Merge branch 'master' into run-sim

The Arduino docs probably has mistake offering non-existent ~/local/bin path instead of ~/.local/bin.
Some systems lack ~/.local/bin as well, so simply use /usr/local/bin.
Also install arduino-cli in CI the same way as in the docs to check them.

.editorconfig

@@ -9,3 +9,7 @@ charset = utf-8
 indent_style = tab
 tab_width = 4
 trim_trailing_whitespace = true
+
+[{*.yml,*.yaml,CMakeLists.txt}]
+indent_style = space
+indent_size = 2

.gitattributes

@@ -0,0 +1,2 @@
+# https://github.com/github-linguist/linguist/blob/master/docs/overrides.md
+*.h linguist-language=C++

.github/workflows/build.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - name: Install Arduino CLI
-      uses: arduino/setup-arduino-cli@v1.1.1
+      run: curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=/usr/local/bin sh
     - name: Build firmware
       run: make
 
@@ -39,6 +39,8 @@ jobs:
   build_simulator:
     runs-on: ubuntu-latest
     steps:
+    - name: Install Arduino CLI
+      uses: arduino/setup-arduino-cli@v1.1.1
     - uses: actions/checkout@v3
     - name: Install Gazebo
       run: curl -sSL http://get.gazebosim.org | sh
@@ -46,19 +48,34 @@ jobs:
       run: sudo apt-get install libsdl2-dev
     - name: Build simulator
       run: make build_simulator
+    - name: Run simulator
+      run: timeout --preserve-status 30 make simulator GAZEBO=gzserver || [ $? -eq 143 ]
     - uses: actions/upload-artifact@v3
       with:
         name: gazebo-plugin-binary
         path: gazebo/build/*.so
         retention-days: 1
 
-  # build_simulator_macos:
-  #   runs-on: macos-latest
-  #   steps:
-  #   - uses: actions/checkout@v3
-  #   - name: Install Gazebo
-  #     run: brew tap osrf/simulation && brew install gazebo11
-  #   - name: Install SDL2
-  #     run: brew install sdl2
-  #   - name: Build simulator
-  #     run: make build_simulator
+  build_simulator_macos:
+    runs-on: macos-latest
+    steps:
+    - name: Install Arduino CLI
+      run: brew install arduino-cli
+    - uses: actions/checkout@v3
+    - name: Clean up python binaries # Workaround for https://github.com/actions/setup-python/issues/577
+      run: |
+        rm -f /usr/local/bin/2to3*
+        rm -f /usr/local/bin/idle3*
+        rm -f /usr/local/bin/pydoc3*
+        rm -f /usr/local/bin/python3*
+        rm -f /usr/local/bin/python3*-config
+    - name: Install Gazebo
+      run: brew update && brew tap osrf/simulation && brew install gazebo11
+    - name: Install SDL2
+      run: brew install sdl2
+    - name: Build simulator
+      run: make build_simulator
+    - name: Run simulator
+      run: |
+        brew install coreutils
+        timeout --preserve-status 30 make simulator GAZEBO=gzserver || [ $? -eq 143 ]

.gitignore

@@ -1,5 +1,5 @@
 *.hex
 *.elf
-gazebo/build/
+build/
 tools/log/
 .dependencies

Makefile

@@ -1,5 +1,5 @@
 BOARD = esp32:esp32:d1_mini32
-PORT := $(wildcard /dev/serial/by-id/usb-Silicon_Labs_CP2104_USB_to_UART_Bridge_Controller_* /dev/serial/by-id/usb-1a86_USB_Single_Serial_* /dev/cu.usbserial-*)
+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
@@ -14,21 +14,23 @@ monitor:
 dependencies .dependencies:
 	arduino-cli core update-index --config-file arduino-cli.yaml
 	arduino-cli core install esp32:esp32@2.0.11 --config-file arduino-cli.yaml
-	arduino-cli lib install "Bolder Flight Systems SBUS"@1.0.1
-	arduino-cli lib install --git-url https://github.com/okalachev/MPU9250.git --config-file arduino-cli.yaml
+	arduino-cli lib update-index
+	arduino-cli lib install "FlixPeriph"
+	arduino-cli lib install "MAVLink"@2.0.1
 	touch .dependencies
 
 gazebo/build cmake: gazebo/CMakeLists.txt
 	mkdir -p gazebo/build
 	cd gazebo/build && cmake ..
 
-build_simulator: gazebo/build
+build_simulator: .dependencies gazebo/build
 	make -C gazebo/build
 
+GAZEBO ?= gazebo
 simulator: build_simulator
 	GAZEBO_MODEL_PATH=$$GAZEBO_MODEL_PATH:${CURDIR}/gazebo/models \
 	GAZEBO_PLUGIN_PATH=$$GAZEBO_PLUGIN_PATH:${CURDIR}/gazebo/build \
-	gazebo --verbose ${CURDIR}/gazebo/flix.world
+	$(GAZEBO) --verbose ${CURDIR}/gazebo/flix.world
 
 log:
 	PORT=$(PORT) tools/grab_log.py
@@ -36,9 +38,6 @@ log:
 plot:
 	plotjuggler -d $(shell ls -t tools/log/*.csv | head -n1)
 
-docs:
-	for FILE in docs/*.d2; do d2 $$FILE; done
-
 clean:
 	rm -rf gazebo/build flix/build flix/cache .dependencies
 

README.md

@@ -2,19 +2,20 @@
 
 **flix** (*flight + X*) — making an open source ESP32-based quadcopter from scratch.
 
-<img src="docs/img/flix.jpg" width=500>
+<img src="docs/img/flix.jpg" width=500 alt="Flix quadcopter">
 
 ## Features
 
-* Simple and clear Arduino based source code.
+* Simple and clean Arduino based source code.
 * Acro and Stabilized flight using remote control.
 * Precise simulation using Gazebo.
 * In-RAM logging.
 * Command line interface through USB port.
 * Wi-Fi support.
+* MAVLink support.
+* Control using mobile phone (with QGroundControl app).
 * ESCs with reverse mode support.
 * *Textbook and videos for students on writing a flight controller\*.*
-* *MAVLink support\*.*
 * *Completely 3D-printed frame*.*
 * *Position control and autonomous flights using external camera\**.
 * [Building and running instructions](docs/build.md).
@@ -31,28 +32,38 @@ See YouTube demo video: https://youtu.be/8GzzIQ3C6DQ.
 
 Simulation in Gazebo using a plugin that runs original Arduino code is implemented:
 
-<img src="docs/img/simulator.png" width=500>
+<img src="docs/img/simulator.png" width=500 alt="Flix simulator">
 
 ## Schematics
 
-<img src="docs/img/schematics.svg" width=800>
+<img src="docs/img/schematics.svg" width=800 alt="Flix schematics">
 
-## Version 0
+You can also check a user contributed [variant of complete circuit diagram](https://miro.com/app/board/uXjVN-dTjoo=/) of the drone.
 
-### Components
+*\* — SBUS inverter is not needed as ESP32 supports [software pin inversion](https://github.com/bolderflight/sbus#inverted-serial).*
+
+## Components (version 0)
 
 |Component|Type|Image|Quantity|
 |-|-|-|-|
 |ESP32 Mini|Microcontroller board|<img src="docs/img/esp32.jpg" width=100>|1|
 |GY-91|IMU+LDO+barometer board|<img src="docs/img/gy-91.jpg" width=100>|1|
 |K100|Quadcopter frame|<img src="docs/img/frame.jpg" width=100>|1|
-|8520 3.7V brushed motor|Motor|<img src="docs/img/motor.jpeg" width=100>|4|
+|8520 3.7V brushed motor (**shaft 0.8mm!**)|Motor|<img src="docs/img/motor.jpeg" width=100>|4|
 |Hubsan 55 mm| Propeller|<img src="docs/img/prop.jpg" width=100>|4|
 |2.7A 1S Dual Way Micro Brush ESC|Motor ESC|<img src="docs/img/esc.jpg" width=100>|4|
 |KINGKONG TINY X8|RC transmitter|<img src="docs/img/tx.jpg" width=100>|1|
 |DF500 (SBUS)|RC receiver|<img src="docs/img/rx.jpg" width=100>|1|
-||SBUS inverter|<img src="docs/img/inv.jpg" width=100>|1|
+||~~SBUS inverter~~*|<img src="docs/img/inv.jpg" width=100>|~~1~~|
 |3.7 Li-Po 850 MaH 60C|Battery|||
 ||Battery charger|<img src="docs/img/charger.jpg" width=100>|1|
-||Wires, connectors, tape, ...||
-||3D-printed frame parts||
+||Wires, connectors, tape, ...|||
+||3D-printed frame parts|||
+
+*\* — not needed as ESP32 supports [software pin inversion](https://github.com/bolderflight/sbus#inverted-serial).*
+
+## Materials
+
+Subscribe to Telegram-channel on developing the drone and the flight controller (in Russian): https://t.me/opensourcequadcopter.
+
+Detailed article on Habr.com about the development of the drone (in Russian): https://habr.com/ru/articles/814127/.

arduino-cli.yaml

@@ -1,5 +1,3 @@
 board_manager:
   additional_urls:
     - https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
-library:
-  enable_unsafe_install: true

docs/build.md

@@ -1,12 +1,23 @@
 # Building and running
 
+To build the firmware or the simulator, you need to clone the repository using git:
+
+```bash
+git clone https://github.com/okalachev/flix.git
+cd flix
+```
+
 ## Simulation
 
-Dependencies are [Gazebo Classic simulator](https://classic.gazebosim.org) and [SDL2](https://www.libsdl.org) library.
-
 ### Ubuntu
 
-1. Install Gazebo 11:
+1. Install Arduino CLI:
+
+   ```bash
+   curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=/usr/local/bin sh
+   ```
+
+2. Install Gazebo 11:
 
    ```bash
    curl -sSL http://get.gazebosim.org | sh
@@ -19,13 +30,19 @@ Dependencies are [Gazebo Classic simulator](https://classic.gazebosim.org) and [
    source ~/.bashrc
    ```
 
-2. Install SDL2:
+3. Install SDL2 and other dependencies:
 
    ```bash
-   sudo apt-get install libsdl2-dev
+   sudo apt-get update && sudo apt-get install build-essential libsdl2-dev
    ```
 
-3. Run the simulation:
+4. Add your user to the `input` group to enable joystick support (you need to re-login after this command):
+
+   ```bash
+   sudo usermod -a -G input $USER
+   ```
+
+5. Run the simulation:
 
    ```bash
    make simulator
@@ -39,27 +56,44 @@ Dependencies are [Gazebo Classic simulator](https://classic.gazebosim.org) and [
    /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
    ```
 
-2. Install Gazebo 11 and SDL2:
+2. Install Arduino CLI, Gazebo 11 and SDL2:
 
    ```bash
    brew tap osrf/simulation
+   brew install arduino-cli
    brew install gazebo11
    brew install sdl2
    ```
 
+   Set up your Gazebo environment variables:
+
+   ```bash
+   echo "source /opt/homebrew/share/gazebo/setup.sh" >> ~/.zshrc
+   source ~/.zshrc
+   ```
+
 3. Run the simulation:
 
    ```bash
    make simulator
    ```
 
+### Flight
+
+Use USB remote control or QGroundControl mobile app (with *Virtual Joystick* setting enabled) to control the drone. *Auto-Center Throttle* setting **should be disabled**.
+
 ## Firmware
 
 ### Arduino IDE (Windows, Linux, macOS)
 
-1. Install [Arduino IDE](https://www.arduino.cc/en/software).
+1. Install [Arduino IDE](https://www.arduino.cc/en/software) (version 2 is recommended).
 2. Install ESP32 core using [Boards Manager](https://docs.arduino.cc/learn/starting-guide/cores).
-3. Build and upload the firmware using Arduino IDE.
+3. Install the following libraries using [Library Manager](https://docs.arduino.cc/software/ide-v2/tutorials/ide-v2-installing-a-library):
+   * `FlixPeriph`.
+   * `MAVLink`, version 2.0.1.
+4. Clone the project using git or [download the source code as a ZIP archive](https://codeload.github.com/okalachev/flix/zip/refs/heads/master).
+5. Open the downloaded Arduino sketch `flix/flix.ino` in Arduino IDE.
+6. [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)
 
