Reduce angle drift adding level correction to the estimator

Utilize a-priori knowledge that the overall average attitude of the flying drone is level.

.github/workflows/build.yml

@@ -23,8 +23,6 @@ jobs:
       with:
         name: firmware-binary
         path: flix/build
-    - name: Build firmware for ESP32-C3
-      run: make BOARD=esp32:esp32:esp32c3
     - name: Build firmware for ESP32-S3
       run: make BOARD=esp32:esp32:esp32s3
     - name: Check c_cpp_properties.json

.vscode/c_cpp_properties.json

@@ -17,7 +17,21 @@
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
 				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32/Arduino.h",
-				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h"
+				"~/.arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
+				"${workspaceFolder}/flix/cli.ino",
+				"${workspaceFolder}/flix/control.ino",
+				"${workspaceFolder}/flix/estimate.ino",
+				"${workspaceFolder}/flix/flix.ino",
+				"${workspaceFolder}/flix/imu.ino",
+				"${workspaceFolder}/flix/led.ino",
+				"${workspaceFolder}/flix/log.ino",
+				"${workspaceFolder}/flix/mavlink.ino",
+				"${workspaceFolder}/flix/motors.ino",
+				"${workspaceFolder}/flix/rc.ino",
+				"${workspaceFolder}/flix/time.ino",
+				"${workspaceFolder}/flix/wifi.ino",
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
 			"compilerPath": "~/.arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++",
 			"cStandard": "c11",
@@ -50,7 +64,21 @@
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.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"
+				"~/Library/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
+				"${workspaceFolder}/flix/flix.ino",
+				"${workspaceFolder}/flix/cli.ino",
+				"${workspaceFolder}/flix/control.ino",
+				"${workspaceFolder}/flix/estimate.ino",
+				"${workspaceFolder}/flix/imu.ino",
+				"${workspaceFolder}/flix/led.ino",
+				"${workspaceFolder}/flix/log.ino",
+				"${workspaceFolder}/flix/mavlink.ino",
+				"${workspaceFolder}/flix/motors.ino",
+				"${workspaceFolder}/flix/rc.ino",
+				"${workspaceFolder}/flix/time.ino",
+				"${workspaceFolder}/flix/wifi.ino",
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
 			"compilerPath": "~/Library/Arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++",
 			"cStandard": "c11",
@@ -84,7 +112,21 @@
 			"forcedInclude": [
 				"${workspaceFolder}/.vscode/intellisense.h",
 				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/cores/esp32/Arduino.h",
-				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h"
+				"~/AppData/Local/Arduino15/packages/esp32/hardware/esp32/3.3.6/variants/d1_mini32/pins_arduino.h",
+				"${workspaceFolder}/flix/cli.ino",
+				"${workspaceFolder}/flix/control.ino",
+				"${workspaceFolder}/flix/estimate.ino",
+				"${workspaceFolder}/flix/flix.ino",
+				"${workspaceFolder}/flix/imu.ino",
+				"${workspaceFolder}/flix/led.ino",
+				"${workspaceFolder}/flix/log.ino",
+				"${workspaceFolder}/flix/mavlink.ino",
+				"${workspaceFolder}/flix/motors.ino",
+				"${workspaceFolder}/flix/rc.ino",
+				"${workspaceFolder}/flix/time.ino",
+				"${workspaceFolder}/flix/wifi.ino",
+				"${workspaceFolder}/flix/parameters.ino",
+				"${workspaceFolder}/flix/safety.ino"
 			],
 			"compilerPath": "~/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2511/bin/xtensa-esp32-elf-g++.exe",
 			"cStandard": "c11",

Makefile

@@ -1,5 +1,6 @@
 BOARD = esp32:esp32:d1_mini32
-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*))
+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))
 
 build: .dependencies
 	arduino-cli compile --fqbn $(BOARD) flix
@@ -18,10 +19,6 @@ dependencies .dependencies:
 	arduino-cli lib install "MAVLink"@2.0.25
 	touch .dependencies
 
-upload_proxy: .dependencies
-	arduino-cli compile --fqbn $(BOARD) tools/espnow-proxy
-	arduino-cli upload --fqbn $(BOARD) -p "$(PORT)" tools/espnow-proxy
-
 gazebo/build cmake: gazebo/CMakeLists.txt
 	mkdir -p gazebo/build
 	cd gazebo/build && cmake ..

