DIY Arduino Geiger Counter




About: Just do things, electronics, woodwork, etc.

Hello everybody! How do you do? This is project How-ToDo my name is Konstantin, and today I want to show you how i made this Geiger counter. I started to build this device almost from the beginning of last year. Since then it has gone through 3 complete rework and my laziness. The idea to make a dosimeter appeared from the very beginning of my passion of electronics, the topic of radiation was always interesting to me.

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Step 1: Theory

So actually dosimeter is very simple device, we need the sensing element, in our case - the Geiger tube, power for it, usually it is about 400V DC and an indicator, in the simplest way is just a speaker. When ionizing radiation striking the wall of Geiger counter and knocked out electrons from it, it makes the gas in the tube conductive, so power goes directly to the speaker and it clicks, you can much better explanation on the web if interested. I think everyone will agree that clicks are not the most informative indicator, although it will be able to warn about the increasing radiation, but counting them with a stopwatch for an accurate results is kind of weird, so I decided to add display some brains.

Step 2: Design

Lets move to the practice, for the brain I choose arduino nano, program is very simple it's counting pulse of the tube for a certain time and display it on LCD, also it's show nice radiation warning sing and battery level. As a power source I use 18650 battery, but arduino needs 5v, so I DC-DC bust converter and li-ion charger to make devise completely autonomous.

Step 3: High Voltage DC-DC

I have hard time working on a high voltage power supply, originally I build it by myself, wound a transformer about 600 turns in secondary coil , drive it with MOSFET transistor and PWM from arduino. It's working, but I want to keep things simple, it's better when u can just buy 5 modules, solder 10 wires and get working devise then winding a coil, adjusting PWM, I want anyone to be able to repeat it. So I found high voltage DC-DC bust converter, it's strange but it's hard to find and most popular module has about 100 sales. I ordered it, made a new case, but when start to test - it gives out a maximum of 300V but the description says up to 620v, I tried to fix it, but the problem probably was in transformer. Whatever, I bought another module and it came in different size description says the same... I returned money but keep this module because it gives 400v we need, but anyway maximum 450 instead 1200 (something is really wrong with Chinese measuring devises... ) I made a new case, again.

Step 4: Components

And so in the end we have a design almost entirely consisting of modules:

Battery, optional active piezo buzzer and Geiger counter itself, I'm using old made in USSR tube, called STS-5 it's pretty cheap and easy to find on ebay or amazon, also it's going to work with a SBM-20 tube or any other, you just need to write parameters to a program, in my case the value of micro-roentgen per hour is equal to the number of tube pulse in 60 second. And well, the case printed on a 3d printer .

Also there are pretty cheap Geiger Counter Kits u might be interested. ( Aliexpress OR Amazon )

Step 5: Assembly

Lets start an assembly, the first thing to do is to set the voltage on the high voltage DC-DC with this potentiometer, for STS-5 it is approximately 410V. Then simply solder all the modules together by this circuit, I use solid wires, it will increase stability of construction and it is possible to assemble the device on the table, and then just insert it into the case. An important point, we need to connect in and out minus of the high voltage converter, I simply solder a jumper. Since we can't just connect an arduino to the 400v, we need a simple transistor circuit, I make it point-to-point wiring and wrapped it in a heat shrink tube, a 10MΩ resistor from + 400V was fixed right into the connector. It's better to make a cupper foil bracket for the tube, but I just twist a wire around, it's working fine, don't reverse plus and minus of Geiger counter. I connect display to the detachable cable, insulate it carefully, it's very near to the high voltage module. Some hot glue. And assembly is done!

Step 6: Final

Put it in the case and we are to test it. But I don't anything for tests, by the way Background radiation is looks fine. What can I say, is this devise working? Yes, sure. But I see a lots of way to upgrade it, for example large display so u can draw graphics, Bluetooth module, or use Sievert instead of Roentgen. I'm okay with device, but if u will upgrade it, please share! So thats all I got for today, hope u like it, and if u do please share this video in social media, it's really helps. Thanks for watching, see u next time!
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    32 Discussions


    Question 7 months ago

    hello can you tell me what is the purpose of the resistance 10 M at the output of the high voltage step up DC-DC. because at home it makes the voltage drop to 80 V. Is this an error on my part? I do not understand the fritzing assembly plan because the module is not the same as the one used in the 5v DC-DC bust converter. Thank you.

