawGyro.x, rawGyro.y, rawGyro.z);
 	imu.getAccel(rawAcc.x, rawAcc.y, rawAcc.z);
 	print("raw gyro: %f %f %f\n", rawGyro.x, rawGyro.y, rawGyro.z);
 	print("raw acc: %f %f %f\n", rawAcc.x, rawAcc.y, rawAcc.z);
 }
--- a/flix/log.ino
+++ b/flix/log.ino
@@ -4,12 +4,13 @@
 // In-RAM logging
 #include "vector.h"
 #include "util.h"
 #define LOG_RATE 100
 #define LOG_DURATION 10
 #define LOG_PERIOD 1.0 / LOG_RATE
 #define LOG_SIZE LOG_DURATION * LOG_RATE
 float tFloat;
 Vector attitudeEuler;
 Vector attitudeTargetEuler;
@@ -19,7 +20,7 @@ struct LogEntry {
 };
 LogEntry logEntries[] = {
-	{"t", &t},
+	{"t", &tFloat},
 	{"rates.x", &rates.x},
 	{"rates.y", &rates.y},
 	{"rates.z", &rates.z},
@@ -39,6 +40,7 @@ const int logColumns = sizeof(logEntries) / sizeof(logEntries[0]);
 float logBuffer[LOG_SIZE][logColumns];
 void prepareLogData() {
 	tFloat = t;
 	attitudeEuler = attitude.toEuler();
 	attitudeTargetEuler = attitudeTarget.toEuler();
 }
@@ -46,8 +48,9 @@ void prepareLogData() {
 void logData() {
 	if (!armed) return;
 	static int logPointer = 0;
-	static Rate period(LOG_RATE);
+	static double logTime = 0;
-	if (!period) return;
+	if (t - logTime < LOG_PERIOD) return;
 	logTime = t;
 	prepareLogData();
@@ -61,13 +64,12 @@ void logData() {
 	}
 }
-void printLogHeader() {
+void dumpLog() {
 	// Print header
 	for (int i = 0; i < logColumns; i++) {
 		print("%s%s", logEntries[i].name, i < logColumns - 1 ? "," : "\n");
 	}
-}
+	// Print data
 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++) {
--- a/flix/mavlink.ino
+++ b/flix/mavlink.ino
@@ -6,17 +6,17 @@
 #if WIFI_ENABLED
 #include <MAVLink.h>
 #include "util.h"
 #define SYSTEM_ID 1
-#define MAVLINK_RATE_SLOW 1
+#define PERIOD_SLOW 1.0
-#define MAVLINK_RATE_FAST 10
+#define PERIOD_FAST 0.1
 #define MAVLINK_CONTROL_YAW_DEAD_ZONE 0.1f
-bool mavlinkConnected = false;
+float mavlinkControlScale = 0.7;
 String mavlinkPrintBuffer;
-extern float controlTime;
+extern double controlTime;
-extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlMode;
+extern float controlRoll, controlPitch, controlThrottle, controlYaw, controlArmed, controlMode;
 void processMavlink() {
 	sendMavlink();
@@ -26,27 +26,30 @@ void processMavlink() {
 void sendMavlink() {
 	sendMavlinkPrint();
 	static double lastSlow = 0;
 	static double lastFast = 0;
 	mavlink_message_t msg;
 	uint32_t time = t * 1000;
-	static Rate slow(MAVLINK_RATE_SLOW), fast(MAVLINK_RATE_FAST);
+	if (t - lastSlow >= PERIOD_SLOW) {
 		lastSlow = t;
 	if (slow) {
 		mavlink_msg_heartbeat_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, MAV_TYPE_QUADROTOR, MAV_AUTOPILOT_GENERIC,
-			(armed ? MAV_MODE_FLAG_SAFETY_ARMED : 0) |
+			(armed * MAV_MODE_FLAG_SAFETY_ARMED) |
-			((mode == STAB) ? MAV_MODE_FLAG_STABILIZE_ENABLED : 0) |
+			(mode == STAB) * MAV_MODE_FLAG_STABILIZE_ENABLED |
 			((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
 		mavlink_msg_extended_sys_state_pack(SYSTEM_ID, 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) {
+	if (t - lastFast >= PERIOD_FAST) {
 		lastFast = t;
 		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
@@ -78,7 +81,6 @@ void sendMessage(const void *msg) {
 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;
@@ -99,11 +101,14 @@ void handleMavlink(const void *_msg) {
 		if (m.target && m.target != SYSTEM_ID) return; // 0 is broadcast
 		controlThrottle = m.z / 1000.0f;
-		controlPitch = m.x / 1000.0f;
+		controlPitch = m.x / 1000.0f * mavlinkControlScale;
-		controlRoll = m.y / 1000.0f;
+		controlRoll = m.y / 1000.0f * mavlinkControlScale;
-		controlYaw = m.r / 1000.0f;
+		controlYaw = m.r / 1000.0f * mavlinkControlScale;
-		controlMode = NAN;
+		controlMode = NAN; // keep mode
 		controlArmed = NAN;
 		controlTime = t;
 		if (abs(controlYaw) < MAVLINK_CONTROL_YAW_DEAD_ZONE) controlYaw = 0;
 	}
 	if (msg.msgid == MAVLINK_MSG_ID_PARAM_REQUEST_LIST) {
@@ -190,6 +195,7 @@ void handleMavlink(const void *_msg) {
 		ratesExtra = Vector(0, 0, 0);
 		if (m.type_mask & ATTITUDE_TARGET_TYPEMASK_ATTITUDE_IGNORE) attitudeTarget.invalidate();
 		armed = m.thrust > 0;
 	}
@@ -200,25 +206,7 @@ void handleMavlink(const void *_msg) {
 		mavlink_msg_set_actuator_control_target_decode(&msg, &m);
