Design Highlight:

Automatic Cup Holder

A cupholder that hides when you don't need it and slides out with a wave of your hand. Set your mug down and it stays put for as long as the cup is there. Pick it up and walk away, and after a few minutes it quietly tucks itself back in.

The whole mechanism is self-contained, so you can build it into a desk, a shelf, or whatever housing fits your setup. It runs on an ESP32 with a few cheap parts, and the STL files and instructions are available now.