today i found some cheap led christmas fairy lights in the supermarket. they are ideal for building jeff han’s multitouch displays. it’s a line of 40 leds in a row with a 3V power supply. each blue led can be easily replaced by a IR led without soldering.
i built a small setup in 10 minutes. it works. the edges of the plexiglass have to be polished and the blue leds replaced by IR ones..