 		if (m.target_system && m.target_system != SYSTEM_ID) return;
 		attitudeTarget.invalidate();
 		ratesTarget.invalidate();
 		torqueTarget.invalidate();
 		memcpy(motors, m.controls, sizeof(motors)); // copy motor thrusts
 		armed = motors[0] > 0 || motors[1] > 0 || motors[2] > 0 || motors[3] > 0;
 	}
 	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;
 		// 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);
 		}
 	}
 	// Handle commands
@@ -226,33 +214,30 @@ void handleMavlink(const void *_msg) {
 		mavlink_command_long_t m;
 		mavlink_msg_command_long_decode(&msg, &m);
 		if (m.target_system && m.target_system != SYSTEM_ID) return;
 		mavlink_message_t ack;
 		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_command_ack_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &ack, m.command, MAV_RESULT_ACCEPTED, UINT8_MAX, 0, msg.sysid, msg.compid);
 			sendMessage(&ack);
 			mavlink_msg_autopilot_version_pack(SYSTEM_ID, 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
 			accepted = true;
 			armed = m.param1 == 1;
 		}
 		if (m.command == MAV_CMD_DO_SET_MODE) {
-			if (m.param2 < 0 || m.param2 > AUTO) return; // incorrect mode
+			if (!(m.param2 >= 0 && m.param2 <= AUTO)) return; // incorrect mode
 			accepted = true;
 			mode = m.param2;
 			mavlink_msg_command_ack_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &ack, m.command, MAV_RESULT_ACCEPTED, UINT8_MAX, 0, msg.sysid, msg.compid);
 			sendMessage(&ack);
 		}
-		// send command ack
+		if (m.command == MAV_CMD_COMPONENT_ARM_DISARM) {
-		mavlink_message_t ack;
+			armed = m.param1 == 1;
-		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(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &ack, m.command, MAV_RESULT_ACCEPTED, UINT8_MAX, 0, msg.sysid, msg.compid);
 			sendMessage(&ack);
 		}
 	}
 }
 // Send shell output to GCS
--- a/flix/motors.ino
+++ b/flix/motors.ino
@@ -38,9 +38,9 @@ void setupMotors() {
 int getDutyCycle(float value) {
 	value = constrain(value, 0, 1);
-	float pwm = mapf(value, 0, 1, PWM_MIN, PWM_MAX);
+	float pwm = mapff(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);
+	float duty = mapff(pwm, 0, 1000000 / PWM_FREQUENCY, 0, (1 << PWM_RESOLUTION) - 1);
 	return round(duty);
 }
--- a/flix/parameters.ino
+++ b/flix/parameters.ino
@@ -4,51 +4,51 @@
 // Parameters storage in flash memory
 #include <Preferences.h>
 #include "util.h"
 extern float channelZero[16];
 extern float channelMax[16];
 extern float rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
 extern float mavlinkControlScale;
 Preferences storage;
 struct Parameter {
-	const char *name; // max length is 15 (Preferences key limit)
+	const char *name; // max length is 16
 	float *variable;
 	float value; // cache
 };
 Parameter parameters[] = {
 	// control
-	{"CTL_R_RATE_P", &rollRatePID.p},
+	{"ROLLRATE_P", &rollRatePID.p},
-	{"CTL_R_RATE_I", &rollRatePID.i},
+	{"ROLLRATE_I", &rollRatePID.i},
-	{"CTL_R_RATE_D", &rollRatePID.d},
+	{"ROLLRATE_D", &rollRatePID.d},
-	{"CTL_R_RATE_WU", &rollRatePID.windup},
+	{"ROLLRATE_I_LIM", &rollRatePID.windup},
-	{"CTL_P_RATE_P", &pitchRatePID.p},
+	{"PITCHRATE_P", &pitchRatePID.p},
-	{"CTL_P_RATE_I", &pitchRatePID.i},
+	{"PITCHRATE_I", &pitchRatePID.i},
-	{"CTL_P_RATE_D", &pitchRatePID.d},
+	{"PITCHRATE_D", &pitchRatePID.d},
-	{"CTL_P_RATE_WU", &pitchRatePID.windup},
+	{"PITCHRATE_I_LIM", &pitchRatePID.windup},
-	{"CTL_Y_RATE_P", &yawRatePID.p},
+	{"YAWRATE_P", &yawRatePID.p},
-	{"CTL_Y_RATE_I", &yawRatePID.i},
+	{"YAWRATE_I", &yawRatePID.i},
-	{"CTL_Y_RATE_D", &yawRatePID.d},
+	{"YAWRATE_D", &yawRatePID.d},
-	{"CTL_R_P", &rollPID.p},
+	{"ROLL_P", &rollPID.p},
-	{"CTL_R_I", &rollPID.i},
+	{"ROLL_I", &rollPID.i},
-	{"CTL_R_D", &rollPID.d},
+	{"ROLL_D", &rollPID.d},
-	{"CTL_P_P", &pitchPID.p},
+	{"PITCH_P", &pitchPID.p},
-	{"CTL_P_I", &pitchPID.i},
+	{"PITCH_I", &pitchPID.i},
-	{"CTL_P_D", &pitchPID.d},
+	{"PITCH_D", &pitchPID.d},
-	{"CTL_Y_P", &yawPID.p},
+	{"YAW_P", &yawPID.p},
-	{"CTL_P_RATE_MAX", &maxRate.y},
+	{"PITCHRATE_MAX", &maxRate.y},
-	{"CTL_R_RATE_MAX", &maxRate.x},
+	{"ROLLRATE_MAX", &maxRate.x},
-	{"CTL_Y_RATE_MAX", &maxRate.z},
+	{"YAWRATE_MAX", &maxRate.z},
-	{"CTL_TILT_MAX", &tiltMax},