@@ -84,3 +118,13 @@ Dependencies are [Gazebo Classic simulator](https://classic.gazebosim.org) and [
    ```
 
 See other available Make commands in the [Makefile](../Makefile).
+
+### Firmware code structure
+
+See [firmware overview](firmware.md) for more details.
+
+## Setup
+
+Before flight in simulation and on the real drone, you need to calibrate your remote control. Use drone's command line interface (`make monitor` on the real drone) and type `cr` command. Copy calibration results to the source code (`flix/rc.ino` and/or `gazebo/joystick.h`).
+
+On the real drone, you also need to calibrate the accelerometer and the gyroscope. Use `ca` and `cg` commands for that. Copy calibration results to the source code (`flix/imu.ino`).

docs/firmware.md

@@ -0,0 +1,37 @@
+# Firmware overview
+
+## Dataflow
+
+<img src="img/dataflow.svg" width=800 alt="Firmware dataflow diagram">
+
+The main loop is running at 1000 Hz. All the dataflow is happening through global variables (for simplicity):
+
+* `t` *(float)* — current step time, *s*.
+* `dt` *(float)* — time delta between the current and previous steps, *s*.
+* `gyro` *(Vector)* — data from the gyroscope, *rad/s*.
+* `acc` *(Vector)* — acceleration data from the accelerometer, *m/s<sup>2</sup>*.
+* `rates` *(Vector)* — filtered angular rates, *rad/s*.
+* `attitude` *(Quaternion)* — estimated attitude (orientation) of drone.
+* `controls` *(float[])* — user control inputs from the RC, normalized to [-1, 1] range.
+* `motors` *(float[])* — motor outputs, normalized to [-1, 1] range; reverse rotation is possible.
+
+## Source files
+
+Firmware source files are located in `flix` directory. The key files are:
+
+* [`flix.ino`](../flix/flix.ino) — main entry point, Arduino sketch. Includes global variables definition and the main loop.
+* [`imu.ino`](../flix/imu.ino) — reading data from the IMU sensor (gyroscope and accelerometer), IMU calibration.
+* [`rc.ino`](../flix/rc.ino) — reading data from the RC receiver, RC calibration.
+* [`estimate.ino`](../flix/estimate.ino) — drone's attitude estimation, complementary filter.
+* [`control.ino`](../flix/control.ino) — drone's attitude and rates control, three-dimensional two-level cascade PID controller.
+* [`motors.ino`](../flix/motors.ino) — PWM motor outputs control.
+
+Utility files include:
+
+* [`vector.h`](../flix/vector.h), [`quaternion.h`](../flix/quaternion.h) — project's vector and quaternion libraries implementation.
+* [`pid.h`](../flix/pid.h) — generic PID controller implementation.
+* [`lpf.h`](../flix/lpf.h) — generic low-pass filter implementation.
+
+## Building
+
+See build instructions in [build.md](build.md).

docs/img/dataflow.svg

@@ -0,0 +1,330 @@
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+<!-- Created with Inkscape (http://www.inkscape.org/) -->
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+           style="font-variant:normal;font-weight:normal;font-size:40px;font-family:Tahoma;writing-mode:lr-tb;fill:#000000;fill-opacity:1;fill-rule:nonzero;stroke:none"
+           x="0 22.108 42.028 56.248001 77.400002 89.508003 102.008 123.004 141.34399"
+           y="0"
+           sodipodi:role="line"
+           id="tspan21">gyro, acc</tspan></text></g><g
+       id="g22" /><g
+       id="g23"><text
+         id="text23"
+         xml:space="preserve"
+         transform="matrix(1.1983404,-0.58460093,0.58460093,1.1983404,1777.5907,805.62947)"
+         clip-path="url(#clipPath23)"><tspan
+           style="font-variant:normal;font-weight:normal;font-size:40px;font-family:Tahoma;writing-mode:lr-tb;fill:#000000;fill-opacity:1;fill-rule:nonzero;stroke:none"
+           x="0 18.455999 40.175999 62.48 75.860001 90.080002 111.8 120.94 138.79201 154.104 175.94 197.776"
+           y="0"
+           sodipodi:role="line"
+           id="tspan23">controls[16]</tspan></text></g><g
+       id="g24" /><g
+       id="g25"><text
+         id="text25"
+         xml:space="preserve"
+         transform="matrix(1.3130771,-0.23153093,0.23153093,1.3130771,1576.0787,449.35853)"
+         clip-path="url(#clipPath25)"><tspan
+           style="font-variant:normal;font-weight:normal;font-size:40px;font-family:Tahoma;writing-mode:lr-tb;fill:#000000;fill-opacity:1;fill-rule:nonzero;stroke:none"
+           x="0 13.732 34.743999 48.116001 69.167999 87.019997 99.112 111.604 132.616 145.668 159.03999 168.252 181.62399 203.916 226.008"
+           y="0"
+           sodipodi:role="line"
+           id="tspan25">rates, attitude</tspan></text></g><g
+       id="g26"><path
+         id="path26"
+         d="M 0,306.3767 C 237.7238,253.1408 395.5189,158.083 473.3852,21.20323 l 1.4097,-2.65533"
+         style="fill:none;stroke:#d5d5d5;stroke-width:6;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+         transform="matrix(1.3333333,0,0,1.3333333,1509.3427,411.03613)"
+         clip-path="url(#clipPath27)" /><path
+         id="path28"
+         d="m 1615.994,744.8981 0.656,26.8248 -21.853,-15.5703 z"
+         style="fill:#d5d5d5;fill-opacity:1;fill-rule:nonzero;stroke:none"
+         transform="matrix(1.3333333,0,0,-1.3333333,0,1440)" /></g><g
+       id="g28"><path
+         id="path29"
+         d="M 0,60.29815 C 99.1961,49.5746 200.9904,31.41576 305.383,5.821648 l 2.914,-0.728473"
+         style="fill:none;stroke:#d5d5d5;stroke-width:6;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+         transform="matrix(1.3333333,0,0,1.3333333,1523.908,396.89747)"
+         clip-path="url(#clipPath30)" /><path
+         id="path31"
+         d="m 1451.228,764.8644 20.373,17.4625 -26.194,5.821 z"
+         style="fill:#d5d5d5;fill-opacity:1;fill-rule:nonzero;stroke:none"
+         transform="matrix(1.3333333,0,0,-1.3333333,0,1440)" /></g><g
+       id="g31"><path
+         id="path32"
+         d="M 5.061111,0 C 39.5121,116.8397 39.6576,251.1261 5.497595,402.859 l -0.68786,2.9234"
+         style="fill:none;stroke:#d5d5d5;stroke-width:6;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+         transform="matrix(1.3333333,0,0,1.3333333,2208.68,411.0324)"
+         clip-path="url(#clipPath33)" /><path
+         id="path34"
+         d="m 1650.326,371.6119 6.184,-26.1104 17.178,20.6136 z"
+         style="fill:#d5d5d5;fill-opacity:1;fill-rule:nonzero;stroke:none"
+         transform="matrix(1.3333333,0,0,-1.3333333,0,1440)" /></g><g
+       id="g34" /><g
+       id="g35"><text
+         id="text35"
+         xml:space="preserve"
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+         clip-path="url(#clipPath35)"><tspan
+           style="font-variant:normal;font-weight:normal;font-size:40px;font-family:Tahoma;writing-mode:lr-tb;fill:#000000;fill-opacity:1;fill-rule:nonzero;stroke:none"
+           x="0 33.591999 55.312 68.692001 90.412003 104.828"
+           y="0"
+           sodipodi:role="line"
+           id="tspan35">motors</tspan></text></g><g
+       id="g36"><path
+         id="path36"
+         d="M 1200.4,523.3549 C 431.1994,677.8194 31.45986,511.3581 1.181784,23.97107 L 1.034053,20.97453"
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+         transform="matrix(1.3333333,0,0,1.3333333,360.54,411.088)"
+         clip-path="url(#clipPath37)" /><path
+         id="path38"
+         d="m 283.5722,748.304 -13.1672,23.38 -10.8036,-24.5618 z"
+         style="fill:#ff9300;fill-opacity:1;fill-rule:nonzero;stroke:none"
+         transform="matrix(1.3333333,0,0,-1.3333333,0,1440)" /></g></g></svg>

flix/cli.ino

@@ -27,9 +27,11 @@ const char* motd =
 "rc - show RC data\n"
 "mot - show motor data\n"
 "log - dump in-RAM log\n"
+"cr - calibrate RC\n"
 "cg - calibrate gyro\n"
 "ca - calibrate accel\n"
-"fullmot <n> - test motor on all signals\n"
+"mfr, mfl, mrr, mrl - test appropriate motor\n"
+"fullmot <n> - full motor test\n"
 "reset - reset drone's state\n";
 
 const struct Param {
@@ -57,8 +59,7 @@ const struct Param {
 	{"t", &t, nullptr},
 };
 
-void doCommand(String& command, String& value)
-{
+void doCommand(String& command, String& value) {
 	if (command == "help" || command == "motd") {
 		Serial.println(motd);
 	} else if (command == "show") {
@@ -72,19 +73,22 @@ void doCommand(String& command, String& value)
 		Serial.printf("gyro: %f %f %f\n", rates.x, rates.y, rates.z);
 		Serial.printf("acc: %f %f %f\n", acc.x, acc.y, acc.z);
 		printIMUCal();
+		Serial.printf("frequency: %f\n", loopFreq);
 	} else if (command == "rc") {
-		Serial.printf("Raw: throttle %d yaw %d pitch %d roll %d aux %d mode %d\n",
+		Serial.printf("Raw: throttle %d yaw %d pitch %d roll %d armed %d mode %d\n",
 			channels[RC_CHANNEL_THROTTLE], channels[RC_CHANNEL_YAW], channels[RC_CHANNEL_PITCH],
-			channels[RC_CHANNEL_ROLL], channels[RC_CHANNEL_AUX], channels[RC_CHANNEL_MODE]);
-		Serial.printf("Control: throttle %f yaw %f pitch %f roll %f aux %f mode %f\n",
+			channels[RC_CHANNEL_ROLL], channels[RC_CHANNEL_ARMED], channels[RC_CHANNEL_MODE]);
+		Serial.printf("Control: throttle %f yaw %f pitch %f roll %f armed %f mode %f\n",
 			controls[RC_CHANNEL_THROTTLE], controls[RC_CHANNEL_YAW], controls[RC_CHANNEL_PITCH],
-			controls[RC_CHANNEL_ROLL], controls[RC_CHANNEL_AUX], controls[RC_CHANNEL_MODE]);
+			controls[RC_CHANNEL_ROLL], controls[RC_CHANNEL_ARMED], controls[RC_CHANNEL_MODE]);
 		Serial.printf("Mode: %s\n", getModeName());
 	} else if (command == "mot") {
 		Serial.printf("MOTOR front-right %f front-left %f rear-right %f rear-left %f\n",
 			motors[MOTOR_FRONT_RIGHT], motors[MOTOR_FRONT_LEFT], motors[MOTOR_REAR_RIGHT], motors[MOTOR_REAR_LEFT]);
 	} else if (command == "log") {
 		dumpLog();
+	} else if (command == "cr") {
+		calibrateRC();
 	} else if (command == "cg") {
 		calibrateGyro();
 	} else if (command == "ca") {
@@ -119,8 +123,7 @@ void doCommand(String& command, String& value)
 	}
 }
 
-void showTable()
-{
+void showTable() {
 	for (uint8_t i = 0; i < sizeof(params) / sizeof(params[0]); i++) {
 		Serial.print(params[i].name);
 		Serial.print(" ");
@@ -128,8 +131,7 @@ void showTable()
 	}
 }
 
-void cliTestMotor(uint8_t n)
-{
+void cliTestMotor(uint8_t n) {
 	Serial.printf("Testing motor %d\n", n);
 	motors[n] = 1;
 	sendMotors();
@@ -139,8 +141,7 @@ void cliTestMotor(uint8_t n)
 	Serial.println("Done");
 }
 
-void parseInput()
-{
+void parseInput() {
 	static bool showMotd = true;
 	static String command;
 	static String value;

flix/control.ino

@@ -27,15 +27,14 @@
 #define PITCH_I ROLL_I
 #define PITCH_D ROLL_D
 #define YAW_P 3
-#define PITCHRATE_MAX 360 * DEG_TO_RAD
-#define ROLLRATE_MAX 360 * DEG_TO_RAD
-#define YAWRATE_MAX 360 * DEG_TO_RAD
-#define MAX_TILT 30 * DEG_TO_RAD
+#define PITCHRATE_MAX radians(360)
+#define ROLLRATE_MAX radians(360)
+#define YAWRATE_MAX radians(360)
+#define MAX_TILT radians(30)
 
