Reduce angle drift adding level correction to the estimator

Utilize a-priori knowledge that the overall average attitude of the flying drone is level.
Expose lpf alpha of rate pids to parameters
2026-08-16 00:38:56 +00:00 · 2026-05-04 16:48:20 +03:00 · 2026-05-03 15:04:16 +03:00 · 2026-05-01 15:26:59 +03:00 · 2026-04-29 15:07:44 +03:00 · 2026-04-28 20:46:49 +03:00
61 changed files with 337 additions and 1231 deletions
@@ -10,33 +10,21 @@ on:
 jobs:
  build_linux:
    runs-on: ubuntu-latest
-    env:
-        ARDUINO_SKETCH_ALWAYS_EXPORT_BINARIES: 1
    steps:
    - uses: actions/checkout@v4
    - name: Install Arduino CLI
      run: curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=/usr/local/bin sh
-    - name: Build firmware for ESP32
+    - name: Build firmware
+      env:
+        ARDUINO_SKETCH_ALWAYS_EXPORT_BINARIES: 1
      run: make
-    - name: Build firmware for ESP32-C3
-      run: make BOARD=esp32:esp32:esp32c3
-    - name: Build firmware for ESP32-S3
-      run: make BOARD=esp32:esp32:esp32s3:CDCOnBoot=cdc
-    - name: Build firmware for ESP32-S3 with QSPI PSRAM
-      run: make BOARD=esp32:esp32:esp32s3:CDCOnBoot=cdc,PSRAM=enabled EXTRA=--output-dir=flix/build/esp32.esp32.esp32s3.qspi
-    - name: Build firmware for ESP32-S3 with OPI PSRAM
-      run: make BOARD=esp32:esp32:esp32s3:CDCOnBoot=cdc,PSRAM=opi EXTRA=--output-dir=flix/build/esp32.esp32.esp32s3.opi
-    - name: Build firmware for Flix2
-      run: make BOARD=esp32:esp32:esp32s3:FlashSize=4M,CDCOnBoot=cdc,PSRAM=opi EXTRA='--build-property "compiler.cpp.extra_flags=-DFLIX2" --output-dir=flix/build/esp32.esp32.flix2'
-    - name: Build firmware for STM32F4
-      run: |
-        arduino-cli core install STMicroelectronics:stm32 --additional-urls https://github.com/stm32duino/BoardManagerFiles/raw/main/package_stmicroelectronics_index.json  
-        make BOARD=STMicroelectronics:stm32:GenF4
    - name: Upload binaries
      uses: actions/upload-artifact@v4
      with:
        name: firmware-binary
        path: flix/build
+    - name: Build firmware for ESP32-S3
+      run: make BOARD=esp32:esp32:esp32s3
    - name: Check c_cpp_properties.json
      run: tools/check_c_cpp_properties.py

@@ -74,7 +62,7 @@ jobs:
        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
-      run: curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=/usr/local/bin sh
+      uses: arduino/setup-arduino-cli@v1.1.1
    - uses: actions/checkout@v4
    - name: Install Gazebo
      run: |
@@ -8,7 +8,6 @@ on:

 permissions:
  contents: read
-  actions: read
  pages: write
  id-token: write

@@ -31,38 +30,6 @@ jobs:
      run: cargo install mdbook --vers 0.4.43 --locked
    - name: Build book
      run: cd docs && mdbook build
-    - name: Wait for Build to complete
-      uses: lewagon/wait-on-check-action@v1.9.1
-      with:
-        ref: ${{ github.sha }}
-        check-name: build_linux
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        wait-interval: 30
-    - name: Find firmware binaries
-      id: build_run
-      run: |
-        RUN_ID=$(gh api "repos/${{ github.repository }}/actions/workflows/build.yml/runs?head_sha=${{ github.sha }}&per_page=1" --jq '.workflow_runs[0].id')
-        echo "id=$RUN_ID" >> $GITHUB_OUTPUT
-      env:
-        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    - name: Download firmware binaries
-      uses: actions/download-artifact@v4
-      with:
-        github-token: ${{ secrets.GITHUB_TOKEN }}
-        repository: ${{ github.repository }}
-        run-id: ${{ steps.build_run.outputs.id }}
-        name: firmware-binary
-        path: docs/build
-    - name: Create shortcuts for firmware binaries
-      working-directory: docs/build
-      run: |
-        for FQBN in esp32.esp32.*; do
-          zip -r $FQBN.zip $FQBN
-          BOARD="${FQBN#esp32.esp32.}"
-          ln -s "$FQBN/flix.ino.merged.bin" "flix.$BOARD.merged.bin"
-          ln -s "$FQBN/flix.ino.bin" "flix.$BOARD.bin"
-          ln -s "$FQBN/flix.ino.bootloader.bin" "flix.$BOARD.bootloader.bin"
-        done
    - name: Upload artifact
      uses: actions/upload-pages-artifact@v3
      with:
@@ -4,10 +4,9 @@ build/
 tools/log/
 tools/dist/
 *.egg-info/
-.core
-.libs
+.dependencies
 .vscode/*
-!.vscode/settings.default.json
+!.vscode/settings.json
 !.vscode/c_cpp_properties.json
 !.vscode/tasks.json
 !.vscode/launch.json
@@ -6,18 +6,18 @@
 				"${workspaceFolder}/flix",
 				"${workspaceFolder}/gazebo",
 				"${workspaceFolder}/tools/**",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/libraries/**",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32",
-				"~/.arduino15/packages/esp32/tools/esp32-libs/3.3.10/include/**",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/libraries/**",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32",
+				"~/.arduino15/packages/esp32/tools/esp32-libs/3.3.6/include/**",
 				"~/Arduino/libraries/**",
 				"/usr/include/gazebo-11/",
 				"/usr/include/ignition/math6/"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32/Arduino.h",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32/pins_arduino.h",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32/Arduino.h",
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
 				"${workspaceFolder}/flix/estimate.ino",
@@ -33,7 +33,7 @@
 				"${workspaceFolder}/flix/parameters.ino",
 				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/.arduino15/packages/esp32/tools/esp-x32/2601/bin/xtensa-esp32-elf-g++",
+			"compilerPath": "~/.arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [
@@ -53,18 +53,18 @@
 			"name": "Mac",
 			"includePath": [
 				"${workspaceFolder}/flix",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/libraries/**",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32",
-				"~/Library/Arduino15/packages/esp32/tools/esp32-libs/3.3.10/include/**",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/libraries/**",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32",
+				"~/Library/Arduino15/packages/esp32/tools/esp32-libs/3.3.6/include/**",
 				"~/Documents/Arduino/libraries/**",
 				"/opt/homebrew/include/gazebo-11/",
 				"/opt/homebrew/include/ignition/math6/"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32/Arduino.h",
-				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32/pins_arduino.h",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32/Arduino.h",
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/flix.ino",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
@@ -80,7 +80,7 @@
 				"${workspaceFolder}/flix/parameters.ino",
 				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/Library/Arduino15/packages/esp32/tools/esp-x32/2601/bin/xtensa-esp32-elf-g++",
+			"compilerPath": "~/Library/Arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [
@@ -103,16 +103,16 @@
 				"${workspaceFolder}/flix",
 				"${workspaceFolder}/gazebo",
 				"${workspaceFolder}/tools/**",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/libraries/**",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32",
-				"~/AppData/Local/Arduino15/packages/esp32/tools/esp32-libs/3.3.10/include/**",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/libraries/**",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32",
+				"~/AppData/Local/Arduino15/packages/esp32/tools/esp32-libs/3.3.6/include/**",
 				"~/Documents/Arduino/libraries/**"
 			],
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/cores/esp32/Arduino.h",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.10/variants/d1_mini32/pins_arduino.h",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32/Arduino.h",
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
 				"${workspaceFolder}/flix/cli.ino",
 				"${workspaceFolder}/flix/control.ino",
 				"${workspaceFolder}/flix/estimate.ino",
@@ -128,7 +128,7 @@
 				"${workspaceFolder}/flix/parameters.ino",
 				"${workspaceFolder}/flix/safety.ino"
 			],
-			"compilerPath": "~/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2601/bin/xtensa-esp32-elf-g++.exe",
+			"compilerPath": "~/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++.exe",
 			"cStandard": "c11",
 			"cppStandard": "c++17",
 			"defines": [
@@ -1,7 +1,6 @@
 {
 	// See https://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
 	"recommendations": [
-		"dangmai.workspace-default-settings",
 		"ms-vscode.cpptools",
 		"ms-vscode.cmake-tools",
 		"ms-python.python"
@@ -1,40 +1,29 @@
-BOARD = esp32:esp32:esp32
-PORT := $(strip $(wildcard /dev/serial/by-id/usb-Silicon_Labs_CP21* /dev/serial/by-id/usb-1a86_USB_Single_Serial_* /dev/cu.usbserial-* /dev/cu.usbmodem*))
+BOARD = esp32:esp32:d1_mini32
+PORT := $(wildcard /dev/serial/by-id/usb-Silicon_Labs_CP21* /dev/serial/by-id/usb-1a86_USB_Single_Serial_* /dev/cu.usbserial-*)
+PORT := $(strip $(PORT))

-export ARDUINO_NETWORK_CONNECTION_TIMEOUT := 1h
-
-build: .core .libs
-	arduino-cli compile --fqbn $(BOARD) --build-property "build.core_debug_level=1" flix $(EXTRA)
+build: .dependencies
+	arduino-cli compile --fqbn $(BOARD) flix

 upload: build
 	arduino-cli upload --fqbn $(BOARD) -p "$(PORT)" flix

-erase:
-	arduino-cli burn-bootloader --fqbn $(BOARD) -p "$(PORT)" -P esptool
-
 monitor:
 	arduino-cli monitor -p "$(PORT)" -c baudrate=115200

-core .core:
-	arduino-cli core update-index --additional-urls https://espressif.github.io/arduino-esp32/package_esp32_index.json
-	arduino-cli core install esp32:esp32@3.3.10 --additional-urls https://espressif.github.io/arduino-esp32/package_esp32_index.json
-	touch .core
-
-libs .libs:
+dependencies .dependencies:
+	arduino-cli core update-index --config-file arduino-cli.yaml
+	arduino-cli core install esp32:esp32@3.3.6 --config-file arduino-cli.yaml
 	arduino-cli lib update-index
 	arduino-cli lib install "FlixPeriph"
 	arduino-cli lib install "MAVLink"@2.0.25
-	touch .libs
-
-upload_proxy: .core .libs
-	arduino-cli compile --fqbn $(BOARD) tools/espnow-proxy
-	arduino-cli upload --fqbn $(BOARD) -p "$(PORT)" tools/espnow-proxy
+	touch .dependencies

 gazebo/build cmake: gazebo/CMakeLists.txt
 	mkdir -p gazebo/build
 	cd gazebo/build && cmake ..

-build_simulator: .libs gazebo/build
+build_simulator: .dependencies gazebo/build
 	make -C gazebo/build

 simulator: build_simulator
@@ -49,6 +38,6 @@ plot:
 	plotjuggler -d $(shell ls -t tools/log/*.csv | head -n1)

 clean:
-	rm -rf gazebo/build flix/build flix/cache .core .libs
+	rm -rf gazebo/build flix/build flix/cache .dependencies

-.PHONY: build upload monitor core libs cmake build_simulator simulator log clean
+.PHONY: build upload monitor dependencies cmake build_simulator simulator log clean
@@ -21,8 +21,8 @@
 * Dedicated for education and research.
 * Made from general-purpose components.
 * Simple and clean source code in Arduino (<2k lines firmware).
-* Communication using MAVLink protocol over Wi-Fi or ESP-NOW.
-* Control with USB gamepad, remote control or smartphone.
+* Connectivity using Wi-Fi and MAVLink protocol.
+* Control using USB gamepad, remote control or smartphone.
 * Wireless command line interface and analyzing.
 * Precise simulation with Gazebo.
 * Python library for scripting and automatic flights.
@@ -47,27 +47,13 @@ See the [user builds gallery](docs/user.md):

 <a href="docs/user.md"><img src="docs/img/user/user.jpg" width=500></a>

-### PCB
-
-The official PCB *(Flix2)* is in development now. Follow the [project's channel](https://t.me/opensourcequadcopter) to track the progress.
-
-Outdoor flights demo video of the current prototype:
-
-<a href="https://youtu.be/KXlNmvUTi4g"><img width=300 src="https://i3.ytimg.com/vi/KXlNmvUTi4g/maxresdefault.jpg"></a>
-
-### Position control
-
-The position control feature is in development. RoboCamp 2026 demo (using an overhead camera, [sources](https://github.com/xTimop/flix-poscontrol/compare/robolager2026...xTimop:flix-poscontrol:poscontrol)):
-
-<a href="https://youtu.be/369Xowm4HcU"><img width=300 src="https://i3.ytimg.com/vi/369Xowm4HcU/maxresdefault.jpg"></a>
-
 ## Simulation

 The simulator is implemented using Gazebo and runs the original Arduino code:

 <img src="docs/img/simulator1.png" width=500 alt="Flix simulator">

-## Documentation articles
+## Documentation

 1. [Assembly instructions](docs/assembly.md).
 2. [Usage: build, setup and flight](docs/usage.md).
@@ -85,14 +71,14 @@ Additional articles:

 |Type|Part|Image|Quantity|
 |-|-|:-:|:-:|
-|Microcontroller board|ESP32 Mini.<br>ESP32-S3/ESP32-C3 boards are also supported.|<img src="docs/img/esp32.jpg" width=100>|1|
-|IMU (and barometer¹) board|GY‑91, MPU-9265 (or other MPU‑9250/MPU‑6500 board)<br>ICM20948V2 (ICM‑20948)<br>GY-521 (MPU-6050)|<img src="docs/img/gy-91.jpg" width=90 align=center><br><img src="docs/img/icm-20948.jpg" width=100><br><img src="docs/img/gy-521.jpg" width=100>|1|
-|*Boost converter (optional, for more stable power supply)*|*5V output*|<img src="docs/img/buck-boost.jpg" width=100>|1|
+|Microcontroller board|ESP32 Mini|<img src="docs/img/esp32.jpg" width=100>|1|
+|IMU (and barometer¹) board|GY‑91, MPU-9265 (or other MPU‑9250/MPU‑6500 board)<br>ICM20948V2 (ICM‑20948)³<br>GY-521 (MPU-6050)³⁻¹|<img src="docs/img/gy-91.jpg" width=90 align=center><br><img src="docs/img/icm-20948.jpg" width=100><br><img src="docs/img/gy-521.jpg" width=100>|1|
+|Boost converter (optional, for more stable power supply)|5V output|<img src="docs/img/buck-boost.jpg" width=100>|1|
 |Motor|8520 3.7V brushed motor.<br>Motor with exact 3.7V voltage is needed, not ranged working voltage (3.7V — 6V).<br>Make sure the motor shaft diameter and propeller hole diameter match!|<img src="docs/img/motor.jpeg" width=100>|4|
-|Propeller|55 mm or 65 mm|<img src="docs/img/prop.jpg" width=100>|4|
-|MOSFET (transistor)|UMW 100N03A or [analog](https://t.me/opensourcequadcopter/33).<br>Warning: don't use KIA 100N03A or other manufacturers, they might not work!|<img src="docs/img/100n03a.jpg" width=100>|4|
+|Propeller|55 mm (alternatively 65 mm)|<img src="docs/img/prop.jpg" width=100>|4|
+|MOSFET (transistor)|100N03A or [analog](https://t.me/opensourcequadcopter/33)|<img src="docs/img/100n03a.jpg" width=100>|4|
 |Pull-down resistor<br>Voltage measurement resistor|10 kΩ|<img src="docs/img/resistor10k.jpg" width=100>|6|
-|3.7V Li-Po battery|LW 952540 (or any compatible by the size).<br>Make sure the battery has enough discharge rate — 25C or more!|<img src="docs/img/battery.jpg" width=100>|1|
+|3.7V Li-Po battery|LW 952540 (or any compatible by the size)|<img src="docs/img/battery.jpg" width=100>|1|
 |Battery connector cable|MX2.0 2P female|<img src="docs/img/mx.png" width=100>|1|
 |Li-Po Battery charger|Any|<img src="docs/img/charger.jpg" width=100>|1|
 |Screws for IMU board mounting|M3x5|<img src="docs/img/screw-m3.jpg" width=100>|2|
@@ -166,16 +152,18 @@ 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)|GPIO4|
+  |Signal (TX)|GPIO4¹|

-* Optionally connect the battery voltage divider for voltage monitoring to any ADC1 pin (e. g. *GPIO32* on ESP32, *GPIO3* on ESP32-S3).
+  *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.*

-  ESP32 and ESP32-S3 [can measure](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/adc.html#analogsetattenuation) up to 3.1 V and ESP32-S3/ESP32-C3 can measure up to 2.5 V, so choose the voltage divider resistors accordingly.
+* Optionally connect the battery voltage divider for voltage monitoring to any ADC1 pin (e. g. *GPIO32* on ESP32, *GPIO3* on ESP32S3).
+
+  ESP32 and ESP32S3 [can measure](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/adc.html#analogsetattenuation) up to 3.1 V and ESP32S3/ESP32C3 can measure up to 2.5 V, so choose the voltage divider resistors accordingly.