README.md

@@ -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.
+* Connectivity using Wi-Fi and MAVLink protocol.
-* Control with USB gamepad, remote control or smartphone.
+* 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.
@@ -53,7 +53,7 @@ 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).
@@ -71,14 +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|
+|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)<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|
+|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|
+|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|
@@ -152,16 +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

docs/assembly.md

@@ -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]

docs/firmware.md

@@ -67,35 +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).
-
-## Adding a subsystem
-
-To add a new subsystem:
-
-1. Create a new `*.ino` file for your subsystem.
-2. Define setup and loop functions for the subsystem, for example `setupMySubsystem()` and `loopMySubsystem()`.
-3. Use `Rate` class if you need to limit the loop frequency, for example:
-
-    ```cpp
-    Rate mySubsystemRate(100); // 100 Hz
-
-    void loopMySubsystem() {
-    	if (!mySubsystemRate) return;
-    	// Do something...
-    }
-4. Add setup and loop calls in to `setup()` and `loop()` functions in `flix.ino`.
-
 ## Building the firmware
 
 See build instructions in [usage.md](usage.md).

docs/troubleshooting.md

@@ -12,25 +12,20 @@ Do the following:
 
 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 voltage**. Use a multimeter to measure the battery voltage. It should be in range of 3.7-4.2 V.
-* **Check the battery you use has enough discharge current**. The battery should be able to provide 15A of current. So the C-rating for a 1000 mAh battery should be at least 15C (higher is better).
 * **Check if there are some startup errors**. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button or `reboot` command to see the whole startup output.
 * **Check the baudrate is correct**. If you see garbage characters in the Serial Monitor, make sure the baudrate is set to 115200.
+* **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
 * **Check if the 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:
+* **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).
-  <a href="https://youtu.be/yVRN23-GISU"><img width=200 src="https://i3.ytimg.com/vi/yVRN23-GISU/maxresdefault.jpg"></a>
-
-* **Check the IMU output**. Connect to the drone using QGroundControl on your computer. Go to the *Analyze* tab, *MAVLINK Inspector*. Plot the data from the `SCALED_IMU` message. The gyroscope and accelerometer data should change according to the drone movement.
 * **Check the motors type**. Motors with exact 3.7V voltage are needed, not ranged working voltage (3.7V — 6V).
 * **Check the motors**. Perform the following commands using Serial Monitor:
   * `mfr` — should rotate front right motor (counter-clockwise).
@@ -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">
-
+* **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 an SBUS receiver**:
+* **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.

docs/usage.md

@@ -114,7 +114,7 @@ You can also work with parameters using `p` command in the console. Parameter na
 
 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">
 
@@ -122,10 +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-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-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-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|
+|<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
 
@@ -138,7 +138,7 @@ 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).
 
-Certain ESP32 models (such as ESP32-S3 and ESP32-C3) support a lower maximum PWM frequency; on these boards the parameter `MOT_PWM_FREQ` should be set to 38000 Hz.