+	{"TILT_MAX", &tiltMax},
 	// imu
-	{"IMU_ACC_BIAS_X", &accBias.x},
+	{"ACC_BIAS_X", &accBias.x},
-	{"IMU_ACC_BIAS_Y", &accBias.y},
+	{"ACC_BIAS_Y", &accBias.y},
-	{"IMU_ACC_BIAS_Z", &accBias.z},
+	{"ACC_BIAS_Z", &accBias.z},
-	{"IMU_ACC_SCALE_X", &accScale.x},
+	{"ACC_SCALE_X", &accScale.x},
-	{"IMU_ACC_SCALE_Y", &accScale.y},
+	{"ACC_SCALE_Y", &accScale.y},
-	{"IMU_ACC_SCALE_Z", &accScale.z},
+	{"ACC_SCALE_Z", &accScale.z},
 	// rc
 	{"RC_ZERO_0", &channelZero[0]},
 	{"RC_ZERO_1", &channelZero[1]},
@@ -70,7 +70,12 @@ Parameter parameters[] = {
 	{"RC_PITCH", &pitchChannel},
 	{"RC_THROTTLE", &throttleChannel},
 	{"RC_YAW", &yawChannel},
 	{"RC_ARMED", &armedChannel},
 	{"RC_MODE", &modeChannel},
 #if WIFI_ENABLED
 	// MAVLink
 	{"MAV_CTRL_SCALE", &mavlinkControlScale},
 #endif
 };
 void setupParameters() {
@@ -119,9 +124,10 @@ bool setParameter(const char *name, const float value) {
 }
 void syncParameters() {
-	static Rate rate(1);
+	static double lastSync = 0;
-	if (!rate) return; // sync once per second
+	if (t - lastSync < 1) return; // sync once per second
 	if (motorsActive()) return; // don't use flash while flying, it may cause a delay
 	lastSync = t;
 	for (auto &parameter : parameters) {
 		if (parameter.value == *parameter.variable) continue;
--- a/flix/pid.h
+++ b/flix/pid.h
@@ -9,44 +9,40 @@
 class PID {
 public:
-	float p, i, d;
+	float p = 0;
-	float windup;
+	float i = 0;
-	float dtMax;
+	float d = 0;
 	float windup = 0;
 	float derivative = 0;
 	float integral = 0;
 	LowPassFilter<float> lpf; // low pass filter for derivative term
-	PID(float p, float i, float d, float windup = 0, float dAlpha = 1, float dtMax = 0.1) :
+	PID(float p, float i, float d, float windup = 0, float dAlpha = 1) : p(p), i(i), d(d), windup(windup), lpf(dAlpha) {};
 		p(p), i(i), d(d), windup(windup), lpf(dAlpha), dtMax(dtMax) {}
-	float update(float error) {
+	float update(float error, float dt) {
 		float dt = t - prevTime;
 		if (dt > 0 && dt < dtMax) {
 		integral += error * dt;
-			derivative = lpf.update((error - prevError) / dt); // compute derivative and apply low-pass filter
+
-		} else {
+		if (isfinite(prevError) && dt > 0) {
-			integral = 0;
+			// calculate derivative if both dt and prevError are valid
-			derivative = 0;
+			derivative = (error - prevError) / dt;
 			// apply low pass filter to derivative
 			derivative = lpf.update(derivative);
 		}
 		prevError = error;
 		prevTime = t;
 		return p * error + constrain(i * integral, -windup, windup) + d * derivative; // PID
 	}
 	void reset() {
 		prevError = NAN;
 		prevTime = NAN;
 		integral = 0;
 		derivative = 0;
 		lpf.reset();
 	}
 private:
 	float prevError = NAN;
 	float prevTime = NAN;
 };
--- a/flix/quaternion.h
+++ b/flix/quaternion.h
@@ -45,7 +45,7 @@ public:
 			cx * cy * sz - sx * sy * cz);
 	}
-	static Quaternion fromBetweenVectors(const Vector& u, const Vector& v) {
+	static Quaternion fromBetweenVectors(Vector u, Vector v) {
 		float dot = u.x * v.x + u.y * v.y + u.z * v.z;
 		float w1 = u.y * v.z - u.z * v.y;
 		float w2 = u.z * v.x - u.x * v.z;
@@ -79,7 +79,6 @@ public:
 		z = NAN;
 	}
 	float norm() const {
 		return sqrt(w * w + x * x + y * y + z * z);
 	}
@@ -132,31 +131,29 @@ public:
 		return euler;
 	}
 	float getRoll() const {
 		return toEuler().x;
 	}
 	float getPitch() const {
 		return toEuler().y;
 	}
 	float getYaw() const {
-		return toEuler().z;
+		// https://github.com/ros/geometry2/blob/589caf083cae9d8fae7effdb910454b4681b9ec1/tf2/include/tf2/impl/utils.h#L122
 		float yaw;
 		float sqx = x * x;
 		float sqy = y * y;
 		float sqz = z * z;
 		float sqw = w * w;
 		double sarg = -2 * (x * z - w * y) / (sqx + sqy + sqz + sqw);
 		if (sarg <= -0.99999) {
 			yaw = -2 * atan2(y, x);
 		} else if (sarg >= 0.99999) {
 			yaw = 2 * atan2(y, x);
 		} else {
 			yaw = atan2(2 * (x * y + w * z), sqw + sqx - sqy - sqz);
 		}
-
+		return yaw;
 	void setRoll(float roll) {
 		Vector euler = toEuler();
 		*this = Quaternion::fromEuler(Vector(roll, euler.y, euler.z));
 	}
 	void setPitch(float pitch) {
 		Vector euler = toEuler();
 		*this = Quaternion::fromEuler(Vector(euler.x, pitch, euler.z));
 	}
 	void setYaw(float yaw) {
 		// TODO: optimize?
