Scratch DJs, or turntablists as they like to be known, thrive on the tactile interface of a vinyl record which they carefully spin and manipulate by hand to create their art. More recently people have come up with various way to control digital files as if they were records, but none seem quite a slick as this setup using two iPod Touches or iPhones.
With Mopho DJ you mount an iPod Touch or iPhone on each platter where the record would normally sit, and then as the platter moves, the accelerometer and gyro data is sent wirelessly to a laptop. This data is then used to control the playback of digital files just as if they were records. What's really cool is that the Touch's display gives a visual readout of the audio in both directions, making it easier for the DJ to locate the precise location of a downbeat.
Similar systems are available that use special records with timing data on them, but Mopho DJ achieves the same thing without having to worry about bent needles, skipping records and phono preamps. Now your main concern will be trying to stop people from swiping your iPods.
Developed by Nick Bryan and Ge Wang at Stanford University's Center for Computer Research in Music and Acoustics, Mopho DJ will be presented at the New Interfaces for Musical Expression conference in Norway at the end of May. A commercial version is expected to follow later.