Ethan David just messaged me and sent me a video:

“ I made the robot using an arduino, a servo motor, and cardboard boxes. Most of the heavy lifting is taken care of in python doing the fast fourier transform on the sound detected by the microphone to find the frequency being played. This allows me to compare the frequency to the known frequency of the musical scale. It then becomes trivial to just program in the correct sequence of notes for the song and see if what I play matches it. „