-#define RATES_LFP_ALPHA 0.8 // cutoff frequency ~ 250 Hz
 #define RATES_D_LPF_ALPHA 0.2 // cutoff frequency ~ 40 Hz
 
-enum { MANUAL, ACRO, STAB } mode = STAB;
+enum { MANUAL, ACRO, STAB, USER } mode = STAB;
 enum { YAW, YAW_RATE } yawMode = YAW;
 bool armed = false;
 
@@ -46,15 +45,12 @@ PID rollPID(ROLL_P, ROLL_I, ROLL_D);
 PID pitchPID(PITCH_P, PITCH_I, PITCH_D);
 PID yawPID(YAW_P, 0, 0);
 
-LowPassFilter<Vector> ratesFilter(RATES_LFP_ALPHA);
-
 Quaternion attitudeTarget;
 Vector ratesTarget;
 Vector torqueTarget;
 float thrustTarget;
 
-void control()
-{
+void control() {
 	interpretRC();
 	if (mode == STAB) {
 		controlAttitude();
@@ -68,17 +64,18 @@ void control()
 	}
 }
 
-void interpretRC()
-{
+void interpretRC() {
+	armed = controls[RC_CHANNEL_THROTTLE] >= 0.05 && controls[RC_CHANNEL_ARMED] >= 0.5;
+
+	// NOTE: put ACRO or MANUAL modes there if you want to use them
 	if (controls[RC_CHANNEL_MODE] < 0.25) {
-		mode = MANUAL;
+		mode = STAB;
 	} else if (controls[RC_CHANNEL_MODE] < 0.75) {
-		mode = ACRO;
+		mode = STAB;
 	} else {
 		mode = STAB;
 	}
 
-	armed = controls[RC_CHANNEL_THROTTLE] >= 0.05 && controls[RC_CHANNEL_AUX] >= 0.5;
 	thrustTarget = controls[RC_CHANNEL_THROTTLE];
 
 	if (mode == ACRO) {
@@ -90,10 +87,10 @@ void interpretRC()
 	} else if (mode == STAB) {
 		yawMode = controls[RC_CHANNEL_YAW] == 0 ? YAW : YAW_RATE;
 
-		attitudeTarget = Quaternion::fromEulerZYX(
+		attitudeTarget = Quaternion::fromEulerZYX(Vector(
 			controls[RC_CHANNEL_ROLL] * MAX_TILT,
 			-controls[RC_CHANNEL_PITCH] * MAX_TILT,
-			attitudeTarget.getYaw());
+			attitudeTarget.getYaw()));
 		ratesTarget.z = controls[RC_CHANNEL_YAW] * YAWRATE_MAX;
 
 	} else if (mode == MANUAL) {
@@ -108,8 +105,7 @@ void interpretRC()
 	}
 }
 
-void controlAttitude()
-{
+void controlAttitude() {
 	if (!armed) {
 		rollPID.reset();
 		pitchPID.reset();
@@ -131,8 +127,7 @@ void controlAttitude()
 	}
 }
 
-void controlRate()
-{
+void controlRate() {
 	if (!armed) {
 		rollRatePID.reset();
 		pitchRatePID.reset();
@@ -140,24 +135,24 @@ void controlRate()
 		return;
 	}
 
-	Vector ratesFiltered = ratesFilter.update(rates);
+	Vector error = ratesTarget - rates;
 
-	torqueTarget.x = rollRatePID.update(ratesTarget.x - ratesFiltered.x, dt); // un-normalized "torque"
-	torqueTarget.y = pitchRatePID.update(ratesTarget.y - ratesFiltered.y, dt);
-	torqueTarget.z = yawRatePID.update(ratesTarget.z - ratesFiltered.z, dt);
+	// Calculate desired torque, where 0 - no torque, 1 - maximum possible torque
+	torqueTarget.x = rollRatePID.update(error.x, dt);
+	torqueTarget.y = pitchRatePID.update(error.y, dt);
+	torqueTarget.z = yawRatePID.update(error.z, dt);
 }
 
-void controlTorque()
-{
+void controlTorque() {
 	if (!armed) {
 		memset(motors, 0, sizeof(motors));
 		return;
 	}
 
-	motors[MOTOR_FRONT_LEFT] = thrustTarget + torqueTarget.y + torqueTarget.x - torqueTarget.z;
-	motors[MOTOR_FRONT_RIGHT] = thrustTarget + torqueTarget.y - torqueTarget.x + torqueTarget.z;
-	motors[MOTOR_REAR_LEFT] = thrustTarget - torqueTarget.y + torqueTarget.x + torqueTarget.z;
-	motors[MOTOR_REAR_RIGHT] = thrustTarget - torqueTarget.y - torqueTarget.x - torqueTarget.z;
+	motors[MOTOR_FRONT_LEFT] = thrustTarget + torqueTarget.x + torqueTarget.y - torqueTarget.z;
+	motors[MOTOR_FRONT_RIGHT] = thrustTarget - torqueTarget.x + torqueTarget.y + torqueTarget.z;
+	motors[MOTOR_REAR_LEFT] = thrustTarget + torqueTarget.x - torqueTarget.y + torqueTarget.z;
+	motors[MOTOR_REAR_RIGHT] = thrustTarget - torqueTarget.x - torqueTarget.y - torqueTarget.z;
 
 	motors[0] = constrain(motors[0], 0, 1);
 	motors[1] = constrain(motors[1], 0, 1);
@@ -165,17 +160,16 @@ void controlTorque()
 	motors[3] = constrain(motors[3], 0, 1);
 }
 
-bool motorsActive()
-{
+bool motorsActive() {
 	return motors[0] > 0 || motors[1] > 0 || motors[2] > 0 || motors[3] > 0;
 }
 
-const char* getModeName()
-{
+const char* getModeName() {
 	switch (mode) {
 		case MANUAL: return "MANUAL";
 		case ACRO: return "ACRO";
 		case STAB: return "STAB";
+		case USER: return "USER";
 		default: return "UNKNOWN";
 	}
 }

flix/estimate.ino

@@ -5,28 +5,30 @@
 
 #include "quaternion.h"
 #include "vector.h"
+#include "lpf.h"
 
 #define ONE_G 9.807f
-#define ACC_MIN 0.9f
-#define ACC_MAX 1.1f
 #define WEIGHT_ACC 0.5f
+#define RATES_LFP_ALPHA 0.2 // cutoff frequency ~ 40 Hz
 
-void estimate()
-{
+LowPassFilter<Vector> ratesFilter(RATES_LFP_ALPHA);
+
+void estimate() {
 	applyGyro();
 	applyAcc();
 	signalizeHorizontality();
 }
 
-void applyGyro()
-{
-	// applying gyro
+void applyGyro() {
+	// filter gyro to get angular rates
+	rates = ratesFilter.update(gyro);
+
+	// apply rates to attitude
 	attitude *= Quaternion::fromAngularRates(rates * dt);
 	attitude.normalize();
 }
 
-void applyAcc()
-{
+void applyAcc() {
 	// test should we apply accelerometer gravity correction
 	float accNorm = acc.norm();
 	bool landed = !motorsActive() && abs(accNorm - ONE_G) < ONE_G * 0.1f;
@@ -42,8 +44,7 @@ void applyAcc()
 	attitude.normalize();
 }
 
-void signalizeHorizontality()
-{
+void signalizeHorizontality() {
 	float angle = Vector::angleBetweenVectors(attitude.rotate(Vector(0, 0, -1)), Vector(0, 0, -1));
-	setLED(angle < 15 * DEG_TO_RAD);
+	setLED(angle < radians(15));
 }

flix/flix.ino

@@ -11,32 +11,33 @@
 #define WIFI_ENABLED 0
 
 #define RC_CHANNELS 6
+#define RC_CHANNEL_ROLL 0
+#define RC_CHANNEL_PITCH 1
 #define RC_CHANNEL_THROTTLE 2
 #define RC_CHANNEL_YAW 3
-#define RC_CHANNEL_PITCH 1
-#define RC_CHANNEL_ROLL 0
-#define RC_CHANNEL_AUX 4
+#define RC_CHANNEL_ARMED 4
 #define RC_CHANNEL_MODE 5
 
 #define MOTOR_REAR_LEFT 0
-#define MOTOR_FRONT_LEFT 3
-#define MOTOR_FRONT_RIGHT 2
 #define MOTOR_REAR_RIGHT 1
+#define MOTOR_FRONT_RIGHT 2
+#define MOTOR_FRONT_LEFT 3
 
 float t = NAN; // current step time, s
 float dt; // time delta from previous step, s
 float loopFreq; // loop frequency, Hz
-uint16_t channels[16]; // raw rc channels
+int16_t channels[16]; // raw rc channels
 float controls[RC_CHANNELS]; // normalized controls in range [-1..1] ([0..1] for throttle)
-Vector rates; // angular rates, rad/s
+Vector gyro; // gyroscope data
 Vector acc; // accelerometer data, m/s/s
+Vector rates; // filtered angular rates, rad/s
 Quaternion attitude; // estimated attitude
 float motors[4]; // normalized motors thrust in range [-1..1]
 
-void setup()
-{
+void setup() {
 	Serial.begin(SERIAL_BAUDRATE);
 	Serial.println("Initializing flix");
+	disableBrownOut();
 	setupLED();
 	setupMotors();
 	setLED(true);
@@ -50,10 +51,8 @@ void setup()
 	Serial.println("Initializing complete");
 }
 
-void loop()
-{
-	if (!readIMU()) return;
-
+void loop() {
+	readIMU();
 	step();
 	readRC();
 	estimate();
@@ -61,7 +60,7 @@ void loop()
 	sendMotors();
 	parseInput();
 #if WIFI_ENABLED == 1
-	sendMavlink();
+	processMavlink();
 #endif
 	logData();
 }

flix/imu.ino

@@ -6,100 +6,116 @@
 #include <SPI.h>
 #include <MPU9250.h>
 
-#define IMU_CS_PIN 4 // chip-select pin for IMU SPI connection
-#define CALIBRATE_GYRO_ON_START true
+#define ONE_G 9.80665
 
-MPU9250 IMU(SPI, IMU_CS_PIN);
+// NOTE: use 'ca' command to calibrate the accelerometer and put the values here
+Vector accBias(0, 0, 0);
+Vector accScale(1, 1, 1);
 
-void setupIMU()
-{
+MPU9250 IMU(SPI);
+Vector gyroBias;
+
+void setupIMU() {
 	Serial.println("Setup IMU");
-
-	auto status = IMU.begin();
-	if (status < 0) {
+	bool status = IMU.begin();
+	if (!status) {
 		while (true) {
-			Serial.printf("IMU begin error: %d\n", status);
+			Serial.println("IMU begin error");
 			delay(1000);
 		}
 	}
+	calibrateGyro();
+}
 
-	if (CALIBRATE_GYRO_ON_START) {
-		calibrateGyro();
-	} else {
-		loadGyroCal();
-	}
-
-	loadAccelCal();
-
+void configureIMU() {
+	IMU.setAccelRange(IMU.ACCEL_RANGE_4G);
+	IMU.setGyroRange(IMU.GYRO_RANGE_2000DPS);
+	IMU.setDlpfBandwidth(IMU.DLPF_BANDWIDTH_184HZ);
 	IMU.setSrd(0); // set sample rate to 1000 Hz
-	// NOTE: very important, without the above the rate would be terrible 50 Hz
 }
 
-bool readIMU()
-{
-	if (IMU.readSensor() < 0) {
-		Serial.println("IMU read error");
-		return false;
-	}
-
-	auto lastRates = rates;
-
-	rates.x = IMU.getGyroX_rads();
-	rates.y = IMU.getGyroY_rads();
-	rates.z = IMU.getGyroZ_rads();
-	acc.x = IMU.getAccelX_mss();
-	acc.y = IMU.getAccelY_mss();
-	acc.z = IMU.getAccelZ_mss();
-
-	return rates != lastRates;
+void readIMU() {
+	IMU.waitForData();
+	IMU.getGyro(gyro.x, gyro.y, gyro.z);
+	IMU.getAccel(acc.x, acc.y, acc.z);
+	// apply scale and bias
+	acc = (acc - accBias) / accScale;
+	gyro = gyro - gyroBias;
 }
 
