I needed a rotary encoder — I pulled a cheap one out of one of those “49 boards for Arduino” kits you see around. Not the finest encoder in the land, I’m sure, but it should do the job.

Linear encoders measure straight-line motion and are ideal for systems requiring precise linear displacement, such as milling machines or precision stages. NOTE: The choice between linear and rotary ...

Encoders bearing the CE mark (Communaute Europeene) are guaranteed to meet electromagnetic compatibility standards. Historic notes. BEI’s roots in optical encoders go back to the late 1940s ...

Optical encoders are beneficial for robotics applications that need precise and dependable feedback and control of the rotation, speed, or positioning of motors, wheels, arms, and other moving parts.

Rotary encoders come in two basic varieties: absolute encoders report the actual position of the shaft at a specific time, while incremental encoders indicate relative changes in the shaft’s position.