 		Vector euler = toEuler();
-		*this = Quaternion::fromEuler(Vector(euler.x, euler.y, yaw));
+		euler.z = yaw;
 		(*this) = Quaternion::fromEuler(euler);
 	}
 	Quaternion operator * (const Quaternion& q) const {
--- a/flix/rc.ino
+++ b/flix/rc.ino
@@ -6,24 +6,24 @@
 #include <SBUS.h>
 #include "util.h"
-SBUS rc(Serial2); // NOTE: Use RC(Serial2, 16, 17) if you use the old UART2 pins
+SBUS RC(Serial2); // NOTE: Use RC(Serial2, 16, 17) if you use the old UART2 pins
 uint16_t channels[16]; // raw rc channels
-float controlTime; // time of the last controls update
+double controlTime; // time of the last controls update
 float channelZero[16]; // calibration zero values
 float 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 rollChannel = NAN, pitchChannel = NAN, throttleChannel = NAN, yawChannel = NAN, armedChannel = NAN, modeChannel = NAN;
 void setupRC() {
 	print("Setup RC\n");
-	rc.begin();
+	RC.begin();
 }
 bool readRC() {
-	if (rc.read()) {
+	if (RC.read()) {
-		SBUSData data = rc.data();
+		SBUSData data = RC.data();
 		for (int i = 0; i < 16; i++) channels[i] = data.ch[i]; // copy channels data
 		normalizeRC();
 		controlTime = t;
@@ -42,6 +42,7 @@ void normalizeRC() {
 	controlPitch = pitchChannel >= 0 ? controls[(int)pitchChannel] : NAN;
 	controlYaw = yawChannel >= 0 ? controls[(int)yawChannel] : NAN;
 	controlThrottle = throttleChannel >= 0 ? controls[(int)throttleChannel] : NAN;
 	controlArmed = armedChannel >= 0 ? controls[(int)armedChannel] : NAN;
 	controlMode = modeChannel >= 0 ? controls[(int)modeChannel] : NAN;
 }
@@ -49,15 +50,16 @@ void calibrateRC() {
 	uint16_t zero[16];
 	uint16_t center[16];
 	uint16_t max[16];
-	print("1/8 Calibrating RC: put all switches to default positions [3 sec]\n");
+	print("1/9 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, zero, zero, "2/9 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(NULL, center, center, "3/9 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(&throttleChannel, zero, max, "4/9 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(&yawChannel, center, max, "5/9 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(&pitchChannel, zero, max, "6/9 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(&rollChannel, zero, max, "7/9 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(&armedChannel, zero, max, "8/9 Switch to armed [3 sec]\n");
 	calibrateRCChannel(&modeChannel, zero, max, "9/9 Disarm and switch mode to max [3 sec]\n");
 	printRCCalibration();
 }
@@ -92,5 +94,6 @@ void printRCCalibration() {
 	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("Armed     %-7g%-7g%-7g\n", armedChannel, armedChannel >= 0 ? channelZero[(int)armedChannel] : NAN, armedChannel >= 0 ? channelMax[(int)armedChannel] : NAN);
 	print("Mode      %-7g%-7g%-7g\n", modeChannel, modeChannel >= 0 ? channelZero[(int)modeChannel] : NAN, modeChannel >= 0 ? channelMax[(int)modeChannel] : NAN);
 }
--- a/flix/time.ino
+++ b/flix/time.ino
@@ -6,7 +6,7 @@
 float loopRate; // Hz
 void step() {
-	float now = micros() / 1000000.0;
+	double now = micros() / 1000000.0;
 	dt = now - t;
 	t = now;
@@ -18,7 +18,7 @@ void step() {
 }
 void computeLoopRate() {
-	static float windowStart = 0;
+	static double windowStart = 0;
 	static uint32_t rate = 0;
 	rate++;
 	if (t - windowStart >= 1) { // 1 second window
--- a/flix/util.h
+++ b/flix/util.h
@@ -10,9 +10,12 @@
 #include <soc/rtc_cntl_reg.h>
 const float ONE_G = 9.80665;
 extern float t;
-float mapf(float x, float in_min, float in_max, float out_min, float out_max) {
+float mapf(long x, long in_min, long in_max, float out_min, float out_max) {
 	return (float)(x - in_min) * (out_max - out_min) / (float)(in_max - in_min) + out_min;
 }
 float mapff(float x, float in_min, float in_max, float out_min, float out_max) {
 	return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
 }
@@ -49,37 +52,3 @@ void splitString(String& str, String& token0, String& token1, String& token2) {
 	token1 = strtok(NULL, " "); // String(NULL) creates empty string
 	token2 = strtok(NULL, "");
 }
 // Rate limiter
 class Rate {
 public:
 	float rate;
 	float last = 0;
 	Rate(float rate) : rate(rate) {}
 	operator bool() {
 		if (t - last >= 1 / rate) {
 			last = t;
 			return true;
 		}
 		return false;
 	}
 };
 // Delay filter for boolean signals - ensures the signal is on for at least 'delay' seconds
 class Delay {
 public:
 	float delay;
 	float start = NAN;
 	Delay(float delay) : delay(delay) {}
 	bool update(bool on) {
 		if (!on) {
 			start = NAN;
 			return false;
 		} else if (isnan(start)) {
 			start = t;
 		}
 		return t - start >= delay;
 	}
 };
--- a/flix/vector.h
+++ b/flix/vector.h
@@ -35,7 +35,6 @@ public:
 		z = NAN;
 	}
 	float norm() const {
 		return sqrt(x * x + y * y + z * z);
 	}
--- a/flix/wifi.ino
+++ b/flix/wifi.ino
@@ -13,7 +13,6 @@
 #define WIFI_PASSWORD "flixwifi"
 #define WIFI_UDP_PORT 14550
 #define WIFI_UDP_REMOTE_PORT 14550
 #define WIFI_UDP_REMOTE_ADDR "255.255.255.255"
 WiFiUDP udp;
@@ -25,7 +24,7 @@ void setupWiFi() {
 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);
+	udp.beginPacket(WiFi.softAPBroadcastIP(), WIFI_UDP_REMOTE_PORT);
 	udp.write(buf, len);
 	udp.endPacket();
 }
@@ -35,15 +34,4 @@ int receiveWiFi(uint8_t *buf, int len) {
 	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());
 	print("MAVLink connected: %d\n", mavlinkConnected);
 }
 #endif
--- a/gazebo/CMakeLists.txt
+++ b/gazebo/CMakeLists.txt
@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
 project(flix_gazebo)
-# Gazebo plugin
+# === gazebo plugin
 find_package(gazebo REQUIRED)
 find_package(SDL2 REQUIRED)
 include_directories(${GAZEBO_INCLUDE_DIRS})
--- a/gazebo/README.md
+++ b/gazebo/README.md
@@ -1,99 +1,15 @@
-# Simulation
+# Gazebo Simulation
-The Flix drone simulator is based on Gazebo 11 and runs the firmware code in virtual physical environment.
+<img src="../docs/img/simulator.png" width=500 alt="Flix simulator">
-Gazebo 11 works on **Ubuntu 20.04** and used to work on macOS. However, on the recent macOS versions it seems to be broken, so Ubuntu 20.04 is recommended.
+## Building and running
-<img src="../docs/img/simulator1.png" width=600 alt="Flix simulator running on macOS">
+See [building and running instructions](../docs/build.md#simulation).
