Encoder wheels to be used with fork sensors/fork light barriers.
Generate an encoder and export the file. As open scad currently only exports lines you need to fill the interrupter areas in a separate program (e.g. Inkscape), and make the lines as thin as you desire.
Once done print it on a transparent sheet. Make sure to set your printer to print with maximum contrast. Even with those settings I had to print two layers in order to make it work reliably.
3D: !!!!not tested yet!!!!
generate, print, enjoy