So far, I have decided to use a standard NEMA 17 stepper motor, and have tested it out to confirm that it has enough torque to turn the pegs on my ukulele. I used a L298 motor module with an arduino uno, using code i found that comes with the arduino program. Now, I'm splitting my time between using peizo vibration sensors and designing the overall product with CAD. I am working on an initial design that will connect the motor to the peg better the than very ratchet set up I have shown. The first design has too much space so my next attempt will just be a slot that the peg can be inserted into. Once I get that sorted out, I will focus on getting readable and accurate vibration data from the piezo sensor/accelerometer that I've ordered.