Codewheel
It lets you design a codewheel for any type of homebrew optical encoder.
The codewheel generator is a versatile, simple program that lets a user design a codewheel for just about any type of homebrew optical encoder project, then easily print the wheel image on a home inkjet or laser printer.
With a good code whee in hand and having cobbled some way to mount said codewheel to a shaft, building and mounting suitable photodetector arrangement(s) will let the experimenter replace very expensive commercial optical encoders in home-built equipment. For projects where encoders were previously cost prohibitive, the homebrew encoder option expands a hobbyists design horizons.