madflight

Manless Aerial Device

This is a 1500 line Arduino ESP32 & RP2040 flight controller, forked from dRehmFlight.

Required Hardware

• Development board: RP2040 (e.g. Raspberry Pi Pico) or ESP32 (e.g. Espressiv DevKitC)
• SPI or I2C IMU sensor: MPU6050, MP6500, MPU9150, or MPU9250
• RC Receiver: PPM, SBUS, or DMX
• BEC or DC-DC converter to power your board from a battery
• ESC (OneShot125 or 50-490Hz PWM) and/or servos (50-490Hz PWM)

Getting Started

1. Setup the USER-SPECIFIED DEFINES section in the main code, and configure the pins in hw_ESP32.h or hw_RP2040.h
2. Connect the IMU sensor and radio receiver to your development board according to the selected pinout.
3. Edit the RC RECEIVER CONFIG section in the main code. Either match you RC equipment to the settings, or change the settings to match your RC equipment. Uncomment print_rcin_RadioPWM() to check.
4. Uncomment print_ahrs_RollPitchYaw() and check that IMU sensor and AHRS are working correctly. Uncomment lines in setup() to calibate the sensor.
5. Connect motors (no props) and battery and check that motor outputs are working correctly. For debugging, use print_out_MotorCommands() and calibrate_ESCs()
6. Mount props, go to an wide open space, and FLY!

Software Design

• Keep it simple!!!
• No external dependencies, all library code included in src directory
• The main .ino is the full flight controller running standard setup() and loop().
• Plain C with minimal function arguments.
• Global variables to communicate between the different modules.
• Function names are prefixed with the module it belongs to:
  • loop_ Main loop control
  • imu_ Inertial Measurement Unit, retrieves accelerometer, gyroscope, and magnetometer sensor data
  • ahrs_ Attitude Heading Reference System, estimates roll, yaw, pitch
  • rcin_ RC INput, retrieves RC receiver data
  • control_ PID controller and output mixer
  • out_ Output to motors and servos
  • print_ Prints debugging info
  • calibrate_ Calibration

Default Pinout for ESP32 DevKitC (38 pin)

Function	GPIO	Board	GPIO	Function
3V3 out	3V3	Antenna side	GND	GND
reset button	EN		23	I2C_SDA
VSPI_MISO	VP 36 input only		22	I2C_SCL
IMU_INT	VN 39 input only		1 TX	USB Serial Debug TX
FREE	34 input only		3 RX	USB Serial Debug RX
RCIN_RX	35 input only		21	VSPI_MOSI
RCIN_TX	32		GND	GND
PWM1	33		19	VSPI_SCLK
PWM2	25		18	VSPI_CS
PWM3	26		strap 5	PMW13
PWM4	27		17	PMW12
PWM5	14		16	PWM11
PWM6	12		4	PWM10
GND	GND		boot 0	PWM9
PWM7	13		strap 2	LED
nc	D2 9 flash		strap 15	PWM8
nc	D3 10 flash		flash 8 D1	nc
nc	CMD 11 flash		flash 7 D0	nc
5V in (*)	5V	USB connector	flash 6 CLK	nc

(*) 5V input via diode from BEC. Without a diode take care not connect USB and the battery at the same time!

Default Pinout for Raspberry Pi Pico

Function	GPIO	Board	GPIO	Function
RCIN_TX(tx0)	0	USB connector	VBUS	nc
RCIN_RX(rx0)	1		VSYS	5V input via diode (*)
-	GND		GND	-
PWM1	2		EN	nc
PWM2	3		3.3V out	3V3
PWM3	4		VREF	nc
PWM4	5		28_A2	FREE
-	GND		GND	-
PWM5	6		27_A1	FREE
PWM6	7		26_A0	FREE
PWM7	8		RUN	reset button to GND
PWM8	9		22	IMU_INT
-	GND		GND	-
PWM9	10		21	I2C0_SCL
PWM10	11		20	I2C0_SDA
PWM11	12		19	SPI0_MOSI
PWM12	13		18	SPI0_SCLK
-	GND		GND	-
PWM13	14		17	SPI0_CS
PWM14	15	JTAG pins	16	SPI0_MISO

(*) 5V input via diode from BEC. Without a diode take care not connect USB and the battery at the same time!

Change Log

2023-12-11 Use C++ template for flexible I2C implementations 2023-12-06 Add setup1() and loop1() for ESP32
2023-12-06 Add IMU orientation setting
2023-12-05 Initial release

Changes from dRehmFlight

• Add support for RP2040 and ESP32
• Dropped Teensy support, but could be re-added by creating a hw_TEENSY.h file. (I just don't have the hardware to test on)
• Moved all hardware specific code to hw_ESP32.h and hw_RP2040.h and added hardware specific libraries
• Reduced the number of global variables
• Oneshot is implemented as PWM up to 3.9kHz
• New libs for IMU sensors
• Changed arming logic

Flight Controllers on Github

In increasing order of complexity.

• lobodol/drone-flight-controller Arduino ATmega328P, single 700 line ino file, no libs
• dRehmFlight Arduino Teensy 4
• madflight Arduino RP2040 & ESP32
• Crazyflie STM32F405
• esp-drone ESP32, forked from Crazyflie
• Betaflight STM32
• Ardupilot STM32 or Linux based