Measure radiation with military surplus

It’s really amazing what you can find at military surplus shops. [David] just built a radiation detector out of a DT-590A scintillation probe originally made to test if Air Force bases were contaminated with Plutonium. Who says nothing good came out of massive nuclear arsenals?

DT-590A / PDR-56 Gamma ray probes were made obsolete by the US Air Force a few years ago and they’re trickling into military surplus stores around the country and the Internet. [David] found the manual for this probe and put together a little circuit to drive this x-ray sensor. The build uses an ammeter as a simple dial, and includes a piezo speaker for the prerequisite Geiger counter ‘clicks.’

[David] also threw up a post on converting this x-ray probe into a general purpose Gamma probe, effectively making it a Geiger counter for the really dangerous radiation. You could always use your smart phone for the same task, but recycling military hardware imparts a good bit of geek cred.

Turn your camera phone into a Geiger counter

Next time you’re waiting in the security line in an airport, why don’t you pull out your smartphone and count all the radiation being emitted by those body scanners and x-rays? There’s an app for that, courtesy of Mr. [Rolf-Dieter Klein].

The app works by blocking all the light coming into a phone’s camera sensor with a piece of tape or plastic. Because high energy radiation will cause artifacts on the CMOS camera sensor inside the phone, radiation will be captured as tiny specks of white light. The title picture for this post was taken from a camera phone at the Helmholtz Research Center in Munich being bathed in 10 Sieverts per hour of Gamma radiation from the decay of Cesium-137.

We have to note that blips of ‘bad data’ from a CMOS camera sensor aren’t unusual. These can come from electrical weirdness in the sensor itself or even the heat from the battery. [Rolf]’s app takes a reading of the noise floor and subtracts it from the counter. Radioactive decay resulting in Beta particles such as the Potassium-40 in bananas or the Uranium in granite counter tops don’t really register, although [Rolf] did have some success with Potassium chloride and a long measurement time. Still though, it’s a really cool way to turn a phone into a tricorder.

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Radiation sensor shield for the Arduino

The [Libelium] team wanted to help people in Japan measure radiation in their surroundings following the nuclear accident in Fukushima. Because of the affordability and seeming ubiquity of the Arduino platform, they have been hard at work this last month trying to get their Geiger counter sensor board for an Arduino out the door. We think they’ve done a remarkable job.

A Geiger tube is a remarkably simple device, but getting the part can be a fairly expensive proposition. Thankfully, [Libelium] has already tested and verified a number of tubes from different manufacturers – very helpful if you don’t want to be tied down to one specific component.

This looks like this is just the sort of thing that the folks at [Seed Studio] wanted for an open hardware radiation detector, and [Libelium] has already shipped their first batch to the Tokyo Hackerspace. It’s good to know that help is going where it’s needed.

Video of the sensor board being tested after the break.

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Geiger counter built in an Ohmmeter enclosure

Here’s a Geiger Counter that makes itself at home inside of an old Ohmmeter (translated). [Anilandro] set out to built this radiation detector in order to learn how they work. Like other diy Geiger Counter builds we’ve seen, this project assembles a circuit to interface with a gas-filled tube which serves as the detector. [Anilandro] takes a few paragraphs to discuss how this works; the Geiger tube is basically a capacitor whose electrical characteristics change as an ionizing particle passes through it.

Once he had the theory worked out he scavenged some parts to use. A broken emergency light donated its transformer to provide the high voltage needed. The rest of the circuit was built on some protoboard, and a speaker was added to output the clicking noises that have become a familiar part of the detector hardware. The tube itself is housed in a wand that attaches to the base unit through a cable. Check out some test footage of the finished unit after the break.

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Geiger counter A/D conversion for radiation level crowdsourcing


[Akiba] and the crew at Tokyo Hakerspace are still hard at work trying to help out their fellow countrymen after the recent earthquake, tsunami, and ongoing nuclear crisis in Japan. You may remember the group as they are behind the Kimono Lantern project we featured last week. This time around, their efforts are focused on getting usable information out to those who need it.

With all of the talk about nuclear fallout, they wanted to see what sort of measurements they could get in Tokyo, however they could not locate a Geiger counter anywhere nearby. Luckily, they were eventually able to source two old counters from the Reuseum in Idaho. One is being lent out to individuals in order to check if their home’s radiation levels are safe, but it was decided that the other would reside outdoors in order to collect radiation readings from the air.

[Akiba] wanted to put the results from the external Geiger counter up on Pachube, however these old units are all analog. He figured that a quick and dirty way to do analog to digital conversion would be to monitor the chirps coming off the counter’s speaker. This was done by wiring up an Arduino to the speaker leads, and keeping track of each time the speaker was activated. This resulted in an accurate digital radiation reading, matching that of the counter’s analog display. The Arduinio wirelessly sends the information to another Arduino stationed inside his apartment, which then uploads the data to Pachube.

A walkthrough of his conversion as well as the source code for both the Arduino counter and the Pachube uploader are available on his site, in case anyone else in the Tokyo area has a Geiger counter handy and wishes to do the same.

HERF gun zaps more than your dinner

Instructables user [Jimmy Neutron] had an old microwave sitting around and figured he might as well gut it to build a high-energy radio frequency (HERF) gun.

The concept of a HERF gun is not incredibly complex. Much like your microwave at home functions, a high voltage power source is used to drive a magnetron, which produces micro wave radiation at 2.45GHz. These waves are then guided away from the magnetron using a waveguide, towards whatever the target might be. These waves then energize the target in a similar fashion as the water molecules in your food are energized during cooking.

[Jimmy] has not quite finished his HERF gun as he still needs to build a waveguide for it and then safely mount it for use. In the meantime, check out the pair of HERF guns we found in the videos below.

As a parting note, we must stress that building a similar device is dangerous, very dangerous – especially if you do not know what you are doing. Microwaves contain high voltage components, and exposure to microwave radiation can be deadly under certain circumstances. Stay safe!

Looking for more microwave fun? Check these out!

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More radiation test gear

This is a multifunction too for measuring radiation (translated). The measurements center around gas discharge tubes that react when ionizing particles pass through them. After reading about the counting circuit for the pair of tubes used in this handheld it’s easy to understand why these are tricky to calibrate. The handheld features a real-time clock as well as a GPS module. This way, it can not only give a readout of the radiation currently measured, but can record how much radiation exposure has accumulated over time (making this a dosimeter). An accompanying dataset records the location of the exposure. An ATmega128 drives the device, which is composed of two separate boards, a series of five navigation buttons, and a salvaged cellphone LCD for the readout. The translated page can be a bit hard to read at times, but there’s plenty of information including an abundance of schematic breakdowns with accompanying explanations of each.

This is certainly feature-rich and we think it goes way beyond the type of device that Seeed is trying to develop.

[Thanks Andrew]