Geiger counter with SBM20 tube



I “rebuild” my Geiger counter, the SBM-20 tube was initially inside the box, so, i have put this one inside a 32mm diam plastic tube, for more convenience, wired through a XLR3 cable.

The LCD display alternatively, the “count per minutes” and result on: milli Sievert/year or nano Sievert/hour, you can switch off/on the buzzer, also 3 modes on measure are available, 15/30/120 secs.

This counter is from “Electronique-Pratique” n°368, a French electronic magazine. Shem, pcb, and PIC hex & C source code available. (Microchip compiler C18 v2.40/MPLAB 8.4)










  • Do you have a case file drawn on this geiger counter 3d printer?

    2 years ago
    • admin

      For this project a plastic or metallic case can be used. We are sorry we don’t have any 3d file for a case.

      2 years ago
  • Is not the code written in the pic source file working?

    2 years ago
    • admin

      According to the author the code is tested and working properly. Please be sure to program and verify your PIC microcontroller.

      2 years ago
  • 18f2550 is used in the circuit. 18f2455 is used in the code. Is this a problem?

    2 years ago
    • admin

      The two PICs are compatible and 18F2550 has more Flash memory, so the code should work on both of them.

      2 years ago

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