For this hackathon, we did…drumroll please… Piano Stairs! We installed these (very sneakily) on a staircase in the Friend Engineering Center.
How did we do this? Along one side of the stairs are photoresistors (aka light sensors). On the other are flashlights. An Arduino Uno reads in values from the photoresistors, and calibrates itself appropriately when started. Then, it determines when a footstep occurs based on those light values. It sends that info to a Raspberry Pi, which handles producing the actual sounds.
People really enjoyed the piano stairs, so, I think it was a success.
Most terrifying was when they asked us to move the stairs into the final demo room (there were two rounds of demos). We had ~10 minutes to move everything. Shockingly, it worked, and we won 2nd place for hardware!