 ## Installation
 1. Clone the Flix repository using it:
   ```bash
   git clone https://github.com/okalachev/flix.git && cd flix
   ```
 2. Install Arduino CLI:
   ```bash
   curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=~/.local/bin sh
   ```
 3. Install Gazebo 11:
   ```bash
   sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu-stable `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-stable.list'
   wget https://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -
   sudo apt-get update
   sudo apt-get install -y gazebo11 libgazebo11-dev
   ```
   Set up your Gazebo environment variables:
   ```bash
   echo "source /usr/share/gazebo/setup.sh" >> ~/.bashrc
   source ~/.bashrc
   ```
 4. Install SDL2 and other dependencies:
   ```bash
   sudo apt-get update && sudo apt-get install build-essential libsdl2-dev
   ```
 5. Add your user to the `input` group to enable joystick support (you need to re-login after this command):
   ```bash
   sudo usermod -a -G input $USER
   ```
 6. Run the simulation:
   ```bash
   make simulator
   ```
 ## Usage
 Just like the real drone, the simulator can be controlled using a USB remote control or a smartphone.
 ### Control with smartphone
 1. Install [QGroundControl mobile app](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/getting_started/download_and_install.html#android) on your smartphone. For **iOS**, use [QGroundControl build from TAJISOFT](https://apps.apple.com/ru/app/qgc-from-tajisoft/id1618653051).
 2. Connect your smartphone to the same Wi-Fi network as the machine running the simulator.
 3. If you're using a virtual machine, make sure that its network is set to the **bridged** mode with Wi-Fi adapter selected.
 4. Run the simulation.
 5. Open QGroundControl app. It should connect and begin showing the virtual drone's telemetry automatically.
 6. Go to the settings and enable *Virtual Joystick*. *Auto-Center Throttle* setting **should be disabled**.
 7. Use the virtual joystick to fly the drone!
 > [!TIP]
 > Decrease `CTL_TILT_MAX` parameter when flying using the smartphone to make the controls less sensitive.
 ### Control with USB remote control
 1. Connect your USB remote control to the machine running the simulator.
 2. Run the simulation.
 3. Calibrate the RC using `cr` command in the command line interface.
 4. Use the USB remote control to fly the drone!
 ### Piloting
 To start the flight, arm the drone moving the throttle stick to the bottom right position:
 <img src="../docs/img/arming.svg" width="150">
 To disarm, move the throttle stick to the bottom left position:
 <img src="../docs/img/disarming.svg" width="150">
 See other piloting and usage details in general [usage article](../docs/usage.md).
 ## Code structure
-Flix simulator consists of the following components:
+Flix simulator is based on [Gazebo Classic](https://classic.gazebosim.org) and consists of the following components:
-* Physical model of the drone in Gazebo format: [`models/flix/flix.sdf`](models/flix/flix.sdf).
+* Physical model of the drone: [`models/flix/flix.sdf`](models/flix/flix.sdf).
 * Plugin for Gazebo: [`simulator.cpp`](simulator.cpp). The plugin is attached to the physical model. It receives stick positions from the controller, gets the data from the virtual sensors, and then passes this data to the Arduino code.
-* Arduino emulation: [`Arduino.h`](Arduino.h). This file contains partial implementation of the Arduino API, that is working within Gazebo plugin environment.
+* Arduino imitation: [`Arduino.h`](Arduino.h). This file contains partial implementation of the Arduino API, that is working within Gazebo plugin environment.
--- a/gazebo/flix.h
+++ b/gazebo/flix.h
@@ -12,11 +12,11 @@
 #define WIFI_ENABLED 1
-float t = NAN;
+double t = NAN;
 float dt;
 float motors[4];
 float controlRoll, controlPitch, controlYaw, controlThrottle = NAN;
-float controlMode = NAN;
+float controlArmed = NAN, controlMode = NAN;
 Vector acc;
 Vector gyro;
 Vector rates;
@@ -45,8 +45,7 @@ void normalizeRC();
 void calibrateRC();
 void calibrateRCChannel(float *channel, uint16_t zero[16], uint16_t max[16], const char *str);
 void printRCCalibration();
-void printLogHeader();
+void dumpLog();
 void printLogData();
 void processMavlink();
 void sendMavlink();
 void sendMessage(const void *msg);
@@ -57,8 +56,8 @@ void sendMavlinkPrint();
 inline Quaternion fluToFrd(const Quaternion &q);
 void failsafe();
 void rcLossFailsafe();
 void descend();
 void autoFailsafe();
 void descend();
 int parametersCount();
 const char *getParameterName(int index);
 float getParameter(int index);
@@ -73,5 +72,4 @@ void calibrateGyro() { print("Skip gyro calibrating\n"); };
 void calibrateAccel() { print("Skip accel calibrating\n"); };
 void printIMUCalibration() { print("cal: N/A\n"); };
 void printIMUInfo() {};
 void printWiFiInfo() {};
 Vector accBias, gyroBias, accScale(1, 1, 1);
--- a/gazebo/simulator.cpp
+++ b/gazebo/simulator.cpp
@@ -21,7 +21,7 @@
 #include "cli.ino"
 #include "control.ino"
 #include "estimate.ino"
-#include "safety.ino"
+#include "failsafe.ino"
 #include "log.ino"
 #include "lpf.h"
 #include "mavlink.ino"
@@ -59,7 +59,6 @@ public:
 	void OnReset() {
 		attitude = Quaternion(); // reset estimated attitude
 		armed = false;
 		__resetTime += __micros;
 		gzmsg << "Flix plugin reset" << endl;
 	}
--- a/gazebo/wifi.h
+++ b/gazebo/wifi.h
@@ -13,7 +13,6 @@
 #define WIFI_UDP_PORT 14580
 #define WIFI_UDP_REMOTE_PORT 14550
 #define WIFI_UDP_REMOTE_ADDR "255.255.255.255"
 int wifiSocket;
@@ -36,7 +35,7 @@ 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_addr.s_addr = INADDR_BROADCAST; // send UDP broadcast
 	addr.sin_port = htons(WIFI_UDP_REMOTE_PORT);
 	sendto(wifiSocket, buf, len, 0, (sockaddr *)&addr, sizeof(addr));
 }
--- a/tools/check_c_cpp_properties.py
+++ b/tools/check_c_cpp_properties.py
@@ -49,8 +49,6 @@ for configuration in props['configurations']:
    print('Check configuration', configuration['name'])
    for include_path in configuration.get('includePath', []):
        if include_path.startswith('/opt/') or include_path.startswith('/usr/'): # don't check non-Arduino libs
            continue
        check_path(include_path)
    for forced_include in configuration.get('forcedInclude', []):
--- a/tools/log.py
+++ b/tools/log.py
@@ -3,49 +3,21 @@
 # Download flight log remotely and save to file
 import os
 import time
 import datetime
 import struct
 from pymavlink.dialects.v20.common import MAVLink_log_data_message
 from pyflix import Flix
 DIR = os.path.dirname(os.path.realpath(__file__))
 flix = Flix()
 print('Downloading log...')
