Quadcopter

Minimal quadcopter demo program

Required Hardware

IMU sensor (SPI or I2C)
RC receiver with 5 channels (CRSF/ELRS preferred)
4 brushless motors with ESCs

Connecting Hardware

SPI IMU: connect IMU_EXTI, IMU_CS, SPI_MISO, SPI_MOSI, SPI_CLK
or for I2C IMU: connect IMU_EXTI, I2C_SDA, I2C_SCL
RC receiver: connect RCIN_RX to receiver TX pin
ESCs: PWM1-4 to the ESC inputs

Motor order diagram (Betaflight order)

      front
 CW -->   <-- CCW
     4     2 
      \ ^ /
       |X|
      / - \
     3     1 
CCW -->   <-- CW

Default flight mode is RATE. The mode can be changed to ANGLE by changing the PID controller in imu_loop(). Important: calibrate the accelometer before using ANGLE.

RATE Mode

The roll/pitch stick inputs control the rate of change. Keeping the sticks centered will keep turning at the current rate.

ANGLE mode

The roll/pitch stick inputs control the roll/pitch angle. Keeping the sticks centered will keep the quadcopter horizontal.

Arming / Disarming

Arming: Set throttle low, then flip arm switch from DISARMED to ARMED.
Disarming: Flip arm switch from ARMED to DISARMED, at any throttle position. "Kill switch".

LED Status

OFF - not powered
startup - a couple blinks then ON while running gyro calibration (don't move)
blinking long OFF short ON - DISARMED
blinking long ON short OFF - ARMED
blink interval longer than 1 second - imu_loop() is taking too much time
fast blinking - something is wrong, connect USB serial for info

Building and Flying

This is one of the quads I use for testing. Note that it does not use the default board for ESP32. And a custom pinout is used, so that the MPU6500 board can be soldered directly with pins to the ESP32 board, and just requires the red wire for 3V. The I2C sensor boards are also soldered directly with pins, plus one black ground wire.