The echoing sounds of a mad pianist banging out the theme to Harry Potter drew me to find the source. Hidden behind a crowd of bedazzled onlookers a piano plays its music.
This is the work of Ramon Yvarra, and his piano. Once a standard player piano, this musical anachronism has been retrofitted with brains that can speak to computers. He created his own custom circuits to drive the system, and it has an Arduino as the brains. He can connect from his laptop via Wi-Fi to feed the instrument new music and visualizations at the push of a button.
Many modern versions of player pianos end up with solenoids completely replacing the original mechanics. Yvarra opted instead to keep as much of the original pneumatic system in place as possible to keep the authentic sound. That massive LCD panel departs from this direction a bit, but once you see it in action, you’ll agree that it all works together quite harmoniously!
If you would like to know more and see pictures of his build process, you can read this in-depth account by Yvarra.