If you need to know the position of a shaft, this encoder can do what you want. You will need to line up a row of surface-mount LEDs on one side and phototransistors on the other. The output is in binary from 0-127. The outer row of holes is the 'clock', that is, the data is valid only when light is shining through one of these holes. You can decode the wheel either with a microcontroller or simply use an 8 bit latch. I designed this wheel to provide feedback to a servomotor driving a tracking antenna.

A good printer is needed to print this!