Detect radiation for fun and profit

Before, every well-stocked doomsday bunker had a Geiger counter. These days you don't need to have a big tube meter. You can inexpensively get a compact digital instrument to meet your radiation detection needs. [DiodeGoneWild] examines and dismantles such an FNIRSI unit. The case looks like several other similar instruments we've seen recently, so presumably someone is mass producing these portable meter cases. You can see the video, below. The meter reads absolute radioactivity and can also measure cumulative exposure.

After measuring some common radioactive elements, we come to disassembly. Inside, of course, is an ordinary tube. A few screws reveal a typical rechargeable battery, a fairly simple circuit board with a microcontroller and a battery backup for the real-time clock. Much of the board is involved in voltage multiplication up to the several hundred volts needed for the Geiger tube.

The other side of the PCB only has buttons, a vibration motor and, of course, the LCD screen. We don't know how you could test relative accuracy other than by comparing it to a working meter. The bare tube was, of course, more sensitive without the plastic cover, but that could also be calibrated.

A Geiger counter does not need to have a lot of parts. Either way, a surprising number of things will trigger them.