Prepping 101: DIY Geiger Counter – The Basics of Measuring Radiation

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This DIY Geiger counter is under $60 if you buy the tube separately on Ebay. I soldered it in about an hour, and as you can see, it is going crazy next to these radioactive Thorium treated lantern mantles.

This DIY Geiger counter is under $60 if you buy the tube separately on Ebay. I soldered it in about an hour, and as you can see, it is going crazy next to these radioactive Thorium treated lantern mantles.

Measuring radiation isn’t as complicated as all of the terminology makes it sound. Any radiation measuring device has some sort of Geiger–Müller tube, also called a G-M tube. The tube is a surprisingly simple device that turns any type of ionizing radiation into an electrical pulse. The rest of the machine we call “Geiger Counter” or “radiation meter” is just a signal amplification circuit that can contain computing chips and measurement dials or readouts. In a nuclear emergency there won’t be time for news of it to hit The Drudge Report. You’ll have to take evasive measures immediately (a topic for a future article). We are all waiting for the next big false flag or hoax catastrophe, and if it turns out to be nuclear, you’ll want some sort of Geiger counter, both to tell you when it is time to go inside, and also when it is ok to come out. For the most part, Geiger counters aren’t cheap. But I found a source for a DIY Geiger counter that takes only basic soldering for under $60, including the G-M tube. You can also get a no-solder option for still under $100, and they work great.
The kit starts as a handful of components and a board. But no fear, you can buy the assembled kit for only $12.50 more.

The kit starts as a handful of components and a board. But no fear, you can buy the assembled kit for only $12.50 more.


The Geiger counter business is not a business you want to be in. Like most of the survival/prepper market, it is feast or famine. When things are good, the sheeple are lost in their bread and circuses, you can’t sell anything. Then, when an event like Fukushima happens (a nuclear reactor meltdown in Japan in 2011), you cant ship them out fast enough, and your customers hate you because you charged them three times what you charged before the event. That’s the way it is though, and that is why I am telling you to go out and buy a radiation meter today. The overall prepper demand is very low and prices, while not at rock bottom, are as low as you will see in the foreseeable future. You can buy hand held units from Russia made by a company called Soeks for well under $200 on Ebay. The American-made unit you see here has both a round tube and a pancake sensor on the back, making it more sensitive to particle radiation called Alpha and Beta, and they are in the $500-$600 range. But all G-M tubes detect Alpha, Beta, and Gamma radiation, and in my own testing there is little difference in the overpriced American meters.
The same electronics hobby store sells a more advanced kit with a measurement display. It measured the same as this Soeks from Russia, and the American made Inspector.

The same electronics hobby store sells a more advanced kit with a measurement display. It measured the same as this Soeks from Russia, and the American made Inspector.


The DIY kits you see that I tested her don’t have to be entirely DIY. You do have to build an enclosure for them, and attach the battery wires to the board, but the boards themselves are available pre-soldered and working perfectly for only $12.50 more than unsoldered. The blue board that I did solder myself is available in kit form from the seller’s website for $32.50, or you can buy it assembled on Ebay for $45.50 from the same guy. You also need the SBM-20 G-M tube that fits all of these kits, and I bought a whole box of them from this guy in Bulgaria on Ebay for $20 each shipped. The blue kit is not very flexible unless you are an Arduino electronics hobbyist and you have a separate digitizing board. The blue kit only clicks and lights when it detects radiation, but like with many other things, what else do you need? It clicks and lights with a test radiation source, like crazy.
In all of these kits you have to buy the G-M tube separately, for $20 each, shipped.

In all of these kits you have to buy the G-M tube separately, for $20 each, shipped.


You can easily test any radiation meter with a little known radiation source also available on Ebay. They are cloth mantles made for camping lanterns that are treated with Thorium, a radioactive element. The normal background radiation rate is 5-50 counts per minute in most areas. It amounts to an occasional click on the meter. When you put the Thorium mantles next to the meter it goes crazy. Just don’t sleep with them under your pillow.
The Soeks meter contains two of these SBM-20 Russian G-M tubes, but it didn't measure any more accurately.