 ## Resources

 * Telegram channel on developing the drone and the flight controller (in Russian): https://t.me/opensourcequadcopter.
-* Official Telegram chat: https://t.me/opensourcequadcopterchat (English / Russian).
+* 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/.

 ## Disclaimer
@@ -0,0 +1,5 @@
+board_manager:
+  additional_urls:
+    - https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
+network:
+  connection_timeout: 1h
@@ -28,8 +28,6 @@ Soldered components ([schematics variant](https://miro.com/app/board/uXjVN-dTjoo

 <img src="img/assembly/7.jpg" width=600>

-See an alternative assembly process photos here: https://drive.google.com/drive/folders/1FG5BH9RCzdf1XmJcC70PymiRMXcz6Fx7?usp=sharing.
-
 ## Motor directions

 > [!WARNING]
@@ -67,38 +67,6 @@ In order to add a console command, modify the `doCommand()` function in `cli.ino
 >
 > For on-the-ground commands, use `pause()` function, instead of `delay()`. This function allows to pause in a way that MAVLink connection will continue working.

-### Parameter subsystem
-
-Parameters subsystem (`parameters.ino`) uses standard [Preferences.h](https://docs.espressif.com/projects/arduino-esp32/en/latest/tutorials/preferences.html) ESP32 library to store parameters in non-volatile memory. Each parameter is a regular global variable, which is registered in the `parameters` array.
-
-To add a new parameter:
-
-1. Define a global variable for the parameter, two types are supported: `float` and `int`.
-2. Add an entry to the `parameters` array, with the parameter name, a pointer to the variable, and optionally a callback function to call when the parameter is changed.
-3. Everything else will be handled automatically.
-
-See examples of adding new parameters in commits: [c434107](https://github.com/okalachev/flix/commit/c434107), [a687303](https://github.com/okalachev/flix/commit/a687303).
-
-> [!NOTE]
-> Since all the parameters are internally stored and passed as floats, the safe range for `int` parameters is -16777216 to 16777215.
-
-## Adding a subsystem
-
-To add a new subsystem:
-
-1. Create a new `*.ino` file for your subsystem.
-2. Define setup and loop functions for the subsystem, for example `setupMySubsystem()` and `loopMySubsystem()`.
-3. Use `Rate` class if you need to limit the loop frequency, for example:
-
-    ```cpp
-    Rate mySubsystemRate(100); // 100 Hz
-
-    void loopMySubsystem() {
-    	if (!mySubsystemRate) return;
-    	// Do something...
-    }
-4. Add setup and loop calls in to `setup()` and `loop()` functions in `flix.ino`.
-
 ## Building the firmware

 See build instructions in [usage.md](usage.md).
@@ -5,32 +5,27 @@
 Do the following:

 * **Check ESP32 core is installed**. Check if the version matches the one used in the [tutorial](usage.md#building-the-firmware).
-* **Check libraries**. Install all the required libraries from the tutorial. Make sure there are no MPU-9250 or other peripherals libraries that may conflict with the ones used in the tutorial.
+* **Check 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

 Do the following:

-* **Check the battery voltage**. Use a multimeter to measure the battery voltage. The fully charged battery should have about 4.2V.
-* **Check the battery you use has enough discharge current**. The battery should be able to provide 15A of current. So the C-rating for a 1000 mAh battery should be at least 15C (higher is better).
+* **Check 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 or `reboot` command to see the whole startup output.
 * **Check the baudrate is correct**. If you see garbage characters in the Serial Monitor, make sure the baudrate is set to 115200.
+* **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
 * **Check if the console is working**. Perform `help` command in Serial Monitor. You should see the list of available commands. You can also access the console using QGroundControl *(Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console)*.
 * **Configure QGroundControl correctly before connecting to the drone** if you use it to control the drone. Go to the settings and enable *Virtual Joystick*. *Auto-Center Throttle* setting **should be disabled**.
 * **If QGroundControl doesn't connect**, you might need to disable the firewall and/or VPN on your computer.
-* **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
 * **Check the IMU is working**. Perform `imu` command and check its output:
  * The `status` field should be `OK`.
  * The `rate` field should be about 1000 (Hz).
  * The `accel` and `gyro` fields should change as you move the drone.
-* **Check the IMU orientation is set correctly**. If the attitude estimation is rotated, set the correct IMU orientation as described in the [tutorial](usage.md#define-imu-orientation).
 * **Calibrate the accelerometer.** if is wasn't done before. Type `ca` command in Serial Monitor and follow the instructions.
-* **Check the attitude estimation**. Connect to the drone using QGroundControl. Rotate the drone in different orientations and check if the attitude estimation is shown exactly as on the video below:
-
-  <a href="https://youtu.be/yVRN23-GISU"><img width=200 src="https://i3.ytimg.com/vi/yVRN23-GISU/maxresdefault.jpg"></a>
-
-* **Check the IMU output**. Connect to the drone using QGroundControl on your computer. Go to the *Analyze* tab, *MAVLINK Inspector*. Plot the data from the `SCALED_IMU` message. The gyroscope and accelerometer data should change according to the drone movement.
+* **Check the attitude estimation**. Connect to the drone using QGroundControl. Rotate the drone in different orientations and check if the attitude estimation shown in QGroundControl is correct.
+* **Check the IMU orientation is set correctly**. If the attitude estimation is rotated, set the correct IMU orientation as described in the [tutorial](usage.md#define-imu-orientation).
 * **Check the motors type**. Motors with exact 3.7V voltage are needed, not ranged working voltage (3.7V — 6V).
 * **Check the motors**. Perform the following commands using Serial Monitor:
  * `mfr` — should rotate front right motor (counter-clockwise).
@@ -38,10 +33,9 @@ Do the following:
  * `mrl` — should rotate rear left motor (counter-clockwise).
  * `mrr` — should rotate rear right motor (clockwise).
 * **Check the propeller directions are correct**. Make sure your propeller types (A or B) are installed as on the picture:
-
  <img src="img/user/peter_ukhov-2/1.jpg" width="200">
-
-* **If using an SBUS receiver**:
+* **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**:
  * **Define the used GPIO pin** in `RC_RX_PIN` parameter.
  * **Calibrate the RC** using `cr` command in the console.
-  * **Check the controls** using `rc` command. All the controls should change between -1 and 1, and the throttle between 0 and 1.
+* **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.
@@ -1,63 +1,34 @@
 # Usage: build, setup and flight

-To fly Flix quadcopter, you need to upload the firmware to the ESP32 board, and set up the drone for flight.
+To fly Flix quadcopter, you need to build the firmware, upload it to the ESP32 board, and set up the drone for flight.

-## Uploading the firmware
-
-You can either use the **prebuilt binaries** or **build the firmware** from sources — this will let you modify the firmware and add new features.
-
-### Prebuilt binaries (the easiest way)
-
-1. Download the latest firmware file using the following links:
-
-   <!-- markdownlint-disable MD044 -->
-   |Type|Boards|Link|
-   |-|-|-|
-   |ESP32|DevKit, D1 Mini|[`quadcopter.dev/flix.esp32.merged.bin`](https://quadcopter.dev/flix.esp32.merged.bin)|
-   |ESP32-S3|Most S3 based|[`quadcopter.dev/flix.esp32s3.merged.bin`](https://quadcopter.dev/flix.esp32s3.merged.bin)|
-   |ESP32-S3 (2MB PSRAM)|S3 Super Mini, S3 Zero (2MB PSRAM)|[`quadcopter.dev/flix.esp32s3.qspi.merged.bin`](https://quadcopter.dev/flix.esp32s3.qspi.merged.bin)|
-   |ESP32-S3 (8/16MB PSRAM)|S3 Zero (8MB PSRAM)|[`quadcopter.dev/flix.esp32s3.opi.merged.bin`](https://quadcopter.dev/flix.esp32s3.opi.merged.bin)|
-   |ESP32-C3|C3 Super Mini|[`quadcopter.dev/flix.esp32c3.merged.bin`](https://quadcopter.dev/flix.esp32c3.merged.bin)|
-   |Flix2|Flix2 board|[`quadcopter.dev/flix.flix2.merged.bin`](https://quadcopter.dev/flix.flix2.merged.bin)|
-   <!-- markdownlint-enable MD044 -->
-
-2. Flash your ESP32 board using [ESP32 Web Flasher](https://www.espboards.dev/tools/program/):
-
-   <img src="img/web-flasher.png" width="400">
-
-   * Connect the board to your computer, press *Connect to ESP*, choose the serial port.
-   * Go to the *Flash* tab.
-   * Choose the downloaded firmware file, set *Flash address* to *0* (important).
-   * Click *Program* button and wait until the process is finished.
-
-### Building from sources (flexible)
-
-You can build and upload the firmware using either **Arduino IDE** (easier for beginners) or **command line**.
-
-Get the sources using git:
+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 sources as a ZIP archive](https://github.com/okalachev/flix/archive/refs/heads/master.zip).
+Beginners can [download the source code as a ZIP archive](https://github.com/okalachev/flix/archive/refs/heads/master.zip).

-#### Arduino IDE (Windows, Linux, macOS)
+## 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 3.3.10. See the [official Espressif's instructions](https://docs.espressif.com/projects/arduino-esp32/en/latest/installing.html#installing-using-arduino-ide) on installing ESP32 Core in Arduino IDE.
+3. Install ESP32 core, version 3.3.6. 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 2.0.25.
 5. Open the `flix/flix.ino` sketch from downloaded firmware sources in Arduino IDE.
-6. Connect your ESP32 board to the computer and choose correct board type in Arduino IDE (*WEMOS D1 MINI ESP32* for ESP32 Mini, *ESP32S3 Dev Module* for ESP32-S3 Super Mini) and the port.
-7. Set *Tools* ⇒ *Core Debug Level* to *Error* to see the errors in the serial console. Set *Tools* ⇒ *USB CDC on Boot* to *Enabled* for ESP32-S3/ESP32-C3 boards.
-8. [Build and upload](https://docs.arduino.cc/software/ide-v2/tutorials/getting-started/ide-v2-uploading-a-sketch) the firmware using Arduino IDE.
+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)
+### Command line (Windows, Linux, macOS)

 1. [Install Arduino CLI](https://arduino.github.io/arduino-cli/installation/).

@@ -86,12 +57,6 @@ Beginners can [download the sources as a ZIP archive](https://github.com/okalach
   make upload monitor
   ```

-   For ESP32-S3/ESP32-C3 boards, set the appropriate [FQBN](https://docs.arduino.cc/arduino-cli/FAQ/#whats-the-fqbn-string) using `BOARD` parameter:
-
-   ```bash
-   make BOARD=esp32:esp32:esp32s3:FlashSize=4M,CDCOnBoot=cdc upload
-   ```
-
 See other available Make commands in [Makefile](../Makefile).

 > [!TIP]
@@ -99,6 +64,15 @@ See other available Make commands in [Makefile](../Makefile).

 ## 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
+```
+
 ### Connect using QGroundControl

 QGroundControl is a ground control station software that can be used to monitor and control the drone.
@@ -108,9 +82,6 @@ QGroundControl is a ground control station software that can be used to monitor
 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.

-> [!TIP]
-> If QGroundControl doesn't connect, try to disable the firewall and/or VPN on your computer, as they may block the connection.
-
 ### Access console

 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)**.
@@ -124,7 +95,7 @@ To access the console using serial port:
 To access the console using QGroundControl:

 1. Connect to the drone using QGroundControl app.
-2. Go to the QGroundControl menu ⇒ *Analyze Tools* ⇒ *MAVLink Console*.
+2. Go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console*.

 <img src="img/cli.png" width="400">

@@ -139,22 +110,11 @@ The drone is configured using parameters. To access and modify them, go to the Q

 You can also work with parameters using `p` command in the console. Parameter names are case-insensitive.

-### Configure the IMU
-
-1. Configure the following parameters for the IMU:
-   * `IMU_MODEL` — IMU model (1 for MPU-9250/MPU-6500, 2 for ICM-20948, 3 for MPU-6050, 4 for ICM-40609-D).
-   * `IMU_BUS` — communication bus (0 for SPI, 1 for I²C).
-   * `IMU_PIN_SCK`, `IMU_PIN_MISO`, `IMU_PIN_MOSI`, `IMU_PIN_CS` — SPI pin numbers.
-   * `IMU_PIN_SCL`, `IMU_PIN_SDA` — I²C pin numbers.
-   * `IMU_PIN_INT` — IMU data ready pin number (-1 if not used).
-2. Reboot the drone.
-3. Check the IMU is working using `imu` command in the console (should print `status: OK`).
-
 ### Define IMU orientation

 The IMU orientation (relative to the drone's axes) is defined using the parameters: `IMU_ROT_ROLL`, `IMU_ROT_PITCH`, and `IMU_ROT_YAW`.

-The drone has *X* axis pointing forward, *Y* axis pointing left, and *Z* axis pointing up, and the supported IMU boards have *X* axis pointing to the mounting holes side and *Z* axis pointing up from the component side:
+The drone has *X* axis pointing forward, *Y* axis pointing left, and *Z* axis pointing up, and the supported IMU boards have *X* axis pointing to the pins side and *Z* axis pointing up from the component side:

 <img src="img/imu-axes.png" width="200">

@@ -162,10 +122,10 @@ Use the following table to set the parameters for common IMU orientations:

 |Orientation|Parameters|Orientation|Parameters|
 |:-:|-|-|-|
-|<img src="img/imu-rot-3.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0    |<img src="img/imu-rot-7.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0|
-|<img src="img/imu-rot-2.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|<img src="img/imu-rot-6.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|
-|<img src="img/imu-rot-1.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|<img src="img/imu-rot-5.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|
-|<img src="img/imu-rot-4.png" width="180"><br>☑️ **Default**|<br>`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|<img src="img/imu-rot-8.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|
+|<img src="img/imu-rot-1.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0    |<img src="img/imu-rot-5.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0|
+|<img src="img/imu-rot-2.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|<img src="img/imu-rot-6.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|
+|<img src="img/imu-rot-3.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|<img src="img/imu-rot-7.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|
+|<img src="img/imu-rot-4.png" width="180"><br>☑️ **Default**|<br>`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|<img src="img/imu-rot-8.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|

 ### Calibrate accelerometer

@@ -178,9 +138,9 @@ Before flight you need to calibrate the accelerometer:

 If using non-default motor pins, set the pin numbers using the parameters: `MOTOR_PIN_FL`, `MOTOR_PIN_FR`, `MOTOR_PIN_RL`, `MOTOR_PIN_RR` (front-left, front-right, rear-left, rear-right respectively).

