Add Flix 1.5 to builds

It's much better for voltage measuring and slightly better for gyro bias estimation.

.github/workflows/build.yml

@@ -23,6 +23,8 @@ 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

Makefile

@@ -1,6 +1,5 @@
 BOARD = esp32:esp32:d1_mini32
-PORT := $(wildcard /dev/serial/by-id/usb-Silicon_Labs_CP21* /dev/serial/by-id/usb-1a86_USB_Single_Serial_* /dev/cu.usbserial-*)
+PORT := $(strip $(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 := $(strip $(PORT))
 
 build: .dependencies
 	arduino-cli compile --fqbn $(BOARD) flix

README.md

@@ -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
+## Documentation articles
 
 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|<img src="docs/img/esp32.jpg" width=100>|1|
+|Microcontroller board|ESP32 Mini.<br>ESP32-S3/ESP32-C3 boards are also supported.|<img src="docs/img/esp32.jpg" width=100>|1|
-|IMU (and barometer¹) board|GY‑91, MPU-9265 (or other MPU‑9250/MPU‑6500 board)<br>ICM20948V2 (ICM‑20948)³<br>GY-521 (MPU-6050)³⁻¹|<img src="docs/img/gy-91.jpg" width=90 align=center><br><img src="docs/img/icm-20948.jpg" width=100><br><img src="docs/img/gy-521.jpg" width=100>|1|
+|IMU (and barometer¹) board|GY‑91, MPU-9265 (or other MPU‑9250/MPU‑6500 board)<br>ICM20948V2 (ICM‑20948)<br>GY-521 (MPU-6050)|<img src="docs/img/gy-91.jpg" width=90 align=center><br><img src="docs/img/icm-20948.jpg" width=100><br><img src="docs/img/gy-521.jpg" width=100>|1|
 |Boost converter (optional, for more stable power supply)|5V output|<img src="docs/img/buck-boost.jpg" width=100>|1|
 |Motor|8520 3.7V brushed motor.<br>Motor with exact 3.7V voltage is needed, not ranged working voltage (3.7V — 6V).<br>Make sure the motor shaft diameter and propeller hole diameter match!|<img src="docs/img/motor.jpeg" width=100>|4|
-|Propeller|55 mm (alternatively 65 mm)|<img src="docs/img/prop.jpg" width=100>|4|
+|Propeller|55 mm or 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)|<img src="docs/img/battery.jpg" width=100>|1|
+|3.7V Li-Po battery|LW 952540 (or any compatible by the size).<br>Make sure the battery has enough discharge rate — 25C or more!|<img src="docs/img/battery.jpg" width=100>|1|
 |Battery connector cable|MX2.0 2P female|<img src="docs/img/mx.png" width=100>|1|
 |Li-Po Battery charger|Any|<img src="docs/img/charger.jpg" width=100>|1|
 |Screws for IMU board mounting|M3x5|<img src="docs/img/screw-m3.jpg" width=100>|2|
@@ -152,18 +152,16 @@ You can see a user-contributed [variant of complete circuit diagram](https://mir
   |-|-|
   |GND|GND|
   |VIN|VCC (or 3.3V depending on the receiver)|
-  |Signal (TX)|GPIO4¹|
+  |Signal (TX)|GPIO4|
 
-  *¹ — UART2 RX pin was [changed](https://docs.espressif.com/projects/arduino-esp32/en/latest/migration_guides/2.x_to_3.0.html#id14) to GPIO4 in Arduino ESP32 core 3.0.*
+* Optionally connect the battery voltage divider for voltage monitoring to any ADC1 pin (e. g. *GPIO32* on ESP32, *GPIO3* on ESP32-S3).
 
-* Optionally connect the battery voltage divider for voltage monitoring to any ADC1 pin (e. g. *GPIO32* on ESP32, *GPIO3* on ESP32S3).
+  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.
-
-  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.
+* Official Telegram chat: https://t.me/opensourcequadcopterchat (English / Russian).
 * Detailed article on Habr.com about the development of the drone (in Russian): https://habr.com/ru/articles/814127/.
 
