uRADMonitor KIT1

Open-Source, easy to make, Digital Geiger Counter with Internet connectivity

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This is an Open Source Digital Radiation Dosimeter, that can be used both as a portable detector, but also as a monitoring station to upload readings to the uRADMonitor network. It relies on a Geiger tube to detect radiation. When used as a portable detector, readings are displayed on the LCD. There is also a speaker that beeps on radiation events or is used to sound an alarm for higher readings. When used as a monitoring station (uRADMonitor KIT1), an ENC28J60 Ethernet module must be plugged in for Internet connectivity, to allow it to function as an automated detector, that doesn't need a separate computer to send the readings to the uRADMonitor network. Designed for makers, this circuit will provide excellent performance comparable to commercial detectors or better.

Finally an open source compact radiation dosimeter, that has an LCD and thus allows mobile use, but also comes with an Ethernet adapter so it can do radiation monitoring (uRADMonitorcompatible). This is a DIY Geiger Counter Kit, named the uRADMonitor KIT1, designed due to popular demand. Now, all those asking for a uRADMonitor Kit have a nice alternative in this device. This circuit uses a single layer PCB and only trough hole components, making the construction so much easier for all the DIY enthusiasts.


The video shows the first prototype of version KIT1.0, built using the toner transfer method. As said, it was designed using through hole components, on a single layer PCB board. Currently, the variant KIT1.1 is available:

uRADMonitor_KIT1_3What's new in 1.1 is that this revision replaces the ferrite transformer in the high voltage inverter, with a ferrite choke circuit, so the complicated part of building the custom transformer is gone. You can build this using shelf components, and the Gerbers files for making the PCBs are also included. Just send the gerbers to your favorite PCB manufacturer, get the BOM and start soldering. With just a couple of components, you'll have an excellent dosimeter of wonderful performance.
uRADMonitor_KIT1_6There's a slot to mount a SBM-20 Geiger tube, a connector for the Ethernet module and one for the Nokia 5110 LCD screen. Both the LCD and the Ethernet adapter can be removed, allowing you to configure the final device: make that a portable dosimeter, a monitoring station or both. A speaker provides audible signals, including clicks and alarm, and a push button permits user interaction with the software. There are two pins at the bottom side that can be used to connect a 3V battery (two AA in series) or the unit can be powered using the DC connector, via a LM317 regulator and then it takes in any voltage in the 5-9V interval. The entire board runs on 3V, and the high voltage inverter boosts that up to 380V, configurable in software up to 600V if a different Geiger tube needs to be used.

The circuit

Released as Open Source

uRADMonitor KIT1.1 is released as Open Source, under GPL v2. It includes the circuit diagram as Eagle files, and the firmware source code. To review the GPL v2 license, click here.
Code is on Github, or a first release can be downloaded here.

Precompiled firmware

For those of you that want to avoid the hassle of downloading and compiling the code, I have included the compiled code as well: firmware. There are two hex files inside:
One variant is a simple, offline code that works without the Ethernet module: uradmonitor-kit1-local.hex while the second adds support for Ethernet as well: uradmonitor-kit1-eth.hex . Some instructions on how to burn a hex firmware file to the microcontroller are provided here. To correctly burn any of the two hex files into your microcontroller, see the script that invokes avrdude. It also sets the fuses for the 8MHz crystal.

Important note:

The HEX code for joining the uRADMonitor network is currently available to anyone that builds a KIT1.1, but only on request due to sensitive security details involved. With this code a valid uRADMonitor device ID is also provided.
Also make sure to read the previous article on the uRADMonitor KIT1.0 for more interesting details related to this project

  • 1 × atmega328p Microprocessors, Microcontrollers, DSPs / ARM, RISC-Based Microcontrollers
  • 1 × LM317 Power Management ICs / Linear Voltage Regulators and LDOs
  • 1 × PIN Headers in various sizes
  • 1 × momentary push button
  • 1 × 1n4148 Discrete Semiconductors / Diodes and Rectifiers
  • 1 × 2.1MM DC Jack
  • 1 × 2.2K resistor Thermal Management and Protection / Thermistors
  • 1 × 2.2mH Inductor
  • 3 × 2n2222 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
  • 2 × 2n2907 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs

View all 30 components

  • getting the KIT on HaD

    Radu Motisan10/04/2015 at 18:11 0 comments

    This is probably the easiest way one can take to have a good digital radiation dosimeters. It was built for the SBM20 Geiger tube, widely available at reasonable prices. Alternatively, other tubes can be used and the PCB has been designed to fit various tubes. The high voltage inverter can also go as high as 600V, to accommodate any custom tubes. The version currently posted on HaD is the latest, the KIT 1.1 and brings several improvements as presented in the project description.



    The best thing about this update is the high voltage inverter update, that now uses a choke instead of the custom ferrite core transformer. So all this can be built in just a couple of minutes with readily available components, for a low cost.

    The software has been updated as well, having nice improvements in place like timeout for the LCD backlight or UI split into pages, to show all the relevant details and measurements grouped together. Just press the main button to navigate through them.

View project log

  • 1

    Step 1: open the Source code repo and identify the latest PCB version (currently 1.1). Take the Gerber files and send them to a PCB manufacturer or make them yourself (toner transfer works great).

  • 2

    Step 2: check the BOM list and the schematics, and get all components. There are only a few, so this will be easy. Start soldering everything. This brings a lot of fun, as the entire design is done with through hole components, so easy to do with basic tools like just a soldering iron.

  • 3

    Step 3: with the device assembled, use an usbAsp programmer (or any other that works) and burn the fuses and the software into the microcontroller. You can either download the source and compile it yourself, or use one of the two precompiled hex files on the project page.

View all 3 instructions

Enjoy this project?



kleibe wrote 03/10/2016 at 19:06 point

I wanna see how measurements levels here in Goiania city where I live....There were a radioactive incident in 1987. Is there any pcb left?

  Are you sure? yes | no

Jacob wrote 10/19/2015 at 14:13 point

Any PCBs left? :) If not, guess I'll have to find my ferric chloride :D

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Radu Motisan wrote 10/23/2015 at 19:28 point

Hi Jacob, I gave away most of what I had! But I'll check that again

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ben biles wrote 10/05/2015 at 11:45 point

Hi, this looks cool ! I'm living in north west Japan and sometimes pop into Fukashima ( not near the disaster area but still.. I should order one of these boards and build !!! :)

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Radu Motisan wrote 10/05/2015 at 16:25 point

That would be great! I'll also check to see if I have any left.

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Radu Motisan wrote 10/04/2015 at 23:28 point

@Bruce Land hi Bruce! Thanks for the skull. As I wrote to Kumar, I also want to offer you a #uRADMonitor KIT1 PCB (free including shipping) , should you be interested in building one of these detectors. Using it you can join the global monitoring program on  and keep track of Gamma levels at your location .

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Bruce Land wrote 10/05/2015 at 11:29 point

Let me see if I can find an interested student.

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Radu Motisan wrote 10/05/2015 at 16:24 point

Sounds good. 

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Radu Motisan wrote 10/04/2015 at 19:49 point

@Kumar, Abhishek thanks for the skull Kumar! I'd be happy to send you a PCB  if you want to build this. I still have a few extra. 

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Radu Motisan wrote 10/04/2015 at 18:17 point

This is probably the easiest and most convenient way for any DIY enthusiast to build a radiation dosimeter for personal purposes or for joining the uRADMonitor network of detectors.

  Are you sure? yes | no

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