Geoff997 on SlotForum did some clever updates to the machine, to improve the debris shield, as well as to make a standalone/portable machine that runs on battery power. Check out his posts on SlotForum here: https://www.slotforum.com/threads/the-g-s-tire-grinder.211214/post-2606992
The images above include a photo of the inside of the base with electronics, as well as the wiring diagram.
Parts List (non-affiliate links to Amazon)
If you make this version, be sure to pop into SlotForum to say thanks to Geoff997 for his work!
The author remixed this model.