-#### Brushless motors
+Certain ESP32 models (such as ESP32-S3) support a lower maximum PWM frequency; on these boards the parameter `MOT_PWM_FREQ` should be set to 40000 Hz.

-If using brushless motors with ESCs:
+If using brushless motors and ESCs:

 1. Set the appropriate PWM using the parameters: `MOT_PWM_STOP`, `MOT_PWM_MIN`, and `MOT_PWM_MAX` (1000, 1000, and 2000 is typical).
 2. Decrease the PWM frequency using the `MOT_PWM_FREQ` parameter (400 is typical).
@@ -188,7 +148,7 @@ If using brushless motors with ESCs:
 > [!CAUTION]
 > **Remove the props when configuring the motors!** If improperly configured, you may not be able to stop them.

-### Battery voltage monitoring (optional)
+### Battery voltage monitoring

 ESP32 ADC can measure only up to 3.3 V, so you need to use a voltage divider to monitor the battery voltage. To enable voltage measurement, set the following parameters:

@@ -210,7 +170,7 @@ After this setup, you should see the battery voltage in QGroundControl top panel

 2. Check the attitude estimation: connect to the drone using QGroundControl, rotate the drone in different orientations and check if the attitude estimation shown in QGroundControl is correct. Compare your attitude indicator (in the *large vertical* mode) to the video:

-   <a href="https://youtu.be/yVRN23-GISU"><img width=300 src="https://i3.ytimg.com/vi/yVRN23-GISU/maxresdefault.jpg"></a>
+    <a href="https://youtu.be/yVRN23-GISU"><img width=300 src="https://i3.ytimg.com/vi/yVRN23-GISU/maxresdefault.jpg"></a>

 3. Perform motor tests. Use the following commands **— remove the propellers before running the tests!**

@@ -228,22 +188,10 @@ After this setup, you should see the battery voltage in QGroundControl top panel

 ## 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/ESP-NOW).
+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 a smartphone

-#### Using Mavlink Joystick app (Android)
-
-<img src="https://github.com/goldarte/mavlink-joystick/blob/master/app_screen.png?raw=true" width="400">
-
-1. Download and install [Mavlink Joystick app](https://github.com/goldarte/mavlink-joystick/releases/latest).
-2. Power the drone using the battery.
-3. Connect your smartphone to the appeared `flix` Wi-Fi network (password: `flixwifi`).
-4. Open Mavlink Joystick app. It should connect and begin showing the drone's telemetry automatically.
-5. Use the virtual joystick to fly the drone!
-
-#### Using QGroundControl app
-
 1. Install [QGroundControl mobile app](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/getting_started/download_and_install.html#android) on your smartphone.
 2. Power the drone using the battery.
 3. Connect your smartphone to the appeared `flix` Wi-Fi network (password: `flixwifi`).
@@ -256,11 +204,11 @@ There are several ways to control the drone's flight: using **smartphone** (Wi-F

 ### Control with a remote control

-If using SBUS-connected remote control you need to enable SBUS and calibrate it:
+Before using SBUS-connected remote control you need to enable SBUS and calibrate it:

 1. Connect to the drone using QGroundControl.
 2. In parameters, set the `RC_RX_PIN` parameter to the GPIO pin number where the SBUS signal is connected, for example: 4. Negative value disables SBUS.
-3. Check if the receiver is working using `rc` command in the console.
+3. Reboot the drone to apply changes.
 4. Open the console, type `cr` command and follow the instructions to calibrate the remote control.
 5. Use the remote control to fly the drone!

@@ -273,7 +221,7 @@ If your drone doesn't have RC receiver installed, you can use USB remote control
 3. Power up the drone.
 4. Connect your computer to the appeared `flix` Wi-Fi network (password: `flixwifi`).
 5. Launch QGroundControl app. It should connect and begin showing the drone's telemetry automatically.
-6. Go to the QGroundControl menu ⇒ *Vehicle Setup* ⇒ *Joystick*. Calibrate your USB remote control there.
+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
@@ -330,8 +278,11 @@ The Wi-Fi mode is chosen using `WIFI_MODE` parameter in QGroundControl or in the

 * `0` — Wi-Fi is disabled.
 * `1` — Access Point mode *(AP)* — the drone creates a Wi-Fi network.
-* `2` — Client mode *(STA)* — the drone connects to an existing Wi-Fi network (may cause additional delays, so generally not recommended).
-* `3` — ESP-NOW mode — the drone uses ESP-NOW protocol for communication.
+* `2` — Client mode *(STA)* — the drone connects to an existing Wi-Fi network.
+* `3` — *ESP-NOW (not implemented yet)*.
+
+> [!WARNING]
+> Tests showed that Client mode may cause **additional delays** in remote control (due to retranslations), so it's generally not recommended.

 The SSID and password are configured using the `ap` and `sta` console commands:

@@ -353,43 +304,9 @@ Disabling Wi-Fi:
 p WIFI_MODE 0
 ```

-### Using ESP-NOW
-
-[ESP-NOW](https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/network/esp_now.html) is a low level wireless communication protocol. It can provide lower latency, better reliability, and longer range than Wi-Fi. However, it requires a second ESP32 board to be used as a proxy for the computer.
-
-<img src="img/espnow-connection.jpg" width="600">
-
-To setup ESP-NOW communication:
-
-1. Flash the second ESP32 board with ESP-NOW proxy sketch: [`tools/espnow-proxy/espnow-proxy.ino`](../tools/espnow-proxy/espnow-proxy.ino). Use Arduino IDE or command line: `make upload_proxy`.
-
-2. Open Serial Monitor in Arduino IDE or use `make monitor` command. The ESP32 will print its MAC address and generated encryption key, for example:
-
-   ```
-   espnow 7a:c8:e3:eb:bf:e9 &PiuSysxP9+$L&5E
-   ```
-
-   Run this line as a console command on each drone you want to bind to this proxy board. [The maximum number](https://github.com/espressif/esp-idf/blob/e95cab4be8fd293e3f3323181e7a2280874da6f7/components/esp_wifi/include/esp_now.h#L32-L33) of simultaneously connected drones is 20 (unencrypted) or 6 (encrypted).
-
-3. Set the `WIFI_MODE` parameter to `3` on the drone:
-
-   ```
-   p WIFI_MODE 3
-   ```
-
-4. Go to the QGroundControl menu ⇒ *Application Settings* ⇒ *Comm Links*, add new link with the following settings:
-   * Name: ESP32.
-   * Type: Serial.
-   * Serial Port: choose the port of the proxy ESP32 board, e. g. `/dev/cu.usbserial-0001`.
-   * Baud Rate: 115200.
-5. Click *Save*, click *Connect*. QGroundControl should connect to the drone using ESP-NOW and begin showing the telemetry.
-
-> [!TIP]
-> Make sure Arduino IDE is not running when using ESP-NOW proxy board, as it may block the serial port.
-
 ## Flight log

-After the flight, you can download the flight log wirelessly for analysis. Use the following command on your computer for that:
+After the flight, you can download the flight log for analysis wirelessly. Use the following command on your computer for that:

 ```bash
 make log
@@ -4,71 +4,6 @@ This page contains user-built drones based on the Flix project. Publish your pro

 ---

-Author: [Oleg1405](https://t.me/Oleg1405).<br>
-Description: ESP32 Mini, MPU-6500 IMU, boost converter, BT2.0 power connector, 65 mm props, BetaFPV ELRS Lite Receiver, Radiomaster Pocket + Mavlink Joystick (Android) control.
-
-<img src="img/user/oleg1405/1.jpg" height=300>
-
-[Flight video](https://www.youtube.com/shorts/rbXV4sHbpso).
-
---
-
-Author: Alican Erüst.<br>
-Description: QX95 mm frame, 55 mm propellers, 3.7 V 25C 1050 mAh LiPo battery, MPU6050 IMU, Logitech F310 gamepad controller, with a total quadcopter weight of 66 g.
-
-<img src="img/user/alicanerus/1.jpg" height=200> <img src="img/user/alicanerus/2.jpg" height=200> <img src="img/user/alicanerus/3.jpg" height=200>
-
-[Flight video](https://drive.google.com/file/d/1k0WeWTKnCAfaugkX7LcmNxsUuq79RL8Z/view?usp=sharing).
-
---
-
-Author: [Неруш Михаил](https://t.me/NerushMV).<br>
-Description: custom frame made of 4 mm plywood, 8520 brushed motors, 75 mm propellers, MPU-6500. FlySky FS-i6X with ESP32-based adapter for ESP-NOW communication (using PPM output).<br>
-Sources and materials: [link](https://drive.google.com/drive/folders/1uWiDcuorLrtVs_IIR7Y13omij-7Q1nx8).
-
-<img src="img/user/nerush/1.jpg" height=200> <img src="img/user/nerush/2.jpg" height=200>
-
-[Flight video](https://drive.google.com/file/d/1jRXeGx34lJpUfw0GKLQeIzkWZvooQJSE/view?usp=sharing).
-
---
-
-Author: [Konstantinos Paraskevas](https://github.com/Frapais).<br>
-Description: drone with a custom single-boarded airframe, extending the [Sprig-C3 module](https://github.com/Frapais/Sprig-C3).
-ESP32-C3 microcontroller, ICM-20948 IMU, on-board fuel-gauge, status LED indicator.<br>
-Repository with all the code and PCB sources: https://github.com/Frapais/Sprig-Drone.
-
-<img src="img/user/kostas/1.jpg" height=150> <img src="img/user/kostas/2.jpg" height=150>
-
-Detailed video about making the drone:
-
-<a href="https://youtu.be/82Q-uBq6s48"><img width=400 src="https://i3.ytimg.com/vi/82Q-uBq6s48/maxresdefault.jpg"></a>
-
---
-
-Author: [Awab Anas](http://t.me/AW_VENOM).<br>
-Description: ESP32 D1 Mini, MPU-6050, 8520 3.7V brushed motors, 55 mm propellers, battery li-po 1200 mAh, controlling via [Mavlink Joystick app](https://github.com/goldarte/mavlink-joystick/releases/latest).<br>
-[Flight validation](https://drive.google.com/file/d/12z0jfctZDBA6b5UKCG0Uje5rAxj6DhF-/view?usp=sharing).
-
-<img src="img/user/aw_venom/1.jpg" height=200>
-
---
-
-Author: [Ina Tix](https://t.me/ina_tix).<br>
-Description: XR2981 based DC-DC converter, ELRS MINI 2.4GHz RX SX1280 receiver (SBUS interface), Radiomaster TX12 remote control.<br>
-[Flight validation](https://drive.google.com/file/d/1yqkKNuz4R_yxGqUNQxVpixJbXqEEcUSj/view?usp=share_link).
-
-<img src="img/user/ina_tix/1.jpg" height=200> <img src="img/user/ina_tix/2.jpg" height=200> <img src="img/user/ina_tix/3.jpg" height=200>
-
---
-
-Author: Oleg Kalachev.<br>
-Description: the first attempt on making an official PCB based Flix drone (Flix2 board). The IMU is not working on this version, so an external MPU-6050 board was used, therefore considered as **Flix version 1.5**.<br>
-[Flight video](https://drive.google.com/file/d/1R7tuUsFmPY0CGcOCFfMFaCp9kR49K3bl/view?usp=sharing).
-
-<img src="img/flix1.5.jpg" width=300>
-
---
-
 Author: [FanBy0ru](https://https://github.com/FanBy0ru).<br>
 Description: custom 3D-printed frame.<br>
 Frame STLs and flight validation: https://cults3d.com/en/3d-model/gadget/armature-pour-flix-drone.
@@ -106,17 +41,6 @@ Author: [goldarte](https://t.me/goldarte).<br>

 ---

-Author: [malagis](https://oshwhub.com/malagis).<br>
-
-A Chinese custom PCB version of Flix with a big community of users, lots of materials and modifications.
-
-Main project's page: https://oshwhub.com/malagis/esp32-mini-plane.<br>
-Video about the project: https://www.bilibili.com/video/BV14vyqBFEJn/.
-
-<img src="img/user/malagis/1.jpg" height=200> <img src="img/user/malagis/2.jpg" height=200> <img src="img/user/malagis/3.jpg" height=200>
-
---
-
 ## School 548 course

 Special course on quadcopter design and engineering took place in october-november 2025 in School 548, Moscow. The course included UAV control theory, electronics, drone assembly and setup practice, using the Flix project.
@@ -10,7 +10,6 @@

 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 W_AP, W_STA, W_ESPNOW;
 extern float t, dt, loopRate;
 extern uint16_t channels[16];
 extern float controlTime;
@@ -20,44 +19,42 @@ extern LowPassFilter<Vector> gyroBiasFilter;
 extern float voltage;

 const char* motd =
+"\nWelcome to\n"
 " _______  __       __  ___   ___\n"
 "|   ____||  |     |  | \\  \\ /  /\n"
 "|  |__   |  |     |  |  \\  V  /\n"
 "|   __|  |  |     |  |   >   <\n"
 "|  |     |  `----.|  |  /  .  \\\n"
 "|__|     |_______||__| /__/ \\__\\\n\n"
-"(C) Oleg Kalachev\n"
-"https://github.com/okalachev/flix\n\n"
 "Commands:\n\n"
 "help - show help\n"
 "p - show all parameters\n"
-"p <str> - show parameters starting with str\n"
+"p <name> - show parameter\n"
 "p <name> <value> - set parameter\n"
 "preset - reset parameters\n"
 "time - show time info\n"
+"ps - show pitch/roll/yaw\n"
+"psq - show attitude quaternion\n"
 "imu - show IMU data\n"
-"ca - calibrate accel\n"
-"st - show state estimation\n"
 "arm - arm the drone\n"
 "disarm - disarm the drone\n"
 "raw/stab/acro/auto - set mode\n"
 "rc - show RC data\n"
-"cr - calibrate RC\n"
 "pw - show power info\n"
 "wifi - show Wi-Fi info\n"
-"wifi ap/sta/espnow/off - set Wi-Fi mode\n"
-"ap <ssid> <password> - configure Wi-Fi access point\n"
-"sta <ssid> <password> - configure Wi-Fi client mode\n"
-"espnow <mac> [<key>] - configure ESP-NOW peer\n"
+"ap <ssid> <password> - setup Wi-Fi access point\n"
+"sta <ssid> <password> - setup Wi-Fi client mode\n"
 "mot - show motor output\n"
 "log [dump] - print log header [and data]\n"
-"mfr/mfl/mrr/mrl [<thrust>] - test motor (remove props)\n"
+"cr - calibrate RC\n"
+"ca - calibrate accel\n"
+"mfr, mfl, mrr, mrl - test motor (remove props)\n"
 "sys - show system info\n"
 "reset - reset drone's state\n"
 "reboot - reboot the drone\n";

