A cheap 555-based Geiger counter | Hacker News Reader

A cheap 555-based Geiger counter

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127 pointsdragonbonheur45 comments

No, it is not based on the 555 IC, it is based on the Geiger Tube.

Before clicking the link I was racking my brain try to guess what kind of crazy hack they where using to measure radioactivity using a 555. Was very disappointed when clicked the link.

Well, my reaction was to check first what they are actually using for interfacing with the radioactivity, but yes, the title brings up exactly the ideas what you describe.

The title is still not without merit. Would "Arduino based Geiger counter" sound a plausible title? As I think that in principle this is what they are suggesting - a simple logic IC is used instead of complex micro controller board.

well it's using a 555-based power supply (555 drivers a step-up transformer), bit ambiguous but I think it qualifies.

I'm really glad to see this kind of thing on HN, much nicer than the usual "framework for X".

Unless you have become used to see it on other sites.

Do the resistors out there qualify as well? What makes a car what it is? Certainly not it's right headlight.

Just to clarify. I do not want to downplay the accomplishment here. The circuit is certainly very interesting.

Well, it sure beats those inaccurate diode-based ones that circulate around the Amazonosphere that plug into the headphone jacks of phones... Wouldn't mind replacing the pizzo with a 3.5mm jack to hook this up to my smartphone and use as a portable gamma detector for my vacations to Chernobyl.

I once tried to make Geiger counter from webcam. I covered the lid with dark paper. I put it in front of a banana and then I read frames from it and counted noise spikes. Didn't work.

Was the banana radioactive ? If it wasn't I imgaine it did work.

Bananas are the 2nd most radioactive food, due to their Potassium content. Brazil nuts are the most radioactive.

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

Btw. just for curiosity, there is a difference in the source of radiation as it pertains to how dangerous it is.

Banana (potassium) radiation is mostly harmless to humans. Nuclear weapon or reactor radiation (for example caesium) is not.

The Banana equivalent dose is therefore a bit of a misleading term, and I have sometimes seen it used to dismiss other more harmful radiation sources as harmless, because of this incorrect banana comparison.

http://www.washingtonsblog.com/2013/04/fake-science-alert-fu...

Here is an example of using the banana comparison in an incorrect manner:

http://www.forbes.com/sites/timworstall/2013/08/10/the-fukus...

To clarify, the gamma energy from K-40 in bananas is around 1.5 MeV, which is dangerous to humans. It's not the most dangerous, but it is dangerous in significant amounts (which are much much higher than what is in a banana).

A BED is usually taken as 1 micro-Sievert. Sieverts are a unit for measuring the biological effect of radiation, hence they are normalized to adjust for how harmful the given type of radiation is. A dose of 1 Sievert represents a 5.5% chance of eventually developing cancer. 1 Sievert is 10000000 BEDs.

The part that is a bit misleading about the BED is that it's not the same as the dose you get from eating a banana. This is because of how potassium is absorbed in the body; all the K-40 in the banana isn't staying around in your body. The BED is the dose you would be exposed to for absorbing the equivalent amount of K-40 in the same number of bananas. Bananas are fine for putting small doses or activities into perspective since the biological effects are negligible, but are not really great for comparing against more significant doses.

It isn't so much the source of the radiation, as it is what your body does with the material. When you eat a banana, your body gains additional potassium, and over the next several days your kidneys will expel that excess. So, your exposure to the tiny amount of Potassium-40 in the banana is very brief. OTOH, your body treats the Strontium-90 in nuclear fallout like calcium, depositing it in your bones and bone marrow subjecting you to continuous radiation exposure. Likewise Iodine-131 will concentrate in the thyroid.

What about then if you eat a banana daily, so there is no chance of fully expelling the potassium

Bear in mind that your body always contains potassium (mostly non-radioactive, but a tiny bit is radioactive). Eating a banana just slightly increases your exposure for a short time.

If we take a look at our handy dandy xkcd radiation chart[1], we can see that eating a banana every day for a year exposes you to about 36.5 uSv radiation, slightly less than you get during a six hour airline flight. By comparison, the potassium naturally contained in your body already exposes you to 390 uSv radiation in a year.

[1]: http://xkcd.com/radiation/

Kidney beans have far more potassium (1406 mg per 100g) than bananas (358 mg per 100g). Potatoes (421 mg), sunflower seeds (645 mg), kale (421 mg) and spinach (558 mg) all also have more potassium than bananas. Bananas are not that high in potassium relative to all other foods; they are merely high relative to other fruits. (But even in fruits, avocados and figs both have more potassium than bananas.)

As the Wikipedia article on Bananas[1] states: "Although bananas are commonly thought to supply exceptional potassium content,[86] their actual potassium content is relatively low per typical food serving at only 8% of the Daily Value (right table). A compilation of potassium content in common foods consumed in the United States shows that raw bananas rank 1,611th, supplying 358 mg of potassium per 100 g".

[1] https://en.wikipedia.org/wiki/Banana

Actually that sounds like a fun project.

I tried this with a radioactive probe. It didn't work aswell.

Should have tried cooling it. :)

http://petapixel.com/2016/10/11/cooled-nikon-d5500a-chills-s...

This is really cool! I found a couple of projects online (e.g. http://www.randombio.com/webcam.html) where people tested out their webcam counter by using a smoke detector as an alpha source, and had some success.

It's definitely possible to use a phone camera [0]. I know someone who has a few radiation samples and it worked very well.

[0]: https://play.google.com/store/apps/details?id=com.rdklein.ra...

Pedantry: It wasn't a geiger counter because it wasn't using a Geiger-Müller tube.