+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 and ESCs:
 
@@ -192,18 +192,6 @@ There are several ways to control the drone's flight: using **smartphone** (Wi-F
 
 ### 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`).
@@ -216,11 +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!
 
@@ -290,8 +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).
+* `2` — Client mode *(STA)* — the drone connects to an existing Wi-Fi network.
-* `3` — ESP-NOW mode — the drone uses ESP-NOW protocol for communication.
+* `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:
 
@@ -313,37 +304,6 @@ 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 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.
-
-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*. QGroundControl should connect to the drone using ESP-NOW and begin showing the telemetry.
-
 ## Flight log
 
 After the flight, you can download the flight log for analysis wirelessly. Use the following command on your computer for that:

docs/user.md

@@ -4,22 +4,6 @@ This page contains user-built drones based on the Flix project. Publish your pro
 
 ---
 
-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.

flix/cli.ino

@@ -3,8 +3,6 @@
 
 // Implementation of command line interface
 
-#include <Arduino.h>
-#include "flix.h"
 #include "pid.h"
 #include "vector.h"
 #include "util.h"
@@ -12,7 +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;
@@ -22,14 +19,13 @@ 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"
@@ -48,7 +44,6 @@ const char* motd =
 "wifi - show Wi-Fi info\n"
 "ap <ssid> <password> - setup Wi-Fi access point\n"
 "sta <ssid> <password> - setup Wi-Fi client mode\n"
-"espnow <mac> [<key>] - setup ESP-NOW peer\n"
 "mot - show motor output\n"
 "log [dump] - print log header [and data]\n"
 "cr - calibrate RC\n"
@@ -78,7 +73,7 @@ void pause(float duration) {
 	}
 }
 
-void doCommand(String str, bool echo) {
+void doCommand(String str, bool echo = false) {
 	// parse command
 	String command, arg0, arg1;
 	splitString(str, command, arg0, arg1);
@@ -147,11 +142,9 @@ void doCommand(String str, bool echo) {
 	} else if (command == "wifi") {
 		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());
+		configWiFi(false, arg0.c_str(), arg1.c_str());
-	} else if (command == "espnow") {
-		configWiFi(W_ESPNOW, arg0.c_str(), arg1.c_str());
 	} else if (command == "mot") {
 		print("front-right %g front-left %g rear-right %g rear-left %g\n",
 			motors[MOTOR_FRONT_RIGHT], motors[MOTOR_FRONT_LEFT], motors[MOTOR_REAR_RIGHT], motors[MOTOR_REAR_LEFT]);
@@ -175,7 +168,6 @@ void doCommand(String str, bool echo) {
 		print("Chip: %s\n", ESP.getChipModel());
 		print("Temperature: %.1f °C\n", temperatureRead());
 		print("Free heap: %d\n", ESP.getFreeHeap());
-		print("Firmware: " __DATE__ " " __TIME__ "\n");
 		// Print tasks table
 		print("Num  Task                Stack  Prio  Core  CPU%%\n");
 		int taskCount = uxTaskGetNumberOfTasks();

flix/config.h

@@ -1,55 +0,0 @@
-// Wi-Fi
-#define WIFI_ENABLED 1
-#define WIFI_SSID "flix"
-#define WIFI_PASSWORD "flixwifi"
-#define WIFI_UDP_PORT 14550
-#define WIFI_UDP_REMOTE_PORT 14550
-#define WIFI_UDP_REMOTE_ADDR "255.255.255.255"
-
-// Motors
-#define MOTOR_0_PIN 12 // rear left
-#define MOTOR_1_PIN 13 // rear right
-#define MOTOR_2_PIN 14 // front right
-#define MOTOR_3_PIN 15 // front left
-#define PWM_FREQUENCY 78000
-#define PWM_RESOLUTION 10
-#define PWM_STOP 0
-#define PWM_MIN 0
-#define PWM_MAX 1000000 / PWM_FREQUENCY
-
-// Control
-#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
-
-// Estimation
-#define WEIGHT_ACC 0.003
-#define RATES_LFP_ALPHA 0.2 // cutoff frequency ~ 40 Hz
-
-// MAVLink
-#define SYSTEM_ID 1
-
-// Safety
-#define RC_LOSS_TIMEOUT 1
-#define DESCEND_TIME 10

flix/control.ino

@@ -3,16 +3,38 @@
 
 // Flight control
 
-#include "config.h"