 void print(const char* format, ...) {
-	char buf[3000];
+	char buf[1000];
 	va_list args;
 	va_start(args, format);
 	vsnprintf(buf, sizeof(buf), format, args);
@@ -92,8 +89,10 @@ void doCommand(String str, bool echo = false) {
 	// execute command
 	if (command == "help" || command == "motd") {
 		print("%s\n", motd);
-	} else if (command == "p" && arg1 == "") {
-		printParameters(arg0.c_str());
+	} else if (command == "p" && arg0 == "") {
+		printParameters();
+	} else if (command == "p" && arg0 != "" && arg1 == "") {
+		print("%s = %g\n", arg0.c_str(), getParameter(arg0.c_str()));
 	} else if (command == "p") {
 		bool success = setParameter(arg0.c_str(), arg1.toFloat());
 		if (success) {
@@ -107,15 +106,15 @@ void doCommand(String str, bool echo = false) {
 		print("Time: %f\n", t);
 		print("Loop rate: %.0f\n", loopRate);
 		print("dt: %f\n", dt);
+	} else if (command == "ps") {
+		Vector a = attitude.toEuler();
+		print("roll: %f pitch: %f yaw: %f\n", degrees(a.x), degrees(a.y), degrees(a.z));
+	} else if (command == "psq") {
+		print("qw: %f qx: %f qy: %f qz: %f\n", attitude.w, attitude.x, attitude.y, attitude.z);
 	} else if (command == "imu") {
 		printIMUInfo();
 		printIMUCalibration();
 		print("landed: %d\n", landed);
-	} else if (command == "st") {
-		print("rates: %g %g %g\n", rates.x, rates.y, rates.z);
-		print("attitude: %g %g %g %g\n", attitude.w, attitude.x, attitude.y, attitude.z);
-		print("roll: %g° pitch: %g° yaw: %g°\n", degrees(attitude.getRoll()), degrees(attitude.getPitch()), degrees(attitude.getYaw()));
-		print("landed: %d\n", landed);
 	} else if (command == "arm") {
 		armed = true;
 	} else if (command == "disarm") {
@@ -140,16 +139,12 @@ void doCommand(String str, bool echo = false) {
 		print("armed: %d\n", armed);
 	} else if (command == "pw") {
 		print("Voltage: %.1f V\n", voltage);
-	} else if (command == "wifi" && arg0 == "") {
-		printWiFiInfo();
 	} else if (command == "wifi") {
-		setWiFiMode(arg0);
+		printWiFiInfo();
 	} else if (command == "ap") {
-		configWiFi(W_AP, arg0.c_str(), arg1.c_str());
+		configWiFi(true, arg0.c_str(), arg1.c_str());
 	} else if (command == "sta") {
-		configWiFi(W_STA, arg0.c_str(), arg1.c_str());
-	} else if (command == "espnow") {
-		configWiFi(W_ESPNOW, arg0.c_str(), arg1.c_str());
+		configWiFi(false, arg0.c_str(), arg1.c_str());
 	} else if (command == "mot") {
 		print("front-right %g front-left %g rear-right %g rear-left %g\n",
 			motors[MOTOR_FRONT_RIGHT], motors[MOTOR_FRONT_LEFT], motors[MOTOR_REAR_RIGHT], motors[MOTOR_REAR_LEFT]);
@@ -161,22 +156,20 @@ void doCommand(String str, bool echo = false) {
 	} else if (command == "ca") {
 		calibrateAccel();
 	} else if (command == "mfr") {
-		testMotor(MOTOR_FRONT_RIGHT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
+		testMotor(MOTOR_FRONT_RIGHT);
 	} else if (command == "mfl") {
-		testMotor(MOTOR_FRONT_LEFT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
+		testMotor(MOTOR_FRONT_LEFT);
 	} else if (command == "mrr") {
-		testMotor(MOTOR_REAR_RIGHT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
+		testMotor(MOTOR_REAR_RIGHT);
 	} else if (command == "mrl") {
-		testMotor(MOTOR_REAR_LEFT, arg0.isEmpty() ? 0.2 : arg0.toFloat());
+		testMotor(MOTOR_REAR_LEFT);
 	} else if (command == "sys") {
 #ifdef ESP32
 		print("Chip: %s\n", ESP.getChipModel());
 		print("Temperature: %.1f °C\n", temperatureRead());
-		print("Total RAM: %d KB\n", ESP.getHeapSize() / 1024);
-		print("Free heap: %d KB\n", ESP.getFreeHeap() / 1024);
-		print("Firmware: " __DATE__ " " __TIME__ "\n");
+		print("Free heap: %d\n", ESP.getFreeHeap());
 		// Print tasks table
-		print("Num  Task                MinSt  Prio  Core  CPU%%\n");
+		print("Num  Task                Stack  Prio  Core  CPU%%\n");
 		int taskCount = uxTaskGetNumberOfTasks();
 		TaskStatus_t *systemState = new TaskStatus_t[taskCount];
 		uint32_t totalRunTime;
@@ -210,7 +203,7 @@ void handleInput() {

 	while (Serial.available()) {
 		char c = Serial.read();
-		if (c == '\n' || c == '\r') {
+		if (c == '\n') {
 			doCommand(input);
 			input.clear();
 		} else {
@@ -1,27 +0,0 @@
-// Copyright (c) 2026 Oleg Kalachev <okalachev@gmail.com>
-// Repository: https://github.com/okalachev/flix
-
-// Parameter defaults
-
-#pragma once
-
-void setDefaults() {
-	// Set defaults here
-
-	#if defined(CONFIG_IDF_TARGET_ESP32S3) || defined(CONFIG_IDF_TARGET_ESP32C3)
-		pwmFrequency = 38000;
-	#endif
-
-	#ifdef FLIX2
-		imuModel = 4; // ICM-40609-D
-		imuIntPin = 10;
-		imuCsPin = 14;
-
-		motorPins[MOTOR_REAR_LEFT] = 41;
-		motorPins[MOTOR_REAR_RIGHT] = 7;
-		motorPins[MOTOR_FRONT_RIGHT] = 18;
-		motorPins[MOTOR_FRONT_LEFT] = 38;
-
-		voltagePin = 3;
-	#endif
-}
@@ -9,6 +9,31 @@
 #include "lpf.h"
 #include "util.h"

+#define PITCHRATE_P 0.05
+#define PITCHRATE_I 0.2
+#define PITCHRATE_D 0.001
+#define PITCHRATE_I_LIM 0.3
+#define ROLLRATE_P PITCHRATE_P
+#define ROLLRATE_I PITCHRATE_I
+#define ROLLRATE_D PITCHRATE_D
+#define ROLLRATE_I_LIM PITCHRATE_I_LIM
+#define YAWRATE_P 0.3
+#define YAWRATE_I 0.0
+#define YAWRATE_D 0.0
+#define YAWRATE_I_LIM 0.3
+#define ROLL_P 6
+#define ROLL_I 0
+#define ROLL_D 0
+#define PITCH_P ROLL_P
+#define PITCH_I ROLL_I
+#define PITCH_D ROLL_D
+#define YAW_P 3
+#define PITCHRATE_MAX radians(360)
+#define ROLLRATE_MAX radians(360)
+#define YAWRATE_MAX radians(300)
+#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
 int mode = STAB;
 bool armed = false;
@@ -19,14 +44,14 @@ Vector ratesExtra; // feedforward rates
 Vector torqueTarget;
 float thrustTarget;

-PID rollRatePID(0.05, 0.2, 0.001, 0.3, 0.2);
-PID pitchRatePID(0.05, 0.2, 0.001, 0.3, 0.2);
-PID yawRatePID(0.3, 0, 0, 0.3);
-PID rollPID(6);
-PID pitchPID(6);
-PID yawPID(3);
-Vector maxRate(radians(360), radians(360), radians(360));
-float tiltMax = radians(30);
+PID rollRatePID(ROLLRATE_P, ROLLRATE_I, ROLLRATE_D, ROLLRATE_I_LIM, RATES_D_LPF_ALPHA);
+PID pitchRatePID(PITCHRATE_P, PITCHRATE_I, PITCHRATE_D, PITCHRATE_I_LIM, RATES_D_LPF_ALPHA);
+PID yawRatePID(YAWRATE_P, YAWRATE_I, YAWRATE_D);
+PID rollPID(ROLL_P, ROLL_I, ROLL_D);
+PID pitchPID(PITCH_P, PITCH_I, PITCH_D);
+PID yawPID(YAW_P, 0, 0);
+Vector maxRate(ROLLRATE_MAX, PITCHRATE_MAX, YAWRATE_MAX);
+float tiltMax = TILT_MAX;
 int flightModes[] = {STAB, STAB, STAB}; // map for rc mode switch

 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
@@ -124,7 +149,6 @@ void controlTorque() {
 	motors[MOTOR_REAR_LEFT] = thrustTarget + torqueTarget.x + torqueTarget.y - torqueTarget.z;
 	motors[MOTOR_REAR_RIGHT] = thrustTarget - torqueTarget.x + torqueTarget.y + torqueTarget.z;

-	// Prioritize angle control over thrust control
 	desaturate(motors[MOTOR_FRONT_LEFT], motors[MOTOR_FRONT_RIGHT], motors[MOTOR_REAR_LEFT], motors[MOTOR_REAR_RIGHT]);

 	motors[0] = constrain(motors[0], 0, 1);
@@ -32,7 +32,8 @@ void applyGyro() {

 void applyAcc() {
 	// test should we apply accelerometer gravity correction
-	landed = !motorsActive() && abs(acc.norm() - ONE_G) < ONE_G * 0.1f;
+	float accNorm = acc.norm();
+	landed = !motorsActive() && abs(accNorm - ONE_G) < ONE_G * 0.1f;

 	if (!landed) return;

@@ -46,7 +47,6 @@ void applyAcc() {

 void applyLevel() {
 	if (landed) return;
-	if (thrustTarget < 0.1) return; // skip at idle thrust

 	// assume the pilot keeps the drone more or less level in flight
 	Vector up = Quaternion::rotateVector(Vector(0, 0, 1), attitude);
@@ -17,7 +17,7 @@ extern float motors[4];

 void setup() {
 	Serial.begin(115200);
-	print("Initializing Flix\n");
+	print("Initializing flix\n");
 	setupParameters();
 	setupPower();
 	setupLED();
@@ -4,18 +4,13 @@
 // Work with the IMU sensor

 #include <SPI.h>
-#include <Wire.h>
 #include <FlixPeriph.h>
 #include "vector.h"
 #include "lpf.h"
 #include "util.h"

-IMU *imu;
-int imuModel = -1; // 1 - MPU9250, 2 - ICM20948, 3 - MPU6050, 4 - ICM40609D
-int imuBus = 0; // 0 - SPI, 1 - I2C
-int imuSckPin = SCK, imuMisoPin = MISO, imuMosiPin = MOSI, imuCsPin = SS, imuIntPin = -1;
-int imuSdaPin = SDA, imuSclPin = SCL;
-Vector imuRotation(0, 0, PI / 2); // imu orientation as Euler angles
+MPU9250 imu(SPI);
+Vector imuRotation(0, 0, -PI / 2); // imu orientation as Euler angles

 Vector gyro; // gyroscope output, rad/s
 Vector gyroBias;
@@ -28,42 +23,27 @@ LowPassFilter<Vector> gyroBiasFilter(0.001);

 void setupIMU() {
 	print("Setup IMU\n");
-	free(imu);
-	if (imuModel == 3) imuBus = 1; // MPU6050 is I2C only
-
-	if (imuBus == 0) {
-		// SPI connection
-		SPI.begin(imuSckPin, imuMisoPin, imuMosiPin);
-		imu = IMU::create(imuModel, SPI, imuCsPin, imuIntPin);
-	} else {
-		// I2C connection
-		Wire.setPins(imuSdaPin, imuSclPin);
-		imu = IMU::create(imuModel, Wire, imuIntPin);
-	}
-
-	imu->begin();
+	imu.begin();
 	configureIMU();
 }

 void configureIMU() {
-	imu->setAccelRange(IMU::ACCEL_RANGE_4G);
-	imu->setGyroRange(IMU::GYRO_RANGE_2000DPS);
-	imu->setDLPF(IMU::DLPF_MAX);
-	imu->setRate(IMU::RATE_1KHZ_APPROX);
-	imu->setupInterrupt();
+	imu.setAccelRange(imu.ACCEL_RANGE_4G);
+	imu.setGyroRange(imu.GYRO_RANGE_2000DPS);
+	imu.setDLPF(imu.DLPF_MAX);
+	imu.setRate(imu.RATE_1KHZ_APPROX);
+	imu.setupInterrupt();
 }

 void readIMU() {
-	imu->waitForData();
-	imu->getGyro(gyro.x, gyro.y, gyro.z);
-	imu->getAccel(acc.x, acc.y, acc.z);
+	imu.waitForData();
+	imu.getGyro(gyro.x, gyro.y, gyro.z);
+	imu.getAccel(acc.x, acc.y, acc.z);
 	calibrateGyroOnce();
-
-	// Apply scale and bias
+	// apply scale and bias
 	acc = (acc - accBias) / accScale;
 	gyro = gyro - gyroBias;
-
-	// Rotate to body frame
+	// rotate to body frame
 	Quaternion rotation = Quaternion::fromEuler(imuRotation);
 	acc = Quaternion::rotateVector(acc, rotation.inversed());
 	gyro = Quaternion::rotateVector(gyro, rotation.inversed());
@@ -72,13 +52,12 @@ void readIMU() {
 void calibrateGyroOnce() {
 	static Delay landedDelay(2);
 	if (!landedDelay.update(landed)) return; // calibrate only if definitely stationary
-
 	gyroBias = gyroBiasFilter.update(gyro);
 }

 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);
@@ -112,9 +91,9 @@ 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;
@@ -126,7 +105,6 @@ void calibrateAccelOnce() {
 	if (acc.x < accMin.x) accMin.x = acc.x;
 	if (acc.y < accMin.y) accMin.y = acc.y;
 	if (acc.z < accMin.z) accMin.z = acc.z;
-
 	// Compute scale and bias
 	accScale = (accMax - accMin) / 2 / ONE_G;
 	accBias = (accMax + accMin) / 2;
@@ -139,18 +117,16 @@ void printIMUCalibration() {
 }

 void printIMUInfo() {
-	imu->status() ? print("status: ERROR %d\n", imu->status()) : print("status: OK\n");
-	print("model: %s\n", imu->getModel());
-	print("who am I: 0x%02X\n", imu->whoAmI());
+	imu.status() ? print("status: ERROR %d\n", imu.status()) : print("status: OK\n");
+	print("model: %s\n", imu.getModel());
+	print("who am I: 0x%02X\n", imu.whoAmI());
 	print("rate: %.0f\n", loopRate);
-	print("interrupt mode: %s\n", imuIntPin != -1 ? "pin" : "timer");
-	print("temperature: %.1f °C\n", imu->getTemp());
 	print("gyro: %f %f %f\n", gyro.x, gyro.y, gyro.z);
 	print("acc: %f %f %f\n", acc.x, acc.y, acc.z);
-	imu->waitForData();
+	imu.waitForData();
 	Vector rawGyro, rawAcc;
-	imu->getGyro(rawGyro.x, rawGyro.y, rawGyro.z);
-	imu->getAccel(rawAcc.x, rawAcc.y, rawAcc.z);
+	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);
 }
@@ -14,10 +14,6 @@ public:
 	LowPassFilter(float alpha): alpha(alpha) {};

 	T update(const T input) {
-		if (!init) {
-			init = true;
-			return output = input;
-		}
 		return output += alpha * (input - output);
 	}

@@ -26,9 +22,6 @@ public:
 	}

 	void reset() {
-		init = false;
+		output = T(); // set to zero
 	}
-
-private:
-	bool init = false;
 };
@@ -10,14 +10,10 @@ extern float controlTime;
 extern float voltage;

 int mavlinkSysId = 1;
-
+Rate telemetryFast(10);
 Rate telemetrySlow(2);
-Rate telemetryAttitude(20);
-Rate telemetryRC(10);
-Rate telemetryMotors(10);
-Rate telemetryIMU(15);

-float mavlinkTime = NAN; // time of last received message
+bool mavlinkConnected = false;
 String mavlinkPrintBuffer;

 void processMavlink() {
@@ -38,18 +34,14 @@ void sendMavlink() {
 			((mode == AUTO) ? MAV_MODE_FLAG_AUTO_ENABLED : MAV_MODE_FLAG_MANUAL_INPUT_ENABLED),
 			mode, MAV_STATE_STANDBY);
 		sendMessage(&msg);
-	}

-	if (!valid(mavlinkTime)) return; // send only heartbeat until connected
+		if (!mavlinkConnected) return; // send only heartbeat until connected

-	if (telemetrySlow) {
 		mavlink_msg_extended_sys_state_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			MAV_VTOL_STATE_UNDEFINED, landed ? MAV_LANDED_STATE_ON_GROUND : MAV_LANDED_STATE_IN_AIR);
 		sendMessage(&msg);
-	}

