video://www.youtube.com/watch?v=N5rGj1xyUdA
Check out this cool DIY servo electric guitar. I am not a guitar expert here but this thing is cool!
A servoelectric guitar is a fretless guitar that is played by controlling servomotors that change the tension of the strings over an octave or more on a real-time basis. Tuning is maintained by closed loop tension feedback for rapid and predictable response. Relatively small electrical motors and DC servo amplifiers are possible through a novel compensator spring design.

Other interesting stuff at Zedomax.com: electric guitar, fretless guitar, guitar expert, novel, predictable response, real time, servo amplifiers, servomotors, spring design, tension, time basis
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