-void calibrateGyro()
-{
+void calibrateGyro() {
+	const int samples = 1000;
 	Serial.println("Calibrating gyro, stand still");
-	delay(500);
-	int status = IMU.calibrateGyro();
-	Serial.printf("Calibration status: %d\n", status);
-	IMU.setSrd(0);
+	IMU.setGyroRange(IMU.GYRO_RANGE_250DPS); // the most sensitive mode
+
+	gyroBias = Vector(0, 0, 0);
+	for (int i = 0; i < samples; i++) {
+		IMU.waitForData();
+		IMU.getGyro(gyro.x, gyro.y, gyro.z);
+		gyroBias = gyroBias + gyro;
+	}
+	gyroBias = gyroBias / samples;
+
 	printIMUCal();
+	configureIMU();
 }
 
-void calibrateAccel()
-{
-	Serial.println("Cal accel: place level"); delay(3000);
-	IMU.calibrateAccel();
-	Serial.println("Cal accel: place nose up"); delay(3000);
-	IMU.calibrateAccel();
-	Serial.println("Cal accel: place nose down"); delay(3000);
-	IMU.calibrateAccel();
-	Serial.println("Cal accel: place on right side"); delay(3000);
-	IMU.calibrateAccel();
-	Serial.println("Cal accel: place on left side"); delay(3000);
-	IMU.calibrateAccel();
-	Serial.println("Cal accel: upside down"); delay(300);
-	IMU.calibrateAccel();
+void calibrateAccel() {
+	Serial.println("Calibrating accelerometer");
+	IMU.setAccelRange(IMU.ACCEL_RANGE_2G); // the most sensitive mode
+	IMU.setDlpfBandwidth(IMU.DLPF_BANDWIDTH_20HZ);
+	IMU.setSrd(19);
+
+	Serial.setTimeout(60000);
+	Serial.print("Place level [enter] "); Serial.readStringUntil('\n');
+	calibrateAccelOnce();
+	Serial.print("Place nose up [enter] "); Serial.readStringUntil('\n');
+	calibrateAccelOnce();
+	Serial.print("Place nose down [enter] "); Serial.readStringUntil('\n');
+	calibrateAccelOnce();
+	Serial.print("Place on right side [enter] "); Serial.readStringUntil('\n');
+	calibrateAccelOnce();
+	Serial.print("Place on left side [enter] "); Serial.readStringUntil('\n');
+	calibrateAccelOnce();
+	Serial.print("Place upside down [enter] "); Serial.readStringUntil('\n');
+	calibrateAccelOnce();
+
 	printIMUCal();
+	configureIMU();
 }
 
-void loadAccelCal()
-{
-	// NOTE: this should be changed to the actual values
-	IMU.setAccelCalX(-0.0048542023, 1.0008112192);
-	IMU.setAccelCalY(0.0521845818, 0.9985780716);
-	IMU.setAccelCalZ(0.5754694939, 1.0045746565);
+void calibrateAccelOnce() {
+	const int samples = 100;
+	static Vector accMax(-INFINITY, -INFINITY, -INFINITY);
+	static Vector accMin(INFINITY, INFINITY, INFINITY);
+
+	// Compute the average of the accelerometer readings
+	acc = Vector(0, 0, 0);
+	for (int i = 0; i < samples; i++) {
+		IMU.waitForData();
+		Vector sample;
+		IMU.getAccel(sample.x, sample.y, sample.z);
+		acc = acc + sample;
+	}
+	acc = acc / samples;
+
+	// Update the maximum and minimum values
+	if (acc.x > accMax.x) accMax.x = acc.x;
+	if (acc.y > accMax.y) accMax.y = acc.y;
+	if (acc.z > accMax.z) accMax.z = acc.z;
+	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;
+	Serial.printf("acc %f %f %f\n", acc.x, acc.y, acc.z);
+	Serial.printf("max %f %f %f\n", accMax.x, accMax.y, accMax.z);
+	Serial.printf("min %f %f %f\n", accMin.x, accMin.y, accMin.z);
+	// Compute scale and bias
+	accScale = (accMax - accMin) / 2 / ONE_G;
+	accBias = (accMax + accMin) / 2;
 }
 
-void loadGyroCal()
-{
-	// NOTE: this should be changed to the actual values
-	IMU.setGyroBiasX_rads(-0.0185128022);
-	IMU.setGyroBiasY_rads(-0.0262369743);
-	IMU.setGyroBiasZ_rads(0.0163032326);
-}
-
-void printIMUCal()
-{
-	Serial.printf("gyro bias: %f %f %f\n", IMU.getGyroBiasX_rads(), IMU.getGyroBiasY_rads(), IMU.getGyroBiasZ_rads());
-	Serial.printf("accel bias: %f %f %f\n", IMU.getAccelBiasX_mss(), IMU.getAccelBiasY_mss(), IMU.getAccelBiasZ_mss());
-	Serial.printf("accel scale: %f %f %f\n", IMU.getAccelScaleFactorX(), IMU.getAccelScaleFactorY(), IMU.getAccelScaleFactorZ());
+void printIMUCal() {
+	Serial.printf("gyro bias: %f %f %f\n", gyroBias.x, gyroBias.y, gyroBias.z);
+	Serial.printf("accel bias: %f %f %f\n", accBias.x, accBias.y, accBias.z);
+	Serial.printf("accel scale: %f %f %f\n", accScale.x, accScale.y, accScale.z);
 }

flix/led.ino

@@ -5,17 +5,18 @@
 
 #define BLINK_PERIOD 500000
 
-void setupLED()
-{
+#ifndef LED_BUILTIN
+#define LED_BUILTIN 2 // for ESP32 Dev Module
+#endif
+
+void setupLED() {
 	pinMode(LED_BUILTIN, OUTPUT);
 }
 
-void setLED(bool on)
-{
+void setLED(bool on) {
 	digitalWrite(LED_BUILTIN, on ? HIGH : LOW);
 }
 
-void blinkLED()
-{
+void blinkLED() {
 	setLED(micros() / BLINK_PERIOD % 2);
 }

flix/log.ino

@@ -12,8 +12,7 @@
 float logBuffer[LOG_SIZE][LOG_COLUMNS]; // * 4 (float)
 int logPointer = 0;
 
-void logData()
-{
+void logData() {
 	if (!armed) return;
 
 	static float logTime = 0;
@@ -41,11 +40,11 @@ void logData()
 	}
 }
 
-void dumpLog()
-{
+void dumpLog() {
 	Serial.printf("t,rates.x,rates.y,rates.z,ratesTarget.x,ratesTarget.y,ratesTarget.z,"
 		"attitude.x,attitude.y,attitude.z,attitudeTarget.x,attitudeTarget.y,attitudeTarget.z,thrustTarget\n");
 	for (int i = 0; i < LOG_SIZE; i++) {
+		if (logBuffer[i][0] == 0) continue; // skip empty records
 		for (int j = 0; j < LOG_COLUMNS - 1; j++) {
 			Serial.printf("%f,", logBuffer[i][j]);
 		}

flix/lpf.h

@@ -6,16 +6,14 @@
 #pragma once
 
 template <typename T> // Using template to make the filter usable for scalar and vector values
-class LowPassFilter
-{
+class LowPassFilter {
 public:
 	float alpha; // smoothing constant, 1 means filter disabled
 	T output;
 
 	LowPassFilter(float alpha): alpha(alpha) {};
 
-	T update(const T input)
-	{
+	T update(const T input) {
 		if (alpha == 1) { // filter disabled
 			return input;
 		}
@@ -27,13 +25,11 @@ public:
 		return output = output * (1 - alpha) + input * alpha;
 	}
 
-	void setCutOffFrequency(float cutOffFreq, float dt)
-	{
+	void setCutOffFrequency(float cutOffFreq, float dt) {
 		alpha = 1 - exp(-2 * PI * cutOffFreq * dt);
 	}
 
-	void reset()
-	{
+	void reset() {
 		initialized = false;
 	}
 

flix/mavlink.ino

@@ -5,14 +5,20 @@
 
 #if WIFI_ENABLED == 1
 
-#include "mavlink/common/mavlink.h"
+#include <MAVLink.h>
 
 #define SYSTEM_ID 1
 #define PERIOD_SLOW 1.0
 #define PERIOD_FAST 0.1
+#define MAVLINK_CONTROL_SCALE 0.7f
+#define MAVLINK_CONTROL_YAW_DEAD_ZONE 0.1f
 
-void sendMavlink()
-{
+void processMavlink() {
+	sendMavlink();
+	receiveMavlink();
+}
+
+void sendMavlink() {
 	static float lastSlow = 0;
 	static float lastFast = 0;
 
@@ -23,7 +29,7 @@ void sendMavlink()
 		lastSlow = t;
 
 		mavlink_msg_heartbeat_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, MAV_TYPE_QUADROTOR,
-			MAV_AUTOPILOT_GENERIC, MAV_MODE_FLAG_MANUAL_INPUT_ENABLED | armed ? MAV_MODE_FLAG_SAFETY_ARMED : 0,
+			MAV_AUTOPILOT_GENERIC, MAV_MODE_FLAG_MANUAL_INPUT_ENABLED | (armed ? MAV_MODE_FLAG_SAFETY_ARMED : 0),
 			0, MAV_STATE_STANDBY);
 		sendMessage(&msg);
 	}
@@ -39,27 +45,56 @@ void sendMavlink()
 		mavlink_msg_rc_channels_scaled_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, time, 0,
 			controls[0] * 10000, controls[1] * 10000, controls[2] * 10000,
 			controls[3] * 10000, controls[4] * 10000, controls[5] * 10000,
-			UINT16_MAX, UINT16_MAX, 255);
+			INT16_MAX, INT16_MAX, UINT8_MAX);
 		sendMessage(&msg);
 
 		float actuator[32];
-		memcpy(motors, actuator, 4 * sizeof(float));
+		memcpy(actuator, motors, sizeof(motors));
 		mavlink_msg_actuator_output_status_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, time, 4, actuator);
 		sendMessage(&msg);
 
 		mavlink_msg_scaled_imu_pack(SYSTEM_ID, MAV_COMP_ID_AUTOPILOT1, &msg, time,
 			acc.x * 1000, acc.y * 1000, acc.z * 1000,
-			rates.x * 1000, rates.y * 1000, rates.z * 1000,
+			gyro.x * 1000, gyro.y * 1000, gyro.z * 1000,
 			0, 0, 0, 0);
 		sendMessage(&msg);
 	}
 }
 
-inline void sendMessage(const void *msg)
-{
+void sendMessage(const void *msg) {
 	uint8_t buf[MAVLINK_MAX_PACKET_LEN];
-	uint16_t len = mavlink_msg_to_send_buffer(buf, (mavlink_message_t *)msg);
+	int len = mavlink_msg_to_send_buffer(buf, (mavlink_message_t *)msg);
 	sendWiFi(buf, len);
 }
 
