flix/docs/troubleshooting.md

Troubleshooting

The sketch doesn't compile

Do the following:

• Check ESP32 core is installed. Check if the version matches the one used in the tutorial.
• Check libraries. Install all the required libraries from the tutorial. Make sure there are no MPU9250 or other peripherals libraries that may conflict with the ones used in the tutorial.

The drone doesn't fly

Do the following:

• Check the battery voltage. Use a multimeter to measure the battery voltage. It should be in range of 3.7-4.2 V.
• Check if there are some startup errors. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button to make sure you see the whole ESP32 output.
• Make sure correct IMU model is chosen. If using ICM-20948 board, change MPU9250 to ICM20948 everywhere in the imu.ino file.
• Check if the CLI is working. Perform help command in Serial Monitor. You should see the list of available commands.
• 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.
• Make sure you're not moving the drone several seconds after the power on. The drone calibrates its gyroscope on the start so it should stay still for a while.
• Check the IMU sample rate. Perform imu command. The rate field should be about 1000 (Hz).
• Check the IMU data. Perform imu command, check raw accelerometer and gyro output. The output 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, make sure rotateIMU function is defined correctly in imu.ino file.
• 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).
  • mfl — should rotate front left motor (clockwise).
  • mrl — should rotate rear left motor (counter-clockwise).
  • mrr — should rotate rear right motor (clockwise).
• Calibrate the RC if you use it. Type cr command in Serial Monitor and follow the instructions.
• Check the RC data if you use it. Use rc command, Control should show correct values between -1 and 1, and between 0 and 1 for the throttle.
• Check the IMU output using QGroundControl. Connect to the drone using QGroundControl on your computer. Go to the Analyze tab, MAVLINK Inspector. Plot the data from the SCALED_IMU message. The gyroscope and accelerometer data should change according to the drone movement.
• Check the gyroscope only attitude estimation. Comment out applyAcc(); line in estimate.ino and check if the attitude estimation in QGroundControl. It should be stable, but only drift very slowly.