https://www.techradar.com/news/nintendo-labo-contest-winners-turn-the-switch-into-an-accordion-and-alarm-clock

Nintendo has announced the winners of its Labo Creator Contest. Intrepid cardboard wranglers have turned the Switch into a “solar-powered” accordion and an alarm clock.

Momonga906’s entry is the Labo accordion. It uses holes punched into a “kleenex box”. A light sensor underneath detects which hole is being blocked, to determine the right note.