+void receiveMavlink() {
+	uint8_t buf[MAVLINK_MAX_PACKET_LEN];
+	int len = receiveWiFi(buf, MAVLINK_MAX_PACKET_LEN);
+
+	// 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)) {
+			handleMavlink(&msg);
+		}
+	}
+}
+
+void handleMavlink(const void *_msg) {
+	mavlink_message_t *msg = (mavlink_message_t *)_msg;
+	if (msg->msgid == MAVLINK_MSG_ID_MANUAL_CONTROL) {
+		mavlink_manual_control_t manualControl;
+		mavlink_msg_manual_control_decode(msg, &manualControl);
+		controls[RC_CHANNEL_THROTTLE] = manualControl.z / 1000.0f;
+		controls[RC_CHANNEL_PITCH] = manualControl.x / 1000.0f * MAVLINK_CONTROL_SCALE;
+		controls[RC_CHANNEL_ROLL] = manualControl.y / 1000.0f * MAVLINK_CONTROL_SCALE;
+		controls[RC_CHANNEL_YAW] = manualControl.r / 1000.0f * MAVLINK_CONTROL_SCALE;
+		controls[RC_CHANNEL_MODE] = 1; // STAB mode
+		controls[RC_CHANNEL_ARMED] = 1; // armed
+
+		if (abs(controls[RC_CHANNEL_YAW]) < MAVLINK_CONTROL_YAW_DEAD_ZONE) controls[RC_CHANNEL_YAW] = 0;
+	}
+}
+
 #endif

flix/motors.ino

@@ -9,16 +9,13 @@
 #define MOTOR_1_PIN 13
 #define MOTOR_2_PIN 14
 #define MOTOR_3_PIN 15
-
 #define PWM_FREQUENCY 200
 #define PWM_RESOLUTION 8
-
 #define PWM_NEUTRAL 1500
-
-const uint16_t pwmMin[] = {1600, 1600, 1600, 1600};
-const uint16_t pwmMax[] = {2300, 2300, 2300, 2300};
-const uint16_t pwmReverseMin[] = {1390, 1440, 1440, 1440};
-const uint16_t pwmReverseMax[] = {1100, 1100, 1100, 1100};
+#define PWM_MIN 1600
+#define PWM_MAX 2300
+#define PWM_REVERSE_MIN 1400
+#define PWM_REVERSE_MAX 700
 
 void setupMotors() {
 	Serial.println("Setup Motors");
@@ -39,14 +36,13 @@ void setupMotors() {
 	Serial.println("Motors initialized");
 }
 
-uint16_t getPWM(float val, int n)
-{
+uint16_t getPWM(float val, int n) {
 	if (val == 0) {
 		return PWM_NEUTRAL;
 	} else if (val > 0) {
-		return mapff(val, 0, 1, pwmMin[n], pwmMax[n]);
+		return mapff(val, 0, 1, PWM_MIN, PWM_MAX);
 	} else {
-		return mapff(val, 0, -1, pwmReverseMin[n], pwmReverseMax[n]);
+		return mapff(val, 0, -1, PWM_REVERSE_MIN, PWM_REVERSE_MAX);
 	}
 }
 
@@ -54,16 +50,14 @@ uint8_t pwmToDutyCycle(uint16_t pwm) {
 	return map(pwm, 0, 1000000 / PWM_FREQUENCY, 0, (1 << PWM_RESOLUTION) - 1);
 }
 
-void sendMotors()
-{
+void sendMotors() {
 	ledcWrite(0, pwmToDutyCycle(getPWM(motors[0], 0)));
 	ledcWrite(1, pwmToDutyCycle(getPWM(motors[1], 1)));
 	ledcWrite(2, pwmToDutyCycle(getPWM(motors[2], 2)));
 	ledcWrite(3, pwmToDutyCycle(getPWM(motors[3], 3)));
 }
 
-void fullMotorTest(int n, bool reverse)
-{
+void fullMotorTest(int n, bool reverse) {
 	printf("Full test for motor %d\n", n);
 	for (int pwm = PWM_NEUTRAL; pwm <= 2300 && pwm >= 700; pwm += reverse ? -100 : 100) {
 		printf("Motor %d: %d\n", n, pwm);

flix/pid.h

@@ -7,8 +7,7 @@
 
 #include "lpf.h"
 
-class PID
-{
+class PID {
 public:
 	float p = 0;
 	float i = 0;
@@ -22,8 +21,7 @@ public:
 
 	PID(float p, float i, float d, float windup = 0, float dAlpha = 1) : p(p), i(i), d(d), windup(windup), lpf(dAlpha) {};
 
-	float update(float error, float dt)
-	{
+	float update(float error, float dt) {
 		integral += error * dt;
 
 		if (isfinite(prevError) && dt > 0) {
@@ -39,8 +37,7 @@ public:
 		return p * error + constrain(i * integral, -windup, windup) + d * derivative; // PID
 	}
 
-	void reset()
-	{
+	void reset() {
 		prevError = NAN;
 		integral = 0;
 		derivative = 0;

flix/quaternion.h

@@ -15,8 +15,7 @@ public:
 
 	Quaternion(float w, float x, float y, float z): w(w), x(x), y(y), z(z) {};
 
-	static Quaternion fromAxisAngle(float a, float b, float c, float angle)
-	{
+	static Quaternion fromAxisAngle(float a, float b, float c, float angle) {
 		float halfAngle = angle * 0.5;
 		float sin2 = sin(halfAngle);
 		float cos2 = cos(halfAngle);
@@ -24,27 +23,20 @@ public:
 		return Quaternion(cos2, a * sinNorm, b * sinNorm, c * sinNorm);
 	}
 
-	static Quaternion fromAngularRates(float x, float y, float z)
-	{
-		return Quaternion::fromAxisAngle(x, y, z, sqrt(x * x + y * y + z * z));
-	}
-
-	static Quaternion fromAngularRates(const Vector& rates)
-	{
+	static Quaternion fromAngularRates(const Vector& rates) {
 		if (rates.zero()) {
 			return Quaternion();
 		}
 		return Quaternion::fromAxisAngle(rates.x, rates.y, rates.z, rates.norm());
 	}
 
-	static Quaternion fromEulerZYX(float x, float y, float z)
-	{
-		float cx = cos(x / 2);
-		float cy = cos(y / 2);
-		float cz = cos(z / 2);
-		float sx = sin(x / 2);
-		float sy = sin(y / 2);
-		float sz = sin(z / 2);
+	static Quaternion fromEulerZYX(const Vector& euler) {
+		float cx = cos(euler.x / 2);
+		float cy = cos(euler.y / 2);
+		float cz = cos(euler.z / 2);
+		float sx = sin(euler.x / 2);
+		float sy = sin(euler.y / 2);
+		float sz = sin(euler.z / 2);
 
 		return Quaternion(
 			cx * cy * cz + sx * sy * sz,
@@ -53,8 +45,7 @@ public:
 			cx * cy * sz - sx * sy * cz);
 	}
 
-	static Quaternion fromBetweenVectors(Vector u, Vector v)
-	{
+	static Quaternion fromBetweenVectors(Vector u, Vector v) {
 		float dot = u.x * v.x + u.y * v.y + u.z * v.z;
 		float w1 = u.y * v.z - u.z * v.y;
 		float w2 = u.z * v.x - u.x * v.z;
@@ -69,33 +60,46 @@ public:
 		return ret;
 	}
 
-	void toAxisAngle(float& a, float& b, float& c, float& angle)
-	{
+	void toAxisAngle(float& a, float& b, float& c, float& angle) {
 		angle = acos(w) * 2;
 		a = x / sin(angle / 2);
 		b = y / sin(angle / 2);
 		c = z / sin(angle / 2);
 	}
 
-	Vector toEulerZYX() const
-	{
-		return Vector(
-			atan2(2 * (w * x + y * z), 1 - 2 * (x * x + y * y)),
-			asin(2 * (w * y - z * x)),
-			atan2(2 * (w * z + x * y), 1 - 2 * (y * y + z * z)));
+	Vector toEulerZYX() const {
+		// https://github.com/ros/geometry2/blob/589caf083cae9d8fae7effdb910454b4681b9ec1/tf2/include/tf2/impl/utils.h#L87
+		Vector euler;
+		float sqx = x * x;
+		float sqy = y * y;
+		float sqz = z * z;
+		float sqw = w * w;
+		// Cases derived from https://orbitalstation.wordpress.com/tag/quaternion/
+		float sarg = -2 * (x * z - w * y) / (sqx + sqy + sqz + sqw); /* normalization added from urdfom_headers */
+		if (sarg <= -0.99999) {
+			euler.x = 0;
+			euler.y = -0.5 * PI;
+			euler.z = -2 * atan2(y, x);
+		} else if (sarg >= 0.99999) {
+			euler.x = 0;
+			euler.y = 0.5 * PI;
+			euler.z = 2 * atan2(y, x);
+		} else {
+			euler.x = atan2(2 * (y * z + w * x), sqw - sqx - sqy + sqz);
+			euler.y = asin(sarg);
+			euler.z = atan2(2 * (x * y + w * z), sqw + sqx - sqy - sqz);
+		}
+		return euler;
 	}
 
-	float getYaw() const
-	{
+	float getYaw() const {
 		// https://github.com/ros/geometry2/blob/589caf083cae9d8fae7effdb910454b4681b9ec1/tf2/include/tf2/impl/utils.h#L122
 		float yaw;
 		float sqx = x * x;
 		float sqy = y * y;
 		float sqz = z * z;
 		float sqw = w * w;
-
 		double sarg = -2 * (x * z - w * y) / (sqx + sqy + sqz + sqw);
-
 		if (sarg <= -0.99999) {
 			yaw = -2 * atan2(y, x);
 		} else if (sarg >= 0.99999) {
@@ -106,15 +110,14 @@ public:
 		return yaw;
 	}
 
-	void setYaw(float yaw)
-	{
+	void setYaw(float yaw) {
 		// TODO: optimize?
 		Vector euler = toEulerZYX();
-		(*this) = Quaternion::fromEulerZYX(euler.x, euler.y, yaw);
+		euler.z = yaw;
+		(*this) = Quaternion::fromEulerZYX(euler);
 	}
 
-	Quaternion& operator *= (const Quaternion& q)
-	{
+	Quaternion& operator *= (const Quaternion& q) {
 		Quaternion ret(
 			w * q.w - x * q.x - y * q.y - z * q.z,
 			w * q.x + x * q.w + y * q.z - z * q.y,
@@ -123,8 +126,7 @@ public:
 		return (*this = ret);
 	}
 
-	Quaternion operator * (const Quaternion& q)
-	{
+	Quaternion operator * (const Quaternion& q) {
 		return Quaternion(
 			w * q.w - x * q.x - y * q.y - z * q.z,
 			w * q.x + x * q.w + y * q.z - z * q.y,
@@ -132,8 +134,7 @@ public:
 			w * q.z + z * q.w + x * q.y - y * q.x);
 	}
 
-	Quaternion inversed() const
-	{
+	Quaternion inversed() const {
 		float normSqInv = 1 / (w * w + x * x + y * y + z * z);
 		return Quaternion(
 			w * normSqInv,
@@ -142,13 +143,11 @@ public:
 			-z * normSqInv);
 	}
 
-	float norm() const
-	{
+	float norm() const {
 		return sqrt(w * w + x * x + y * y + z * z);
 	}
 
-	void normalize()
-	{
+	void normalize() {
 		float n = norm();
 		w /= n;
 		x /= n;
@@ -156,27 +155,24 @@ public:
 		z /= n;
 	}
 
-	Vector conjugate(const Vector& v)
-	{
+	Vector conjugate(const Vector& v) {
 		Quaternion qv(0, v.x, v.y, v.z);
 		Quaternion res = (*this) * qv * inversed();
 		return Vector(res.x, res.y, res.z);
 	}
 
-	Vector conjugateInversed(const Vector& v)
-	{
+	Vector conjugateInversed(const Vector& v) {
 		Quaternion qv(0, v.x, v.y, v.z);
 		Quaternion res = inversed() * qv * (*this);
 		return Vector(res.x, res.y, res.z);
 	}
 
-	inline Vector rotate(const Vector& v)
-	{
+	// Rotate vector by quaternion
+	inline Vector rotate(const Vector& v) {
 		return conjugateInversed(v);
 	}
 
-	inline bool finite() const
-	{
+	inline bool finite() const {
 		return isfinite(w) && isfinite(x) && isfinite(y) && isfinite(z);
 	}
 

flix/rc.ino

@@ -5,29 +5,50 @@
 
 #include <SBUS.h>
 
-const uint16_t channelNeutral[] = {995, 883, 200, 972, 512, 512};
-const uint16_t channelMax[] = {1651, 1540, 1713, 1630, 1472, 1472};
+// NOTE: use 'cr' command to calibrate the RC and put the values here
+int channelNeutral[] = {995, 883, 200, 972, 512, 512};
+int channelMax[] = {1651, 1540, 1713, 1630, 1472, 1472};
 
 SBUS RC(Serial2);
 
-void setupRC()
-{
+void setupRC() {
 	Serial.println("Setup RC");
 	RC.begin();
 }
 
-void readRC()
-{
-	bool failSafe, lostFrame;
-	if (RC.read(channels, &failSafe, &lostFrame)) {
-		if (failSafe) { return; } // TODO:
-		if (lostFrame) { return; }
+void readRC() {
+	if (RC.read()) {
+		SBUSData data = RC.data();
+		memcpy(channels, data.ch, sizeof(channels)); // copy channels data
 		normalizeRC();
 	}
 }
 