The Soeks meter contains two of these SBM-20 Russian G-M tubes, but it didn’t measure any more accurately.


The red kits are much more elaborate and I bought two of them to see if they behaved differently with the same tubes. As you can see, these kits use a chip and display to calculate and show you the current radiation dose in milli-Sieverts, designated as μSv/h, which is per hour. The Sievert is one of many units that are used to measure radiation, and exposure to radiation. The Russians have had to deal with the Chernobyl disaster aftereffects in Ukraine since 1986, and there is even tourist travel in the effected areas today. That is why those handheld Soeks meters are such mature products compared to the big cludgy American meters. They aren’t any better, but they have a bunch of easy functions to measure accumulated radiation dosage and many other factors. These red kits don’t do any of that, but the display does give you μSv/h and the actual counts per minute. Additionally, you can download free software from that same RH Electronics and connect the board to a computer with a UART TTL module (about $8) if you want to log a history. I couldn’t get the software to work with Windows 8 though, FYI.
Likewise the American made Inspector Alert has an additional pancake sensor, but didn't detect anymore background radiation than the kits. Nor did it differ much on the lantern mantles.

Likewise the American made Inspector Alert has an additional pancake sensor, but didn’t detect anymore background radiation than the kits. Nor did it differ much on the lantern mantles.


As I write this there are only 9 of those red kits left for sale by RH Electronics on their website. They are discounted to $50 until they are gone, because this kit was upgraded with some more features. I paid $70 each for my two kits, and the new red kit is $80. It apparently connects directly to the computer USB for data, and it comes with its own battery. Assembly is $15 now for this kit, and shipping is free, or $5 if you want it quick.
The radioactive mantles made the meters go crazy.

The radioactive mantles made the meters go crazy.


It wouldn’t be right to talk about radiation meters without mentioning the Victoreen Civil Defense meters you see all the time on Ebay, the yellow ones. There are three basic models with slight variations. One is just a yellow box with a meter. One is the same yellow box with a removable base that extends on a cord, and a third has an actual wand and headphones. These devices all measure in Rads, which is a completely different but valid system of measuring radiation exposure. The problem is, you don’t know what you are getting when you buy them, and many of them have had exploded batteries over the years of sitting. A new batch seems to have recently hit the market that were serviced as late as the 1990s, but the sellers are getting upwards of $100 each for them. For that price, I don’t see any reason to buy them over the RH Electronics kits, or maybe just spend a little more on a Soeks. The Victoreens offer no real benefit over any other radiation meter. Again, they are very simple devices with a very specialized circuit for a 300-400 volts specialty tube. I haven’t figured out what the yellow cardboard tube “dosimeters” do, but I have never tested on to work either.
All of the kits can be powered off of a printer D cable through USB power, or they can take a battery pack. The red kits can also send data to free software for your computer. The old red kit requires a TTL module and the new kit goes direct.

All of the kits can be powered off of a printer D cable through USB power, or they can take a battery pack. The red kits can also send data to free software for your computer. The old red kit requires a TTL module and the new kit goes direct.


It is hard to imagine a U.S. Government that bought Geiger counters to distribute among local quasi-militias, hoping to protect the citizenry. Now they arm themselves with tanks and millions of rounds of ammunition against us. Don’t be caught at the end of this horrible downward spiral with nothing to support the survival of your family through what may be the worst of times. A Geiger counter isn’t priority one, but if the powers that be pop a nuke to start their next manufactured war, you are going to wish you had one. Then you won’t be able to get one, even if the nuke pops across the world. There are plenty of Youtube videos on basic soldering, and those blue and red boards with the shiny solder pads make it really easy. You don’t even have to solder. The guy will do the work for fifteen bucks, a no brainer. Just don’t forget, you have to also buy the G-M tube.
Note that the G-M tubes are polarized. Make sure the plus terminal is on the plus end of the tube.

