Untrickable laser alarm, with an easy-to-knock-out fusebox.

A tribute to (the alarms in) Mark of the Ninja.



In the game you have to sneak into buildings with high tech alarms. Some of the laser traps can be deactivated by knocking out the fuse box with a dart.

So I made a laser alarm with a fusebox that can be knocked out. This is mainly to keep kids occupied, and motivated to practice throwing.


  • Glowing ⚡ with simple animations and color changes (start-up, alarm, sparks)
  • Laser triggered alarm, which can’t be fooled by using a separate laser or flash light. This is done by pulsing the laser and making sure photo resistor is relatively dark when laser is off.
  • Motion activated “play dead” (throw somehting on the fuse box, and it will black out for 10 seconds).
  • Play sounds for alarm, sparks, start-up


Demo setup

Knocking out the alarm (~3MB).

Attempting to fool the alarm (~2MB).


Not shown here: speaker and tiltsensor.

See gitlab for build instructions and code.