Here’s a quick demo that FAT’s [Theo Watson] put together. It uses the iPod’s accelerometer to measure how fast it’s spinning and plays the sound file accordingly. This only works on the iPod touch 2nd gen because of its curved case. He says scratching is coming next, but currently the app doesn’t know which direction it’s spinning since it’s measuring outward force. This project was done in response to [vanderlin]‘s AR scratching that used fiducials on records.