 ## Disclaimer

docs/assembly.md

@@ -28,6 +28,8 @@ Soldered components ([schematics variant](https://miro.com/app/board/uXjVN-dTjoo
 
 <img src="img/assembly/7.jpg" width=600>
 
+See an alternative assembly process photos here: https://drive.google.com/drive/folders/1FG5BH9RCzdf1XmJcC70PymiRMXcz6Fx7?usp=sharing.
+
 ## Motor directions
 
 > [!WARNING]

docs/firmware.md

@@ -67,6 +67,35 @@ 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

@@ -12,20 +12,25 @@ Do the following:
 
 Do the following:
 
-* **Check the battery voltage**. Use a multimeter to measure the battery voltage. It should be in range of 3.7-4.2 V.
+* **Check the battery voltage**. Use a multimeter to measure the battery voltage. The fully charged battery should have about 4.2V.
+* **Check the battery you use has enough discharge current**. The battery should be able to provide 15A of current. So the C-rating for a 1000 mAh battery should be at least 15C (higher is better).
 * **Check if there are some startup errors**. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button or `reboot` command to see the whole startup output.
 * **Check the baudrate is correct**. If you see garbage characters in the Serial Monitor, make sure the baudrate is set to 115200.
-* **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
 * **Check if the 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.
-* **Calibrate the accelerometer.** if is wasn't done before. Type `ca` command in Serial Monitor and follow the instructions.
-* **Check the attitude estimation**. Connect to the drone using QGroundControl. Rotate the drone in different orientations and check if the attitude estimation shown in QGroundControl is correct.
 * **Check the IMU orientation is set correctly**. If the attitude estimation is rotated, set the correct IMU orientation as described in the [tutorial](usage.md#define-imu-orientation).
+* **Calibrate the accelerometer.** if is wasn't done before. Type `ca` command in Serial Monitor and follow the instructions.
+* **Check the attitude estimation**. Connect to the drone using QGroundControl. Rotate the drone in different orientations and check if the attitude estimation is shown exactly as on the video below:
+
+  <a href="https://youtu.be/yVRN23-GISU"><img width=200 src="https://i3.ytimg.com/vi/yVRN23-GISU/maxresdefault.jpg"></a>
+
+* **Check the IMU output**. Connect to the drone using QGroundControl on your computer. Go to the *Analyze* tab, *MAVLINK Inspector*. Plot the data from the `SCALED_IMU` message. The gyroscope and accelerometer data should change according to the drone movement.
 * **Check the motors type**. Motors with exact 3.7V voltage are needed, not ranged working voltage (3.7V — 6V).
 * **Check the motors**. Perform the following commands using Serial Monitor:
   * `mfr` — should rotate front right motor (counter-clockwise).
@@ -33,9 +38,10 @@ Do the following:
   * `mrl` — should rotate rear left motor (counter-clockwise).
   * `mrr` — should rotate rear right motor (clockwise).
 * **Check the propeller directions are correct**. Make sure your propeller types (A or B) are installed as on the picture:
+
   <img src="img/user/peter_ukhov-2/1.jpg" width="200">
-* **Check the remote control**. Using `rc` command, check the control values reflect your sticks movement. All the controls should change between -1 and 1, and throttle between 0 and 1.
+
-* **If using SBUS receiver**:
+* **If using an SBUS receiver**:
   * **Define the used GPIO pin** in `RC_RX_PIN` parameter.
   * **Calibrate the RC** using `cr` command in the console.
-* **Check the IMU output using QGroundControl**. Connect to the drone using QGroundControl on your computer. Go to the *Analyze* tab, *MAVLINK Inspector*. Plot the data from the `SCALED_IMU` message. The gyroscope and accelerometer data should change according to the drone movement.
+  * **Check the controls** using `rc` command. All the controls should change between -1 and 1, and the throttle between 0 and 1.