-#include "flix.h"
 #include "vector.h"
 #include "quaternion.h"
 #include "pid.h"
 #include "lpf.h"
 #include "util.h"
 
-extern const int RAW = 0, ACRO = 1, STAB = 2, AUTO = 3; // flight modes
+#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;
 

flix/estimate.ino

@@ -3,8 +3,6 @@
 
 // Attitude estimation using gyro and accelerometer
 
-#include "config.h"
-#include "flix.h"
 #include "quaternion.h"
 #include "vector.h"
 #include "lpf.h"

flix/flix.h

@@ -1,95 +0,0 @@
-// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
-// Repository: https://github.com/okalachev/flix
-
-// All-in-one header file
-
-#pragma once
-
-#include <Arduino.h>
-#include "vector.h"
-#include "quaternion.h"
-
-extern float t, dt;
-extern float loopRate;
-extern float controlRoll, controlPitch, controlYaw, controlThrottle, controlMode;
-extern Vector gyro, acc;
-extern Vector rates;
-extern Quaternion attitude;
-extern bool landed;
-extern int mode;
-extern bool armed;
-extern Quaternion attitudeTarget;
-extern Vector ratesTarget, ratesExtra, torqueTarget;
-extern float thrustTarget;
-extern float motors[4];
-
-void print(const char* format, ...);
-void pause(float duration);
-void doCommand(String str, bool echo = false);
-void handleInput();
-void control();
-void interpretControls();
-void controlAttitude();
-void controlRates();
-void controlTorque();
-void desaturate(float& a, float& b, float& c, float& d);
-const char *getModeName();
-void estimate();
-void applyGyro();
-void applyAcc();
-void applyLevel();
-void setupIMU();
-void configureIMU();
-void readIMU();
-void rotateIMU(Vector& data);
-void calibrateGyroOnce();
-void calibrateAccel();
-void calibrateAccelOnce();
-void printIMUCalibration();
-void printIMUInfo();
-void setupLED();
-void setLED(bool on);
-void blinkLED();
-void prepareLogData();
-void logData();
-void printLogHeader();
-void printLogData();
-void processMavlink();
-void sendMavlink();
-void sendMessage(const void *msg);
-void receiveMavlink();
-void printWiFiInfo();
-void configWiFi(int mode, const char *first, const char *second);
-void handleMavlink(const void *_msg);
-void mavlinkPrint(const char* str);
-void sendMavlinkPrint();
-void setupMotors();
-int getDutyCycle(float value);
-void sendMotors();
-bool motorsActive();
-void testMotor(int n);
-void setupParameters();
-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 syncParameters();
-void printParameters();
-void resetParameters();
-void setupRC();
-bool readRC();
-void normalizeRC();
-void calibrateRC();
-void calibrateRCChannel(int *channel, uint16_t in[16], uint16_t out[16], const char *str);
-void printRCCalibration();
-void setupPower();
-void failsafe();
-void rcLossFailsafe();
-void descend();
-void autoFailsafe();
-void step();
-void computeLoopRate();
-void setupWiFi();
-void sendWiFi(const uint8_t *buf, int len);
-int receiveWiFi(uint8_t *buf, int len);

flix/flix.ino

@@ -3,11 +3,17 @@
 
 // Main firmware file
 
-#include "config.h"
 #include "vector.h"
 #include "quaternion.h"
 #include "util.h"
-#include "flix.h"
+
+extern float t, dt;
+extern float controlRoll, controlPitch, controlYaw, controlThrottle, controlMode;
+extern Vector gyro, acc;
+extern Vector rates;
+extern Quaternion attitude;
+extern bool landed;
+extern float motors[4];
 
 void setup() {
 	Serial.begin(115200);

flix/imu.ino

@@ -10,7 +10,7 @@
 #include "util.h"
 
 MPU9250 imu(SPI);
-Vector imuRotation(0, 0, PI / 2); // imu orientation as Euler angles
+Vector imuRotation(0, 0, -PI / 2); // imu orientation as Euler angles
 
 Vector gyro; // gyroscope output, rad/s
 Vector gyroBias;

flix/led.ino

@@ -3,8 +3,6 @@
 
 // Board's LED control
 
-#include <Arduino.h>
-
 #define BLINK_PERIOD 500000
 
 #ifndef LED_BUILTIN

flix/log.ino

@@ -3,7 +3,6 @@
 
 // In-RAM logging
 
-#include "flix.h"
 #include "vector.h"
 #include "util.h"
 

flix/lpf.h