Note that the G-M tubes are polarized. Make sure the plus terminal is on the plus end of the tube.


If you buy the blue kit and build it yourself, be aware that there are empty slots on the board. He left out some resistors that aren't needed. Be sure to check your circuit using a multimeter like he suggests. Our numbers never got up to the target, but it was close enough and the kit works great.

If you buy the blue kit and build it yourself, be aware that there are empty slots on the board. He left out some resistors that aren’t needed. Be sure to check your circuit using a multimeter like he suggests. Our numbers never got up to the target, but it was close enough and the kit works great.

{ 15 comments… add one }
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  • Former NCO January 3, 2015, 6:52 am

    Have you considered that these electronics may be rendered inoperable during the EMP?
    Seriously .. laptop connections? What sort of bugout are you preparing for?

  • JCitizen June 30, 2014, 6:38 pm

    This is a cool article, and a big surprise coming from this forum!! I am very impressed, and they should have had one of these on those entertaining “Doomsday Prepper” shows on cable!

  • Doc June 30, 2014, 4:21 pm

    As per the DOD Office of Civil Deference publication FG-E-5.9* (YAWN!!!?? DID I HEAR ANYONE YAWN!!!???) . . .

    Ok, it gets complicated really fast. The cap that unscrews is to ‘check’ your dosimeters AND to ‘zero’ the device itself. if you don’t know how to ‘zero’ a device it’s like not knowing that a 30-30 is not even close to a 30-40 (or 30-06). 1 click. is that one click per hundred or per hundred million?

    The device will do you absolutely no good without lots of graphs and straight edges and the ability to convert time from minutes to hours+minutes, and back again. WITHOUT A MISTAKE. There are charts for single doses, and accumulated doses over various amounts of time. Since this is a gun page think about the damage a 5.56 will do at 3000 fps, and what it will do at 1 inch per hour. That’s what we are talking about here. You can take a LOT of hits at 1 inch per hour, not many at 3K fps. So the book is filled with graphs that you have to convert, then convert again then convert again. Then you get an answer. For NOW. You want an answer in an hour, well come back in an hour, or tell me where you are going and what you will be doing and what you will be wearing and how it will be secured and I’ll have a GENERAL idea, maybe.

    If you see rubble you are going to die. If you don’t see rubble you are PROBABLY going to die, especially if you saw a ‘flash’ or dark shadows and your eyes didn’t boil in your head. ( If I might I recommend a film _”Bright Light, Black Rain_” — it’s interviews with survivors of Hiroshima and Nagasaki, it’s not all blood-guts-and gore — it points out the vagaries of survival from “I saw the plane and hen the flash right above my head” to “And now all my friends are dieing of cancer 50 years later, some of them have lost all their limbs in just 2 months or they would have died . . .” .

    If all you saw was a flash and you CAN see the cloud of fire, from a distance you MIGHT die How long it takes you to die, is dependent upon too many things to list. If you are talking a full scale tactical war, figure you have between 1 minute and 25-50+ years before you die. If you are talking about global war, you WILL die. Period. (it’s why you carry one round in your buthole — WTSHTF.

    Sometimes, in ‘dirty bombs’ or ‘tactical’ situations it’s not about above vs below ground, it’s about cross winds and which way YOU want to travel and if you can read a map, and heck! does radiation affect a compass? Let’s see does it “pull to the north and push to the west?” What WAS that saying???? . . .. AND — if you don’t have your MINIMUM of 2 weeks food-water-sanitation you will die. And is 2 weeks really long enough, or is that after most people who are going to die right away die, and it’s better after 4 weeks? But the half life of Plutonium is 250, 000 years, so that means what? – Is it drop the last 3 zeros and divide by 25 to give you how long to stay under ground in weeks? Or is it divide by 50 and that gives you time underground in months? It get’s all so confusing!