    1 answer

    Answer 8 weeks ago

    the resistor is a current limit to protect the tube i believe. im currently building it and will post comments once its finished to help others, as the author isn't responding to anyone, both here and on the youtube video. hopefully my build goes well and i can help others. i also recently found another one gieger counter build on here that features a touch screen, so maybe worth checking out.


    Question 8 weeks ago

    I've got a few questions.

    First, For the charger board, the one you show has 6 connection points. The ones your reference to buy only have 4. So, any idea where to get the 6 connection ones or how to wire the 4 connection ones in place of it? It's not clear to me how to make this substitution.

    Secondly, the switch -- it seems that you have 4 wires connected in the pictures and video, but I don't see any indication of that in the Fritzing diagram. Can you clarify?

    Third, similar question to XavierM72, what's the purpose of the 10M resistor if I need 400V to the tube... it definitely cuts down the voltage....

    Fourth, the bus converter you show in the Fritzing diagram as 3 connections. The ones in the photos and video (and what I got when I ordered using the link) have 4. In+, In-, Out+, Out-. I'm not sure how to wire that up... especially where the yellow wire goes.

    Lastly, a picture of the assembled board showing how it is actually wired would GREATLY add readers attempting to build their own version, if you could add that, you'd definitely help folks out! Thanks in advance....



    Question 4 months ago

    how do i exactly change the code to work with a S13BG tube? im totally a novice at Arduino, this is my first project with one. i really like your design, and i purchased the S13bg tube as its cheap as and smaller size.


    10 months ago

    Great idea, congratulations!
    I did the project (with minor changes:)
    I use SBM-20 tube, this means that the readings in this form are not accurate...
    What should be changed in the arduino code to make the readings accurate?
    Please explain!
    Thanks in advance!


    1 year ago

    You may be wrong about the Chinese voltage measurements! The internal resistance will be very high and as soon as you add the load of a meter, the voltage may come down. It would be best to add a feedback as ChSominUPMC suggested to control the output voltage.


    1 year ago

    Great project mate! I am actually making it myself. Can you please tell me how to modify from microroentgens to microsieverts? Thank you and keep up the good work!


    Question 1 year ago on Step 6

    great work here, mine geiger counter is done and working.. but i used SBM-20 tube so readings are inaccurate.. what i need to change in code, to display correct values please?

    than you :)


    1 year ago

    Yes, please post the code.... I'm going to build one, but without the code the project feels incomplete.

    Also, if you look on e-bay they actually sell Thorium rods (with low, but calibrated counts) that would be useful for testing.

    1 reply

    Reply 1 year ago

    Have a look at Step 2 of the HowTo. There you will find the program linked in... "Lets move to the practice, for the brain I choose arduino nano, program is very simple".


    Answer 1 year ago

    The arduino is a standard "Arduino nano 5v". Juat have a look at ebay, Ali or Amazon.


    Question 1 year ago

    Hi Konstantin,
    thanks for this amazing project. Two friends and I are working on this together.
    Can you do us a favour and explain more detailed the wiring of the switch? I guess you use a 6pin DPDT switch to change between powering the device by battery or by arduino+charging?


    Question 1 year ago

    can you check the schematic? i'm making one of this but arduino wont turn off when i switch the power off with button...also i don't understand what is the red piece next to the battery and how it is connected to the other boards... can you help me?


    1 year ago

    Krásná! Skvělá práce


    1 year ago

    Привет, это замечательный проект .. Спасибо также за точно обработанную схему ..


    Question 1 year ago

    Hi, I'd be interested in the code. Can you share a github link ? thanks