With all the focus on biological problems, we might forget that sometimes it’s handy to know about radiation hazards, too. [Ryan Harrington] shows us how to make a Geiger counter with very few parts, and you can see the results in the video below.
The glut of surplus Russian tubes has made this a common project, but we were amused to see the main part of the high-voltage supply was gutted from a cheap electronic flyswatter sourced from Harbor Freight. Even without a coupon, it only costs about $4.
There’s also a stack of zener diodes, a transistor, and some resistors. A battery, a piezo speaker, and a switch round out the bill of materials. Even then, the switch was upcycled from the flyswatter, so there’s not much to buy.