We used openFrameworks for our Shadow Wall at the Loop festival in Brighton last weekend. After triggering ultrasonic sensors connected to an Arduino, users have their movements recorded until they trigger the stop sensor. The movement is saved as a silhoutte movie and up to twenty past recordings are played backed back as overlays.
Next time it comes out to play we’ll post beforehand.
See it here:
http://loop2008interactiveart.blogspot.com/
cheers