Refreshing Comments...

I was wondering how you would detect radiation with brass and wood, but it turns out this was actually talking about how to build a snazzy enclosure and not at all about how to detect radiation : /
I assumed that someone had made a sensitive 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.

Yeah, I feel like listing out the "raspberry pi, brass and wood" created the expectation that those were the crucial elements. Really the crucial element is a pre-made geiger counter and what they built is a beautiful enclosure and display. It's a cool project and they didn't lie, but it was misleading, and it seems it was the author of the piece who posted it so the confusion is reasonable to call out.
OP links to their repo which has full instructions on how to integrate a geiger counter board with the RPi:

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

I hope you see the difference between building a Geiger tube and buying one.
Building a Geiger tube is probably beyond the reach of most people. That’s a precision piece of equipment.
I'd argue that it is beyond the perceived reach of many people, but it is not beyond the actual reach of many people.

The key ingredients are aspiration and time.

This got me thinking: how far down the current human tech tree could a single person get on their own? It took thousands of years for humans to go from fire to the steam locomotive; could someone do it in a lifetime?

Obviously the ability to skip by basic research and dead ends would cut this down by a ton, but ultimately a lot of the things we’ve created in the past century requires a huge amount of complicated machinery to make, which requires more machines and more labor. Could a person reasonably start from scratch (let’s say skip the mining and just give them coal & metal ores) and make a Geiger tube? Or would it be too difficult?

Another commenter on hacker news completely out of touch with the lives the vast majority of humanity lives. It's amazing how the simplistic intellectual masturbation here is similar to reddit except with reddit it's because they are teenagers and here it's because the users are just basic enough to make decent enough and not much more than that.
Looks fantastic! Well done!

Why didn't you go full brass on the decatrons, instead of mixing stainless and copper? Same goes for the counter box: you only wrapped 2 sides when you pro'lly could have wrapped the whole thing in brass... you probably saved yourself 10 hours by not doing that, but you're already in for what, 30 hours already?

Now I'm going to nitpick. :) My only critique is the high gloss finish on the wood looks unfinished in the final assembly picture: you can see drips/wrinkles, and the grain wasn't filled which isn't a good match with high gloss, or if unfilled a hand-oiled finish would not have called attention. This is a consequence of working with mahogany. (And what's with the hand filed-gouges in the cutouts. Yes they are hidden, but details count, man!)

I'm also jealous you have a machine shop. Very jealous.

Super job!

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!

Super job. More nitpicking: the real fanatics line up the screw heads to the geometry of the piece. For instance the Dekatrons would look nicer if the screwhead slots would form a circle too.
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.
The wood, the brass, the tubes, the clicks, the faint light from the indicators, the tech . . .

Absolutely beautiful, thanks for sharing!

the title reminds me of a Mitch Hedberg joke: """They say the recipe for Sprite is lemon and lime. I tried to make it at home. There's more to it than that."""

This is awesome though, I especially like the mechanical counter.

Great work! I liked how well the vintage look and the modern core fit.

I'm not sure where I read it but it was stated that the Geiger counters which are manufactured after the Chernobyl (?) incident were not as accurate as those manufactured before it. The reason is that all the metal after the incident and the radiation experiments performed afterwards is contaminated with radiation particles which alter the radiation readings of the Geiger counter. Correct me if I'm wrong about this one.

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

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

Some low background steel is recovered from sunken battleships!

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.
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.
3.6 roentgen. Not great. Not terrible.

Very cool project. Always impressed the level craftsmanship some people have.

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]


Incredible! Thank you for writing this up & sharing this! I’ll need to come back and read every word later but wanted to share my thanks. We need more like this on HN and less of the politics
I remember seeing this role (maybe it was listed at Balena last year.

What a fantastic job. Free hardware and freedom to build super interesting projects as long as you can fit Balena in somehow. It's also a much better alternative to facebook ads or similar for a company's marketing spend...

I like seeing some of these “ephemera” projects highlighted (like the kosher search engine and the manila folder 777).

We can do some cool stuff.

Thanks for sharing this!

Lovely piece of work. Scary how active those old gas lamp mantles are (in the video). Makes me wonder how radioactive your average campsite is, given that those things tend to crumble to dust when you change them.
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.

For comparison I have seen statistics that a granite countertop, or granite flooring can emit around 1.7 microsieverts per hour. Granite is mildly radioactive. I imagine working in an old 1920s era office building with granite column facing materials and granite hallway flooring would be a lot more radiation load on the body, unless you spent dedicated time every day seeking out and handling gas lamp mantles.

Lots of people have marble and granite countertops in their kitchen...

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.
This is really fun. I love the idea that something so old looking is running some state of the art stuff behind it.
Yet another blatant marketing piece in the frontpage. I wonder if the pro-adblock HN crowd is becoming more open to these things.
If a company chooses to spend their marketing budget in creating quality content then I don’t see a problem with it. There’s an obvious bias towards their software, but it’s on their website so that is clear, and the project is interesting and worthy of discussion. why wouldn’t it be on HN?
Balena is pretty great. I use its balenaetcher often. It's a great isofile to usb tool! Which also happens to be another free or from the balena company.