-	if (telemetrySlow && valid(voltage)) {
-		uint16_t voltages[] = {(uint16_t)(voltage * 1000), UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX};
+		uint16_t voltages[] = {voltage * 1000, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX, UINT16_MAX};
 		uint16_t voltagesExt[] = {0, 0, 0, 0};
 		float remaining = constrain(mapf(voltage, 3.4, 4.2, 0, 1), 0, 1);
 		mavlink_msg_battery_status_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, 0, MAV_BATTERY_FUNCTION_ALL,
@@ -57,27 +49,21 @@ void sendMavlink() {
 		sendMessage(&msg);
 	}

-	if (telemetryAttitude) {
+	if (telemetryFast && mavlinkConnected) {
 		const float offset[] = {0, 0, 0, 0};
 		mavlink_msg_attitude_quaternion_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg,
 			time, attitude.w, attitude.x, -attitude.y, -attitude.z, rates.x, -rates.y, -rates.z, offset); // convert to frd
 		sendMessage(&msg);
-	}

-	if (telemetryRC && channels[0]) { // 0 means no RC input
 		mavlink_msg_rc_channels_raw_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, controlTime * 1000, 0,
 			channels[0], channels[1], channels[2], channels[3], channels[4], channels[5], channels[6], channels[7], UINT8_MAX);
-		sendMessage(&msg);
-	}
+		if (channels[0] != 0) sendMessage(&msg); // 0 means no RC input

-	if (telemetryMotors) {
 		float controls[8];
 		memcpy(controls, motors, sizeof(motors));
 		mavlink_msg_actuator_control_target_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, time, 0, controls);
 		sendMessage(&msg);
-	}

-	if (telemetryIMU) {
 		mavlink_msg_scaled_imu_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, time,
 			acc.x / ONE_G * 1000, -acc.y / ONE_G * 1000, -acc.z / ONE_G * 1000, // convert to frd
 			gyro.x * 1000, -gyro.y * 1000, -gyro.z * 1000,
@@ -95,13 +81,13 @@ 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;
 	mavlink_status_t status;
 	for (int i = 0; i < len; i++) {
 		if (mavlink_parse_char(MAVLINK_COMM_0, buf[i], &msg, &status)) {
-			mavlinkTime = t;
 			handleMavlink(&msg);
 		}
 	}
@@ -255,7 +241,7 @@ void handleMavlink(const void *_msg) {
 		}

 		if (m.command == MAV_CMD_COMPONENT_ARM_DISARM) {
-			if (m.param1 == 1 && controlThrottle > 0.05) return; // don't arm if throttle is not low
+			if (m.param1 && controlThrottle > 0.05) return; // don't arm if throttle is not low
 			accepted = true;
 			armed = m.param1 == 1;
 		}
@@ -14,38 +14,30 @@ int pwmStop = 0;
 int pwmMin = 0;
 int pwmMax = -1; // -1 means duty cycle mode

-const int MOTOR_REAR_LEFT = 0, MOTOR_REAR_RIGHT = 1, MOTOR_FRONT_RIGHT = 2, MOTOR_FRONT_LEFT = 3;
+const int MOTOR_REAR_LEFT = 0;
+const int MOTOR_REAR_RIGHT = 1;
+const int MOTOR_FRONT_RIGHT = 2;
+const int MOTOR_FRONT_LEFT = 3;

 void setupMotors() {
-	print("Setup motors\n");
-	// Configure pins
-#ifdef ESP32
+	print("Setup Motors\n");
+	// configure pins
 	for (int i = 0; i < 4; i++) {
-		if (motorPins[i] < 0) continue; // skip unassigned motors
 		ledcAttach(motorPins[i], pwmFrequency, pwmResolution);
 		pwmFrequency = ledcChangeFrequency(motorPins[i], pwmFrequency, pwmResolution); // when reconfiguring
 	}
-#else
-	analogWriteResolution(pwmResolution);
-	analogWriteFrequency(pwmFrequency);
-#endif
 	sendMotors();
+	print("Motors initialized\n");
 }

 void sendMotors() {
 	for (int i = 0; i < 4; i++) {
-		if (motorPins[i] < 0) continue; // skip unassigned motors
-#ifdef ESP32
 		ledcWrite(motorPins[i], getDutyCycle(motors[i]));
-#else
-		analogWrite(motorPins[i], getDutyCycle(motors[i]));
-#endif
 	}
 }

 int getDutyCycle(float value) {
 	value = constrain(value, 0, 1);
-
 	if (pwmMax >= 0) { // pwm mode
 		float pwm = mapf(value, 0, 1, pwmMin, pwmMax);
 		if (value == 0) pwm = pwmStop;
@@ -60,9 +52,9 @@ bool motorsActive() {
 	return motors[0] != 0 || motors[1] != 0 || motors[2] != 0 || motors[3] != 0;
 }

-void testMotor(int n, float thrust) {
+void testMotor(int n) {
 	print("Testing motor %d\n", n);
-	motors[n] = thrust;
+	motors[n] = 1;
 	delay(50); // ESP32 may need to wait until the end of the current cycle to change duty https://github.com/espressif/arduino-esp32/issues/5306
 	sendMotors();
 	pause(3);
@@ -3,26 +3,25 @@

 // Parameters storage in flash memory

-#include "prefs.h"
+#include <Preferences.h>
 #include "util.h"

-extern int channelZero[16], channelMax[16];
+extern int channelZero[16];
+extern int channelMax[16];
 extern int rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
-extern int rcRxPin, voltagePin;
-extern int wifiMode, wifiLongRange, wifiBroadcast, udpLocalPort, udpRemotePort, espnowChannel;
-extern float rcLossTimeout, descendTime, disarmTilt;
+extern int rcRxPin;
+extern int wifiMode, udpLocalPort, udpRemotePort;
+extern float rcLossTimeout, descendTime;
+extern int voltagePin;
 extern float voltageScale;
 extern LowPassFilter<float> voltageFilter;

-#include "config.h"
-
 Preferences storage;

 struct Parameter {
 	const char *name; // max length is 15
 	bool integer;
 	union { float *f; int *i; }; // pointer to the variable
-	float inital; // default value
 	float cache; // what's stored in flash
 	void (*callback)(); // called after parameter change
 	Parameter(const char *name, float *variable, void (*callback)() = nullptr) : name(name), integer(false), f(variable), callback(callback) {};
@@ -46,7 +45,6 @@ Parameter parameters[] = {
 	{"CTL_Y_RATE_P", &yawRatePID.p},
 	{"CTL_Y_RATE_I", &yawRatePID.i},
 	{"CTL_Y_RATE_D", &yawRatePID.d},
-	{"CTL_Y_RATE_WU", &yawRatePID.windup},
 	{"CTL_Y_RATE_D_A", &yawRatePID.lpf.alpha},
 	{"CTL_R_P", &rollPID.p},
 	{"CTL_R_I", &rollPID.i},
@@ -63,15 +61,6 @@ Parameter parameters[] = {
 	{"CTL_FLT_MODE_1", &flightModes[1]},
 	{"CTL_FLT_MODE_2", &flightModes[2]},
 	// imu
-	{"IMU_MODEL", &imuModel},
-	{"IMU_BUS", &imuBus},
-	{"IMU_PIN_SCK", &imuSckPin},
-	{"IMU_PIN_MISO", &imuMisoPin},
-	{"IMU_PIN_MOSI", &imuMosiPin},
-	{"IMU_PIN_CS", &imuCsPin},
-	{"IMU_PIN_SDA", &imuSdaPin},
-	{"IMU_PIN_SCL", &imuSclPin},
-	{"IMU_PIN_INT", &imuIntPin},
 	{"IMU_ROT_ROLL", &imuRotation.x},
 	{"IMU_ROT_PITCH", &imuRotation.y},
 	{"IMU_ROT_YAW", &imuRotation.z},
@@ -97,7 +86,7 @@ Parameter parameters[] = {
 	{"MOT_PWM_MIN", &pwmMin},
 	{"MOT_PWM_MAX", &pwmMax},
 	// rc
-	{"RC_RX_PIN", &rcRxPin, setupRC},
+	{"RC_RX_PIN", &rcRxPin},
 	{"RC_ZERO_0", &channelZero[0]},
 	{"RC_ZERO_1", &channelZero[1]},
 	{"RC_ZERO_2", &channelZero[2]},
@@ -121,39 +110,30 @@ Parameter parameters[] = {
 	{"RC_MODE", &modeChannel},
 	// wifi
 	{"WIFI_MODE", &wifiMode},
-	{"WIFI_PORT_LOC", &udpLocalPort},
-	{"WIFI_PORT_REM", &udpRemotePort},
-	{"WIFI_LONG_RANGE", &wifiLongRange},
-	{"WIFI_BROADCAST", &wifiBroadcast},
-	// espnow
-	{"ESPNOW_CHANNEL", &espnowChannel},
+	{"WIFI_LOC_PORT", &udpLocalPort},
+	{"WIFI_REM_PORT", &udpRemotePort},
 	// mavlink
 	{"MAV_SYS_ID", &mavlinkSysId},
 	{"MAV_RATE_SLOW", &telemetrySlow.rate},
-	{"MAV_RATE_ATT", &telemetryAttitude.rate},
-	{"MAV_RATE_RC", &telemetryRC.rate},
-	{"MAV_RATE_MOT", &telemetryMotors.rate},
-	{"MAV_RATE_IMU", &telemetryIMU.rate},
+	{"MAV_RATE_FAST", &telemetryFast.rate},
 	// power
-	{"PWR_VOLT_PIN", &voltagePin, setupPower},
+	{"PWR_VOLT_PIN", &voltagePin},
 	{"PWR_VOLT_SCALE", &voltageScale},
 	{"PWR_VOLT_LPF_A", &voltageFilter.alpha},
 	// safety
 	{"SF_RC_LOSS_TIME", &rcLossTimeout},
 	{"SF_DESCEND_TIME", &descendTime},
-	{"SF_DISARM_TILT", &disarmTilt},
 };

 void setupParameters() {
 	print("Setup parameters\n");
-	setDefaults();
 	storage.begin("flix");
 	// Read parameters from storage
 	for (auto &parameter : parameters) {
-		parameter.inital = parameter.getValue();
-		if (storage.isKey(parameter.name)) {
-			parameter.setValue(storage.getFloat(parameter.name));
+		if (!storage.isKey(parameter.name)) {
+			storage.putFloat(parameter.name, parameter.getValue()); // store default value
 		}
+		parameter.setValue(storage.getFloat(parameter.name, 0));
 		parameter.cache = parameter.getValue();
 	}
 }
@@ -199,23 +179,17 @@ void syncParameters() {
 	if (motorsActive()) return; // don't use flash while flying, it may cause a delay

 	for (auto &parameter : parameters) {
-		if (floatEquals(parameter.getValue(), parameter.cache)) continue; // no change
+		if (parameter.getValue() == parameter.cache) continue; // no change
+		if (isnan(parameter.getValue()) && isnan(parameter.cache)) continue; // both are NAN

 		storage.putFloat(parameter.name, parameter.getValue());
 		parameter.cache = parameter.getValue(); // update cache
 	}
 }

-void printParameters(const char *filter) {
-	print("Name             Value          [Default]\n");
+void printParameters() {
 	for (auto &parameter : parameters) {
-		if (strncasecmp(parameter.name, filter, strlen(filter))) continue;
-
-		if (floatEquals(parameter.getValue(), parameter.inital)) { // parameter changed
-			print("%-15s  %-13g\n", parameter.name, parameter.getValue());
-		} else {
-			print("%-15s  %-13g  [%g]\n", parameter.name, parameter.getValue(), parameter.inital);
-		}
+		print("%s = %g\n", parameter.name, parameter.getValue());
 	}
 }

@@ -18,7 +18,7 @@ public:

 	LowPassFilter<float> lpf; // low pass filter for derivative term

-	PID(float p, float i = 0, float d = 0, float windup = 0, float dAlpha = 1, float dtMax = 0.1) :
+	PID(float p, float i, float d, float windup = 0, float dAlpha = 1, float dtMax = 0.1) :
 		p(p), i(i), d(d), windup(windup), lpf(dAlpha), dtMax(dtMax) {}

 	float update(float error) {
@@ -3,28 +3,23 @@

 // Power management

-#ifdef ESP32
 #include <soc/soc.h>
 #include <soc/rtc_cntl_reg.h>
-#endif
 #include "lpf.h"
 #include "util.h"

-float voltage = NAN;
-LowPassFilter<float> voltageFilter(1);
+float voltage;
+LowPassFilter<float> voltageFilter(0.2);
 int voltagePin = -1;
 float voltageScale = 2;

 void setupPower() {
-#ifdef ESP32
-	REG_CLR_BIT(RTC_CNTL_BROWN_OUT_REG, RTC_CNTL_BROWN_OUT_ENA); // disable reset on low voltage
-#endif
-	if (digitalPinToAnalogChannel(voltagePin) == -1) voltagePin = -1; // test ADC pin
+	// Disable reset on low voltage
+	REG_CLR_BIT(RTC_CNTL_BROWN_OUT_REG, RTC_CNTL_BROWN_OUT_ENA);
 }

 void readVoltage() {
 	if (voltagePin < 0) return;
-
 	static Rate rate(10);
 	if (!rate) return;

