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.
This project is an update to the previous Geiger Counter Kit 1.0. 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.
Since this is an update, most of the features were already covered in the original article and the presentation video.
What’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.
There’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.
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.
The PCB as PDF is available here: KIT1.1.102_PDF
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 prog.sh script that invokes avrdude. It also sets the fuses for the 8MHz crystal.
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.
Variants built by my readers:
Chris and Frederik redesigned the KIT1 using SMD components, and added a rechargeable battery! They also built a 3D printable case:
Eagle design files for Chris’s variant: SMD Geigercounter