[Donut]

I don't know how to do an angle sensor, but an idea I've had is to attach an intake roller to an axle, then position a limit switch so the metal end of it gets hit by the intake roller. Since the roller and metal are flexible, they can bend and let the roller spin. The roller spinning one way will trigger the limit switch, the other way it won't.

I haven't tested this of course, just an idea.