A new Hackaday project, ArcaEge’s Capacitor Alarm Clock, is built around an ESP32 that triggers a relay to overload a low-voltage electrolytic capacitor—creating an explosion meant to wake its owner. The creator frames it strictly as entertainment, not a safe
There are alarm clocks that chirp. There are alarm clocks that vibrate. And then there’s ArcaEge’s Capacitor Alarm Clock. a project that wakes its owner by blowing up electrolytic capacitors with reverse voltage. It’s the kind of idea you don’t try to recreate—ever—but it’s also exactly the sort of build that makes the Hackaday feed hard to scroll past.
The premise is simple: an ESP32 serves as the clock, then triggers a relay for the alarm. That relay, in turn, overloads a suitably low-voltage electrolytic capacitor placed in a socket. The capacitor failure is the wake-up call—an explosion captured in a video included with the project.
The design draws inspiration from an ElectroBoom video, and the warning that comes with it is just as direct as the mechanism. The project is presented only for entertainment, with an explicit note that it isn’t the safest of hacks and shouldn’t be done at home.
What makes the build more than just a spectacle is the attention to the details of electrolytic capacitors. It even offers a point of interest around identifying the difference between capacitors with a vent and those without—something that matters when you’re dealing with how these components fail under stress.
This isn’t the first time makers have built projects around exploding capacitors. The earlier one, the write-up notes, was also a “don’t-do-this-at-home too” situation.
If you’re looking for a gentle wake-up routine, this isn’t it. But if you’re looking at how far an ESP32 and a relay can push a deliberately vulnerable component into spectacular failure, the Capacitor Alarm Clock is certainly doing its job—provided you’re the one who survives the lesson.
Capacitor Alarm Clock ESP32 electrolytic capacitors reverse voltage relay alarm Hackaday ElectroBoom DIY electronics electronics hack warning