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A touch screen Geiger counter without a Geiger tube

geiger

We’re assuming [Toumal] was desperately bored one day, because in the depths of the Internet he found some really cool components to build a solid state Geiger counter.

The Arduino and touchscreen are rather standard fare [Toumal] picked up on eBay for about $30. What really sets this project apart from all the other geiger counter builds we’ve seen is the solid state geiger counter [Toumal] used. This device uses a specially-made photodiode made by First Sensor to detect gamma emissions from 5 to 1000 keV.

[Toumal] put all the software for his Arduino touch screen radiation detector up on github. To be honest, we’re really impressed with the rad sensor [Toumal] used for this project, so if you ever decide to pick one of those up, he’s got your back with an Arduino library for it.

A very tiny gamma ray detector

gamma

When you think of a radiation detector, you’re probably thinking of a Geiger tube and its high voltage circuitry. That isn’t the only way to measure gamma radiation, though, and [Alan] has a great circuit to measure even relatively weak radiation sources. It uses a very small photodiode, and draws so little power it’s perfect for projects with the smallest power budgets.

The detector circuit uses a miniature solar cell and a JFET wired up in a small brass tube to block most of the light and to offer some EM shielding. This, in turn, is attached to a small amplifier circuit with a LED, Piezo clicker, and in [Alan]‘s case a small counter module. The photodiode is actually sensitive enough to detect the small amounts of gamma radiation produced from a smoke alarm americium source, and also registers [Alan]‘s other more powerful radioactive sources.

The circuit only draws about 1mA, but [Alan] says he can probably get that down to a few micoAmps. A perfect radiation sensor for lightweight and low power applications, and gives us the inspiration to put a high altitude balloon project together.

Geiger counter tells you if your dishes are radioactive

geiger-counter-build

[Henrik] really turned out a nice little Geiger counter board based on a cold war era Geiger tube.

It works in much the same way as other projects along the same lines. It does run on batteries if needed, which is no small feat since the tube wants high voltage to operate correctly. And the video after the break shows it spitting out readings to a terminal window when connected to a computer via USB.

But what really caught our eye is the radioactive source material he used for testing. Since he didn’t have anything on hand he had to order something, and ended up going with a couple shards from a dinner plate. A radioactive dinner plate to exact and it’s a brand name you’ve probably heard of before. Red Fiesta Ware apparently used to be radioactive. It’s even mentioned in the intro to the Wikipedia article. Go figure!

One other thing we noticed was [Henrik's] method of interfacing his multimeter with a breadboard. One of the project photos shows the probe with thin wire wrapped around the tip. We assume this is to make it easy to plug into the breadboard.

Despite this little digression away from the main project we did really enjoy learning about his build. And you can see him showing it off in the clip after the break.

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Online radiation monitoring station

geiger-counter-build

This is a Geiger counter which charts its readings on a webpage. [Radu Motisan] put a lot of time into the build and it shows. This thing is packed with features and the hardware choices were the best combinations found through several iterations of development.

In addition to radiation levels the sensor unit takes several other measurements. These include temperature, humidity, luminosity, and barometric pressure. All of the sensor data is monitored and gathered by an ATmega168 which can be charted on a webpage with the help of an ENC28J60 Ethernet chip. The collection and display of this data is detailed at the post linked above.

For those interested in the hardware development, [Radu] published many updates along the way. These are available in his forums posts, as well as his build log. He doesn’t have any videos of his recent work, but way back in May he did publish a clip (found after the break) which shows the testing of different Geiger tubes.

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Beautifully crafted Geiger counter a must if you live in a hot zone

Have a little class when you’re screening for radioactive particles. You can follow the example which [Moustachenator] has set with this gorgeous Geiger counter case.

The business end includes the same Geiger tube we see in all of these projects, but he took the time to solder together a tidy circuit board and housed it in an acrylic tube. it connects to the base unit using a springy telephone handset cord. The laser cut walnut enclosure offers plenty of room for the ATX power supply hidden inside. This feeds the Arduino which runs the system, and provides a powerful source for the Nixie tubes which serve as the display. The attention to detail when it came time to assemble the case is what lends an antique look to the project, even though everything was built from the ground up. Check out the video after the break to see a brief demonstration.

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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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