
A cheap 555-based Geiger counter - dragonbonheur
http://hackaday.com/2016/10/16/a-cheap-555-based-geiger-counter/
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eveningcoffee
No, it is not based on the 555 IC, it is based on the Geiger Tube.

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new299
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".

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

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dvh
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.

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new299
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.

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mef51
if you're a little crazy you can take the radioactive americium out of a smoke
detector and use that as a source

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

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monocasa
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](https://en.wikipedia.org/wiki/Fusor)

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IgorPartola
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...](http://electronics.stackexchange.com/questions/70143/dc-dc-
converter-12v-to-400v-is-this-possible)

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Animats
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...](http://www.rhelectronics.net/store/radiation-detector-geiger-
counter-diy-kit-second-edition.html) [2]
[https://www.maximintegrated.com/en/app-
notes/index.mvp/id/22...](https://www.maximintegrated.com/en/app-
notes/index.mvp/id/2236) [3] [https://github.com/John-
Nagle/ttyloopdriver](https://github.com/John-Nagle/ttyloopdriver)

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ageofwant
I have assembled two of these:
[http://www.ebay.com.au/itm/like/321502371329?lpid=107&chn=ps](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...](http://www.ebay.com.au/itm/Geiger-Counter-Test-Source-
Thorium-Mantle-scintillator-
check-/322274097903?hash=item4b09087aef:g:nVAAAOSw0fhXlKuP)

You are welcome.

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flashman
Where did you source your Geiger-Müller tube?

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ageofwant
The Russians sell them by the bucket on ebay:

[http://www.ebay.com.au/itm/TESTED-SBM-20-GEIGER-MULLER-
TUBE-...](http://www.ebay.com.au/itm/TESTED-SBM-20-GEIGER-MULLER-TUBE-COUNTER-
STS-5-NOS-SBM20-20-/121971429216?hash=item1c66104f60:g:n~0AAOSw9N1VkV7W)

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bartl
400V on non-isolated wires? Sounds dangerous.

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dz0ny
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...](http://www.allaboutcircuits.com/textbook/direct-
current/chpt-3/ohms-law-again/)

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gravypod
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.

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mohn
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...](http://www.eevblog.com/forum/blog/eevblog-776-world's-smallest-
digital-dosimeter/)

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

[2]
[https://misrv.com/%D0%B4%D0%BE%D0%B7%D0%B8%D0%BC%D0%B5%D1%82...](https://misrv.com/%D0%B4%D0%BE%D0%B7%D0%B8%D0%BC%D0%B5%D1%82%D1%80-%D1%83%D0%BB%D1%8C%D1%82%D1%80%D0%B0-%D0%BC%D0%B8%D0%BA%D1%80%D0%BE%D0%BD/)

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throwaway98237
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.

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dekhn
just use a reverse-biased zener diode.

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

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throwaway98237
Ty!

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Koshkin
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).

