Radioactivity Counter (IoT) and Monitoring Eco-system

This D.I.Y low cost (50$/43€) C-GM Counter project provides hardware and firmware for building a Geiger-Müller counter device aka G.M. counter for continuous measurement of the radioactivity level.
Hardware Components
Arduino nano
X 1
lcd display
X 1
400V power supply
X 1
X 1

Radio activ.PNG

Original link:

This D.I.Y low cost (50$/43€C-GM Counter project provides hardware and firmware for building a Geiger-Müller counter device aka G.M. counter for continuous measurement of the radioactivity level. It is based on an Arduino Nano, a 20 chars x 4 lines LCD display, a W5100 Ethernet card, a 400V power supply and very few components around. The number of components has been kept to minimum for easy assembling and reducing the cost.

  • The C-GM Counter is able to run as a standalone radioactivity counter
  • or for ensuring long term radioactivity monitoring, the C-GM counter can be used in association with A-GM Manager (in the sequel) that is an open-source web application running on a SOHO server (e.g. QNAP sells Small Office Home Office servers). A-GM Manager is also able to publish the C-GM Counter measures on the worldwide shared map managed by GMC MAP. Finally, there is also a Node-RED version for integration of the C-GM Counter with Node-RED such as the QNAP IoT framework.

See also the W-GM Counter, a portable battery powered Wifi version (22$/27€) based on ESP32 Heltec compatible with the current Eco-System .

IMPORTANT (risk of electrical shocks)

The device requires a 400 Volts power supply. Despite the current delivered will remain very low, I discourage people not accustomed dealing with electronics and electricity to try building this device but to choose a commercial product instead (see available compatible products in the Eco-system section).

Step 1: The Eco-system

The Eco-system
The Eco-system
The Eco-system

You may be ONLY interested to build the C-GM Counter. Of course you can!

But you may also be willing to implement your local radioactivity measuring point and trace level’s evolution over the time. This can be done using our Eco-system above.

For those having difficulties to build hardware, I found counters from GQ Electronics LLC© such as the GMC-320V5 that is compatible with our A-GM Manager (I have neither interests nor contacts with this company so don’t ask me more about their products).

Comprehensive documentations regarding both the C-GM Counter device and the A-GM Manager are available in PDF format to guide you across device building and Eco-system implementation.

All pieces of information required for assembling the C-GM Counter device hardware and firmware can be found and downloaded from SourceForge.

Step 2: The C-GM Counter Device

The C-GM Counter Device
The C-GM Counter Device
The C-GM Counter Device
The C-GM Counter Device


  • Radiation detection : beta, gamma, X-ray
  • GM tube : STS-5 (CTC-5) / SBM-20 (400 V operating voltage)
  • Language support : English only
  • Maximum value 65 535 CPM / 425 µSv/h (theoretical)
  • Display values :
    • Current CPM
    • Current µSv/h
    • Maximum µSv/h since startup
    • Average µSv/h since startup
    • Elapsed time since startup
    • Level on bar graph
    • Alarm
      • User defined threshold
      • Alarm messages on LCD
      • LCD backlight blinking
    • LED flash for each beta/gamma radiation pulse
      • LED blink every second if GM tube is detective
      • LED still on when Network connection fail
    • Audio sound
      • Beep for each beta/gamma radiation pulse
      • Audible sound alarm
    • Device control from :
      • Device internal menu
      • USB (require a serial console such as Termite) or Ethernet (using a web browser)
    • Network connection using DHCP
    • Support for A-GM Manager web interface
    • User defined parameters (from Menu or through web interface)
      • GM tube conversion factor (CPM to µSv/h)
      • Alarm threshold in CPM
      • Buzzer On or Off
      • Display timeout
      • Enable Network for communication to A-GM Manager
      • A-GM server IP definition (through USB or A-GM Manager)
      • Internal H.V. voltmeter calibration (through USB or A-GM Manager)
      • Parameters can be permanently saved into EEPROM

Step 3: Building the C-GM Counter

Building the C-GM Counter
Building the C-GM Counter
Building the C-GM Counter

Short description

See the PDF file for details


The assembly of the C-GM counter hardware has been made the simplest as possible using minimum components available from the selves (e.g. Amazon or eBay) and the minimum of wiring. There is no dedicated printed circuit board (PCB) but instead an inexpensive single face dot board (aka Perfboard) with solder pad for each hole (Veroboard).

  • The GM 5.6MΩ resistor is sold directly on the RCA socket.
  • The Ethernet board is connected to the Arduino Nano using a 2×5 connector.
  • Ethernet board connector pins pass through the Perforboard to ensure its fixation.
  • The Arduino Nano is weld on the Perfboard.
  • The C1 capacitance (10nF/2kV) is weld on the output connector on the back of the H.V. module.
  • There is a strap wire weld on the back of the H.V. module between the input and output GND.
  • The R6 resistor (47KΩ) is weld directly on the ground pin of the LED.
  • The W5100 Ethernet module RST is not connected to the Arduino RST. On the RST pin of the W5100 module pin there is a resistor and capacitance. If connected to the Arduino RST, this prevents downloading new firmware in the Arduino. The drawback is the need to switch off the power supply for resetting the Ethernet.


