Derek writes in with this awesome ribbon controller that could be hiding in your wallet… –
“Using the magnetic strip on the back of my driver’s license to make a ribbon controller which then controls Autofilter in Live 6 via MIDI.
5v is connected to one side of the license’s mag strip, ground to the other. The 3rd alligator clip is connected to one input of an ADC0808 8 bit parallel ADC with is being clocked by a Ubicom SX microcontroller, the other end to the silver tape on the license (the sliver tape is metal tape for duct work, etc., available at Lowe’s, Home Depot, etc.). Bridging the tape with your finger makes the ADC “see” the voltage at that point.” – Link.