-static void normalizeRC() {
+void normalizeRC() {
 	for (uint8_t i = 0; i < RC_CHANNELS; i++) {
 		controls[i] = mapf(channels[i], channelNeutral[i], channelMax[i], 0, 1);
 	}
 }
+
+void calibrateRC() {
+	Serial.println("Calibrate RC: move all sticks to maximum positions within 4 seconds");
+	Serial.println("··o     ··o\n···     ···\n···     ···");
+	delay(4000);
+	for (int i = 0; i < 30; i++) readRC(); // ensure the values are updated
+	for (int i = 0; i < RC_CHANNELS; i++) {
+		channelMax[i] = channels[i];
+	}
+	Serial.println("Calibrate RC: move all sticks to neutral positions within 4 seconds");
+	Serial.println("···     ···\n···     ·o·\n·o·     ···");
+	delay(4000);
+	for (int i = 0; i < 30; i++) readRC(); // ensure the values are updated
+	for (int i = 0; i < RC_CHANNELS; i++) {
+		channelNeutral[i] = channels[i];
+	}
+	printRCCal();
+}
+
+void printRCCal() {
+	printArray(channelNeutral, RC_CHANNELS);
+	printArray(channelMax, RC_CHANNELS);
+}

flix/time.ino

@@ -3,8 +3,7 @@
 
 // Time related functions
 
-void step()
-{
+void step() {
 	float now = micros() / 1000000.0;
 	dt = now - t;
 	t = now;
@@ -16,8 +15,7 @@ void step()
 	computeLoopFreq();
 }
 
-void computeLoopFreq()
-{
+void computeLoopFreq() {
 	static float windowStart = 0;
 	static uint32_t freq = 0;
 	freq++;

flix/util.ino

@@ -3,31 +3,28 @@
 
 // Utility functions
 
-#include "math.h"
+#include <math.h>
+#include <soc/soc.h>
+#include <soc/rtc_cntl_reg.h>
 
-float mapf(long x, long in_min, long in_max, float out_min, float out_max)
-{
+float mapf(long x, long in_min, long in_max, float out_min, float out_max) {
 	return (float)(x - in_min) * (out_max - out_min) / (float)(in_max - in_min) + out_min;
 }
 
-float mapff(float x, float in_min, float in_max, float out_min, float out_max)
-{
+float mapff(float x, float in_min, float in_max, float out_min, float out_max) {
 	return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
 }
 
-int8_t sign(float x)
-{
+int8_t sign(float x) {
 	return (x > 0) - (x < 0);
 }
 
-float randomFloat(float min, float max)
-{
+float randomFloat(float min, float max) {
 	return min + (max - min) * (float)rand() / RAND_MAX;
 }
 
-// wrap angle to [-PI, PI)
-float wrapAngle(float angle)
-{
+// Wrap angle to [-PI, PI)
+float wrapAngle(float angle) {
 	angle = fmodf(angle, 2 * PI);
 	if (angle > PI) {
 		angle -= 2 * PI;
@@ -36,3 +33,18 @@ float wrapAngle(float angle)
 	}
 	return angle;
 }
+
+template <typename T>
+void printArray(T arr[], int size) {
+	Serial.print("{");
+	for (uint8_t i = 0; i < size; i++) {
+		Serial.print(arr[i]);
+		if (i < size - 1) Serial.print(", ");
+	}
+	Serial.println("}");
+}
+
+// Disable reset on low voltage
+void disableBrownOut() {
+	WRITE_PERI_REG(RTC_CNTL_BROWN_OUT_REG, 0);
+}

flix/vector.h

@@ -5,8 +5,7 @@
 
 #pragma once
 
-class Vector : public Printable
-{
+class Vector : public Printable {
 public:
 	float x, y, z;
 
@@ -14,79 +13,79 @@ public:
 
 	Vector(float x, float y, float z): x(x), y(y), z(z) {};
 
-	float norm() const
-	{
+	float norm() const {
 		return sqrt(x * x + y * y + z * z);
 	}
 
-	bool zero() const
-	{
+	bool zero() const {
 		return x == 0 && y == 0 && z == 0;
 	}
 
-	void normalize()
-	{
+	void normalize() {
 		float n = norm();
 		x /= n;
 		y /= n;
 		z /= n;
 	}
 
-	Vector operator * (const float b) const
-	{
+	Vector operator * (const float b) const {
 		return Vector(x * b, y * b, z * b);
 	}
 
-	Vector operator / (const float b) const
-	{
+	Vector operator / (const float b) const {
 		return Vector(x / b, y / b, z / b);
 	}
 
-	Vector operator + (const Vector& b) const
-	{
+	Vector operator + (const Vector& b) const {
 		return Vector(x + b.x, y + b.y, z + b.z);
 	}
 
-	Vector operator - (const Vector& b) const
-	{
+	Vector operator - (const Vector& b) const {
 		return Vector(x - b.x, y - b.y, z - b.z);
 	}
 
-	inline bool operator == (const Vector& b) const
-	{
+	// Element-wise multiplication
+	Vector operator * (const Vector& b) const {
+		return Vector(x * b.x, y * b.y, z * b.z);
+	}
+
+	// Element-wise division
+	Vector operator / (const Vector& b) const {
+		return Vector(x / b.x, y / b.y, z / b.z);
+	}
+
+	inline bool operator == (const Vector& b) const {
 		return x == b.x && y == b.y && z == b.z;
 	}
 
-	inline bool operator != (const Vector& b) const
-	{
+	inline bool operator != (const Vector& b) const {
 		return !(*this == b);
 	}
 
-	inline bool finite() const
-	{
+	inline bool finite() const {
 		return isfinite(x) && isfinite(y) && isfinite(z);
 	}
 
-	static float dot(const Vector& a, const Vector& b)
-	{
+	static float dot(const Vector& a, const Vector& b) {
 		return a.x * b.x + a.y * b.y + a.z * b.z;
 	}
 
-	static Vector cross(const Vector& a, const Vector& b)
-	{
+	static Vector cross(const Vector& a, const Vector& b) {
 		return Vector(a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x);
 	}
 
-	static float angleBetweenVectors(const Vector& a, const Vector& b)
-	{
+	static float angleBetweenVectors(const Vector& a, const Vector& b) {
 		return acos(constrain(dot(a, b) / (a.norm() * b.norm()), -1, 1));
 	}
 
-	static Vector angularRatesBetweenVectors(const Vector& u, const Vector& v)
-	{
-		Vector direction = cross(u, v);
+	static Vector angularRatesBetweenVectors(const Vector& a, const Vector& b) {
+		Vector direction = cross(a, b);
+		if (direction.zero()) {
+			// vectors are opposite, return any perpendicular vector
+			return cross(a, Vector(1, 0, 0));
+		}
 		direction.normalize();
-		float angle = angleBetweenVectors(u, v);
+		float angle = angleBetweenVectors(a, b);
 		return direction * angle;
 	}
 

flix/wifi.ino

@@ -6,10 +6,8 @@
 #if WIFI_ENABLED == 1
 
 #include <WiFi.h>
-#include <WiFiClient.h>
 #include <WiFiAP.h>
-#include "SBUS.h"
-#include "mavlink/common/mavlink.h"
+#include <WiFiUdp.h>
 
 #define WIFI_SSID "flix"
 #define WIFI_PASSWORD "flixwifi"
@@ -18,18 +16,22 @@
 
 WiFiUDP udp;
 
-void setupWiFi()
-{
+void setupWiFi() {
 	Serial.println("Setup Wi-Fi");
 	WiFi.softAP(WIFI_SSID, WIFI_PASSWORD);
 	IPAddress myIP = WiFi.softAPIP();
+	udp.begin(WIFI_UDP_PORT);
 }
 
-inline void sendWiFi(const uint8_t *buf, size_t len)
-{
+void sendWiFi(const uint8_t *buf, int len) {
 	udp.beginPacket(WIFI_UDP_IP, WIFI_UDP_PORT);
 	udp.write(buf, len);
 	udp.endPacket();
 }
 
+int receiveWiFi(uint8_t *buf, int len) {
+	udp.parsePacket();
+	return udp.read(buf, len);
+}
+
 #endif

gazebo/Arduino.h

@@ -14,6 +14,8 @@
 #define PI 3.1415926535897932384626433832795
 #define DEG_TO_RAD 0.017453292519943295769236907684886
 #define RAD_TO_DEG 57.295779513082320876798154814105
+#define radians(deg) ((deg)*DEG_TO_RAD)
+#define degrees(rad) ((rad)*RAD_TO_DEG)
 
 #define constrain(amt,low,high) ((amt)<(low)?(low):((amt)>(high)?(high):(amt)))
 
@@ -44,8 +46,7 @@ public:
 
 class Print {
 public:
-	size_t printf(const char *format, ...)
-	{
+	size_t printf(const char *format, ...) {
 		va_list args;
 		va_start(args, format);
 		size_t result = vprintf(format, args);
@@ -53,48 +54,43 @@ public:
 		return result;
 	}
 
-	size_t print(float n, int digits = 2)
-	{
+	size_t print(int n) {
+		return printf("%d", n);
+	}
+
+	size_t print(float n, int digits = 2) {
 		return printf("%.*f", digits, n);
 	}
 
-	size_t println(float n, int digits = 2)
-	{
+	size_t println(float n, int digits = 2) {
 		return printf("%.*f\n", digits, n);
 	}
 
-	size_t print(const char* s)
-	{
+	size_t print(const char* s) {
 		return printf("%s", s);
 	}
 
-	size_t println()
-	{
+	size_t println() {
 		return print("\n");
 	}
 
-	size_t println(const char* s)
-	{
+	size_t println(const char* s) {
 		return printf("%s\n", s);
 	}
 
-	size_t println(const Printable& p)
-	{
+	size_t println(const Printable& p) {
 		return p.printTo(*this) + print("\n");
 	}
 
-	size_t print(const String& s)
-	{
+	size_t print(const String& s) {
 		return printf("%s", s.c_str());
 	}
 
-	size_t println(const std::string& s)
-	{
+	size_t println(const std::string& s) {
 		return printf("%s\n", s.c_str());
 	}
 
-	size_t println(const String& s)
-	{
+	size_t println(const String& s) {
 		return printf("%s\n", s.c_str());
 	}
 };
@@ -126,6 +122,8 @@ public:
 		}
 		return -1;
 	}
+
+	void setRxInvert(bool invert) {};
 };
 
 HardwareSerial Serial, Serial2;

gazebo/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
 project(flix_gazebo)
 
 # === gazebo plugin
@@ -10,9 +10,12 @@ list(APPEND CMAKE_CXX_FLAGS "${GAZEBO_CXX_FLAGS}")
 
 set(FLIX_SOURCE_DIR ../flix)
 include_directories(${FLIX_SOURCE_DIR})
-file(GLOB_RECURSE FLIX_INO_FILES ${FLIX_SOURCE_DIR}/*.ino)
 
 set(CMAKE_BUILD_TYPE RelWithDebInfo)
-add_library(flix SHARED flix.cpp)
+add_library(flix SHARED simulator.cpp)
 target_link_libraries(flix ${GAZEBO_LIBRARIES} ${SDL2_LIBRARIES})
 target_include_directories(flix PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+
+# Include dir for MAVLink-Arduino library
+target_include_directories(flix PUBLIC $ENV{HOME}/Arduino/libraries/MAVLink)
+target_include_directories(flix PUBLIC $ENV{HOME}/Documents/Arduino/libraries/MAVLink)

gazebo/README.md

@@ -0,0 +1,15 @@
+# Gazebo Simulation
+
+<img src="../docs/img/simulator.png" width=500 alt="Flix simulator">
+
+## Building and running
+
+See [building and running instructions](../docs/build.md#simulation).
+
+## Code structure
+
+Flix simulator is based on [Gazebo Classic](https://classic.gazebosim.org) and consists of the following components:
+
+* Physical model of the drone: [`models/flix/flix.sdf`](models/flix/flix.sdf).
+* Plugin for Gazebo: [`simulator.cpp`](simulator.cpp). The plugin is attached to the physical model. It receives stick positions from the controller, gets the data from the virtual sensors, and then passes this data to the Arduino code.
+* Arduino imitation: [`Arduino.h`](Arduino.h). This file contains partial implementation of the Arduino API, that is working within Gazebo plugin environment.

