[xander] built this LED valentine for his loved one. It’s interesting because he used Pyralux, a flexible circuit board material from DuPont. He describes the consistency as “tough plastic tissue-paper”, but had no trouble using standard 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.
Normally driving an LCD requires seven connections to pins on the display, but by using a shift register, [Phillip Warner] at Arduino Playground was able to drive an LCD using only 3 wires. The method is cheaper than a serial LCD, but you’ll mainly save yourself a lot of effort and time by using it.
[Warner] used a HEF4094 chip to group the lines together and a variable resistor to control the contrast. A zip file with the requisite code to make this work can be found in the post.