I have cheap, NOS aerial rotator with a broken controller. The way it works is pretty primitive... the motor runs 24V DC with polarity determining the direction of rotation. The controller has a motor geared down to run at the same speed to give crude synchronisation. Due I assume to its age, one of the plastic controller gears has shattered so I intend to make a new controller with a Nano. To do that, I need to sense exactly where the rotor is and ideally add end limit switching besides the software limits.
Under the rotator there is the rotor spindle with not much exposed and the motor with not much access to its spindle.
What ideas do you have for doing the sensing please?