    Like most Wildland fighters will tell you the ‘shake-n-bake’ is only good to keep bodies in one area and so they can be spotted with very little manpower – you don’t worry if that piece of burnt branch is a guys arm or leg or just a piece of brush. In ‘Civil Defense’ part of the idea was to 1) keep the dead off the street, to boost morale, and to help with public health ‘after’ the unthinkable, 2) to ‘concentrate’ the dead for easier burial. 3) to establish ‘centers of distribution’ for your lager public shelters (by vehicles which would likely never arrive since they are coming from target cities or near enough to not do anyone any good).

    BUT one good thing you can do is thank Ike. Most folks don’t know this, but most of your interstates were built NOT to link ‘industrialized’ America, but as evac routs, and it’s why the ‘slow lane’ is built of super-reinforced road-way – for the heavy trucks and tanks and things they thought they might have after a war. So that Interstate used to be your Evac route out of a ‘major population center’ — and we thought we could evac a good 70% of our population given 72 hour notice. I never saw the parts of the training films where they had gas-stations set up along-side the road, but I did learn how to pull civilian vehicles off those roads . . . .

    If you need a ‘giger-counter’ you don’t. You are going to die. — remember 80%+ of America is ‘expendable’ to ‘win’ a war, and in a pinch we could lose 90%+ and ‘win’ since most of the trades and skill-sets needed for survival and rebuilding are rural in of of their very nature. Make friends with your local blacksmithy NOW – not after you need him. Say who IS your local herbalist? Your local cooper?

    If you need to know if the radiation is ‘safe’ outside, you don’t need to know. You already have a pretty good guess. Start your family graves now while you still have he strength. You won’t have it long. Sorry to be so grim. It’s a world where guns will do you very little good, but knowing about medicine, physics, history, reading, writing, carpentry, being a stone-mason or foundry worker will do you FAR more good. Let’s have a show of hands of how many people here can turn a fist full of nails into mass produced arrow heads? Anyone? Anyone? Buler? Buler? Anyone? . . . . . ..

    * yes, there really IS a manual by that name, it’s sitting open on my desk in front of me. It covers the CD- V-700, V-715, V-742 and the V-750. No you don’t want to know what it says. It says you are going to live in a fresh new world free from war and famine . . . . .

    • Administrator June 30, 2014, 4:58 pm

      I have had more than 20 of them and they just don’t work. The manual actually comes with them. We do have a future article coming about radiation though.

    • JCitizen June 30, 2014, 6:35 pm

      I was an NBC NCO in the Army during the cold war, when we took such training deadly serious. Our training aids were very realistic, and in fact our special weapons unit once assembled an actual nuclear bomb, so I know from whence I came. I was more than convinced you CAN survive a full nuclear war, you just have to get educated in the art if survival in such environments, and have use of such tools as this article provides. One thing is for sure, you will not be able to help people much if they are close to ground zero, or if they hung around and let heavy fallout hit them before H+3 hours after the blast. and you’d be wasting you time, because they are probably going to die anyway. The rule for survival is take care of yourself first, so you will be able to help friends and family later. And that is how I see the cookie crumbling!!

      • Doc June 30, 2014, 8:14 pm

        FIRST RULE OF SURVIVAL: NEVER TURN ONE PT INTO TWO! (AND ***NEVER*** argue with an NCO!)

        • Mahatma Muhjesbude December 31, 2014, 8:48 pm

          Yeah, Doc pretty much said it all. But just so everyone who cares about such things understands. He’s describing a close hit by a large bomb. The movies portray scenarios of lone terror groups with nuclear bomb detonating in a major city.. Well, the reality is pretty far from that plot line. The two main reasons are that for the sheer expense and effort of doing that, they could get a flea market special going of combined ‘special purpose’ attacks and do a lot more pervasive long term damage in much simpler endeavor. I’m not going to elaborate here but some of you could guess. Plus when we found out who sponsored it that would be the green light to turn the host country and all their dawa bud neighbors into an ashtray with our nuclear retaliation.