@@ -1,283 +0,0 @@
-#ifdef ESP32
-#include <Preferences.h>
-#else
-
-#include <Arduino.h>
-#include <EEPROM.h>
-#include <string.h>
-
-class Preferences {
-public:
-	Preferences() = default;
-	~Preferences() = default;
-
-	bool begin(const char *name, bool readOnly = false, const char *partition_label = NULL) {
-		(void)name;
-		(void)readOnly;
-		(void)partition_label;
-		load();
-		started = true;
-		return true;
-	}
-
-	void end() {
-		started = false;
-	}
-
-	bool clear() {
-		if (!started) return false;
-		for (auto &entry : entries) {
-			entry = Entry();
-		}
-		return save();
-	}
-
-	size_t putFloat(const char *key, float value) {
-		if (!started) return 0;
-		int index = ensureKey(key);
-		if (index < 0) return 0;
-		entries[index].hasFloat = true;
-		entries[index].hasString = false;
-		entries[index].stringValue = "";
-		entries[index].floatValue = value;
-		if (!save()) return 0;
-		return sizeof(float);
-	}
-
-	float getFloat(const char *key, float defaultValue = NAN) {
-		if (!started) return defaultValue;
-		int index = findKey(key);
-		if (index < 0 || !entries[index].hasFloat) return defaultValue;
-		return entries[index].floatValue;
-	}
-
-	size_t putString(const char *key, const char *value) {
-		if (!started) return 0;
-		int index = ensureKey(key);
-		if (index < 0) return 0;
-		if (!value) value = "";
-		if (strlen(value) > MAX_STRING_LEN) return 0;
-
-		entries[index].hasString = true;
-		entries[index].hasFloat = false;
-		entries[index].stringValue = value;
-		if (!save()) return 0;
-		return entries[index].stringValue.length();
-	}
-
-	size_t putString(const char *key, String value) {
-		return putString(key, value.c_str());
-	}
-
-	String getString(const char *key, String defaultValue = String()) {
-		if (!started) return defaultValue;
-		int index = findKey(key);
-		if (index < 0 || !entries[index].hasString) return defaultValue;
-		return entries[index].stringValue;
-	}
-
-	bool isKey(const char *key) {
-		if (!started) return false;
-		return findKey(key) >= 0;
-	}
-
-private:
-	static const int MAX_ENTRIES = 128;
-	static const int MAX_KEY_LEN = 15;
-	static const int MAX_STRING_LEN = 95;
-	static const uint32_t MAGIC = 0x46504B56; // "VKPF"
-	static const uint8_t VERSION = 1;
-	static const uint8_t TYPE_FLOAT = 1;
-	static const uint8_t TYPE_STRING = 2;
-	static const int STORAGE_SIZE = 4096;
-
-	struct Entry {
-		bool used = false;
-		char key[MAX_KEY_LEN + 1] = {};
-		bool hasFloat = false;
-		float floatValue = NAN;
-		bool hasString = false;
-		String stringValue;
-	};
-
-	bool started = false;
-	Entry entries[MAX_ENTRIES];
-
-	static void writeU16(uint8_t *dst, uint16_t value) {
-		dst[0] = static_cast<uint8_t>(value & 0xFF);
-		dst[1] = static_cast<uint8_t>((value >> 8) & 0xFF);
-	}
-
-	static void writeU32(uint8_t *dst, uint32_t value) {
-		dst[0] = static_cast<uint8_t>(value & 0xFF);
-		dst[1] = static_cast<uint8_t>((value >> 8) & 0xFF);
-		dst[2] = static_cast<uint8_t>((value >> 16) & 0xFF);
-		dst[3] = static_cast<uint8_t>((value >> 24) & 0xFF);
-	}
-
-	static uint16_t readU16(const uint8_t *src) {
-		return static_cast<uint16_t>(src[0]) |
-			(static_cast<uint16_t>(src[1]) << 8);
-	}
-
-	static uint32_t readU32(const uint8_t *src) {
-		return static_cast<uint32_t>(src[0]) |
-			(static_cast<uint32_t>(src[1]) << 8) |
-			(static_cast<uint32_t>(src[2]) << 16) |
-			(static_cast<uint32_t>(src[3]) << 24);
-	}
-
-	int availableStorageSize() {
-		int n = STORAGE_SIZE;
-		if (EEPROM.length() > 0 && EEPROM.length() < n) n = EEPROM.length();
-		return n;
-	}
-
-	bool save() {
-		const int storageSize = availableStorageSize();
-		if (storageSize < 16) return false;
-
-		uint8_t buffer[STORAGE_SIZE] = {};
-		int pos = 0;
-		writeU32(buffer + pos, MAGIC);
-		pos += 4;
-		buffer[pos++] = VERSION;
-		buffer[pos++] = 0;
-		int lengthPos = pos;
-		pos += 2;
-
-		for (int i = 0; i < MAX_ENTRIES; i++) {
-			if (!entries[i].used) continue;
-			if (!entries[i].hasFloat && !entries[i].hasString) continue;
-
-			const uint8_t keyLen = static_cast<uint8_t>(strnlen(entries[i].key, MAX_KEY_LEN));
-			if (keyLen == 0) continue;
-
-			if (entries[i].hasFloat) {
-				const int recordSize = 3 + keyLen + 4;
-				if (pos + recordSize > storageSize) return false;
-
-				buffer[pos++] = TYPE_FLOAT;
-				buffer[pos++] = keyLen;
-				buffer[pos++] = 4;
-				memcpy(buffer + pos, entries[i].key, keyLen);
-				pos += keyLen;
-				float value = entries[i].floatValue;
-				memcpy(buffer + pos, &value, sizeof(value));
-				pos += sizeof(value);
-			} else if (entries[i].hasString) {
-				const uint8_t valueLen = static_cast<uint8_t>(entries[i].stringValue.length());
-				const int recordSize = 3 + keyLen + valueLen;
-				if (pos + recordSize > storageSize) return false;
-
-				buffer[pos++] = TYPE_STRING;
-				buffer[pos++] = keyLen;
-				buffer[pos++] = valueLen;
-				memcpy(buffer + pos, entries[i].key, keyLen);
-				pos += keyLen;
-				if (valueLen > 0) {
-					memcpy(buffer + pos, entries[i].stringValue.c_str(), valueLen);
-					pos += valueLen;
-				}
-			}
-		}
-
-		writeU16(buffer + lengthPos, static_cast<uint16_t>(pos));
-
-		for (int i = 0; i < storageSize; i++) {
-			EEPROM.write(i, buffer[i]);
-		}
-		EEPROM.commit();
-		return true;
-	}
-
-	void load() {
-		const int storageSize = availableStorageSize();
-		if (storageSize < 16) return;
-
-		for (auto &entry : entries) entry = Entry();
-
-		uint8_t buffer[STORAGE_SIZE] = {};
-		for (int i = 0; i < storageSize; i++) {
-			buffer[i] = EEPROM.read(i);
-		}
-
-		int pos = 0;
-		if (readU32(buffer + pos) != MAGIC) return;
-		pos += 4;
-		if (buffer[pos++] != VERSION) return;
-		pos++; // flags
-
-		const uint16_t totalLen = readU16(buffer + pos);
-		pos += 2;
-		if (totalLen < pos || totalLen > storageSize) return;
-
-		while (pos + 3 <= totalLen) {
-			const uint8_t type = buffer[pos++];
-			const uint8_t keyLen = buffer[pos++];
-			const uint8_t valueLen = buffer[pos++];
-			if (keyLen == 0 || keyLen > MAX_KEY_LEN) return;
-			if (pos + keyLen + valueLen > totalLen) return;
-
-			char key[MAX_KEY_LEN + 1] = {};
-			memcpy(key, buffer + pos, keyLen);
-			key[keyLen] = '\0';
-			pos += keyLen;
-
-			int index = ensureKey(key);
-			if (index < 0) return;
-
-			if (type == TYPE_FLOAT && valueLen == 4) {
-				float value = NAN;
-				memcpy(&value, buffer + pos, sizeof(value));
-				entries[index].hasFloat = true;
-				entries[index].hasString = false;
-				entries[index].stringValue = "";
-				entries[index].floatValue = value;
-			} else if (type == TYPE_STRING && valueLen <= MAX_STRING_LEN) {
-				char value[MAX_STRING_LEN + 1] = {};
-				if (valueLen > 0) memcpy(value, buffer + pos, valueLen);
-				value[valueLen] = '\0';
-				entries[index].hasString = true;
-				entries[index].hasFloat = false;
-				entries[index].stringValue = value;
-			}
-
-			pos += valueLen;
-		}
-	}
-
-	int findKey(const char *key) {
-		if (!key) return -1;
-		for (int i = 0; i < MAX_ENTRIES; i++) {
-			if (!entries[i].used) continue;
-			if (strncmp(entries[i].key, key, MAX_KEY_LEN + 1) == 0) return i;
-		}
-		return -1;
-	}
-
-	int ensureKey(const char *key) {
-		if (!key) return -1;
-		if (strlen(key) > MAX_KEY_LEN) return -1;
-
-		int index = findKey(key);
-		if (index >= 0) return index;
-
-		for (int i = 0; i < MAX_ENTRIES; i++) {
-			if (entries[i].used) continue;
-			entries[i].used = true;
-			entries[i].hasFloat = false;
-			entries[i].hasString = false;
-			entries[i].floatValue = NAN;
-			entries[i].stringValue = "";
-			strncpy(entries[i].key, key, MAX_KEY_LEN);
-			entries[i].key[MAX_KEY_LEN] = '\0';
-			return i;
-		}
-
-		return -1;
-	}
-};
-
-
-#endif
@@ -6,7 +6,7 @@
 #include <SBUS.h>
 #include "util.h"

-SBUS rc(Serial1);
+SBUS rc(Serial2);
 int rcRxPin = -1; // -1 means disabled

 uint16_t channels[16]; // raw rc channels
@@ -27,12 +27,14 @@ void setupRC() {

 bool readRC() {
 	if (rcRxPin < 0) return false;
-	if (!rc.read()) return false;
-
-	rc.getChannels(channels);
-	normalizeRC();
-	controlTime = t;
-	return true;
+	if (rc.read()) {
+		SBUSData data = rc.data();
+		for (int i = 0; i < 16; i++) channels[i] = data.ch[i]; // copy channels data
+		normalizeRC();
+		controlTime = t;
+		return true;
+	}
+	return false;
 }

 void normalizeRC() {
@@ -53,19 +55,18 @@ void calibrateRC() {
 		print("RC_RX_PIN = %d, set the RC pin!\n", rcRxPin);
 		return;
 	}
-
-	uint16_t zero[16]; // for zero positions
-	uint16_t center[16]; // for center positions
-	uint16_t _[16]; // for unused data
+	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");
 	pause(3);
-	calibrateRCChannel(NULL, _, zero, "2/8 Move sticks [3 sec]\n...     ...\n...     .o.\n.o.     ...\n");
-	calibrateRCChannel(&throttleChannel, zero, _, "3/8 Move sticks [3 sec]\n.o.     ...\n...     .o.\n...     ...\n");
-	calibrateRCChannel(NULL, _, center, "4/8 Move sticks [3 sec]\n...     ...\n.o.     .o.\n...     ...\n");
-	calibrateRCChannel(&yawChannel, center, _, "5/8 Move sticks [3 sec]\n...     ...\n..o     .o.\n...     ...\n");
-	calibrateRCChannel(&pitchChannel, zero, _, "6/8 Move sticks [3 sec]\n...     .o.\n...     ...\n.o.     ...\n");
-	calibrateRCChannel(&rollChannel, zero, _, "7/8 Move sticks [3 sec]\n...     ...\n...     ..o\n.o.     ...\n");
-	calibrateRCChannel(&modeChannel, zero, _, "8/8 Put mode switch to max [3 sec]\n");
+	calibrateRCChannel(NULL, zero, zero, "2/8 Move sticks [3 sec]\n...     ...\n...     .o.\n.o.     ...\n");
+	calibrateRCChannel(NULL, center, center, "3/8 Move sticks [3 sec]\n...     ...\n.o.     .o.\n...     ...\n");
+	calibrateRCChannel(&throttleChannel, zero, max, "4/8 Move sticks [3 sec]\n.o.     ...\n...     .o.\n...     ...\n");
+	calibrateRCChannel(&yawChannel, center, max, "5/8 Move sticks [3 sec]\n...     ...\n..o     .o.\n...     ...\n");
+	calibrateRCChannel(&pitchChannel, zero, max, "6/8 Move sticks [3 sec]\n...     .o.\n...     ...\n.o.     ...\n");
+	calibrateRCChannel(&rollChannel, zero, max, "7/8 Move sticks [3 sec]\n...     ...\n...     ..o\n.o.     ...\n");
+	calibrateRCChannel(&modeChannel, zero, max, "8/8 Put mode switch to max [3 sec]\n");
 	printRCCalibration();
 }

@@ -8,12 +8,10 @@ extern float controlRoll, controlPitch, controlThrottle, controlYaw;

 float rcLossTimeout = 1;
 float descendTime = 10;
-float disarmTilt = radians(120);

 void failsafe() {
 	rcLossFailsafe();
 	autoFailsafe();
-	tiltFailsafe();
 }

 // RC loss failsafe
@@ -38,7 +36,7 @@ void descend() {
 // Allow pilot to interrupt automatic flight
 void autoFailsafe() {
 	static float roll, pitch, yaw, throttle;
-	if (abs(roll - controlRoll) > 0.05 || abs(pitch - controlPitch) > 0.05 || abs(yaw - controlYaw) > 0.05 || abs(throttle - controlThrottle) > 0.05) {
+	if (roll != controlRoll || pitch != controlPitch || yaw != controlYaw || abs(throttle - controlThrottle) > 0.05) {
 		// controls changed and mode switch is not configured
 		if (mode == AUTO && invalid(controlMode)) mode = STAB; // regain control by the pilot
 	}
@@ -47,15 +45,3 @@ void autoFailsafe() {
 	yaw = controlYaw;
 	throttle = controlThrottle;
 }
-
-// Disarm if tilted too much
-void tiltFailsafe() {
-	if (!armed) return;
-	if (mode != STAB) return;
-
-	Vector up = Quaternion::rotateVector(Vector(0, 0, 1), attitude);
-	float tilt = acos(up.z);
-	if (disarmTilt && tilt > disarmTilt) {
-		armed = false;
-	}
-}
@@ -6,11 +6,6 @@
 #pragma once

 #include <math.h>
-#ifdef ESP32
-#include <soc/soc.h>
-#include <soc/rtc_cntl_reg.h>
-#include <ESP32_NOW_Serial.h>
-#endif

 const float ONE_G = 9.80665;
 extern float t;
@@ -27,12 +22,6 @@ bool valid(float x) {
 	return isfinite(x);
 }

-bool floatEquals(float a, float b, float epsilon = 0) {
-	if (isnan(a) && isnan(b)) return true;
-	if (a == b) return true;
-	return fabsf(a - b) <= epsilon;
-}
-
 // Wrap angle to [-PI, PI)
 float wrapAngle(float angle) {
 	angle = fmodf(angle, 2 * PI);
@@ -47,40 +36,21 @@ float wrapAngle(float angle) {
 // Trim and split string by spaces
 void splitString(String& str, String& token0, String& token1, String& token2) {
 	str.trim();
-	if (str.isEmpty()) return;
 	char chars[str.length() + 1];
 	str.toCharArray(chars, str.length() + 1);
 	token0 = strtok(chars, " ");
-	token1 = strtok(NULL, " ");
+	token1 = strtok(NULL, " "); // String(NULL) creates empty string
 	token2 = strtok(NULL, "");
-	if (token1.c_str() == NULL) token1 = "";
-	if (token2.c_str() == NULL) token2 = "";
 }

-#ifdef ESP32
-// Simplified ESP-NOW Serial without resends
-class ESPNOWSerial : public ESP_NOW_Serial_Class {
-public:
-	int lost = 0;
-	using ESP_NOW_Serial_Class::ESP_NOW_Serial_Class;
-	void onSent(bool success) override {
-		if (!success) lost++;
-		ESP_NOW_Serial_Class::onSent(true); // always report success to avoid resends
-	}
-};
-#endif
-
 // Rate limiter
 class Rate {
 public:
 	float rate;
-	float last = -INFINITY;
+	float last = 0;
 	Rate(float rate) : rate(rate) {}

 	operator bool() {
-		if (t == last) {
-			return true; // the same step
-		}
 		if (t - last >= 1 / rate) {
 			last = t;
 			return true;
@@ -1,155 +1,77 @@
 // Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
 // Repository: https://github.com/okalachev/flix

-// Wi-Fi and ESP-NOW communication
+// Wi-Fi communication

-// #include <WiFi.h>
-// #include <WiFiAP.h>
-// #include <WiFiUdp.h>
-// #include <MacAddress.h>
-// #include <ESP32_NOW_Serial.h>
-// #include "prefs.h"
-// #include "util.h"
+#include <WiFi.h>
+#include <WiFiAP.h>
+#include <WiFiUdp.h>
+#include "Preferences.h"

 extern Preferences storage; // use the main preferences storage

-const int W_DISABLED = 0, W_AP = 1, W_STA = 2, W_ESPNOW = 3;
+const int W_DISABLED = 0, W_AP = 1, W_STA = 2;
 int wifiMode = W_AP;
-
-int wifiLongRange = 0;
-int wifiBroadcast = 0; // 0 - broadcast until connected, 1 - always broadcast
 int udpLocalPort = 14550;
 int udpRemotePort = 14550;
-// IPAddress udpRemoteIP = "255.255.255.255";
-// WiFiUDP udp;
+IPAddress udpRemoteIP = "255.255.255.255";