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 pins 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 mounting holes 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-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-3.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0    |<img src="img/imu-rot-7.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 0|
-|<img src="img/imu-rot-2.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|<img src="img/imu-rot-6.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|
+|<img src="img/imu-rot-2.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|<img src="img/imu-rot-6.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|
-|<img src="img/imu-rot-3.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|<img src="img/imu-rot-7.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|
+|<img src="img/imu-rot-1.png" width="180">|`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|<img src="img/imu-rot-5.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 3.142|
-|<img src="img/imu-rot-4.png" width="180"><br>☑️ **Default**|<br>`IMU_ROT_ROLL` = 0<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = -1.571|<img src="img/imu-rot-8.png" width="180">|`IMU_ROT_ROLL` = 3.142<br>`IMU_ROT_PITCH` = 0<br>`IMU_ROT_YAW` = 1.571|
+|<img src="img/imu-rot-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) support a lower maximum PWM frequency; on these boards the parameter `MOT_PWM_FREQ` should be set to 40000 Hz.
+Certain ESP32 models (such as ESP32-S3 and ESP32-C3) support a lower maximum PWM frequency; on these boards the parameter `MOT_PWM_FREQ` should be set to 38000 Hz.
 
 If using brushless motors and ESCs:
 
@@ -192,6 +192,18 @@ 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`).
@@ -204,11 +216,11 @@ There are several ways to control the drone's flight: using **smartphone** (Wi-F
 
 ### Control with a remote control
 
-Before using SBUS-connected remote control you need to enable SBUS and calibrate it:
+If 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. Reboot the drone to apply changes.
+3. Check if the receiver is working using `rc` command in the console.
 4. Open the console, type `cr` command and follow the instructions to calibrate the remote control.
 5. Use the remote control to fly the drone!
 

docs/user.md

@@ -4,6 +4,22 @@ 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

@@ -19,13 +19,14 @@ 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"
@@ -168,6 +169,7 @@ void doCommand(String str, bool echo = false) {
 		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/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/lpf.h

@@ -14,6 +14,10 @@ public:
 	LowPassFilter(float alpha): alpha(alpha) {};
 
 	T update(const T input) {
+		if (!init) {
+			init = true;
+			return output = input;
+		}
 		return output += alpha * (input - output);
 	}
 
@@ -22,6 +26,9 @@ public:
 	}
 
 	void reset() {
-		output = T(); // set to zero
+		init = false;
 	}
+
+private:
+	bool init = false;
 };

flix/motors.ino

@@ -54,7 +54,7 @@ bool motorsActive() {
 
 void testMotor(int n) {
 	print("Testing motor %d\n", n);
-	motors[n] = 1;
+	motors[n] = 0.2;
 	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

@@ -86,7 +86,7 @@ Parameter parameters[] = {
 	{"MOT_PWM_MIN", &pwmMin},
 	{"MOT_PWM_MAX", &pwmMax},
 	// rc
-	{"RC_RX_PIN", &rcRxPin},
+	{"RC_RX_PIN", &rcRxPin, setupRC},
 	{"RC_ZERO_0", &channelZero[0]},
 	{"RC_ZERO_1", &channelZero[1]},
 	{"RC_ZERO_2", &channelZero[2]},
@@ -110,8 +110,8 @@ Parameter parameters[] = {
 	{"RC_MODE", &modeChannel},
 	// wifi
 	{"WIFI_MODE", &wifiMode},
-	{"WIFI_LOC_PORT", &udpLocalPort},
+	{"WIFI_PORT_LOC", &udpLocalPort},
-	{"WIFI_REM_PORT", &udpRemotePort},
+	{"WIFI_PORT_REM", &udpRemotePort},
 	// mavlink
 	{"MAV_SYS_ID", &mavlinkSysId},
 	{"MAV_RATE_SLOW", &telemetrySlow.rate},

flix/rc.ino

@@ -6,7 +6,7 @@
 #include <SBUS.h>
 #include "util.h"
 
