If you’re reading Hackaday, there’s a good chance you had a rock tumbler in your younger days. Hell, we’d put odds on a few of you having one rumbling away in the background as you read this.

If you’re reading Hackaday, there’s a good chance you had a rock ... being only rated for 12 V, the electromagnet is being fed off of 24 V for this project. This gives the tumbler a bit ...