There’s an RGB LED controlled by an ATtiny85 and coin-cell on a custom PCB. Grab the design files on his repo. There was also a ‘punt’ badge. The SecKC folks built a badge (shown later in ...

The Wildcard Office can create custom 2-1/8" x 3-3/8" plastic badges/ID cards for your school/department for $10 each ($15 for ...