-// ESPNOWSerial espnow(NULL, 0, WIFI_IF_AP);
-// ESPNOWSerial espnowBroadcast(ESP_NOW.BROADCAST_ADDR, 0, WIFI_IF_AP);
-int espnowChannel = 6;
+WiFiUDP udp;

 void setupWiFi() {
-	// print("Setup Wi-Fi\n");
-	// WiFi.enableLongRange(wifiLongRange);
-
-	// if (wifiMode == W_AP) {
-	// 	WiFi.softAP(storage.getString("WIFI_AP_SSID", "flix").c_str(), storage.getString("WIFI_AP_PASS", "flixwifi").c_str());
-	// 	udp.begin(udpLocalPort);
-	// }
-
-	// if (wifiMode == W_STA) {
-	// 	WiFi.begin(storage.getString("WIFI_STA_SSID", "").c_str(), storage.getString("WIFI_STA_PASS", "").c_str());
-	// 	udp.begin(udpLocalPort);
-	// }
-
-	// if (wifiMode == W_ESPNOW) {
-	// 	WiFi.mode(WIFI_AP);
-	// 	WiFi.setChannel(espnowChannel);
-	// 	espnow.addr(MacAddress(storage.getString("ESPNOW_PEER_MAC", "FF:FF:FF:FF:FF:FF").c_str()));
-	// 	String key = storage.getString("ESPNOW_PEER_KEY", "");
-	// 	espnow.setKey(key.isEmpty() ? nullptr : (const uint8_t *)key.c_str());
-	// 	espnow.begin();
-	// 	espnowBroadcast.begin();
-	// }
-
-	// WiFi.setSleep(false); // disable power save
+	print("Setup Wi-Fi\n");
+	if (wifiMode == W_AP) {
+		WiFi.softAP(storage.getString("WIFI_AP_SSID", "flix").c_str(), storage.getString("WIFI_AP_PASS", "flixwifi").c_str());
+	} else if (wifiMode == W_STA) {
+		WiFi.begin(storage.getString("WIFI_STA_SSID", "").c_str(), storage.getString("WIFI_STA_PASS", "").c_str());
+	}
+	WiFi.setSleep(false); // disable power save
+	udp.begin(udpLocalPort);
 }

 void sendWiFi(const uint8_t *buf, int len) {
-	// if (espnow) {
-	// 	espnow.write(buf, len);
-
-	// 	static Rate discovery(2);
-	// 	if (espnow.isEncrypted() && discovery) espnowBroadcast.write((const uint8_t *)"flix", 4); // broadcast message to help finding this device
-	// 	return;
-	// }
-
-	// if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return;
-
-	// bool broadcast = wifiBroadcast || !(t - mavlinkTime < 5); // broadcast if lost connection
-	// udp.beginPacket(broadcast ? IPAddress(255, 255, 255, 255) : udpRemoteIP, udpRemotePort);
-	// udp.write(buf, len);
-	// udp.endPacket();
+	if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return;
+	udp.beginPacket(udpRemoteIP, udpRemotePort);
+	udp.write(buf, len);
+	udp.endPacket();
 }

 int receiveWiFi(uint8_t *buf, int len) {
-	// if (espnow) {
-	// 	return espnow.read(buf, len);
-	// }
-
-	// if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return 0;
-
-	// udp.parsePacket();
-	// if (udp.remoteIP()) udpRemoteIP = udp.remoteIP();
-	// return udp.read(buf, len);
-	return 0;
+	udp.parsePacket();
+	if (udp.remoteIP()) udpRemoteIP = udp.remoteIP();
+	return udp.read(buf, len);
 }

 void printWiFiInfo() {
-	// if (espnow) {
-	// 	print("Mode: ESP-NOW\n");
-	// 	print("ESP-NOW version: %d\n", ESP_NOW.getVersion());
-	// 	print("Max packet size: %d\n", ESP_NOW.getMaxDataLen());
-	// 	print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
-	// 	print("Peer MAC: %s\n", MacAddress(espnow.addr()).toString().c_str());
-	// 	print("Encrypted: %d\n", espnow.isEncrypted());
-	// 	print("Channel: %d\n", espnow.getChannel());
-	// 	print("Lost packets: %d\n", espnow.lost);
-	// } else if (WiFi.getMode() == WIFI_MODE_AP) {
-	// 	print("Mode: Access Point (AP)\n");
-	// 	print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
-	// 	print("SSID: %s\n", WiFi.softAPSSID().c_str());
-	// 	print("Password: ***\n");
-	// 	print("Channel: %d\n", WiFi.channel());
-	// 	print("Clients: %d\n", WiFi.softAPgetStationNum());
-	// 	print("IP: %s\n", WiFi.softAPIP().toString().c_str());
-	// 	print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
-	// } else if (WiFi.getMode() == WIFI_MODE_STA) {
-	// 	print("Mode: Client (STA)\n");
-	// 	print("Connected: %d\n", WiFi.isConnected());
-	// 	print("MAC: %s\n", WiFi.macAddress().c_str());
-	// 	print("SSID: %s\n", WiFi.SSID().c_str());
-	// 	print("Password: ***\n");
-	// 	print("Channel: %d\n", WiFi.channel());
-	// 	print("RSSI: %d dBm\n", WiFi.RSSI());
-	// 	print("IP: %s\n", WiFi.localIP().toString().c_str());
-	// 	print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
-	// } else {
-	// 	print("Mode: Disabled\n");
-	// }
-	// print("MAVLink connected: %d\n", valid(mavlinkTime));
-}
-
-void configWiFi(int mode, const char *first, const char *second) {
-	// MacAddress mac;
-	// if (mode == W_AP && strlen(first) > 0 && strlen(second) >= 8) {
-	// 	storage.putString("WIFI_AP_SSID", first);
-	// 	storage.putString("WIFI_AP_PASS", second);
-	// } else if (mode == W_STA && strlen(first) > 0 && strlen(second) >= 8) {
-	// 	storage.putString("WIFI_STA_SSID", first);
-	// 	storage.putString("WIFI_STA_PASS", second);
-	// } else if (mode == W_ESPNOW && mac.fromString(first)) {
-	// 	storage.putString("ESPNOW_PEER_MAC", first);
-	// 	storage.putString("ESPNOW_PEER_KEY", strlen(second) == ESP_NOW_KEY_LEN ? second : "");
-	// } else {
-	// 	print("Invalid configuration\n");
-	// 	return;
-	// }
-	// print("✓ Reboot to apply new settings\n");
-}
-
-void setWiFiMode(const String& mode) {
-	if (mode == "ap") {
-		wifiMode = W_AP;
-	} else if (mode == "sta") {
-		wifiMode = W_STA;
-	} else if (mode == "espnow") {
-		wifiMode = W_ESPNOW;
-	} else if (mode == "off") {
-		wifiMode = W_DISABLED;
+	if (WiFi.getMode() == WIFI_MODE_AP) {
+		print("Mode: Access Point (AP)\n");
+		print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
+		print("SSID: %s\n", WiFi.softAPSSID().c_str());
+		print("Password: ***\n");
+		print("Clients: %d\n", WiFi.softAPgetStationNum());
+		print("IP: %s\n", WiFi.softAPIP().toString().c_str());
+	} else if (WiFi.getMode() == WIFI_MODE_STA) {
+		print("Mode: Client (STA)\n");
+		print("Connected: %d\n", WiFi.isConnected());
+		print("MAC: %s\n", WiFi.macAddress().c_str());
+		print("SSID: %s\n", WiFi.SSID().c_str());
+		print("Password: ***\n");
+		print("IP: %s\n", WiFi.localIP().toString().c_str());
 	} else {
-		print("Invalid Wi-Fi mode\n");
+		print("Mode: Disabled\n");
 		return;
 	}
-	static const char *modes[] = {"Disabled", "Access Point (AP)", "Client (STA)", "ESP-NOW"};
-	print("✓ Wi-Fi mode set to %s, reboot to apply\n", modes[wifiMode]);
+	print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
+	print("MAVLink connected: %d\n", mavlinkConnected);
+}
+
+void configWiFi(bool ap, const char *ssid, const char *password) {
+	if (ap) {
+		storage.putString("WIFI_AP_SSID", ssid);
+		storage.putString("WIFI_AP_PASS", password);
+	} else {
+		storage.putString("WIFI_STA_SSID", ssid);
+		storage.putString("WIFI_STA_PASS", password);
+	}
+	print("✓ Reboot to apply new settings\n");
 }
@@ -151,7 +151,7 @@ public:
 	void setRxInvert(bool invert) {};
 };

-HardwareSerial Serial, Serial1, Serial2;
+HardwareSerial Serial, Serial2;

 class EspClass {
 public:
@@ -168,7 +168,6 @@ void delay(uint32_t ms) {
 bool ledcAttach(uint8_t pin, uint32_t freq, uint8_t resolution) { return true; }
 bool ledcWrite(uint8_t pin, uint32_t duty) { return true; }
 uint32_t ledcChangeFrequency(uint8_t pin, uint32_t freq, uint8_t resolution) { return freq; }
-int8_t digitalPinToAnalogChannel(uint8_t pin) { return -1; }
 uint32_t analogReadMilliVolts(uint8_t pin) { return 0; }

 unsigned long __micros;
@@ -1,12 +0,0 @@
-// Dummy file for the simulator
-
-class ESP_NOW_Peer {
-protected:
-	size_t send(const uint8_t *data, int len) { return 0; }
-};
-
-class ESP_NOW_Serial_Class : public ESP_NOW_Peer {
-public:
-	virtual void onSent(bool success) {};
-	virtual size_t write(const uint8_t *data, size_t len) { return 0; };
-};
@@ -15,11 +15,12 @@ public:
 	SBUS(HardwareSerial& bus, const int8_t rxpin, const int8_t txpin, const bool inv = true) {};
 	void begin(int rxpin = -1, int txpin = -1, bool inv = true, bool fast = false) {};
 	bool read() { return joystickInit(); };
-	void getChannels(uint16_t (&channels)[16]) const {
-		int16_t ch[16];
-		joystickGet(ch);
+	SBUSData data() {
+		SBUSData data;
+		joystickGet(data.ch);
 		for (int i = 0; i < 16; i++) {
-			channels[i] = map(ch[i], -32768, 32767, 1000, 2000); // convert to pulse width style
+			data.ch[i] = map(data.ch[i], -32768, 32767, 1000, 2000); // convert to pulse width style
 		}
+		return data;
 	};
 };
@@ -21,9 +21,6 @@ extern float motors[4];
 Vector gyro, acc, imuRotation;
 Vector accBias, gyroBias, accScale(1, 1, 1);
 LowPassFilter<Vector> gyroBiasFilter(0);
-int imuModel = 1, imuBus = 0;
-int imuSckPin = 0, imuMisoPin = 0, imuMosiPin = 0, imuCsPin = -1, imuIntPin = -1;
-int imuSdaPin = 0, imuSclPin = 0;

 // declarations
 void step();
@@ -41,15 +38,14 @@ const char* getModeName();
 void sendMotors();
 int getDutyCycle(float value);
 bool motorsActive();
-void testMotor(int, float);
+void testMotor(int n);
 void print(const char* format, ...);
 void pause(float duration);
 void doCommand(String str, bool echo);
 void handleInput();
-void setupRC();
 void normalizeRC();
 void calibrateRC();
-void calibrateRCChannel(int*, uint16_t[16], uint16_t[16], const char*);
+void calibrateRCChannel(int *channel, uint16_t zero[16], uint16_t max[16], const char *str);
 void printRCCalibration();
 void printLogHeader();
 void printLogData();
@@ -61,25 +57,23 @@ void handleMavlink(const void *_msg);
 void mavlinkPrint(const char* str);
 void sendMavlinkPrint();
 inline Quaternion fluToFrd(const Quaternion &q);
-void setupPower();
 void failsafe();
 void rcLossFailsafe();
 void descend();
 void autoFailsafe();
-void tiltFailsafe();
 int parametersCount();
 const char *getParameterName(int index);
 float getParameter(int index);
 float getParameter(const char *name);
 bool setParameter(const char *name, const float value);
-void printParameters(const char *filter);
+void printParameters();
 void resetParameters();

 // mocks
 void setLED(bool on) {};
+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() {};
 void configWiFi(bool, const char*, const char*) { print("Skip WiFi config\n"); };
-void setWiFiMode(const String& mode) { print("Skip WiFi mode set\n"); };
@@ -55,7 +55,6 @@ public:
 		initNode();
 		Serial.begin(0);
 		setupParameters();
-		rcRxPin = 1; // set rc pin to enable rc reading
 		gzmsg << "Flix plugin loaded" << endl;
 	}

@@ -74,8 +73,6 @@ public:
 		gyro = Vector(imu->AngularVelocity().X(), imu->AngularVelocity().Y(), imu->AngularVelocity().Z());
 		acc = this->accFilter.update(Vector(imu->LinearAcceleration().X(), imu->LinearAcceleration().Y(), imu->LinearAcceleration().Z()));

-		voltage = 4.2f; // dummy voltage value
-
 		readRC();
 		estimate();

