Geiger Counter

Geiger Counter Case

Introducing the MightyOhm Geiger Counter kit!

Assembly Instructions

Case Assembly Instructions

Design Files

Source Code

Usage Instructions



  • 100% Open Source Hardware!
  • LED and piezo speaker alert you to detected radioactivity.
  • Mute button for silent operation.
  • An ATtiny2313 microcontroller brain that is begging to be hacked!
  • Support for several common Geiger-Müller tubes: SI-3BG, SI-1G, and SBM-20.  HV supply can be adjusted from ~300-600V.
  • Headers for serial (9600 baud), in-circuit programming of the AVR microcontroller, and pulse output (to connect the geiger counter to other stuff!)
  • Serial data logging!  Counts per second (CPS), counts per minute (CPM), and equivalent dose are reported via the serial port once a second.

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Geiger Counter Parts

There are several ordering options:

  • You can buy a complete package that includes the Geiger Counter kit, Geiger-Muller tube, and a custom laser-cut case (recommended).
  • You can buy just the Geiger Counter kit with a tested, known good SBM-20 Geiger-Muller tube included.
  • You can buy the same kit with all parts except the Geiger tube (in case you already have one).
  • The laser-cut case is available separately.
  • Or, you can purchase a bare PCB only (for experimenters).
See the Shipping Status page for information about current stock and delivery.

You can select one of these options below:

Geiger Kit Options

Shipping is via USPS Priority Mail. US Customers: Allow 1-2 weeks for order processing and delivery. International customers: Orders are shipped via USPS Priority Mail International and can take up to 4 additional weeks to clear customs (typically less). VAT taxes, duties, import tariffs, customs fees, etc. are the responsibility of the buyer!


The HVPS is based on a design that I first saw at BroHogan‘s DIYGeigerCounter site.  The original circuit appears in “Biassing [sic] G-M Tubes Isn’t So Hard” by Tom Napier in the January 2004 issue of Nuts & Volts.

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