MAKE Flickr photo pool member Devowski writes –
“Latest keyboard… thing. Controlled by a record player. In the arm of the turntable there are 3 photo cells (light sensors) that are wired into the circuitry of the casio. The record on the player has three red leds mounted on it… when the leds pass under the photo cells, it causes a glitch in the keyboard, making some stange noises…” – Link & video.