          So the likelihood of having and surviving a nuclear scenario would be on a third world war level. Which is not an impossibility in the world we live in. But not likely. No civilized country wants that. However if you know the reality about such things, even in an all out exchange, which it would never happen as badly here, as it would everywhere else because of our defense system, now including pulse lasers off shore on ships to immediately take out enemy launches caught almost instantly by our ssatelites, nothing would be as everyone thinks. But even if–lets say a thousand warheads get through–which is almost impossible–, what many fail to understand is that there will be some people in places like stankyfarm Indianna or Weed Ohio or Heroin Colorado that won’t even know about it if they weren’t paying attention on the news or radio before communications went out.
          Others would be wondering why they didn’t hear about those unexpected distant ‘thunderstorms’ on last night’s weather report, and then they’d go about their business until the reality set in.

          The reason is if you make little bursting radius circles of one thousand various megaton rated bombs of lets say 30 miles average in diameter for the general single bomb effects– because most people farther out than that, especially inside, would be relatively safe except for the fallout later– on an average scale U.S. road map, you’d find that there is quite a lot of space between all those little circles over the Country, which don’t even look like much in the bigger picture. But then they’d never be targeting for random dispersment. they’d be going for heavily populated areas and military targets,,Airports, nuclear power infrastructure and then critical industry. So it’s likely that entire states wouldn’t even get one hit.

          Bottom line is that Nuclear War would not immediately kill off even most of the population. And many would be fairly immune from fallout depending upon their luck or appropriate preparation.

          The aftermath, however would be less than fun for the forseeable future. This country would immediately become a military dictatorship. But more people would probably die afterward because they won’t have their smart phones intact anymore for a long, long while.

    • Robert P in San Antonio September 8, 2014, 1:55 pm

      Doc, I tried to find useful information in your post and am still searching. Yes, I know your message seems to be just to bend over and kiss your ass goodbye. I googled your DOD Office of Civil Deference publication FG-E-5.9 document and could not find it. The sole website had something close using dollars per page for them. Not useful. GUNSAMERICA put out some useful information for those of us interested in the topic. Since you seem to proclaim yourself so damn smart, how about contributing something of value. I need a direct buy it and use it help for the materitals as I am igorant on the topic overall. For example, the author talks about red and blue boxes, some with solder and some not. My thoughts are this: Any nuke that produces damaging radiation will likely take out the power grid. That means my USB, my computer, my lights, and my connector to the geiger counter will have as much life in them as your article. I want one that I can attach to my batteries. I can buy pounds of long life batteries and that is the power source I hope to be able to use. So, be helpful, and state the model that works that uses batteries and is available online somewhere.

      • Bigmag47 December 31, 2014, 3:29 pm

        Robert…EXACTLY!!!

  • BerferdT June 30, 2014, 10:40 am

    A correction and some additional information would be good for those interested in understanding the information the meters display, and some practical variations in use:
    The meters reading in uSv/h is not milli Seiverts per hour, but one thousandth of that, micro Seiverts per hour. A big difference.
    Another big difference is between alpha, beta, and gamma radiation. None of it is generally good for you, but the thorium-treated mantles are sold as a safe product because the alphas they give off are not able to penetrate very deeply. But in this case they are a handy way to check the meters.
    By developing shields to cover the tubes in the counters, one can have a practical means of measuring the different particle emissions. It is always good to know what you are up against.
    Alpha has a hard time penetrating a cardboard box. Beta has no problem with the cardboard, but has a hard time penetrating aluminum foil. Gammas can zoom right through even thin layers of lead. Gamma is what makes the nuclear blast so dangerous, and the immediate area around the blast site dangerous. The alphas and betas, carried by wind and water, pollute the wider range. Gamma can cause immediate reactions in living tissue – so they use it to kill cancer cells in the hospital. Alpha and beta are a little less dangerous and can cause mutations, both immediatly and genetically, depending on doseages.
    Hope this helps.

  • Davey Jones June 30, 2014, 9:09 am

    FYI, milli-Sieverts would be written as mSv/h, not uSv/h. The “u” or Mu indicates micro, an order of magnitude(1000x) smaller. I think you meant to write micro-Sieverts.

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