3D Digitizer CMM Arm

This is the beginning of a design of a 3D digitizer arm. All parts will be able to be 3D printed. The software is currently being developed on an Arduino Uno, It uses pin change interrupts, Four channels. THere is a github project:

https://github.com/Tek-User/CMM-Arm

The base is hollow to allow it to be filled with a heavy material. I used lead shot, but any heavy non-liquid will work. Sand might not be dense enough, and maybe a bit too fine. The encoder can be inserted/removed without disturbing the weight material.

Encoders are Omron E6B2-CWZ6C 2000P/R. These give 8000 quadrature changes per rotation! That is a rotation resolution of 0.045 degrees! They are available on Ebay for about $25 each. This design uses four of them.

The holes for the encoder axles need to be reamed to 6mm.