 lines = flix.cli('log').splitlines()
-header = flix.cli('log')
+# sort by timestamp
-print('Received header:\n- ' + '\n- '.join(header.split(',')))
+header = lines.pop(0)
-
+lines.sort(key=lambda line: float(line.split(',')[0]))
 records = []
 def on_record(msg: MAVLink_log_data_message):
    global stop
    stop = time.time() + 1  # extend timeout
    records.append([])
    i = 0
    data = bytes(msg.data)
    while i + 4 <= msg.count:
        records[-1].append(struct.unpack('<f', data[i:i+4])[0])
        i += 4
 stop = time.time() + 3
 flix.on('mavlink.LOG_DATA', on_record)
 flix.mavlink.log_request_data_send(flix.system_id, 0, 0, 0, 0xFFFFFFFF)
 while time.time() < stop:
    time.sleep(1)
 flix.off(on_record)
 records.sort(key=lambda record: record[0])
 records = [record for record in records if record[0] != 0]
 print(f'Received records: {len(records)}')
 log = open(f'{DIR}/log/{datetime.datetime.now().isoformat()}.csv', 'wb')
-log.write(header.encode() + b'\n')
+content = header.encode() + b'\n' + b'\n'.join(line.encode() for line in lines)
-for record in records:
+log.write(content)
    line = ','.join(f'{value}' for value in record)
    log.write(line.encode() + b'\n')
 print(f'Written {os.path.relpath(log.name, os.curdir)}')
--- a/tools/pyflix/README.md
+++ b/tools/pyflix/README.md
@@ -1,8 +1,8 @@
 # Flix Python library
-The Flix Python library allows you to remotely connect to a Flix quadcopter. It provides access to telemetry data, supports executing console commands, and controlling the drone's flight.
+The Flix Python library allows you to remotely connect to a Flix quadcopter. It provides access to telemetry data, supports executing CLI commands, and controlling the drone's flight.
-To use the library, connect to the drone's Wi-Fi. To use it with the simulator, ensure the script runs on the same network as the simulator.
+To use the library, connect to the drone's Wi-Fi. To use it with the simulator, ensure the script runs on the same local network as the simulator.
 ## Installation
@@ -30,7 +30,7 @@ flix = Flix()  # create a Flix object and wait for connection
 ### 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 properties names generally match the corresponding variables in the firmware itself:
 ```python
 print(flix.connected)       # True if connected to the drone
@@ -41,16 +41,13 @@ 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]
 print(flix.channels)        # raw RC channels (list)
-print(flix.motors)          # motor outputs (list)
+print(flix.motors)          # motors outputs (list)
 print(flix.acc)             # accelerometer output (list)
 print(flix.gyro)            # gyroscope output (list)
 ```
-The library uses the Front-Left-Up coordinate system — the same as the firmware:
+> [!NOTE]
-
+> The library uses the Front-Left-Up coordinate system — the same as in the firmware. All angles are in radians.
 <img src="../../docs/img/drone-axes-rotate.svg" width="300">
 All angles are in radians.
 ### Events
@@ -62,13 +59,6 @@ flix.on('disconnected', lambda: print('Disconnected from Flix'))
 flix.on('print', lambda text: print(f'Flix says: {text}'))
 ```
 Unsubscribe from events using `off` method:
 ```python
 flix.off('print')  # unsubscribe from print events
 flix.off(callback)  # unsubscribe specific callback
 ```
 You can also wait for specific events using `wait` method. This method returns the data associated with the event:
 ```python
@@ -76,14 +66,13 @@ gyro = flix.wait('gyro')  # wait for gyroscope update
 attitude = flix.wait('attitude', timeout=3)  # wait for attitude update, raise TimeoutError after 3 seconds
 ```
-The second argument (`value`) specifies a condition for filtering events. It can be either an expected value or a callable:
+The `value` argument specifies a condition for filtering events. It can be either an expected value or a callable:
 ```python
-flix.wait('armed', True)  # wait until armed
+flix.wait('armed', value=True)  # wait until armed
-flix.wait('armed', False)  # wait until disarmed
+flix.wait('armed', value=False)  # wait until disarmed
-flix.wait('mode', 'AUTO')  # wait until flight mode is switched to AUTO
+flix.wait('motors', value=lambda motors: not any(motors))  # wait until all motors stop
-flix.wait('motors', lambda motors: not any(motors))  # wait until all motors stop
+flix.wait('attitude_euler', value=lambda att: att[0] > 0)  # wait until roll angle is positive
 flix.wait('attitude_euler', lambda att: att[0] > 0)  # wait until roll angle is positive
 ```
 Full list of events:
@@ -100,17 +89,17 @@ Full list of events:
 |`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*)|
+|`motors`|Motors outputs update|Motors 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|
 |`value`|Named value update (see below)|Name, value|
-|`value.<name>`|Specific named value update (see below)|Value|
+|`value.<name>`|Specific named value update (see bellow)|Value|
 > [!NOTE]
-> Update events trigger on every new piece of data from the drone, and do not mean the value has changed.
+> Update events trigger on every new data from the drone, and do not mean the value is changed.
 ### Common methods
@@ -121,7 +110,7 @@ pitch_p = flix.get_param('PITCH_P')  # get parameter value
 flix.set_param('PITCH_P', 5)      # set parameter value
 ```
-Execute console commands using `cli` method. This method returns the command response:
+Execute CLI commands using `cli` method. This method returns command response:
 ```python
 imu = flix.cli('imu')    # get detailed IMU data
@@ -132,65 +121,21 @@ flix.cli('reboot')       # reboot the drone
 > [!TIP]
 > Use `help` command to get the list of available commands.
