Grumpy_Mike:
No need for a dxf file, it is just a disc with a hole in it.
The sketch to is trivial, either use the standard interrupt count example or simply count the pulseIn the relevant part of the sketch.
I'd like the DXF so I can cut the disk using a mill.
The sketch I'm thinking of using is the one provided here: Redirect Notice
Just, how do I adjust the sketch to suit the 100mm encoder disk?
Also the Opto won't work without breaking the beam, so I'm pretty sure the disk needs a number of breaks/ holes, and the sketch counts the number of interruptions to determine shaft location.
Is this correct?
Thanks again for the help.