@@ -5,8 +5,6 @@
 
 #pragma once
 
-#include <Arduino.h>
-
 template <typename T> // Using template to make the filter usable for scalar and vector values
 class LowPassFilter {
 public:
@@ -16,10 +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);
 	}
 
@@ -28,9 +22,6 @@ public:
 	}
 
 	void reset() {
-		init = false;
+		output = T(); // set to zero
 	}
-
-private:
-	bool init = false;
 };

flix/mavlink.ino

@@ -3,22 +3,18 @@
 
 // MAVLink communication
 
-#include <Arduino.h>
 #include <MAVLink.h>
-#include "config.h"
 #include "util.h"
 
-extern const int RAW, ACRO, STAB, AUTO;
 extern float controlTime;
 extern float voltage;
-extern uint16_t channels[16];
 
 int mavlinkSysId = 1;
 Rate telemetryFast(10);
 Rate telemetrySlow(2);
 
 bool mavlinkConnected = false;
-static String mavlinkPrintBuffer;
+String mavlinkPrintBuffer;
 
 void processMavlink() {
 	sendMavlink();
@@ -50,7 +46,7 @@ void sendMavlink() {
 		float remaining = constrain(mapf(voltage, 3.4, 4.2, 0, 1), 0, 1);
 		mavlink_msg_battery_status_pack(mavlinkSysId, MAV_COMP_ID_AUTOPILOT1, &msg, 0, MAV_BATTERY_FUNCTION_ALL,
 			MAV_BATTERY_TYPE_LIPO, INT16_MAX, voltages, -1, -1, -1, remaining * 100, 0, MAV_BATTERY_CHARGE_STATE_OK, voltagesExt, 0, 0);
-		if (valid(voltage)) sendMessage(&msg);
+		sendMessage(&msg);
 	}
 
 	if (telemetryFast && mavlinkConnected) {
@@ -215,7 +211,6 @@ void handleMavlink(const void *_msg) {
 		armed = motors[0] > 0 || motors[1] > 0 || motors[2] > 0 || motors[3] > 0;
 	}
 
-	/* TODO:
 	if (msg.msgid == MAVLINK_MSG_ID_LOG_REQUEST_DATA) {
 		mavlink_log_request_data_t m;
 		mavlink_msg_log_request_data_decode(&msg, &m);
@@ -229,7 +224,6 @@ void handleMavlink(const void *_msg) {
 			sendMessage(&msg);
 		}
 	}
-	*/
 
 	// Handle commands
 	if (msg.msgid == MAVLINK_MSG_ID_COMMAND_LONG) {

flix/motors.ino

@@ -3,9 +3,6 @@
 
 // PWM control for motors
 
-#include <Arduino.h>
-#include "config.h"
-#include "flix.h"
 #include "util.h"
 
 float motors[4]; // normalized motor thrusts in range [0..1]
@@ -17,7 +14,10 @@ int pwmStop = 0;
 int pwmMin = 0;
 int pwmMax = -1; // -1 means duty cycle mode
 
-extern 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");
@@ -54,7 +54,7 @@ bool motorsActive() {
 
 void testMotor(int n) {
 	print("Testing motor %d\n", n);
-	motors[n] = 0.2;
+	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);

flix/parameters.ino

@@ -4,32 +4,17 @@
 // Parameters storage in flash memory
 
 #include <Preferences.h>
-#include "flix.h"
-#include "pid.h"
-#include "lpf.h"
 #include "util.h"
 
-extern float channelZero[16], channelMax[16];
+extern int channelZero[16];
-extern float rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
+extern int channelMax[16];
-extern float tiltMax;
+extern int rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
-extern int flightModes[3];
+extern int rcRxPin;
-extern PID rollPID, pitchPID, yawPID;
+extern int wifiMode, udpLocalPort, udpRemotePort;
-extern PID rollRatePID, pitchRatePID, yawRatePID;
-extern Vector maxRate;
-extern Vector imuRotation;
-extern Vector accBias, accScale;
-extern float accWeight, levelWeight;
-extern LowPassFilter<Vector> gyroBiasFilter, ratesFilter, voltageFilter;
-extern int rcRxPin, voltagePin;
-extern int motorPins[4];
-extern int pwmFrequency, pwmResolution, pwmStop, pwmMin, pwmMax;
-extern int wifiMode, wifiLongRange, udpLocalPort, udpRemotePort, espnowChannel;
-extern int mavlinkSysId;
-extern Rate telemetrySlow, telemetryFast;
 extern float rcLossTimeout, descendTime;
 extern int voltagePin;
 extern float voltageScale;
-extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
+extern LowPassFilter<float> voltageFilter;
 
 Preferences storage;
 
@@ -45,7 +30,7 @@ struct Parameter {
 	void setValue(const float value) { if (integer) *i = value; else *f = value; };
 };
 
-static Parameter parameters[] = {
+Parameter parameters[] = {
