Alert Sound xkcd.com/3100/
672 reposts4.8K likes
Alert Sound xkcd.com/3100/
672 reposts4.8K likes
butfirstjoy.com/annoy-a-tron... I have the original circuit board with a piezo and battery holder soldered on. With a magnet on the back. It's roughly the size of a stick of gum. These would, randomly, between 2 and 8 minutes, make a "buzz" sound or a beep (it was all random)
Title text: "With a good battery, the device can easily last for 5 or 10 years, although the walls probably won't." Alt text: https://explainxkcd.com/3100#Transcript