Jimi would be proud. Eight Purdue University students have concocted what's being dubbed a Ghost Pedal; for all intents and purposes, it's a sensor-based processor that's worn around the ankle of the player, and it enables wah-like effects to be commanded from anywhere on stage. Specifically: "The variable resistor sensor records what the user is doing with their ankle, and a sustain sensor either accepts the transmission feed or ignores / sustains it." We're also told that once it's turned on, the user enters a 10-second mode during which the variable resistor calibrates the ability to flex the foot from the floor in a normal pedal motion; after calibration mode, the guitarist enters freeplay mode. As of now, it's available for licensing, and there's a video just past the break to help you make up your mind.

Hands-on with TheAppBuilder at SXSW (video)