 	// control
 	{"CTL_R_RATE_P", &rollRatePID.p},
 	{"CTL_R_RATE_I", &rollRatePID.i},
@@ -101,7 +86,7 @@ static 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]},
@@ -125,17 +110,14 @@ static Parameter parameters[] = {
 	{"RC_MODE", &modeChannel},
 	// wifi
 	{"WIFI_MODE", &wifiMode},
-	{"WIFI_PORT_LOC", &udpLocalPort},
+	{"WIFI_LOC_PORT", &udpLocalPort},
-	{"WIFI_PORT_REM", &udpRemotePort},
+	{"WIFI_REM_PORT", &udpRemotePort},
-	{"WIFI_LONG_RANGE", &wifiLongRange},
-	// espnow
-	{"ESPNOW_CHANNEL", &espnowChannel},
 	// mavlink
 	{"MAV_SYS_ID", &mavlinkSysId},
 	{"MAV_RATE_SLOW", &telemetrySlow.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

flix/pid.h

@@ -5,8 +5,6 @@
 
 #pragma once
 
-#include "Arduino.h"
-#include "flix.h"
 #include "lpf.h"
 
 class PID {

flix/power.ino

@@ -8,14 +8,14 @@
 #include "lpf.h"
 #include "util.h"
 
-float voltage = NAN;
+float voltage;
 LowPassFilter<float> voltageFilter(0.2);
 int voltagePin = -1;
 float voltageScale = 2;
 
 void setupPower() {
-	REG_CLR_BIT(RTC_CNTL_BROWN_OUT_REG, RTC_CNTL_BROWN_OUT_ENA); // disable reset on low voltage
+	// Disable reset on low voltage
-	if (digitalPinToAnalogChannel(voltagePin) == -1) voltagePin = -1; // test ADC pin
+	REG_CLR_BIT(RTC_CNTL_BROWN_OUT_REG, RTC_CNTL_BROWN_OUT_ENA);
 }
 
 void readVoltage() {

flix/quaternion.h

@@ -5,7 +5,6 @@
 
 #pragma once
 
-#include <Arduino.h>
 #include "vector.h"
 
 class Quaternion : public Printable {

flix/rc.ino

@@ -6,7 +6,7 @@
 #include <SBUS.h>
 #include "util.h"
 
-static SBUS rc(Serial1);
+SBUS rc(Serial2);
 int rcRxPin = -1; // -1 means disabled
 
 uint16_t channels[16]; // raw rc channels
@@ -55,18 +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 zero[16];
-	uint16_t center[16]; // for center positions
+	uint16_t center[16];
-	uint16_t _[16]; // for unused data
+	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(NULL, zero, 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, center, "3/8 Move sticks [3 sec]\n...     ...\n.o.     .o.\n...     ...\n");
-	calibrateRCChannel(NULL, _, center, "4/8 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, _, "5/8 Move sticks [3 sec]\n...     ...\n..o     .o.\n...     ...\n");
+	calibrateRCChannel(&yawChannel, center, max, "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(&pitchChannel, zero, max, "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(&rollChannel, zero, max, "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(&modeChannel, zero, max, "8/8 Put mode switch to max [3 sec]\n");
 	printRCCalibration();
 }
 

flix/safety.ino

@@ -3,12 +3,8 @@
 
 // Fail-safe functions
 
-#include "config.h"
-#include "flix.h"
-#include "util.h"
-
 extern float controlTime;
-extern const int AUTO, STAB;
+extern float controlRoll, controlPitch, controlThrottle, controlYaw;
 
 float rcLossTimeout = 1;
 float descendTime = 10;

flix/time.ino

@@ -3,9 +3,6 @@
 
 // Time related functions
 
-#include "Arduino.h"
-#include "flix.h"
-
 float t = NAN; // current time, s
 float dt; // time delta with the previous step, s
 float loopRate; // Hz

flix/util.h

@@ -6,25 +6,24 @@
 #pragma once
 
 #include <math.h>
-#include <ESP32_NOW_Serial.h>
-#include "flix.h"
 
 const float ONE_G = 9.80665;
+extern float t;
 
-inline float mapf(float x, float in_min, float in_max, float out_min, float out_max) {
+float mapf(float x, float in_min, float in_max, float out_min, float out_max) {
 	return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
 }
 
-inline bool invalid(float x) {
+bool invalid(float x) {
 	return !isfinite(x);
 }
 
-inline bool valid(float x) {
+bool valid(float x) {
 	return isfinite(x);
 }
 
 // Wrap angle to [-PI, PI)
-inline float wrapAngle(float angle) {
+float wrapAngle(float angle) {
 	angle = fmodf(angle, 2 * PI);
 	if (angle > PI) {
 		angle -= 2 * PI;
@@ -35,28 +34,15 @@ inline float wrapAngle(float angle) {
