This post is an update to my previous DIY/Homemade Radiation Geiger Dosimeter. Back then I’ve built a digital portable radiation dosimeter, using an Atmega8 and a geiger tube. The 2×16 display had sufficient space to show the most relevant data. Now the device got an upgrade: case painted black and a new, improved software:

The small screen space (2×16) has been used to show (in order): time (hhmmss) , tube voltage (in volts) and total counts (in P=pulses, KP=kilopulses, MP=mega pulses). The second line shows an estimation of the radiation dose in Sieverts/h (just an approximation, not accurate), and the radiation dose in CPM (or KCPM / MCPM). The results are averaged at an interval of only 5 seconds.

SBM-20 vs SI-29BG comparison

For my uRADMonitor project I’ll be using small, but sensitive Geiger tubes. These include the SBM-20U and the SI-29BG. The last one is both small and very responsive both to natural radiation field and to check sources. The following video shows a comparison between the two. Make sure to keep an eye on the CPM readings at the bottom-right side of the LCD:

A few more pictures

Open source

This dosimeter is open source, released under GPL v2. You can download the code and specs in part one of this article, link included at the beginning of the post.