This repo contains open source firmware for generic Hoverboard Mainboards.
The firmware you can find here allows you to use your Hoverboard Hardware (like the Mainboard, Motors and Battery) for cool projects like driving armchairs, person-tracking transportation robots and every other application you can imagine that requires controlling the Motors.
The original Hardware supports two 4-pin cables that originally were connected to the two sensor boards. They break out GND, 12/15V and USART2&3 of the Hoverboard mainboard.
Both USART2 & 3 can be used for UART and I2C, PA2&3 can be used as 12bit ADCs.
To build the firmware, just type "make". Make sure you have specified your gcc-arm-none-eabi binary location in the Makefile ("PREFIX = ..."). Right to the STM32, there is a debugging header with GND, 3V3, SWDIO and SWCLK. Connect GND, SWDIO and SWCLK to your SWD programmer, like the ST-Link found on many STM devboards.
Make sure you hold the powerbutton or connect a jumper to the power button pins while flashing the firmware, as the STM might release the power latch and switches itself off during flashing. Battery > 36V have to be connected while flashing.
If the board draws more than 100mA in idle, it's probably broken.
If the motors do something, but don't rotate smooth and quietly, try to use an alternative phase mapping. Usually, color-correct mapping (blue to blue, green to green, yellow to yellow) works fine. However, some hoverboards have a different layout then others, and this might be the reason your motor isn't spinning.
Nunchuck not working: Use the right one of the 2 types of nunchucks. Use i2c pullups.
Nunchuck or PPM working bad: The i2c bus and PPM signal are very sensitive to emv distortions of the motor controller. They get stronger the faster you are. Keep cables short, use shielded cable, use ferrits, stabalize voltage in nunchuck or reviever, add i2c pullups. To many errors leads to very high accelerations which triggers the protection board within the battery to shut everything down.
Most robust way for input is to use the ADC and potis. It works well even on 1m unshielded cable. Solder ~100k Ohm resistors between ADC-inputs and gnd directly on the mainboard. Use potis as pullups to 3.3V.
