Show HN: I built a desktop radiation monitor with Raspberry Pi, brass and wood

OP links to their repo which has full instructions on how to integrate a geiger counter board with the RPi: https://github.com/balenalabs-incubator/background-radiation...

Even has some links to the model(s) used.

I assumed that someone had made a sensitive bolometer.

https://en.wikipedia.org/wiki/Bolometer

Wood is a thermal insulator, so with care, one might be able to build a thermistor bridge capable of detecting the differential temperature rise between pieces of brass when a source was placed near one brass-piece.

I, too, found that the expectations framed by the title were not met by the article. It's a pretty box, though.

Thanks for the compliments, and I appreciate your eye for detail and nitpicking :) I don't even wanna think about how many hours I put into this thing. It was one of those projects when you've got some free time you just keep working on it, then eventually, one day, it turns out there's nothing else to do.

For the Dekatrons, it was simply a case of I had 50mm stainless steel bar already in the shop, but the biggest brass I had was probably 30mm diameter. I bought a whole load of bar stock offcuts from an auction years ago and pretty much everything I make is made from that lot. That being said I broke so many tools trying to work with M2 threads in stainless that I could have just bought some brass bar!

As for the dips/wrinkles in the case, those were caused by my use of an oscillating drum sander. There's a photo in the blog post where you'll see I used the drum sander to bring the lid to size. I foolishly let it mark the previously pristine planed surfaces, and didn't realise until I had coated it with gloss. This is definitely a lesson learned from this project, I won't make that mistake again.

I have no defence for the hand-filed gouges hidden in the openings, and not filling the grain - more lessons learned for next time there. :)

Thanks for the comment!

I know a lot of people don't like being criticized, but this is exactly the sort of criticism I like when I finish a project.

I don’t know about Chernobyl specifically, but so-called low background steel from before 1945 is harvested specifically for use in radiation sensing applications. See https://en.wikipedia.org/wiki/Low-background_steel

I think most of the radionuclide contamination comes from Cold War atmospheric nuclear testing.

Some low background steel is recovered from sunken battleships!

That has to do with atmospheric nuclear weapons testing, not Chernobyl. You can still see some weapons testing isotopes in a 24-hour background count on a high-purity Germanium radiation detector.

It was from atmospheric testing of nuclear weapons in general, but the last atmospheric nuclear test was conducted in 1980, leaving Chernobyl as the last event to disperse significant nuclear material into the atmosphere. Though, I think the bulk of the radionuclides have decayed enough that there's no longer a need to salvage old WW1 battleships for their low radiation steel. Specifically, the two major "medium-lived fission concerns," caesium-137 and strontium-90 have a ~30 year half-life.

I wonder how many people ever get to work with equipment that has the same name as they do!

https://en.wikipedia.org/wiki/Nominative_determinism

If anyone wants some context about radiation dose units across various orders of magnitude, I recommend the charts in this DOE chart (see page 6) [1]

[1] https://www.energy.gov/sites/prod/files/2018/01/f46/doe-ioni...

Remove this man from the comment section, he's in shock!

They are quite radioactive for a household item indeed. The dust is a good point I keep that one double bagged for that reason, although they aren't as fragile when they're new.

Not very. The predominant isotope of thorium is an alpha emitter with a half-life measured in tens of billions of years.

Looking at the video, the counter appears to peak around 200cpm, or (per the Grafana dashboard screenshot) about 2 microsieverts per hour. That'd take 50 hours, a little over two days, of exposure to add up to the dose of a typical chest X-ray. And that's for a whole mantle, placed directly adjacent to the tube; it's not obvious in the video, but the dose rate is highly dependent on distance. Spicy gamma emitters aside, most small samples drop to background just an inch or two from the detector.

So I wouldn't worry all that much about it, really. Eating a mantle, or breathing the dust from a freshly replaced one, wouldn't be a great idea; I'd expect it to increase cancer risk to a degree probably commensurable with some number of years of smoking. (Probably fewer years than I racked up, back when I still had the habit.) Nor would keeping a mantle in your jockeys, or your bra. So don't do any of those things.

But buried, or even just mixed with dirt? I'd worry more about falling into the fire, and that's not something I worry about a lot, even if it does typically get pretty drunk out every time I ever go camping with anyone.

Thanks for the compliment Peter, if I can inspire others like yourself to get building, I'm happy :)

Thanks Greg, nice to see you here :)

for inspiration .... http://www.lovehulten.com/

Thanks - it was so much work, but super rewarding as the thing looks beautiful on my desk. It's awesome to see it's appreciated :)

Marketing? It's a one off build.

Would you prefer a Gartner report?