A homemade alarm clock gives the sleeper five seconds to stop the alarm before a loaded banknote is fed into a shredder. Instead of merely continuing to make noise, the device makes oversleeping carry a physical monetary consequence.

The Arduino-based build was published by the Japanese maker channel Mechatro on September 12, 2026.

If an alarm sound is not enough, why not have the clock play a 720×720 video when it's time to wake up? The Video Alarm Clock uses an ESP32-P4-based Waveshare module and can store plenty of clips on an SD card.

The futuristic part comes with some very old-fashioned requirements: AVI with MJPEG and PCM, plus classic 8.3 filenames. The display feels modern; preparing the files suddenly feels like an earlier era of computing.