GEIGER COUNTER
This radiation detector clicks, flashes,
logs radioactivity levels, and shares
its data with the world.
By John Iovine
I’ve been designing, making, and selling Geiger counters for
15 years through my company, Images Scientific Instruments.
They’re fundamentally simple devices; you just need voltage high
enough to run the Geiger-Müller (GM) tube. Anyone can design a
counter that will work somewhat, but it’s hard to make one that’s
reliable and long-lasting, because the electronics are so touchy.
Last year I was redesigning my basic
Geiger counter circuit when the earthquake,
tsunami, and nuclear crisis hit Japan. We sold
out immediately, and I was so swamped with
orders that I had to put my improved design
on hold. But I finally finished, and here it is.
You can easily configure this counter to use
a variety of GM tubes. Not only will it output
a click and an LED flash with each radioactive
particle detected, you can also connect it to
analog or digital radiation-level meters, a PC
John Iovine is a science and electronics tinkerer and author
who owns and operates Images SI Inc., a small science
company. He resides in Staten Island, N. Y., with his wife
and two children, their dog, Chansey, and their cat, Squeaks.
SET UP: p. 103
MAKE IT: p. 104
USE IT: p. 110
Gregory Hayes
100 Make: makezine.com/29
