An optical encoder used for motor position sensingSimilar in theory to optical tonewheels are these rotary encoder. They’re used for position sensing in robots and high-end machinery. An optical reader can tell the exact position of the motor shaft to a high level of precision.
![opticalEncoder-italsensor[dot]com](https://i0.wp.com/www.jeffreythompson.org/blog/wp-content/uploads/2010/02/opticalEncoder-italsensordotcom.png?resize=525%2C525 "opticalEncoder-italsensor[dot]com")
do you have a higher res version?
I don’t, sorry!