As the turntable rotates, a camera reads the fluorescent tinted plexiglass (red, yellow and blue). The camera acts as the input detection, picking up the colours and positions of the pucks, but also as the visual feedback for the audience (displayed behind the performer). The speed of the turntable can be adjusted, as well as which colours are being detected. Whilst the input remains the same, experiments in using it as a drum machine and granular synthesis have been tried by Spencer.
Also on Create Digital Music.