The C-GM Counter Device programming can be done using the C-GM Counter device HEX file.

You will need a UpLoader utility such as Xloader (Author’s website is currenlty closed a copy is available here) or ArduinoSketchUploader (C# sources to be compiled). Other alternatives may be available from Arduino website.

  • CGM_vx.x.x.hex Use this file to keep the native boot-loader of your Arduino Nano.
  • CGM_v1.x.x.x_bootloader.hex Use this file to flash the C-GM firmware and its boot-loader.

NEW v1.3 : To disable network, keep depressing the button while booting (until entering the menu, then leave the menu). This avoid being continuously blocked due to network connection retries that prevents entering the menu for setting new network parameters (I’m surprised nobody reporting to be bother with this so far!)

Step 4: Using the C-GM Counter

Using the C-GM Counter
Using the C-GM Counter

Short description

Please read the PDF for details

The C-GM Counter device counts the number of radiation pulses (CPM) over a one minute period (shifting window), and convert this count into a micro Sievert per hour (µSv/h) value using the G.M. tube conversion factor.

  • At start-up, the splash screen displays the version and copyrights of the C-GM counter device firmware.
  • About 5 seconds after the power-up, the splash screen closes and the counter starts the radiation measurement.

The user interface was made very simple and there is only one tack switch for control the device screens and menu.

According to the duration of the button push, there are two possible actions.

  1. Short press = SELECT User press the button less than half second.
  2. Long press = NEXT User press the button more than half second.

To ENTER the Menu or validate a menu entry, make one long press.
To WAKE-Up the Display, jump to next screen or menu entry, make one short press.

There are 5 information screens:

The default information screen displays the current radiation values such as the current µSV/h measure, the maximum µSV/h value since power-up, the current CPM value and the average µSV/h since power-up. Messages are displayed on bottom line.


This screen displays values since power-up including the elapsed time, the total number of counts and the equivalent dose expressed both in micro-Sievert and micro-Rem.


Display the GM tube conversion factor CPM to µSv/h, the current high voltage value (read from internal voltmeter) and the Alarm threshold (in CPM).


Display the device (Dev) IP address (allocated by the DHCP service) and the A-GM remote server (Svr) IP address.


Display the firmware version and date as well as the copyrights.


There are 7 menus screens for configuring the device. Some parameters must be set using the communication ports ( Serial or network).

Step 5: Implementing the Overall Eco-system

Implementing the Overall Eco-system
Implementing the Overall Eco-system

Implementing the Overall Eco-system

9 More Images

Short description

Please read the PDF for details

The A-GM project is aimed for providing a long-term continuous measurement of the radioactivity level. It includes an open-source Web application (A-GM Manager) running on a SOHO server (e.g. NAS from QNAP for Small Office Home Office servers) connected to a Geiger-Muller radioactivity counter device such asC-GM Counters or compatible counters from GQ Electronics LLC.

To sum-up the overall system:

  • A-GM Manager
    The web application that continuously monitors and stores the Beta/Gamma radiation levels acquired from Geiger-Muller Counters on a local server. Data can be redirected to the GMC.MAP website for worldwide data sharing using a user account.
  • C-GM Counter
    An open-source hardware and firmware for the Ethernet G.M. counter developed and provided by Ad’Novea® running with the A-GM Manager.
  • GMC-320 device
    GMC-320/5xx/6xx devices are sold by GQ Electronics LLC© and allow the redirection of measures to the GMC.MAP website directly from the device using a WiFi connection. A-GM Manager supports these devices for logging the radiation measures on your server and ensuring the redirection to the GMC.MAP website.


  • Language support for English, French, Japanese, Russian and Chinese
  • Support for C-GM Counters and GQ Electronics LLC Geiger-Muller counter or compatible devices
  • Monitor radioactivity over a user-defined retention period (90 days max) or monthly (see picture)
  • Should the level exceed the user-defined threshold; emails are sent up to 5 email addresses.
  • Display current radiation level in µSv/h and maximum level over the retention period (recording)
  • Plot trace with zoom and pan functions (1 hour, 6 hours, 24 hours, 1 week and 4 weeks)
  • Log over the retention period can be downloaded and monthly data when available
  • Download and Configuration protected with login and password
  • Detection of GM tube failure and send e-mail to the administrator
  • Data redirection to GMC.MAP website (required a user account at gmcmap)
  • Support for Desktop computers, Tablets and Smartphone screens.


The ZIP below can be extracted into the Web directory of your SOHO server. For QNAP NAS owners, there is a QPKG package available from SourceForge.

Latest VERSION 1.3 can be downloaded from SourceForge

Step 6: The IoT Integration

The IoT Integration

Short description

A completely independent Node-RED limited version of A-GM is available for QNAP IoT environment. It is a different and limited A-GM Manager application that can be used for monitoring only.

Because the C-GM Counter is able to provide measurement data in a JSON format, it’s an easy candidate for IoT integration. Some SOHO/NAS providers such as QNAP make available IoT frameworks on their machines for IoT devices supporting the JSON data format.

Here is attached a NodeRED file available that I have developed for integration in the QNAP IOT framework. It make possible to access C-GM Counter data from any computer or mobile devices.


Please Login to comment
Notify of