I attended the NZART branch 5 meeting in ChCh while there last week and was intrigued to see the device pictured below.
Basically a laser is pointed at the mirror suspended on glad-wrap in the ice-cream container. The laser beam is bounced across the room by the mirror where it is focused on the receiver's photo-sensitive pickup.
One person can then speak into the back of the ice-cream container which will vibrate the mirror, therefore oscillating the mirror and subsequently the laser beam. At the other another person can hear the first person speaking.
Voice over light! Very cool :)
