I needed a way to adjust zoom without touching the camera and had some spare parts from upgrading my tornado. I made a remote controlled zoom adjuster for the Canon RF 24-105 using an extra stepper motor, arduino, stepper driver, and old power supply.

This thing includes:

120 tooth lens gear for RF 24-105 lens
40 tooth nema 17 motor gear with 'D-shaft' hole
15mm rail mount compatible with the cheap neewer rail rod support system

The gears fit together perfectly when printed at .1 mm resolution