 You can arm and disarm the drone using `set_armed` method (warning: the drone will fall if disarmed in the air):
 ```python
 flix.set_armed(True)   # arm the drone
 flix.set_armed(False)  # disarm the drone
 ```
 You can pass pilot's controls using `set_controls` method:
 ```python
 flix.set_controls(roll=0, pitch=0, yaw=0, throttle=0.6)
 ```
 > [!WARNING]
 > This method **is not intended for automatic flights**, only for adding support for a custom pilot input device.
 ### Automatic flight
-To perform automatic flight, switch the mode to *AUTO*, either from the remote control, or from the code:
+The flight control feature is in development. List of methods intended for automatic flight control:
-```python
+* `set_position`
-flix.set_mode('AUTO')
+* `set_velocity`
-```
+* `set_attitude`
-
+* `set_rates`
-In this mode you can set flight control targets. Setting attitude target:
+* `set_motors`
-
+* `set_controls`
-```python
+* `set_mode`
 flix.set_attitude([0.1, 0.2, 0.3], 0.6)  # set target roll, pitch, yaw and thrust
 flix.set_attitude([1, 0, 0, 0], 0.6)  # set target attitude quaternion and thrust
 ```
 Setting angular rates target:
 ```python
 flix.set_rates([0.1, 0.2, 0.3], 0.6)  # set target roll rate, pitch rate, yaw rate and thrust
 ```
 You also can control raw motor outputs directly:
 ```python
 flix.set_motors([0.5, 0.5, 0.5, 0.5])  # set motor outputs in range [0, 1]
 ```
 In *AUTO* mode, the drone will arm automatically if the thrust is greater than zero, and disarm if thrust is zero. Therefore, to disarm the drone, set thrust to zero:
 ```python
 flix.set_attitude([0, 0, 0], 0)  # disarm the drone
 ```
 The following methods are in development and are not functional yet:
 * `set_position` — set target position.
 * `set_velocity` — set target velocity.
 To exit *AUTO* mode move control sticks and the drone will switch to *STAB* mode.
 ## Usage alongside QGroundControl
-You can use the Flix library alongside the QGroundControl app, using proxy mode. To do that:
+You can use the Flix library alongside the QGroundControl app, using a proxy mode. To do that:
 1. Run proxy for `pyflix` and QGroundControl in background:
@@ -206,8 +151,6 @@ You can use the Flix library alongside the QGroundControl app, using proxy mode.
   * *Port*: 14560
 4. Restart QGroundControl.
 <img src="../../docs/img/qgc-proxy.png" width="300">
 Now you can run `pyflix` scripts and QGroundControl simultaneously.
 ## Tools
@@ -258,11 +201,11 @@ You can send values from the firmware like this (`mavlink.ino`):
 ```cpp
 // Send float named value
-mavlink_msg_named_value_float_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, t, "loop_rate", loopRate);
+mavlink_msg_named_value_float_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, t, "some_value", loopRate);
 sendMessage(&msg);
 // Send vector named value
-mavlink_msg_debug_vect_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, "gyro_bias", t, gyroBias.x, gyroBias.y, gyroBias.z);
+mavlink_msg_debug_vect_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, "some_vector", t, gyroBias.x, gyroBias.y, gyroBias.z);
 sendMessage(&msg);
 ```
--- a/tools/pyflix/flix.py
+++ b/tools/pyflix/flix.py
@@ -6,7 +6,7 @@
 import os
 import time
 from queue import Queue, Empty
-from typing import Optional, Callable, List, Dict, Any, Union, Sequence
+from typing import Literal, Optional, Callable, List, Dict, Any, Union, Sequence
 import logging
 import errno
 from threading import Thread, Timer
@@ -17,7 +17,7 @@ from pymavlink.dialects.v20 import common as mavlink
 logger = logging.getLogger('flix')
 if not logger.hasHandlers():
    handler = logging.StreamHandler()
-    handler.setFormatter(logging.Formatter('%(name)s: %(message)s'))
+    handler.setFormatter(logging.Formatter('%(name)s - %(levelname)s - %(message)s'))
    logger.addHandler(handler)
    logger.setLevel(logging.INFO)
@@ -36,11 +36,11 @@ class Flix:
    system_id: int
    messages: Dict[str, Dict[str, Any]]  # MAVLink messages storage
-    values: Dict[Union[str, int], Union[float, List[float]]]  # named values
+    values: Dict[Union[str, int], Union[float, List[float]]] = {}  # named values
    _connection_timeout = 3
    _print_buffer: str = ''
-    _modes = ['RAW', 'ACRO', 'STAB', 'AUTO']
+    _modes = ['MANUAL', 'ACRO', 'STAB', 'AUTO']
    def __init__(self, system_id: int=1, wait_connection: bool=True):
        if not (0 <= system_id < 256):
@@ -61,6 +61,7 @@ class Flix:
        self.connection.target_system = system_id
        self.mavlink: mavlink.MAVLink = self.connection.mav
        self._event_listeners: Dict[str, List[Callable[..., Any]]] = {}
        self.messages = {}
        self._disconnected_timer = Timer(0, self._disconnected)
        self._reader_thread = Thread(target=self._read_mavlink, daemon=True)
        self._reader_thread.start()
@@ -78,8 +79,6 @@ class Flix:
        self.motors = [0, 0, 0, 0]
        self.acc = [0, 0, 0]
        self.gyro = [0, 0, 0]
        self.messages = {}
        self.values = {}
    def on(self, event: str, callback: Callable):
        event = event.lower()
@@ -87,15 +86,10 @@ class Flix:
            self._event_listeners[event] = []
        self._event_listeners[event].append(callback)
-    def off(self, event_or_callback: Union[str, Callable]):
+    def off(self, callback: Callable):
        if isinstance(event_or_callback, str):
            event = event_or_callback.lower()
            if event in self._event_listeners:
                del self._event_listeners[event]
        else:
        for event in self._event_listeners:
-                if event_or_callback in self._event_listeners[event]:
+            if callback in self._event_listeners[event]:
