Frank Piesik recently designed a robotic three-stringed instrument for his friend, Gregor, that features a unique sound and mechanical arrangement. Notes are selected by an array of 12 servos — four for each string — which pull down using a loop mechanism. 

The aptly named Greg’s Harp is played by a solenoid-driven “KickUp” device that hits it from below and a small motor that continuously swipes with a “tape-propeller.” A coil assembly is also implemented to give the notes the ability to keep ringing for as long as needed (infinite sustain).

Everything is controlled by pair of Arduino Nano boards, which allow for the large number of outputs needed here, along with a Teensy 3.2 for audio processing and MIDI capabilities. You can see and hear this amazing project in the video below and more info is available in Piesik’s blog post.