YouTuber NonZero needed an loud alarm that would go off if it vibrates for over two minutes. While most of us would design something on a PCB and call it a day, he went the extra mile — several extra miles that is — and built a sensor as if it was going to be used in a tank.
This has apparently paid off, because after five months of 24/7 continuous use, it has worked flawlessly. As the explainer video shown below notes, he’s upgraded it from a perfboard construction to a professionally-made PCB as a sort of reward. He’s using an Arduino Nano for control in the final version, along with industrial-style LEDs to indicate the device is on and when it senses vibration. LEDs, along with a very large alarm, are actuated by MOSFETs, and vibration is detected via an AVXL335 accelerometer. A tilt switch provides the power on/off functionality.
The unit is fastened together with the help of a copious amount of hot glue, including on the wire connections themselves to provide strain relief. The power cabling is protected by a very rugged structure meant for use with a steam iron, and the unit is isolated from the warm surface that it monitors with four long spiky legs.