-                    self._event_listeners[event].remove(event_or_callback)
+                self._event_listeners[event].remove(callback)
    def _trigger(self, event: str, *args):
        event = event.lower()
@@ -154,7 +148,7 @@ class Flix:
    def _handle_mavlink_message(self, msg: mavlink.MAVLink_message):
        if isinstance(msg, mavlink.MAVLink_heartbeat_message):
-            self.mode = self._modes[msg.custom_mode] if msg.custom_mode < len(self._modes) else f'UNKNOWN({msg.custom_mode})'
+            self.mode = self._modes[msg.custom_mode]
            self.armed = msg.base_mode & mavlink.MAV_MODE_FLAG_SAFETY_ARMED != 0
            self._trigger('mode', self.mode)
            self._trigger('armed', self.armed)
@@ -182,7 +176,6 @@ class Flix:
        # TODO: to be removed: the old way of passing motor outputs
        if isinstance(msg, mavlink.MAVLink_actuator_output_status_message):
            self.motors = msg.actuator[:4]  # type: ignore
            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])
@@ -305,9 +298,6 @@ class Flix:
            mode = self._modes.index(mode.upper())
        self._command_send(mavlink.MAV_CMD_DO_SET_MODE, (0, mode, 0, 0, 0, 0, 0))
    def set_armed(self, armed: bool):
        self._command_send(mavlink.MAV_CMD_COMPONENT_ARM_DISARM, (1 if armed else 0, 0, 0, 0, 0, 0, 0))
    def set_position(self, position: List[float], yaw: Optional[float] = None, wait: bool = False, tolerance: float = 0.1):
        raise NotImplementedError('Position control is not implemented yet')
@@ -345,7 +335,7 @@ class Flix:
        if not all(0 <= m <= 1 for m in motors):
            raise ValueError('motors must be in range [0, 1]')
        for _ in range(2):  # duplicate to ensure delivery
-            self.mavlink.set_actuator_control_target_send(int(time.time() * 1000000), 0, self.system_id, 0, motors + [0] * 4)  # type: ignore
+            self.mavlink.set_actuator_control_target_send(time.time() * 1000, 0, self.system_id, 0, motors + [0] * 4)  # type: ignore
    def set_controls(self, roll: float, pitch: float, yaw: float, throttle: float):
        """Send pilot's controls. Warning: not intended for automatic control"""
@@ -353,7 +343,7 @@ class Flix:
            raise ValueError('roll, pitch, yaw must be in range [-1, 1]')
        if not 0 <= throttle <= 1:
            raise ValueError('throttle must be in range [0, 1]')
-        self.mavlink.manual_control_send(self.system_id, int(pitch * 1000), int(roll * 1000), int(throttle * 1000), int(yaw * 1000), 0)  # type: ignore
+        self.mavlink.manual_control_send(self.system_id, roll * 1000, pitch * 1000, yaw * 1000, throttle * 1000, 0)  # type: ignore
    def cli(self, cmd: str, wait_response: bool = True) -> str:
        cmd = cmd.strip()
@@ -370,9 +360,7 @@ class Flix:
                self.mavlink.serial_control_send(0, 0, 0, 0, len(cmd_bytes), cmd_bytes)
                if not wait_response:
                    return ''
-                timeout = 0.1
+                response = self.wait('print_full', timeout=0.1, value=lambda text: text.startswith(response_prefix))
                if cmd == 'log': timeout = 10 # log download may take more time
                response = self.wait('print_full', timeout=timeout, value=lambda text: text.startswith(response_prefix))
                return response[len(response_prefix):].strip()
            except TimeoutError:
                continue
--- a/tools/pyflix/proxy.py
+++ b/tools/pyflix/proxy.py
@@ -24,16 +24,13 @@ def main():
        if addr in TARGETS:  # packet from target
            if source_addr is None:
                continue
            try:
            sock.sendto(data, source_addr)
                packets += 1
            except: pass
        else:  # packet from source
            source_addr = addr
            for target in TARGETS:
                sock.sendto(data, target)
                packets += 1
        packets += 1
        print(f'\rPackets: {packets}', end='')
 if __name__ == '__main__':
--- a/tools/pyproject.toml
+++ b/tools/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "pyflix"
-version = "0.11"
+version = "0.5"
 description = "Python API for Flix drone"
 authors = [{ name="Oleg Kalachev", email="okalachev@gmail.com" }]
 license = "MIT"
Author	SHA1	Message	Date
Oleg Kalachev	24f7b02ed5	Add commands for switching modes Make mode simple int instead of enum for simplify using in other subsystems	2025-08-11 22:35:38 +03:00
Oleg Kalachev	d5c3b5b5f7	Bring back handling old message for motor outputs in pyflix	2025-07-31 12:35:59 +03:00
Oleg Kalachev	37b9a3a41c	Add support form arm/disarm mavlink command	2025-07-31 12:35:41 +03:00
Oleg Kalachev	7f4fc7acea	Make rc loss timeout longer	2025-07-31 12:32:43 +03:00
Oleg Kalachev	3f269f57be	Fixes	2025-07-31 12:23:26 +03:00
Oleg Kalachev	8e043555c5	Fix	2025-07-30 00:38:55 +03:00
Oleg Kalachev	c39e2ca998	Fixes	2025-07-30 00:38:34 +03:00
Oleg Kalachev	f46842f341	Fixed	2025-07-30 00:38:24 +03:00
Oleg Kalachev	3d72224b32	Print armed state in rc command	2025-07-30 00:38:13 +03:00
Oleg Kalachev	dfceb8a6b2	Implement auto mode for automatic flight Use arm/disarm gestures Add arm/disarm commands Add ratesExtra variable for Rename interpretRC to interpretControls Rename controlRate to controlRates Remove USER mode Add invalidate methods for vector and quaternion Add valid/invalid method for vector and quaternion Add valid/invalid function Print armed in rc command Pass auto mode to heartbeat Use actuator_control_target for motors	2025-07-29 18:02:09 +03:00
Oleg Kalachev	2066d05a60	Implement set_mode, set_attitude and set_rates in pyflix	2025-07-28 22:36:41 +03:00