gazebo/SBUS.h

@@ -0,0 +1,24 @@
+// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// SBUS library mock to make it possible to compile simulator with rc.ino
+
+#include "joystick.h"
+
+struct SBUSData {
+	int16_t ch[16];
+};
+
+class SBUS {
+public:
+	SBUS(HardwareSerial& bus, const bool inv = true) {};
+	void begin() {};
+	bool read() { return joystickGet(); };
+	SBUSData data() {
+		SBUSData data;
+		for (uint8_t i = 0; i < 16; i++) {
+			data.ch[i] = channels[i];
+		}
+		return data;
+	};
+};

gazebo/flix.cpp

@@ -1,209 +0,0 @@
-// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
-// Repository: https://github.com/okalachev/flix
-
-// Gazebo plugin for running Arduino code and simulating the drone
-
-#include <functional>
-#include <cmath>
-#include <gazebo/gazebo.hh>
-#include <gazebo/physics/physics.hh>
-#include <gazebo/rendering/rendering.hh>
-#include <gazebo/common/common.hh>
-#include <gazebo/sensors/sensors.hh>
-#include <gazebo/msgs/msgs.hh>
-#include <ignition/math/Vector3.hh>
-#include <ignition/math/Pose3.hh>
-#include <ignition/math/Quaternion.hh>
-#include <iostream>
-#include <fstream>
-
-#include "Arduino.h"
-#include "flix.h"
-#include "util.ino"
-#include "joystick.h"
-#include "time.ino"
-#include "estimate.ino"
-#include "control.ino"
-#include "log.ino"
-#include "cli.ino"
-#include "lpf.h"
-
-using ignition::math::Vector3d;
-using ignition::math::Pose3d;
-using namespace gazebo;
-using namespace std;
-
-Pose3d flu2frd(const Pose3d& p)
-{
-	return ignition::math::Pose3d(p.Pos().X(), -p.Pos().Y(), -p.Pos().Z(),
-	                              p.Rot().W(), p.Rot().X(), -p.Rot().Y(), -p.Rot().Z());
-}
-
-Vector flu2frd(const Vector3d& v)
-{
-	return Vector(v.X(), -v.Y(), -v.Z());
-}
-
-class ModelFlix : public ModelPlugin
-{
-private:
-	physics::ModelPtr model, estimateModel;
-	physics::LinkPtr body;
-	sensors::ImuSensorPtr imu;
-	event::ConnectionPtr updateConnection, resetConnection;
-	transport::NodePtr nodeHandle;
-	transport::PublisherPtr motorPub[4];
-	LowPassFilter<Vector> accFilter = LowPassFilter<Vector>(0.1);
-
-public:
-	void Load(physics::ModelPtr _parent, sdf::ElementPtr /*_sdf*/)
-	{
-		this->model = _parent;
-		this->body = this->model->GetLink("body");
-
-		this->imu = std::dynamic_pointer_cast<sensors::ImuSensor>(sensors::get_sensor(model->GetScopedName(true) + "::body::imu")); // default::flix::body::imu
-		if (imu == nullptr) {
-			gzerr << "IMU sensor not found" << std::endl;
-			return;
-		}
-
-		this->estimateModel = model->GetWorld()->ModelByName("flix_estimate");
-
-		this->updateConnection = event::Events::ConnectWorldUpdateBegin(
-			std::bind(&ModelFlix::OnUpdate, this));
-
-		this->resetConnection = event::Events::ConnectWorldReset(
-			std::bind(&ModelFlix::OnReset, this));
-
-		initNode();
-
-		Serial.begin(0);
-
-		gzmsg << "Flix plugin loaded" << endl;
-	}
-
-public:
-	void OnReset()
-	{
-		attitude = Quaternion();
-		gzmsg << "Flix plugin reset" << endl;
-	}
-
-	void OnUpdate()
-	{
-		__micros = model->GetWorld()->SimTime().Double() * 1000000;
-		step();
-
-		// read imu
-		rates = flu2frd(imu->AngularVelocity());
-		acc = this->accFilter.update(flu2frd(imu->LinearAcceleration()));
-
-		// read rc
-		joystickGet();
-		controls[RC_CHANNEL_MODE] = 1; // 0 acro, 1 stab
-		controls[RC_CHANNEL_AUX] = 1; // armed
-
-		estimate();
-
-		// correct yaw to the actual yaw
-		attitude.setYaw(-this->model->WorldPose().Yaw());
-
-		control();
-		parseInput();
-
-		applyMotorsThrust();
-		updateEstimatePose();
-		publishTopics();
-		logData();
-	}
-
-	void applyMotorsThrust()
-	{
-		// thrusts
-		const double d = 0.035355;
-		const double maxThrust = 0.03 * ONE_G; // 30 g, https://www.youtube.com/watch?v=VtKI4Pjx8Sk
-		// 65 mm prop ~40 g
-
-		const float scale0 = 1.0, scale1 = 1.1, scale2 = 0.9, scale3 = 1.05;
-		const float minThrustRel = 0;
-
-		// apply min thrust
-		float mfl = mapff(motors[MOTOR_FRONT_LEFT], 0, 1, minThrustRel, 1);
-		float mfr = mapff(motors[MOTOR_FRONT_RIGHT], 0, 1, minThrustRel, 1);
-		float mrl = mapff(motors[MOTOR_REAR_LEFT], 0, 1, minThrustRel, 1);
-		float mrr = mapff(motors[MOTOR_REAR_RIGHT], 0, 1, minThrustRel, 1);
-
-		if (motors[MOTOR_FRONT_LEFT] < 0.001) mfl = 0;
-		if (motors[MOTOR_FRONT_RIGHT] < 0.001) mfr = 0;
-		if (motors[MOTOR_REAR_LEFT] < 0.001) mrl = 0;
-		if (motors[MOTOR_REAR_RIGHT] < 0.001) mrr = 0;
-
-		// TODO: min_thrust
-
-		body->AddLinkForce(Vector3d(0.0, 0.0, scale0 * maxThrust * abs(mfl)), Vector3d(d, d, 0.0));
-		body->AddLinkForce(Vector3d(0.0, 0.0, scale1 * maxThrust * abs(mfr)), Vector3d(d, -d, 0.0));
-		body->AddLinkForce(Vector3d(0.0, 0.0, scale2 * maxThrust * abs(mrl)), Vector3d(-d, d, 0.0));
-		body->AddLinkForce(Vector3d(0.0, 0.0, scale3 * maxThrust * abs(mrr)), Vector3d(-d, -d, 0.0));
-
-		// TODO: indicate if > 1
-
-		// torque
-		const double maxTorque = 0.0023614413; // 24.08 g*cm
-		int direction = 1;
-		// z is counter clockwise, normal rotation direction is minus
-		body->AddRelativeTorque(Vector3d(0.0, 0.0, direction * scale0 * maxTorque * motors[MOTOR_FRONT_LEFT]));
-		body->AddRelativeTorque(Vector3d(0.0, 0.0, direction * scale1 * -maxTorque * motors[MOTOR_FRONT_RIGHT]));
-		body->AddRelativeTorque(Vector3d(0.0, 0.0, direction * scale2 * -maxTorque * motors[MOTOR_REAR_LEFT]));
-		body->AddRelativeTorque(Vector3d(0.0, 0.0, direction * scale3 * maxTorque * motors[MOTOR_REAR_RIGHT]));
-	}
-
-	void updateEstimatePose() {
-		if (estimateModel == nullptr) {
-			return;
-		}
-		if (!attitude.finite()) {
-			// gzerr << "attitude is nan" << std::endl;
-			return;
-		}
-		Pose3d pose(
-			model->WorldPose().Pos().X(), model->WorldPose().Pos().Y(), model->WorldPose().Pos().Z(),
-			attitude.w, attitude.x, -attitude.y, -attitude.z // frd to flu
-		);
-		// std::cout << pose.Pos().X() << " " << pose.Pos().Y() << " " << pose.Pos().Z() <<
-		// 	" " << pose.Rot().W() << " " << pose.Rot().X() << " " << pose.Rot().Y() << " " << pose.Rot().Z() << std::endl;
-
-		// calculate attitude estimation error
-
-		Quaternion groundtruthAttitude(estimateModel->WorldPose().Rot().W(), estimateModel->WorldPose().Rot().X(), -estimateModel->WorldPose().Rot().Y(), -estimateModel->WorldPose().Rot().Z());
-		float angle = Vector::angleBetweenVectors(attitude.rotate(Vector(0, 0, -1)), groundtruthAttitude.rotate(Vector(0, 0, -1)));
-		if (angle < 0.3) {
-			//gzwarn << "att err: " << angle << endl;
-			// TODO: warning
-			// position under the floor to make it invisible
-			pose.SetZ(-5);
-		}
-
-		estimateModel->SetWorldPose(pose);
-
-	}
-
-	void initNode() {
-		nodeHandle = transport::NodePtr(new transport::Node());
-		nodeHandle->Init();
-		string ns = "~/" + model->GetName();
-		motorPub[0] = nodeHandle->Advertise<msgs::Int>(ns + "/motor0");
-		motorPub[1] = nodeHandle->Advertise<msgs::Int>(ns + "/motor1");
-		motorPub[2] = nodeHandle->Advertise<msgs::Int>(ns + "/motor2");
-		motorPub[3] = nodeHandle->Advertise<msgs::Int>(ns + "/motor3");
-	}
-
-	void publishTopics() {
-		for (int i = 0; i < 4; i++) {
-			msgs::Int msg;
-			msg.set_data(static_cast<int>(std::round(motors[i] * 1000)));
-			motorPub[i]->Publish(msg);
-		}
-	}
-};
-
-GZ_REGISTER_MODEL_PLUGIN(ModelFlix)

gazebo/flix.h

@@ -8,6 +8,7 @@
 #include "vector.h"
 #include "quaternion.h"
 #include "Arduino.h"
+#include "wifi.h"
 
 #define RC_CHANNELS 6
 
@@ -16,13 +17,16 @@
 #define MOTOR_FRONT_RIGHT 2
 #define MOTOR_REAR_RIGHT 1
 
+#define WIFI_ENABLED 1
+
 float t = NAN;
 float dt;
 float loopFreq;
 float motors[4];
-int16_t channels[16]; // raw rc channels WARNING: unsigned on hardware
+int16_t channels[16]; // raw rc channels
 float controls[RC_CHANNELS];
 Vector acc;
+Vector gyro;
 Vector rates;
 Quaternion attitude;
 
@@ -39,6 +43,12 @@ void controlTorque();
 void showTable();
 bool motorsActive();
 void cliTestMotor(uint8_t n);
+void printRCCal();
+void processMavlink();
+void sendMavlink();
+void sendMessage(const void *msg);
+void receiveMavlink();
+void handleMavlink(const void *_msg);
 
 // mocks
 void setLED(bool on) {};

gazebo/flix.world

@@ -25,18 +25,5 @@
 			<uri>model://flix</uri>
 			<pose>0 0 0.2 0 0 0</pose>
 		</include>
-		<model name="flix_estimate">
-			<static>true</static>
-			<link name="estimate">
-				<visual name="estimate">
-					<pose>0 0 0 0 0 1.57</pose>
-					<geometry>
-						<box>
-							<size>0.125711 0.125711 0.022</size>
-						</box>
-					</geometry>
-				</visual>
-			</link>
-		</model>
 	</world>
 </sdf>

gazebo/joystick.h

@@ -7,64 +7,50 @@
 #include <gazebo/gazebo.hh>
 #include <iostream>
 
-using namespace std;
-
-static const int16_t channelNeutralMin[] = {-1290,	-258,	-26833,	0,	0, 0};
-static const int16_t channelNeutralMax[] = {-1032,	-258,	-27348,	3353,	0, 0};
-
-static const int16_t channelMax[] =        {27090,	27090,	27090,	27090, 0, 0};
+// simulation calibration overrides, NOTE: use `cr` command and replace with the actual values
+const int channelNeutralOverride[] = {-258, -258, -27349, 0, -27349, 0};
+const int channelMaxOverride[] = {27090, 27090, 27090, 27090, -5676, 1};
 
 #define RC_CHANNEL_ROLL 0
 #define RC_CHANNEL_PITCH 1
 #define RC_CHANNEL_THROTTLE 2
 #define RC_CHANNEL_YAW 3
-#define RC_CHANNEL_AUX 4
-#define RC_CHANNEL_MODE 5
-
-static SDL_Joystick *joystick;
+#define RC_CHANNEL_ARMED 5
+#define RC_CHANNEL_MODE 4
 
