I've finished designing and making these really cute robot figures. They will be used for soldering projects in workshops I do. The heart shaped copper tape is cut using the vinyl cutter. The white part of the robot is cut on the laser cutter. They will also be available as finished products in the idea Museum store (while in stock).
These robots are made with 2 transistors, 2 color changing LED's, 2 batteries, melamine (white board type stuff), and copper tape. The way they work is when a tiny amount of current goes through you finger it goes to the transistors. Transistors work by being closed (allowing no current) allowing no current when they aren't activated to allowing current to go through when a small amount of current is applied to the middle pin. By having 2 transistors we can make it more sensitive to a lower amount of current. This is called a Darlington Pair.