@@ -11,12 +11,7 @@
 #include <sys/poll.h>
 #include <gazebo/gazebo.hh>

-// Mocks
-int wifiMode = 1;
-int wifiLongRange = 0;
-int espnowChannel = 6;
-const int W_DISABLED = 0, W_AP = 1, W_STA = 2, W_ESPNOW = 3;
-
+int wifiMode = 1; // mock
 int udpLocalPort = 14580;
 int udpRemotePort = 14550;
 const char *udpRemoteIP = "255.255.255.255";
@@ -1,3 +0,0 @@
-# ESPNOW-proxy
-
-Proxy sketch for using ESP-NOW connection with Flix drone.
@@ -1,88 +0,0 @@
-// Copyright (c) 2026 Oleg Kalachev <okalachev@gmail.com>
-// Repository: https://github.com/okalachev/flix
-
-// Proxy for ESP-NOW connection
-
-#include <vector>
-#include <WiFi.h>
-#include <ESP32_NOW_Serial.h>
-#include <MacAddress.h>
-#include <MAVLink.h>
-#include <Preferences.h>
-#include "../../flix/util.h"
-
-const int CHANNEL = 6;
-char key[ESP_NOW_KEY_LEN + 1] = {0}; // with trailing null
-
-Preferences storage;
-
-std::vector<ESPNOWSerial *> peers;
-
-void onNewPeer(const esp_now_recv_info_t *info, const uint8_t *data, int len, void *arg) {
-	if (len != 4 || memcmp(data, "flix", 4) != 0) return; // check if discovery message
-
-	Serial.printf("New peer: " MACSTR "\n", MAC2STR(info->src_addr));
-	ESPNOWSerial *link = new ESPNOWSerial(info->src_addr, CHANNEL, WIFI_IF_AP);
-	link->begin();
-	link->setKey((const uint8_t *)key);
-	peers.push_back(link);
-}
-
-void setup() {
-	Serial.begin(115200);
-	WiFi.mode(WIFI_AP);
-	WiFi.setSleep(false);
-	WiFi.setChannel(CHANNEL);
-
-	ESP_NOW.onNewPeer(onNewPeer, NULL);
-	ESP_NOW.begin();
-
-	storage.begin("espnow-proxy");
-	if (!storage.isKey("key")) {
-		generateRandomKey();
-		storage.putString("key", key);
-	}
-	strcpy(key, storage.getString("key").c_str());
-
-	// Discover the first peer
-	while (peers.empty()) {
-		Serial.printf("espnow %s %s\n", WiFi.softAPmacAddress().c_str(), key);
-		delay(500);
-	}
-}
-
-void generateRandomKey() {
-	const char chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*-_+=";
-	for (int i = 0; i < ESP_NOW_KEY_LEN; i++) {
-		key[i] = chars[random(0, strlen(chars))];
-	}
-}
-
-void loop() {
-	uint8_t buf[5000];
-
-	// Send from Serial to ESP-NOW
-	while (Serial.available() > 0) {
-		int b = Serial.read();
-		if (b < 0) {
-			break;
-		}
-
-		mavlink_message_t msg;
-		mavlink_status_t status;
-		if (mavlink_parse_char(MAVLINK_COMM_0, (uint8_t)b, &msg, &status)) {
-			int len = mavlink_msg_to_send_buffer(buf, &msg);
-			for (ESPNOWSerial *link : peers) {
-				link->write(buf, len);
-			}
-		}
-	}
-
-	// Send from ESP-NOW to Serial
-	for (ESPNOWSerial *link : peers) {
-		int len = link->read(buf, sizeof(buf));
-		if (len > 0) {
-			Serial.write(buf, len);
-		}
-	}
-}
@@ -28,8 +28,6 @@ from pyflix import Flix
 flix = Flix()  # create a Flix object and wait for connection
 ```

-If using ESP-NOW connection, specify the proxy device name in `FLIX_DEVICE` environment variable or pass it to the constructor: `Flix(device='/dev/cu.usbserial-0001')`.
-
 ### Telemetry

 Basic telemetry is available through object properties. The property names generally match the corresponding variables in the firmware code:
@@ -39,7 +37,7 @@ print(flix.connected)       # True if connected to the drone
 print(flix.mode)            # current flight mode (str)
 print(flix.armed)           # True if the drone is armed
 print(flix.landed)          # True if the drone is landed
-print(flix.voltage)         # battery voltage (NaN - unknown, ~0 - USB powered)
+print(flix.voltage)         # battery voltage
 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]
@@ -222,13 +220,6 @@ The following scripts demonstrate how to use the library:
 * [`log.py`](../log.py) — download flight logs from the drone.
 * [`example.py`](../example.py) — a simple example, prints telemetry data and waits for events.

-> [!TIP]
-> Set `FLIX_DEVICE` environment variable to use these tools with ESP-NOW connection, for example:
->
-> ```bash
-> FLIX_DEVICE=/dev/cu.usbserial-0001 tools/cli.py
-> ```
-
 ## Advanced usage

 ### MAVLink
@@ -5,7 +5,6 @@

 import os
 import time
-import math
 from queue import Queue, Empty
 from typing import Optional, Callable, List, Dict, Any, Union, Sequence
 import logging
@@ -27,7 +26,7 @@ class Flix:
    mode: str = ''
    armed: bool = False
    landed: bool = False
-    voltage: float = math.nan
+    voltage: float = 0
    attitude: List[float]
    attitude_euler: List[float]  # roll, pitch, yaw
    rates: List[float]
@@ -44,27 +43,22 @@ class Flix:
    _print_buffer: str = ''
    _modes = ['RAW', 'ACRO', 'STAB', 'AUTO']

-    def __init__(self, system_id: int=1, wait_connection: bool=True, device=os.getenv('FLIX_DEVICE')):
+    def __init__(self, system_id: int=1, wait_connection: bool=True):
        if not (0 <= system_id < 256):
            raise ValueError('system_id must be in range [0, 255]')
        self._setup_mavlink()
        self.system_id = system_id
        self._init_state()
-        if device is not None:
-            # User defined connection
-            logger.debug(f'Connecting to {device}')
-            self.connection: mavutil.mavfile = mavutil.mavlink_connection(device, source_system=255)  # type: ignore
-        else:
-            try:
-                # Direct connection
-                logger.debug('Listening on port 14550')
-                self.connection: mavutil.mavfile = mavutil.mavlink_connection('udpin:0.0.0.0:14550', source_system=255)  # type: ignore
-            except OSError as e:
-                if e.errno != errno.EADDRINUSE:
-                    raise
-                # Port busy - using proxy
-                logger.debug('Listening on port 14555 (proxy)')
-                self.connection: mavutil.mavfile = mavutil.mavlink_connection('udpin:0.0.0.0:14555', source_system=254)  # type: ignore
+        try:
+            # Direct connection
+            logger.debug('Listening on port 14550')
+            self.connection: mavutil.mavfile = mavutil.mavlink_connection('udpin:0.0.0.0:14550', source_system=255)  # type: ignore
+        except OSError as e:
+            if e.errno != errno.EADDRINUSE:
+                raise
+            # Port busy - using proxy
+            logger.debug('Listening on port 14555 (proxy)')
+            self.connection: mavutil.mavfile = mavutil.mavlink_connection('udpin:0.0.0.0:14555', source_system=254)  # type: ignore
        self.connection.target_system = system_id
        self.mavlink: mavlink.MAVLink = self.connection.mav
        self._event_listeners: Dict[str, List[Callable[..., Any]]] = {}
@@ -1,6 +1,6 @@
 [project]
 name = "pyflix"
-version = "0.16"
+version = "0.14"
 description = "Python API for Flix drone"
 authors = [{ name="Oleg Kalachev", email="okalachev@gmail.com" }]
 license = "MIT"
Author	SHA1	Message	Date
Oleg Kalachev	26b639dfbc	Reduce angle drift adding level correction to the estimator Utilize a-priori knowledge that the overall average attitude of the flying drone is level.	2026-05-04 16:48:20 +03:00
Oleg Kalachev	dbf24ea611	Expose lpf alpha of rate pids to parameters Add parameters: CTL_R_RATE_D_A, CTL_P_RATE_D_A, CTL_Y_RATE_D_A.	2026-05-03 15:04:16 +03:00
Oleg Kalachev	08683d696d	Some updates in the usage doc	2026-05-01 15:26:59 +03:00
Oleg Kalachev	9ca6841558	Exit auto mode when sticks moved only when mode switch is not configured	2026-04-29 15:07:44 +03:00
Oleg Kalachev	28da2d3c8e	Fix in pyflix documentation pyflix@0.14	2026-04-28 20:46:49 +03:00
Oleg Kalachev	c6632ae6e4	Add info on setting flight modes using rc mode switch	2026-04-28 20:43:52 +03:00
Oleg Kalachev	35ca754583	Fix Vector::rotationVectorBetween implementation for parallel vectors	2026-04-28 15:38:52 +03:00
Oleg Kalachev	2ccda03573	Implement motors output desaturation So the drone continues stabilization on max thrust.	2026-04-28 13:23:42 +03:00
Oleg Kalachev	485a39e740	Disable wi-fi power save to improve responsiveness	2026-04-27 16:46:36 +03:00
Oleg Kalachev	9bffe5b52f	Some fixes in docs	2026-04-26 06:05:02 +03:00
Oleg Kalachev	d6a79d6c66	Pass acc data in mG in SCALED_IMU to comply with mavlink standard https://mavlink.io/en/messages/common.html#SCALED_IMU pyflix@0.13	2026-04-24 07:42:39 +03:00
Oleg Kalachev	350a82bfed	Minor fix	2026-04-23 15:34:54 +03:00
Oleg Kalachev	6e439859bc	Move disabling brown-out code to power subsystem	2026-04-23 15:06:07 +03:00
Oleg Kalachev	835b2243e8	Minor fix in sys command String works with printf %s, but actually it's a UB.	2026-04-23 07:25:59 +03:00
Oleg Kalachev	ed4e2d87d1	Fix imu command output Gyro field contained filtered gyro instead of scaled only gyro.	2026-04-23 07:12:25 +03:00
Oleg Kalachev	51cd5fc691	Implement battery voltage monitoring Add power subsystem. Add PWR_VOLT_PIN, PWR_VOLT_SCALE, PWR_VOLT_LPF_A parameters. Support BATTERY_STATUS mavlink messages streaming. Add pw cli command. Add voltage field to pyflix library. pyflix@0.12.	2026-04-22 11:35:37 +03:00
Oleg Kalachev	d8591ea2a9	Fix working with parameters in pyflix examples PITCH_P parameter was renamed to CTL_P_P	2026-04-18 05:23:47 +03:00
Oleg Kalachev	c434107eaf	Add parameter for configuring sbus pin number, disable sbus by default	2026-03-27 00:56:34 +03:00
Oleg Kalachev	814427dbfd	Minor docs change	2026-03-27 00:40:19 +03:00
Oleg Kalachev	0730ceeffa	Add new user builds	2026-02-21 07:12:36 +03:00
Oleg Kalachev	a687303062	Make motor parameters apply without reboot Add callback to parameter definition to call after parameter is changed.	2026-02-19 04:56:12 +03:00
Oleg Kalachev	b2daf2587f	Minor parameters code simplifications readOnly is false by default INFINITY == INFINITY, so remove redundant check	2026-02-19 02:59:38 +03:00
Oleg Kalachev	a8c25d8ac0	Minor updates to usage article	2026-02-04 17:52:23 +03:00
Oleg Kalachev	3e49d41986	Make rc channel numbers and calibration params use int instead of float As parameter subsystems supports int now, and int is much more natural here.	2026-02-02 20:36:22 +03:00
Oleg Kalachev	67430c7aac	Several minor changes	2026-02-02 18:46:36 +03:00
Oleg Kalachev	3631743a29	Drop messages from another systems in pyflix We shouldn't pass messages where system id != our system id. This change may be useful when there are many drones in one network.	2026-02-02 18:28:20 +03:00
Oleg Kalachev	3dde380bb7	Add parameters for list of modes bound to rc switch Parameters: CTL_FLT_MODE_0, CTL_FLT_MODE_1, CTL_FLT_MODE_2. Also fix a bug with incorrect choosing the mode from controlMode.	2026-01-27 16:38:20 +03:00
Oleg Kalachev	377b21429b	Fix error when launching the sim Also make the parameters WIFI_LOC_PORT and WIFI_REM_PORT work in the sim.	2026-01-27 16:32:52 +03:00
Oleg Kalachev	1ac443d6f8	Add a build by Arky Matsekh	2026-01-27 15:17:58 +03:00
Oleg Kalachev	964c0f7bc1	Make setting parameter in console printing actual parameter value. In some cases, it would not be equal to the requested value.	2026-01-27 09:28:01 +03:00
Oleg Kalachev	40bdaacedb	Make motor subsystem configurable using parameters Motor pins: MOT_PIN_FL, MOT_PIN_FR, MOT_PIN_RL, MOT_PIN_RR. PWM configuration: MOT_PWM_FREQ, MOT_PWM_RES, MOT_PWM_STOP, MOT_PWM_MIN, MOT_PWM_MAX. MOT_PWM_MAX = -1 chooses duty cycle mode for brushed motors (default).	2026-01-27 08:40:52 +03:00
Oleg Kalachev	7d74f3d5cd	Minor docs fixes	2026-01-27 07:21:21 +03:00
Oleg Kalachev	9fd35ba361	Simplify lpf filter code Begin with zero instead of the initializing value, as the latter doesn't make much sense in practice, but complicates the code much.	2026-01-24 09:43:46 +03:00
Oleg Kalachev	ca50f75576	Various minor fixes	2026-01-24 09:34:16 +03:00
Oleg Kalachev	e47a31f981	Fix mavlink parameter set acknowledgement value If the parameter is integer the acknowledgement should contain the rounded value.	2026-01-24 09:32:49 +03:00
Oleg Kalachev	7ad3022798	Add parameter for configuring gyro bias lpf + reset the filter on `reset` command	2026-01-24 09:31:32 +03:00
Oleg Kalachev	5b654e4d8e	Update ESP32-Core to 3.3.6	2026-01-23 02:41:43 +03:00
Oleg Kalachev	cf10ec6161	Update MAVLink-Arduino to 2.0.16	2026-01-23 01:11:35 +03:00
Oleg Kalachev	6d01cd2e79	Make failsafe configurable using parameters SF_RC_LOSS_TIME - time without rc to activate failsafe. SD_DESCEND_TIME - total time to decrease the throttle to zero. Make controlTime nan on the start to simplify the logic.	2026-01-22 23:57:52 +03:00
Oleg Kalachev	0abb18c616	Make parameter names case-insensitive + minor fix	2026-01-22 23:11:47 +03:00
Oleg Kalachev	30326a5662	Add parameters for configuring the mavlink subsystem MAV_SYS_ID - mavlink system id. MAV_RATE_SLOW - rate of slow telemetry (e. g. heartbeats). MAV_RATE_FAST - rate of fast telemetry (e. g. attitude, imu data).	2026-01-22 23:04:45 +03:00
Oleg Kalachev	dd3575174b	Add wifi configuration using parameters and cli Add console commands to setup wifi. Add a parameter for choosing between STA and AP mode. Add parameters for udp ports. Remove WIFI_ENABLED macro.	2026-01-22 22:58:43 +03:00
Oleg Kalachev	c0f3301da4	Support integer parameters in addition to floats The variable pointer is stored as a union field. If `.integer` field is true, then integer pointer should be used. Interfaces to parameters (cli and mavlink) keep working using floats. Setting a non-finite value to int parameter will cause an error. `.value` field is renamed to `.cache`.	2026-01-22 22:54:05 +03:00
a.golubtsovandOleg Kalachev	a6bad3a69b	Add log dir creation before log writing	2026-01-22 17:56:23 +03:00
Oleg Kalachev	9a9bd07251	Add correct attitude estimation video to the usage article	2026-01-15 23:46:23 +03:00
Oleg Kalachev	28f5855a57	Re-arrange control.ino declarations to make a bit more sensible So the control command is above the PID controllers.	2026-01-13 17:43:53 +03:00
Oleg Kalachev	7e24ee30f7	Documentation and book updates Improve the main list of features. Use lowercase imu variable for consistency with the firmware code. Minor fixes.	2026-01-13 17:26:40 +03:00
Oleg Kalachev	2a8faf5759	Fix logo svg slightly	2026-01-08 19:45:08 +03:00
Oleg Kalachev	f4e58a652a	Add project logo	2026-01-08 17:58:59 +03:00
Oleg Kalachev	6c46328da1	Minor doc fixes	2026-01-04 15:01:53 +03:00
Oleg Kalachev	c8e5e08b03	Move all global variable declarations to the appropriate subsystems As it makes the subsystems code easier to understand. Declare the most used variables in main sketch file as forward declarations. Make all control input zero by default (except controlMode). Minor changes.	2026-01-03 13:28:18 +03:00
Oleg Kalachev	a5e3dfcf69	Some updates to the docs	2026-01-03 12:18:47 +03:00
Oleg Kalachev	d6e8be0c05	Add parameters for easier IMU orientation definition	2025-12-26 21:14:15 +03:00
Oleg Kalachev	68d16855df	Add motors rotation diagram to usage article	2025-12-25 07:22:09 +03:00
Oleg Kalachev	0547ea548b	Add parameters for acc weight and rates lpf alpha	2025-12-24 05:43:55 +03:00
Oleg Kalachev	c02dba6812	Rename gyroCalibrationFilter to gyroBiasFilter Which seems a better name	2025-12-24 05:36:43 +03:00
Oleg Kalachev	f1dc4a0400	Updates to user builds article	2025-12-17 02:21:51 +03:00
Oleg Kalachev	158827ac55	Add new user builds, add school 548 course overview + minor doc fixes.	2025-12-13 21:09:33 +03:00
Oleg Kalachev	36ca30c3e4	Minor docs fix	2025-11-27 18:34:32 +03:00
Oleg Kalachev	48711b55e1	Add tip about CNT_TILT_MAX parameter to the simulator article	2025-11-26 17:34:08 +03:00
Oleg Kalachev	4d583185a9	Rename manual mode to raw mode Make it callable from the console. Increase the coefficient. Corresponding change in pyflix. pyflix@0.11.	2025-11-25 04:44:16 +03:00
Oleg Kalachev	d757ffa853	Move yaw dead zone handling from mavlink to control subsystem So yaw dead zone works the same for rc and mavlink.	2025-11-22 05:11:46 +03:00
Oleg Kalachev	5352386486	Minor updates to pyflix library, pyflix@0.10 Fixes to documentation. Improve logger format.	2025-11-22 05:07:46 +03:00
Oleg Kalachev	9b5872740f	Add wifi cli command To show wi-fi info.	2025-11-22 04:46:54 +03:00
Oleg Kalachev	31dbdaf241	Group control parameters Also add IMU group to accelerometer calibration parameters.	2025-11-19 01:50:46 +03:00
Oleg Kalachev	f4b56262b1	Remove unneeded SERIAL_BAUDRATE define	2025-11-14 20:23:15 +03:00
Oleg Kalachev	49039f752d	Refactor Wi-Fi log download Use MAVLink LOG_REQUEST_DATA and LOG_DATA for download log instead of console. Make Wi-Fi download default way of downloading the log. Make `log` command only print the header and `log dump` dump the log.	2025-11-14 20:21:05 +03:00
Oleg Kalachev	348721acc9	Updates in documentation Fixes, updates, new illustrations.	2025-11-10 20:16:14 +03:00
Oleg Kalachev	774144c430	Many updates to documentation Updates to main readme. Add much more info to usage article. Move simulator building to simulation's readme. Improve assembly article. Many fixes. Updates in diagrams.	2025-11-06 13:55:52 +03:00
Oleg Kalachev	0e6651ab82	Add Rate class for running the code at fixed rate	2025-11-06 13:41:33 +03:00