 }
 
 // Trim and split string by spaces
-inline void splitString(String& str, String& token0, String& token1, String& token2) {
+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 = "";
 }
 
-// Simplified ESP-NOW Serial without tx buffering and resends
-class ESPNOWSerial : public ESP_NOW_Serial_Class {
-public:
-	using ESP_NOW_Serial_Class::ESP_NOW_Serial_Class;
-	void onSent(bool success) override {} // disable resends
-	size_t write(const uint8_t *data, size_t len) override {
-		return ESP_NOW_Peer::send(data, len); // pure send without buffering
-	}
-};
-
 // Rate limiter
 class Rate {
 public:

flix/vector.h

@@ -5,8 +5,6 @@
 
 #pragma once
 
-#include <Arduino.h>
-
 class Vector : public Printable {
 public:
 	float x, y, z;
@@ -138,5 +136,5 @@ public:
 	}
 };
 
-inline Vector operator * (const float a, const Vector& b) { return b * a; }
+Vector operator * (const float a, const Vector& b) { return b * a; }
-inline Vector operator + (const float a, const Vector& b) { return b + a; }
+Vector operator + (const float a, const Vector& b) { return b + a; }

flix/wifi.cpp

@@ -1,132 +0,0 @@
-// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
-// Repository: https://github.com/okalachev/flix
-
-// Wi-Fi and ESP-NOW communication
-
-#include <WiFi.h>
-#include <WiFiAP.h>
-#include <WiFiUdp.h>
-#include <MacAddress.h>
-#include <ESP32_NOW_Serial.h>
-#include <Preferences.h>
-#include "config.h"
-#include "flix.h"
-#include "util.h"
-
-extern Preferences storage; // use the main preferences storage
-extern bool mavlinkConnected;
-
-extern const int W_DISABLED = 0, W_AP = 1, W_STA = 2, W_ESPNOW = 3;
-int wifiMode = W_AP;
-
-int wifiLongRange = 0;
-int udpLocalPort = 14550;
-int udpRemotePort = 14550;
-static IPAddress udpRemoteIP = "255.255.255.255";
-static WiFiUDP udp;
-
-static ESPNOWSerial espnow(NULL, 0, WIFI_IF_AP);
-static ESPNOWSerial espnowBroadcast(ESP_NOW.BROADCAST_ADDR, 0, WIFI_IF_AP);
-int espnowChannel = 6;
-
-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);
-	} else if (wifiMode == W_STA) {
-		WiFi.begin(storage.getString("WIFI_STA_SSID", "").c_str(), storage.getString("WIFI_STA_PASS", "").c_str());
-		udp.begin(udpLocalPort);
-	} else if (wifiMode == W_ESPNOW) {
-		WiFi.mode(WIFI_AP);
-		WiFi.setChannel(espnowChannel);
-		espnow.addr(MacAddress(storage.getString("ESPNOW_PEER_MAC", "FF:FF:FF:FF:FF:FF").c_str()));
-		String key = storage.getString("ESPNOW_PEER_KEY", "");
-		espnow.setKey(key.isEmpty() ? nullptr : (const uint8_t *)key.c_str());
-		espnow.begin();
-		espnowBroadcast.begin();
-	}
-
-	WiFi.setSleep(false); // disable power save
-}
-
-void sendWiFi(const uint8_t *buf, int len) {
-	if (espnow) {
-		espnow.write(buf, len);
-		static Rate discovery(2);
-		if (discovery) espnowBroadcast.write((const uint8_t *)"flix", 4); // broadcast message to help finding this device
-		return;
-	}
-
-	if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return;
-
-	udp.beginPacket(udpRemoteIP, udpRemotePort);
-	udp.write(buf, len);
-	udp.endPacket();
-}
-
-int receiveWiFi(uint8_t *buf, int len) {
-	if (espnow) {
-		return espnow.read(buf, len);
-	}
-
-	if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return 0;
-
-	udp.parsePacket();
-	if (udp.remoteIP()) udpRemoteIP = udp.remoteIP();
-	return udp.read(buf, len);
-}
-
-void printWiFiInfo() {
-	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());
-	} else if (WiFi.getMode() == WIFI_MODE_AP) {
-		print("Mode: Access Point (AP)\n");
-		print("MAC: %s\n", WiFi.softAPmacAddress().c_str());
-		print("SSID: %s\n", WiFi.softAPSSID().c_str());
-		print("Password: ***\n");
-		print("Channel: %d\n", WiFi.channel());
-		print("Clients: %d\n", WiFi.softAPgetStationNum());
-		print("IP: %s\n", WiFi.softAPIP().toString().c_str());
-		print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
-	} else if (WiFi.getMode() == WIFI_MODE_STA) {