+SDL_Joystick *joystick;
 bool joystickInitialized = false, warnShown = false;
 
 void normalizeRC();
 
-void joystickInit()
-{
+void joystickInit() {
 	SDL_Init(SDL_INIT_JOYSTICK);
 	joystick = SDL_JoystickOpen(0);
 	if (joystick != NULL) {
 		joystickInitialized = true;
-		gzmsg << "Joystick initialized: " << SDL_JoystickNameForIndex(0) << endl;
+		gzmsg << "Joystick initialized: " << SDL_JoystickNameForIndex(0) << std::endl;
 	} else if (!warnShown) {
-		gzwarn << "Joystick not found, begin waiting for joystick..." << endl;
+		gzwarn << "Joystick not found, begin waiting for joystick..." << std::endl;
 		warnShown = true;
 	}
+
+	// apply calibration overrides
+	extern int channelNeutral[RC_CHANNELS];
+	extern int channelMax[RC_CHANNELS];
+	memcpy(channelNeutral, channelNeutralOverride, sizeof(channelNeutralOverride));
+	memcpy(channelMax, channelMaxOverride, sizeof(channelMaxOverride));
 }
 
-void joystickGet()
-{
+bool joystickGet() {
 	if (!joystickInitialized) {
 		joystickInit();
-		return;
+		return false;
 	}
 
 	SDL_JoystickUpdate();
 
-	for (uint8_t i = 0; i < 4; i++) {
+	for (uint8_t i = 0; i < 8; i++) {
 		channels[i] = SDL_JoystickGetAxis(joystick, i);
 	}
-	channels[RC_CHANNEL_MODE] = SDL_JoystickGetButton(joystick, 0) ? 1 : 0;
-	controls[RC_CHANNEL_MODE] = channels[RC_CHANNEL_MODE];
-
-	normalizeRC();
-}
-
-void normalizeRC() {
-	for (uint8_t i = 0; i < 4; i++) {
-		if (channels[i] >= channelNeutralMin[i] && channels[i] <= channelNeutralMax[i]) {
-			controls[i] = 0;
-		} else {
-			controls[i] = mapf(channels[i], (channelNeutralMin[i] + channelNeutralMax[i]) / 2, channelMax[i], 0, 1);
-		}
-	}
-	controls[RC_CHANNEL_THROTTLE] = constrain(controls[RC_CHANNEL_THROTTLE], 0, 1);
+	return true;
 }

gazebo/simulator.cpp

@@ -0,0 +1,133 @@
+// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// Gazebo plugin for running Arduino code and simulating the drone
+
+#include <functional>
+#include <cmath>
+#include <gazebo/gazebo.hh>
+#include <gazebo/physics/physics.hh>
+#include <gazebo/common/common.hh>
+#include <gazebo/sensors/sensors.hh>
+#include <gazebo/msgs/msgs.hh>
+#include <ignition/math/Vector3.hh>
+#include <ignition/math/Pose3.hh>
+#include <iostream>
+#include <fstream>
+
+#include "Arduino.h"
+#include "flix.h"
+#include "util.h"
+#include "util.ino"
+#include "rc.ino"
+#include "time.ino"
+#include "estimate.ino"
+#include "control.ino"
+#include "log.ino"
+#include "cli.ino"
+#include "mavlink.ino"
+#include "lpf.h"
+
+using ignition::math::Vector3d;
+using namespace gazebo;
+using namespace std;
+
+class ModelFlix : public ModelPlugin {
+private:
+	physics::ModelPtr model;
+	physics::LinkPtr body;
+	sensors::ImuSensorPtr imu;
+	event::ConnectionPtr updateConnection, resetConnection;
+	transport::NodePtr nodeHandle;
+	transport::PublisherPtr motorPub[4];
+	LowPassFilter<Vector> accFilter = LowPassFilter<Vector>(0.1);
+
+public:
+	void Load(physics::ModelPtr _parent, sdf::ElementPtr /*_sdf*/) {
+		this->model = _parent;
+		this->body = this->model->GetLink("body");
+		this->imu = dynamic_pointer_cast<sensors::ImuSensor>(sensors::get_sensor(model->GetScopedName(true) + "::body::imu")); // default::flix::body::imu
+		this->updateConnection = event::Events::ConnectWorldUpdateBegin(bind(&ModelFlix::OnUpdate, this));
+		this->resetConnection = event::Events::ConnectWorldReset(bind(&ModelFlix::OnReset, this));
+		initNode();
+		Serial.begin(0);
+		gzmsg << "Flix plugin loaded" << endl;
+	}
+
+	void OnReset() {
+		attitude = Quaternion(); // reset estimated attitude
+		gzmsg << "Flix plugin reset" << endl;
+	}
+
+	void OnUpdate() {
+		__micros = model->GetWorld()->SimTime().Double() * 1000000;
+		step();
+
+		// read imu
+		gyro = flu2frd(imu->AngularVelocity());
+		acc = this->accFilter.update(flu2frd(imu->LinearAcceleration()));
+
+		// read rc
+		readRC();
+		controls[RC_CHANNEL_MODE] = 1; // 0 acro, 1 stab
+		controls[RC_CHANNEL_ARMED] = 1; // armed
+
+		estimate();
+
+		// correct yaw to the actual yaw
+		attitude.setYaw(-this->model->WorldPose().Yaw());
+
+		control();
+		parseInput();
+		processMavlink();
+
+		applyMotorForces();
+		publishTopics();
+		logData();
+	}
+
+	void applyMotorForces() {
+		// thrusts
+		const double dist = 0.035355; // motors shift from the center, m
+		const double maxThrust = 0.03 * ONE_G; // ~30 g, https://youtu.be/VtKI4Pjx8Sk?&t=78
+
+		const float scale0 = 1.0, scale1 = 1.1, scale2 = 0.9, scale3 = 1.05; // imitating motors asymmetry
+		float mfl = scale0 * maxThrust * motors[MOTOR_FRONT_LEFT];
+		float mfr = scale1 * maxThrust * motors[MOTOR_FRONT_RIGHT];
+		float mrl = scale2 * maxThrust * motors[MOTOR_REAR_LEFT];
+		float mrr = scale3 * maxThrust * motors[MOTOR_REAR_RIGHT];
+
+		body->AddLinkForce(Vector3d(0.0, 0.0, mfl), Vector3d(dist, dist, 0.0));
+		body->AddLinkForce(Vector3d(0.0, 0.0, mfr), Vector3d(dist, -dist, 0.0));
+		body->AddLinkForce(Vector3d(0.0, 0.0, mrl), Vector3d(-dist, dist, 0.0));
+		body->AddLinkForce(Vector3d(0.0, 0.0, mrr), Vector3d(-dist, -dist, 0.0));
+
+		// torque
+		const double maxTorque = 0.0024 * ONE_G; // ~24 g*cm
+		body->AddRelativeTorque(Vector3d(0.0, 0.0, scale0 * maxTorque * motors[MOTOR_FRONT_LEFT]));
+		body->AddRelativeTorque(Vector3d(0.0, 0.0, scale1 * -maxTorque * motors[MOTOR_FRONT_RIGHT]));
+		body->AddRelativeTorque(Vector3d(0.0, 0.0, scale2 * -maxTorque * motors[MOTOR_REAR_LEFT]));
+		body->AddRelativeTorque(Vector3d(0.0, 0.0, scale3 * maxTorque * motors[MOTOR_REAR_RIGHT]));
+	}
+
+	void initNode() {
+		nodeHandle = transport::NodePtr(new transport::Node());
+		nodeHandle->Init();
+		string ns = "~/" + model->GetName();
+		// create motors output topics for debugging and plotting
+		motorPub[0] = nodeHandle->Advertise<msgs::Int>(ns + "/motor0");
+		motorPub[1] = nodeHandle->Advertise<msgs::Int>(ns + "/motor1");
+		motorPub[2] = nodeHandle->Advertise<msgs::Int>(ns + "/motor2");
+		motorPub[3] = nodeHandle->Advertise<msgs::Int>(ns + "/motor3");
+	}
+
+	void publishTopics() {
+		for (int i = 0; i < 4; i++) {
+			msgs::Int msg;
+			msg.set_data(static_cast<int>(round(motors[i] * 1000)));
+			motorPub[i]->Publish(msg);
+		}
+	}
+};
+
+GZ_REGISTER_MODEL_PLUGIN(ModelFlix)

gazebo/soc/rtc_cntl_reg.h

@@ -0,0 +1 @@
+// Dummy file to make it possible to compile simulator with util.ino

gazebo/soc/soc.h

@@ -0,0 +1,3 @@
+// Dummy file to make it possible to compile simulator with util.ino
+
+#define WRITE_PERI_REG(addr, val) {}

gazebo/util.h

@@ -0,0 +1,14 @@
+#include <ignition/math/Vector3.hh>
+#include <ignition/math/Pose3.hh>
+
+using ignition::math::Vector3d;
+using ignition::math::Pose3d;
+
+Pose3d flu2frd(const Pose3d& p) {
+	return ignition::math::Pose3d(p.Pos().X(), -p.Pos().Y(), -p.Pos().Z(),
+	                              p.Rot().W(), p.Rot().X(), -p.Rot().Y(), -p.Rot().Z());
+}
+
+Vector flu2frd(const Vector3d& v) {
+	return Vector(v.X(), -v.Y(), -v.Z());
+}

gazebo/wifi.h

@@ -0,0 +1,44 @@
+// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// sendWiFi and receiveWiFi implementations for the simulation
+
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <sys/poll.h>
+#include <gazebo/gazebo.hh>
+
+#define WIFI_UDP_PORT_LOCAL 14580
+#define WIFI_UDP_PORT_REMOTE 14550
+
+int wifiSocket;
+
+void setupWiFi() {
+	wifiSocket = socket(AF_INET, SOCK_DGRAM, 0);
+	sockaddr_in addr;
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = INADDR_ANY;
+	addr.sin_port = htons(WIFI_UDP_PORT_LOCAL);
+	bind(wifiSocket, (sockaddr *)&addr, sizeof(addr));
+	int broadcast = 1;
+	setsockopt(wifiSocket, SOL_SOCKET, SO_BROADCAST, &broadcast, sizeof(broadcast)); // enable broadcast
+	gzmsg << "WiFi UDP socket initialized on port " << WIFI_UDP_PORT_LOCAL << " (remote port " << WIFI_UDP_PORT_REMOTE << ")" << std::endl;
+}
+
+void sendWiFi(const uint8_t *buf, int len) {
+	if (wifiSocket == 0) setupWiFi();
+	sockaddr_in addr;
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = INADDR_BROADCAST; // send UDP broadcast
+	addr.sin_port = htons(WIFI_UDP_PORT_REMOTE);
+	sendto(wifiSocket, buf, len, 0, (sockaddr *)&addr, sizeof(addr));
+}
+
+int receiveWiFi(uint8_t *buf, int len) {
+	struct pollfd pfd = { .fd = wifiSocket, .events = POLLIN };
+	if (poll(&pfd, 1, 0) <= 0) return 0; // check if there is data to read
+	return recv(wifiSocket, buf, len, 0);
+}

tools/grab_log.py

@@ -9,8 +9,7 @@ PORT = os.environ['PORT']
 DIR = os.path.dirname(os.path.realpath(__file__))
 
 dev = serial.Serial(port=PORT, baudrate=115200, timeout=0.5)
-
-log = open(f'{DIR}/log/{datetime.datetime.now().isoformat()}.csv', 'wb')
+lines = []
 
 print('Downloading log...')
 count = 0
@@ -19,8 +18,14 @@ while True:
     line = dev.readline()
     if not line:
         break
-    log.write(line)
+    lines.append(line)
     count += 1
     print(f'\r{count} lines', end='')
 
+# sort by timestamp
+header = lines.pop(0)
+lines.sort(key=lambda line: float(line.split(b',')[0]))
+
+log = open(f'{DIR}/log/{datetime.datetime.now().isoformat()}.csv', 'wb')
+log.writelines([header] + lines)
 print(f'\nWritten {os.path.relpath(log.name, os.curdir)}')

tools/requirements.txt

@@ -0,0 +1,2 @@
+docopt
+matplotlib