-SBUS rc(Serial2);
+SBUS rc(Serial1);
 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];
+	uint16_t zero[16]; // for zero positions
-	uint16_t center[16];
+	uint16_t center[16]; // for center positions
-	uint16_t max[16];
+	uint16_t _[16]; // for unused data
 	print("1/8 Calibrating RC: put all switches to default positions [3 sec]\n");
 	pause(3);
-	calibrateRCChannel(NULL, zero, zero, "2/8 Move sticks [3 sec]\n...     ...\n...     .o.\n.o.     ...\n");
+	calibrateRCChannel(NULL, _, zero, "2/8 Move sticks [3 sec]\n...     ...\n...     .o.\n.o.     ...\n");
-	calibrateRCChannel(NULL, center, center, "3/8 Move sticks [3 sec]\n...     ...\n.o.     .o.\n...     ...\n");
+	calibrateRCChannel(&throttleChannel, zero, _, "3/8 Move sticks [3 sec]\n.o.     ...\n...     .o.\n...     ...\n");
-	calibrateRCChannel(&throttleChannel, zero, max, "4/8 Move sticks [3 sec]\n.o.     ...\n...     .o.\n...     ...\n");
+	calibrateRCChannel(NULL, _, center, "4/8 Move sticks [3 sec]\n...     ...\n.o.     .o.\n...     ...\n");
-	calibrateRCChannel(&yawChannel, center, max, "5/8 Move sticks [3 sec]\n...     ...\n..o     .o.\n...     ...\n");
+	calibrateRCChannel(&yawChannel, center, _, "5/8 Move sticks [3 sec]\n...     ...\n..o     .o.\n...     ...\n");
-	calibrateRCChannel(&pitchChannel, zero, max, "6/8 Move sticks [3 sec]\n...     .o.\n...     ...\n.o.     ...\n");
+	calibrateRCChannel(&pitchChannel, zero, _, "6/8 Move sticks [3 sec]\n...     .o.\n...     ...\n.o.     ...\n");
-	calibrateRCChannel(&rollChannel, zero, max, "7/8 Move sticks [3 sec]\n...     ...\n...     ..o\n.o.     ...\n");
+	calibrateRCChannel(&rollChannel, zero, _, "7/8 Move sticks [3 sec]\n...     ...\n...     ..o\n.o.     ...\n");
-	calibrateRCChannel(&modeChannel, zero, max, "8/8 Put mode switch to max [3 sec]\n");
+	calibrateRCChannel(&modeChannel, zero, _, "8/8 Put mode switch to max [3 sec]\n");
 	printRCCalibration();
 }
 

flix/util.h

@@ -36,11 +36,14 @@ float wrapAngle(float angle) {
 // Trim and split string by spaces
 void splitString(String& str, String& token0, String& token1, String& token2) {
 	str.trim();
+	if (str.isEmpty()) return;
 	char chars[str.length() + 1];
 	str.toCharArray(chars, str.length() + 1);
 	token0 = strtok(chars, " ");
-	token1 = strtok(NULL, " "); // String(NULL) creates empty string
+	token1 = strtok(NULL, " ");
 	token2 = strtok(NULL, "");
+	if (token1.c_str() == NULL) token1 = "";
+	if (token2.c_str() == NULL) token2 = "";
 }
 
 // Rate limiter

flix/wifi.ino

@@ -24,6 +24,8 @@ void setupWiFi() {
 		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());
+	} else {
+		return;
 	}
 	WiFi.setSleep(false); // disable power save
 	udp.begin(udpLocalPort);
@@ -37,6 +39,7 @@ void sendWiFi(const uint8_t *buf, int len) {
 }
 
 int receiveWiFi(uint8_t *buf, int len) {
+	if (WiFi.softAPgetStationNum() == 0 && !WiFi.isConnected()) return 0;
 	udp.parsePacket();
 	if (udp.remoteIP()) udpRemoteIP = udp.remoteIP();
 	return udp.read(buf, len);
@@ -57,10 +60,12 @@ void printWiFiInfo() {
 		print("SSID: %s\n", WiFi.SSID().c_str());
 		print("Password: ***\n");
 		print("IP: %s\n", WiFi.localIP().toString().c_str());
+		print("RSSI: %d dBm\n", WiFi.RSSI());
 	} else {
 		print("Mode: Disabled\n");
 		return;
 	}
+	print("Channel: %d\n", WiFi.channel());
 	print("Remote IP: %s\n", udpRemoteIP.toString().c_str());
 	print("MAVLink connected: %d\n", mavlinkConnected);
 }

gazebo/Arduino.h

@@ -151,7 +151,7 @@ public:
 	void setRxInvert(bool invert) {};
 };
 
-HardwareSerial Serial, Serial2;
+HardwareSerial Serial, Serial1, Serial2;
 
 class EspClass {
 public:

gazebo/flix.h

@@ -43,9 +43,10 @@ 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 *channel, uint16_t zero[16], uint16_t max[16], const char *str);
+void calibrateRCChannel(int*, uint16_t[16], uint16_t[16], const char*);
 void printRCCalibration();
 void printLogHeader();
 void printLogData();