Old Civil Defense survey meters like the V-715 are interesting conversation starters, but of very little practical use today. These devices were intended to be a sort of litmus test that survivors of ...

Every mad scientist’s lair needs a Geiger counter. After all, if that UFO crashes on the back patio, you might need to know if it is hot. [Tanner_Tech] shows you how to build a cheap one that will get ...

I got some Geiger tubes a few days ago and built a very simple Geiger counter circuit that is powered entirely through the microphone jack (microphone connection provides a little power for things ...