Cheap Encoder

thingiverse

A straightforward 16-step encoder can be crafted using Radioshack components, as found here: http://www.radioshack.com/product/index.jsp?productId=2049723. For potential additional steps, consider this option from Thingiverse: http://www.thingiverse.com/thing:1527. Customize this circuit to suit Radioshack parts by referring to this tutorial: http://www.pyroelectro.com/tutorials/simple_motor_encoder/theory.html. It even details microcontroller implementation later on. For optimal signal, print the disk raftless and color dull areas with a sharpie; the reflective plastic surface will suffice. Assemble using a 1 M3x16mm screw.