Mechanical amplificator/synth.
The instrument make use of the rotation of dc motor to excite a wood membrane. Motors have to be strongly tighten to the wood membrane at best including the motors in a wooden bridge pulled by iron strings.
A simple arduino shield has an audio input (for frequency determination) driven by a simple operational preamp and a MIDI input. According to the note to be played the PWM outputs drive a FET power transistor to control motor spin.