Thanks for the feedback - I should have done a proper autopsy and pulled all of it apart (which I've just done so!), and you're right: it's a rotary encoder.Small correction: I am pretty sure that is not a potentiometer ("pot", for short). Pots usually have hard limits on their rotation, and they are usually less than 360 degrees apart. Instead, it is more likely to be a simple, non-addressable rotary encoder: https://en.wikipedia.org/wiki/Rotary_encoder, more specifically, its probably an incremental encoder https://en.wikipedia.org/wiki/Incremental_encoder. These don't have hard stops on them usually, and can rotate more than 360 degree. I supposed you could do the trick with a pot, but I am not sure why you would since it would probably be easier to do with an encoder since that would likely already be digital (and a pot would require an ADC somewhere in the system).