point I had a fully working Geiger counter which could measure radiation rate and data log values to a computer. I did a short logging test run to see if background radiation would match to STUKs measurements. Of course, it depends very much on the place, as ground has all kind of isotopes of elements, and man-made fallout. As you can see, the average value is a bit high, it should be nearer 0.1µSv/h. I made a slightly longer data logging period to get some more accurate data.
For 12h measurement period I got some weird results. What’s with the sudden peak at the end? The average is two times too high as well. I turned high voltage adjustment a little bit down and values came right down to what was expected. I did not thought that it would affect the reading so much. That rising at the end, could it be due to the sunrise? It starts to rise after clock 7. Maybe it was too sensitive when excessive voltage was applied.
After recording of 24h of data with a lower voltage, I got this. Just what I was expecting. Normal spread that averages to similar values that official levels were at that time. I emailed to my lukio’s (Finnish school) physics teacher and asked if I could compare my readings to the Geiger dose meter of the school.
I got a very similar readings from a uranium-rich ore sample. Notice, how my meter is connected to my Android phone with a USB-OTG cable. Radiation can’t be measured absolutely, so I’m pretty happy with the readings I got.
Closing words. This has been an interesting project that has shown me some important things. I could have done it even better, from build view to project managing. I could have planned it better before starting to make the parts. Doing so, I would have avoided some of the mistakes and the redoing of some parts. Maybe I should have used a real PCB. Also , some would say that making my own firmware and circuit design would have been more meritorious, and some other would have wanted to see more work done together by the hacker and maker community. As an open source project I can contribute more.
But nevertheless, this was not a worthless project at all. Now I have a working radiation meter which I could use in various scientific experiments and projects (e.g how weather and season factors to background radiation levels). And as always with my projects, this is not the end. I can always add things and change or repair some. Fro example, I’m waiting for an additional switch to change between display modes, and a new display plate that has some better aligned screw holes.
One has to just continue experimenting and creating things so we can keep this world from ruining and to advance it. Even accidents like Chernobyl, Fukushima and countless others have contributed our science and society.