Steering Angle Sensor
Sensor used is the cheap AS5600
Intended for use with a diametrically magnetized magnet, but works with a normal one turned 90 degrees too. It may be a good idea to find bigger neodymium diametric magnets.
Repo with basic code to read the steering angle sensor (Arduino HAL with VSCode Platformio, no IDE): https://github.com/rubenayla/bluepill-angle-arduino.git