A good friend, Kerry Scharfglass, makes dragonfly badges for DEF CON. I decided to test my soldering skills and make a dead-bug (pun fully intended) version of the badge. It uses a small 0.5mm pitch QFN package MCU, boost regulator from a single AA battery and 10 APA102 LEDs.
The outline of the dragonfly provides the GND connection and every piece of wire carries current. Capacitors were discovered to be great structural elements too!
After programming and verifying functionality, I milled a mold on the Othermill and cast it in polyester resin. The programming header and power connections were all sanded flush with the resin surface so can be accessed. Some polishing later and it came out rather nicely.
Fred Temperton 