-		print("Mode: Client (STA)\n");
-		print("Connected: %d\n", WiFi.isConnected());
-		print("MAC: %s\n", WiFi.macAddress().c_str());
-		print("SSID: %s\n", WiFi.SSID().c_str());
-		print("Password: ***\n");
-		print("Channel: %d\n", WiFi.channel());
-		print("RSSI: %d dBm\n", WiFi.RSSI());
-		print("IP: %s\n", WiFi.localIP().toString().c_str());
-		print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
-	} else {
-		print("Mode: Disabled\n");
-	}
-	print("MAVLink connected: %d\n", mavlinkConnected);
-}
-
-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");
-}

flix/wifi.ino

@@ -0,0 +1,77 @@
+// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// Wi-Fi communication
+
+#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;
+int wifiMode = W_AP;
+int udpLocalPort = 14550;
+int udpRemotePort = 14550;
+IPAddress udpRemoteIP = "255.255.255.255";
+
+WiFiUDP udp;
+
+void setupWiFi() {
+	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 (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return;
+	udp.beginPacket(udpRemoteIP, udpRemotePort);
+	udp.write(buf, len);
+	udp.endPacket();
+}
+
+int receiveWiFi(uint8_t *buf, int len) {
+	udp.parsePacket();
+	if (udp.remoteIP()) udpRemoteIP = udp.remoteIP();
+	return udp.read(buf, len);
+}
+
+void printWiFiInfo() {
+	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("Mode: Disabled\n");
+		return;
+	}
+	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");
+}

gazebo/Arduino.h

@@ -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;

gazebo/CMakeLists.txt

@@ -10,23 +10,9 @@ list(APPEND CMAKE_CXX_FLAGS "${GAZEBO_CXX_FLAGS}")
 
 set(FLIX_SOURCE_DIR ../flix)
 include_directories(${FLIX_SOURCE_DIR})
-set(FLIX_SOURCE_DIR ../flix)
-include_directories(${FLIX_SOURCE_DIR})
-set(FLIX_SOURCES
-  ${FLIX_SOURCE_DIR}/cli.cpp
-  ${FLIX_SOURCE_DIR}/control.cpp
-  ${FLIX_SOURCE_DIR}/estimate.cpp
-  ${FLIX_SOURCE_DIR}/safety.cpp
-  ${FLIX_SOURCE_DIR}/log.cpp
-  ${FLIX_SOURCE_DIR}/mavlink.cpp
-  ${FLIX_SOURCE_DIR}/motors.cpp
-  ${FLIX_SOURCE_DIR}/parameters.cpp
-  ${FLIX_SOURCE_DIR}/rc.cpp
-  ${FLIX_SOURCE_DIR}/time.cpp
-)
 
 set(CMAKE_BUILD_TYPE RelWithDebInfo)
-add_library(flix SHARED simulator.cpp ${FLIX_SOURCES})
+add_library(flix SHARED simulator.cpp)
 target_link_libraries(flix ${GAZEBO_LIBRARIES} ${SDL2_LIBRARIES})
 target_include_directories(flix PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_compile_options(flix PRIVATE -Wno-address-of-packed-member) # disable unneeded mavlink warnings

gazebo/ESP32_NOW_Serial.h

@@ -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; };
-};

gazebo/flix.h

@@ -43,10 +43,9 @@ 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();
@@ -58,7 +57,6 @@ 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();

gazebo/simulator.cpp

@@ -18,6 +18,19 @@
 #include "Arduino.h"
 #include "flix.h"
 
+#include "cli.ino"
+#include "control.ino"
+#include "estimate.ino"
+#include "safety.ino"
+#include "log.ino"
+#include "lpf.h"
+#include "mavlink.ino"
+#include "motors.ino"
+#include "parameters.ino"
+#include "power.ino"
+#include "rc.ino"
+#include "time.ino"
+
 using ignition::math::Vector3d;
 using namespace gazebo;
 using namespace std;
@@ -60,8 +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();
 

tools/espnow-proxy/README.md

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

tools/espnow-proxy/espnow-proxy.ino

@@ -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);
-		}
-	}
-}

tools/pyflix/README.md

@@ -37,7 +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]

tools/pyflix/flix.py

@@ -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]

tools/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "pyflix"
-version = "0.15"
+version = "0.14"
 description = "Python API for Flix drone"
 authors = [{ name="Oleg Kalachev", email="okalachev@gmail.com" }]
 license = "MIT"