FLEXIBLE CIRCUIT VALENTINE

[xander] developed this LED valentine for his liked one. It’s interesting because he used Pyralux, a flexible circuit card material from DuPont. He explains the consistency as “tough plastic tissue-paper”, but had no trouble using conventional toner transfer etching. It has an ATtiny45 microcontroller that pulses the 16 LEDs at an approximation of his heart beat. To avoid soldering a bunch of surface mount resistors, he used two constant current shift registers.