An overhead projector programmed as a musical instrument.
Blair Neal, a Fine Arts student from New York, has created an art project installation called Color a Sound. Each colored marking made on a transparency produces a corresponding sound as it passes a sensor. The user can vary the speed of the composition by changing the rolling speed of the transparency. It can be played backwards and compositions can even be stored and played back later. Different colors produce different octaves, maximizing the range of the device. The application is written in the interactive programming environments of Max/MSP and Jitter.
Here’s a video of Color A Sound in action.