Random four-letter words on a split-flap display (6 minutes)

I just finished building four v0.4 split-flap modules, so what better way to test them than to display a bunch of random four-letter words (no, not that kind!). This design is an open source project I’ve been working on for a few years. The enclosure is laser-cut MDF, flaps are CR80 plastic badge cards with letter stickers applied, driven by 28BYJ-48 motors, and controlled by an Arduino Uno and custom PCB driver board. Each module costs around $25-$30 to build. Source code: