Bare Conductive’s Electric Paint ($24.95) is the perfect way to make a robot’s exterior interactive. The paint works just like a button. When correctly connected to the necessary electronics, touching the paint can trigger all kinds of actions. Design paintable buttons that turn on LEDs, play sounds, or make your robot’s arm move up and down.
Simply apply the water-based paint to the surface of your bot making whatever shape or design you like. You can use copper tape to connect the painted sensor to your bot or, to make things even easier, hook it right up to the Bare Conductive Touch Board ($89.95).
You can buy both products online, from Sparkfun.