I don’t really know where to start. Any tips?
The keyword you are looking for is “encoder”.
So with AOG running the steering wheel is still and you want to detect when it starts to move manually?
If so. You could try printing a ring with magnets say every 1.5” then use a Hall effect sensor with ISR on change. That might trigger false readings if it sits halfway on a magnet. So best would be to put two sensors 1/2” apart and wait for them both to trigger just a high interrupt in a certain period of time.
Just a theory. Don’t have my AOG setup to try yet. But have a bit of a background in sensors and micro controllers.