You Didn’t See Graphite Around This Geiger Counter

Even if you don’t work in a nuclear power plant, you might still want to use a Geiger counter simply out of curiosity. It turns out that there are a lot of things around which emit ionizing radiation naturally, for example granite, the sun, or bananas. If you’ve ever wondered about any of these objects, or just the space you live in, it turns out that putting together a simple Geiger counter is pretty straightforward as [Alex] shows us.

The core of the Geiger counter is the tube that detects the radiation. That’s not something you’ll be able to make on your own (probably) but once you have it the rest of the build comes together quickly. A few circuit boards to provide the tube with the high voltage it needs, a power source, and a 3D printed case make this Geiger counter look like it was ordered from a Fluke catalog.

The project isn’t quite finished ([Alex] is still waiting on a BNC connector to arrive) but seems to work great and isn’t too complicated to put together, as far as Geiger counters go. He did use a lathe for some parts which not everyone will have on hand, but a quick trip to a makerspace or machinist will get you that part too. We’ve seen some other parts bin Geiger counters too, so there’s always a way around things like this.

19 thoughts on “You Didn’t See Graphite Around This Geiger Counter

  1. I am planning to build my own SMB-20 based geiger counter just for laughs

    From standpoint of practical use cases. The core functionality should not be any EPM-sensitive semiconductor. (just jellybean transistors, diode capacitor cascade + EMP filtering).. Just audio + LED blinker

    And it should be compatile to multiple power sources (normal battery, re-chargeable, car battery… hand crank generator).
    In case of nuclear war it would provide at least trend. Is radiation significantly rising or dropping while hiding in shelter or escaping area.

    EMP resistant, low power usage, long shelf life, durable… MVP that just works but does nothing fancy.( Maybe purchacing vintage meter is the most practical way)

    But in case of nuclear accident or distant nuclear war. Cell phones and networks are still working ok and it is possible to re-charge phones almost everywhere. And it is more important to keep monitoring even minor changes in “low” radiation levels. And maybe share results with neighbourhood with GPS tagged points. Or “scout” radioactive spill

    One simple option is to use microphone input of pc or cell phone. Or use microphone + ductape and couple acusticly.. like old modem. High pulse rate might be a problem.

    Early webapp prototype:

  2. Nice one, fwiw I thought of a circular array of reasonable diameter many vertically oriented modified old type fluorescent tubes, that way you could determine x-y direction and with some resolving element in each tube too – some angular direction too. Though probably only good for beta and gamma (alpha won’t go through the glass, unless some suitable coating with a field across it) – I understand under some energies and modified internal grid surface treatment doping might offer a coarse level of neutron detection..
    Thank for post, always interested in variant methods of detection methods, cheers

    1. Hey, nice idea. The next thing on my list is using the SBT-10A Tube’s 10 internal sections separately, so as to show direction. Each section would be coupled to an individual readout and flashing lights would point you in the right direction

  3. Hi. I am actually building something a bit like this using SBM21 <400V tiny tubes as a neural activity detector.

    The problem is getting the data out: as per usual with Geiger tubes versus something like a SiPM or APD based sensor there is some uncertainty and dead time.
    Irony: measuring the dead time can provide useful data if you have more than one sensor triggered simultaneously.
    Also the CCD used in many cheap all in one printers can be modified: reading back the data and init commands can provide enough information to replicate it with a Bus Pirate and Arduino.

  4. After several hours, I was sitting on my couch, and suddenly got the reference. Your article title, dear cultured sir, is appreciated.
    *flies away to go get 5000 tonnes of sand and boron*

  5. I thought the the main reason why most boards that deal with radiation use older silicon was one of statistics.
    e.g 250nm (1996) process up to 10 µm (1971)
    There is a reason most of the hardware in space (outside the protection of Earth’s Magnetosphere) is using fab processes from the 1990’s and earlier.

    The 4000 series chip (40106 hex inverter gate with schmitt-trigger inputs) used would mostly be from designs in the 80’s (so ~1.5 µm process)

    From the info I can find on line the ATmega328P is probably manufactured with a120nm process. So at least an order of magnitude more susceptible to glitching from ionizing radiation.

    But then again if there is enough radiation to cause the Arduino to glitch, I suppose you know you are already dead, so no need to worry the Arduino. If I’m totally honest I was actually expecting the Arduino to be manufactured at a even smaller process, but then again lots of old fabs with larger processes available extremely cheap so it makes total sense.

  6. Nice job! Another practical use for this, when not exploring different sources, is to chart background over time and graph it over time. The easiest way, and most useful to society, is to connect the audio click signal to a computer microphone input, and use free software to upload to a server for all to see. The best example for home-made detectors (or kits or commercial) is

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