I don't think you'd see much of a difference even with a decent Geiger counter from a banana. The levels of radiation in food are tiny, and building equipment to measure it is not easy.

Probably if you found decent radiation source, or perhaps took it up in an airplane you'd see a difference.

if you're a little crazy you can take the radioactive americium out of a smoke detector and use that as a source

And if you're a lot crazy you can build a fission reactor... our maybe that was a different source isotope?

If you're not that crazy, you can build a fusion reactor, although the design necessarily requires more energy than it puts out. Teens have built these for science fair projects.

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

For what it's worth, I've used a (real) Geiger counter to examine not only a banana, but potassium supplement pills. I wasn't able to detect even the slightest increase over background radiation from either.

Unless i'm getting my natural sources mixed up, a banana is slightly radioactive due to Potassium-40 and that decays beta. A standard Geiger counter easily detects x-ray/gamma/photons, where beta decay is via an ejected electron and its detection requires a specially thin 'window'. (Which often occurs as a 'lollipop'[1] detector as opposed to a cylinder. huh, they refer to it as a 'pancake' detector) Fun fact: there are many lab benches with painted splotches on them. Beta source spills being able to be shielded by even a coat of paint.

1. https://en.wikipedia.org/wiki/Geiger_counter#/media/File:Gei...

Are there no voltage boosters that can take 9V to 400V without a transformer? Seems like most of the build here is the power supply with a two component "counter" (which is really just a clicker since it does no counting).

To me the much more interesting part would be where to get cheap geiger tubes.

Edit: this has some answers on the power supply http://electronics.stackexchange.com/questions/70143/dc-dc-c...

You can do it with a simple boost converter. Additionally I don't think you really need a 555 or anything. There are self-resonant converters that should do the trick.

Boost converters beyond 10:1 usually require a transformer. Efficiency of a transformerless boost converter goes down with the voltage gain, so there's a practical limit. It can be done without a transformer if you need very low current, but you need a big inductor. Here's a Geiger counter kit that does it.[1]

It's rare to use a Geiger tube for this today, because PIN diodes can also detect radiation. But they need a low-noise high voltage power supply and a lot of low-noise amplification. Some circuits for that: [2] Geiger tubes have the nice property that the output signal is quite strong.

I've been designing a boost converter that uses a 555 timer as the oscillator. It's part of a driver for my antique teletypes, which need 120VDC at 60mA briefly to pull in the selector magnet, then about 4V to sustain the magnet hold. Existing solutions are bulky and about 5% efficient. I've designed a version that is powered from a USB port. The design is on Github, in KiCAD format.[2] (Work in progress; haven't fabbed the board yet.) I'm using a 10:1 flat surface mount transformer from Coilcraft to get the size down.

[1] http://www.rhelectronics.net/store/radiation-detector-geiger... [2] https://www.maximintegrated.com/en/app-notes/index.mvp/id/22... [3] https://github.com/John-Nagle/ttyloopdriver

I have assembled two of these: http://www.ebay.com.au/itm/like/321502371329?lpid=107&chn=ps they re great fun. Best radiation source are old thorium doped gas incandescent gas mantels: http://www.ebay.com.au/itm/Geiger-Counter-Test-Source-Thoriu...

You are welcome.

Where did you source your Geiger-Müller tube?

The Russians sell them by the bucket on ebay:

http://www.ebay.com.au/itm/TESTED-SBM-20-GEIGER-MULLER-TUBE-...

400V on non-isolated wires? Sounds dangerous.

I'm sure the current output is very limited, though; I didn't see any particularly beefy capacitors when I skimmed the schematic.

It's not voltage alone that will harm you it's the amperage... and resistance of your skin.

You have nice table in this article: http://www.allaboutcircuits.com/textbook/direct-current/chpt...

There was once a project called the ultramicron or something that was sent into the EEVBlog. It was an open source project that was smaller then this.

The owner removed the public schematics and made it a closed source project sadly. I hope someone has a backup of his published files because one day I will be building it.

I hadn't heard of this, but it looks interesting. Thanks for bringing it up!

I found the EEVblog post[0] and was going to suggest that one could reconstruct the schematic by stitching together several frames from that video. However, it looks like someone did fork[1] the public repository before Andrey moved all the files to his server's FTP/GitLab setup.

A long, detailed post from Andrey on 2014-05-19, which presents the finished Ultra Micron, is still up[2]. I can't read Russian, but Google Translate seems to have done an okay job on it. There were also several posts on that blog from just the past couple months, so it looks like he's still actively working on it.

[0] http://www.eevblog.com/forum/blog/eevblog-776-world's-smalle...

[1] https://github.com/virtmedia/ultramicron

[2] https://misrv.com/%D0%B4%D0%BE%D0%B7%D0%B8%D0%BC%D0%B5%D1%82...

This is an awesome find on HN. I was just the other day wanting a Geiger counter to use as a random number generator. I was sure that I wouldn't be able to find one for an affordable price.

just use a reverse-biased zener diode.

either way getting truly unbiased random numbers is entirely non-trivial.

Ty!

Hopefully you are aware of this project to generate random numbers: https://www.fourmilab.ch/hotbits/

If you follow some links you will get to Aware Electronics, where you will find some stuff priced in the $200 range. It really depends on what part of the world you're from as to whether or not that is "affordable".

I was visiting the Chernobyl zone this Saturday. I wish I had seen this a month ago – then I'd have my own geiger counter for the occasion.

Well, a Geiger counter will only give you audio. If you want video, you can build yourself a cloud chamber (there are how-tos on YouTube).

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