The Arduino Eye Shield is a circuit board that can be plugged on top of the Arduino allowing it to interpret analogue video (PAL or NTSC) from a camera or other source. It gives the Arduino the power of sight - www.davidchatting.com/arduinoeyeshield
This has a variety of applications. The Reflections in Cider installation uses it to illuminate a matrix of LEDs in a window display, to create a video-mirror of the passersby.
Photo by Alex Healing