Bunnie Huang's open Geiger counter: design notes and reference

Bunnie Huang, cracker of the Xbox and creator of the Chumby, wanted to do something to help people in Japan following the Fukushima Daiichi disaster. He created a reference design for a cheap, reliable, stylish Geiger counter for everyday carry, under the auspices of Safecast, a group that works on ongoing disaster relief in Japan. Being a consummate hardware hacker, bunnie has documented the steps he took along the way to create his free/open Geiger counter.

After much discussion and review with the Safecast team, we decided that a key component of the user experience should be a graphic display, instead of a 7-segment LED readout. Therefore, a 128×128 pixel OLED panel was incorporated into the design. The OLED panel would be mounted behind a continuous outer shell, so there would be no seams or outward design features resulting from the introduction of the OLED. However, as the OLED is not bright enough to shine through an opaque white plastic exterior shell, a clear window had to be provided for the OLED. As a result, the naturally black color of the OLED caused the preferred color scheme of the exterior case to go from light colors to dark colors. User interaction would occur through a captouch button array hidden behind the same shell, with perhaps silkscreen outlines to provide hints as to where the buttons were underneath the shell. I had originally resisted the idea of using the OLED because it’s very expensive, but once I saw how much an LND7317 tube would cost in volume, I realized that it would be silly to not add a premium feature like an OLED. Due to the sensor alone, the retail price of the device would be in the hundreds of dollars; so adding an OLED display would help make the device “feel” a lot more valuable than a 7-segment LED display, even though the OLED’s presence is largely irrelevant to the core function of the apparatus.

Safecast Geiger Counter Reference Design


  1. The very idea of a “stylish” geiger counter is an obscenity on par with designer body armor and QR code tattoos.

    1. Why? It’s an item for repated private carry and use, so why not let the users have the option of something that also looks decent?

  2. If these (or a similar product) become widely available  i think people would be a lot less scared of radiation.

    1.  Why?  I imagine if I had a geiger counter I’d start taking readings on everything and I’d be horrified to find out how many (mildly, safely) radioactive things are around me every day.

      1. and you would realise that all life on earth has been bathed in low levels of radiation for ever.

        people know that sunlight, cigarettes, and many other things can cause cancer, but they dont freak out when they see them. when they hear that there is mili or micro or nano sievert of radiation they panic because they think it something unusual. 

  3. Where can I get one of these?  I’ll just have it on all the time, in my pocket, with volume down low or in an earbud, and I’ll move away from irradiated things.  Simple.

  4. I was suspicious about its ability to detect all forms of radiation – I dimly recall in lab Radiation Safety Training being taught we had to use a sensor the size and shape of an 8 oz can of tomato paste to detect weaker forms of radiation – but it claims to have incorporated a smaller version of just such a sensor – impressive.
    The lack of Bluetooth is a shame, though – one of the most obvious uses would be to link it to a Smartphone that could log its readings and add GPS data. Apparently it was not included for reasons of cost and battery life.

  5. Very cool.

    I personally credit Bunnie with being the father of the modern tablet computer. The Chumby did it all first: a walled garden app store, a device who’s sole purpose is to entertain (as opposed to being some sort of “assistant”), wifi, small touchscreen. 

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