Video A Low Cost, Open Source Geiger Counter (Video) 46
Tim: Sawaiz, talk a little bit about what it is that you are holding in your hand here?
Sawaiz: In my hand I’m holding a low cost radiation sensor. So it uses wifi and basically tells the amount of radioactive events that are happening. It uses an AtTiny 2313, which is an AVR microcontroller. This is very similar to an Arduino. So it is very easy to program and very easy to share code.
Tim: What is the origin of this? How did you happen to be making a portable Arduino or a Geiger counter anyway?
Sawaiz: The origin of this is, I was working with my professor who is at Georgia State University, [Dr. He], and he does nuclear and particle research. So this is where he used for gathering lots of data. This is what they need to be able to figure out how weather affects, how radiation is affected by weather and stuff like that. It can also be used for health and safety, such as its used for gathering data for homeland security, so any threats that are happening, you will be able to downgrade it high _____01:02.
Tim: So, how difficult was it to actually come up with a way to integrate the two bit cell and the driving hardware? Was that a hard project?
Sawaiz: SoI got the idea for this through something called _____01:17 construction which was used in early missiles. So when you want they want get very compact design, they used to stack _____01:25 top of each other and connect them with components _____01:27, but that was very noble and robust way of building things.
Tim: And this is somewhat of an open source project, is it not?
Sawaiz: Yes, so all the code and information is on GitHub. There is a bill of materials, there is going to be some 3D models and assemblies that is going to go up. So this is both a hardware and software project.
Tim: Can you talk about the cost involved? What is the equivalent cost if you were to try to buy a commercial Geiger counter that does the same sort of thing?
Sawaiz: I haven’t seen any wireless ones on the market, but similar ones with displays built in end up costing about $130, the cost for this device including all the parts is about $23, and $16 of which is actually the Geiger thing, so that’s about $8 for everything else. It also runs on two AA batteries so it is very easy to keep alive, I think it should – presently it lasted for about 3 days but with a couple more of variations it should last for about a year.
Tim: Now it has got wireless capability?
Sawaiz: Yes, currently it uses 2.12 GHz module, to communicate with a base station which can be a Raspberry Pi or an Arduino, so you can just push all of your data straight to a database.
Tim: You could read it with a drone going overhead?
Sawaiz: Exactly, with a drone overhead, you can allow these and just drop downs, all over sites and it will gather data from there. There is also another similar module which uses Wi-Fi, so in a high density environments such as inside buildings, you will use Wi-Fi, so you won’t interfere with already overcrowded channels.
Tim: Now what is your next project, this is a cool one. You’ve got a couple of projects around here that are all yours, you have got a Deltabot over here.
Sawaiz: Yes, Deltabot. Deltabot still needs a lots of calibration, lots of weight, but it is printing. So currently the next project I am working on is this laser cutter, so this is a ______03:22 2.x laser cutter, it’s had 40 watt laser tube that can vaporize half an inch of ______03:27 or 8 inch of steel. So that is something I am really excited about, because I’ve gotten used to having a 3D printer, not something rented.
Tim: Have you considered taking up a hobby at some time?
Sawaiz: Ah... maybe I will think about that.
Slashdot jumps the shark... (Score:5, Insightful)
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is there some kind of confirmation algorithm he could help us with?
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Look again, links to the video are at end of news story; the linkedin profile link at beginning is not the main story
More info? (Score:2)
Is there a project page somewhere with more details?
If you are planning on dropping them... (Score:2)
I'd imagine that for cost, robustness, and duration on battery power, the presence of little gas filled tubes, some with fairly delicate internal structure, that require a high voltage power supply is a necessary evil at best
Better solutions (Score:5, Informative)
I've been building geiger counters as a hobby for the past couple of years. I was consulting with some people in Japan right after Fukishima helping to build reliable detectors.
Geiger Muller tubes require a specific "plateau" of voltage to get consistent results. Too low and you're not picking up much radiation, too high and you get spurious results and can burn out the tube. The correct voltage varies with individual tubes.
This isn't normally a problem, except that there's a glut of surplus Russian geiger tubes [ebay.com] on the market right now with unknown provenance and unknown parameters. Unless you calibrate each tube to find the plateau voltage, and unless you calibrate the resulting counter with a known source, the data you get will have no predictive value.
It's straightforward for a hobbyist to put together a project using one of these tubes and get it to click in the presence of radiation, and this makes a fine project for electronics learning, but you have to take further steps to get a reliable instrument. No one ever does this. The circuits I've seen have an unregulated high-voltage proportional to the battery voltage - it gets lower over time as the battery runs down. The voltage is chosen from the tube spec sheet, instead of determining the correct voltage for the tube. Circuits have design flaws such as using zener diodes for regulation, but not allowing enough current through the diode for proper function. And so on.
I've seen lots of these hobbyist projects in the past few years, especially since Fukishima. They're fine projects and well-intentioned, but generally not of any practical use.
Does radiation detection(with actual accuracy, linearity, and repeatability, not just a quick demonstration that you can add some noise to a webcam by pointing a small sealed source at it) have currently good, or at least promising for the not too distant future, solid state options?
Virtually any semiconductor will detect radiation. What you want is a semiconductor with a large capture aperture(*), which is the area through which the radiation passes. A 2n2222 transistor will detect radiation quite well, but it's capture area is tiny and won't see much of the radiation (saw the top off of a metal-can version and use a charge amplifier).
Power transistors such as the 2n3055 have large silicon dies and therefore larger apertures - as much as a square centimeter - but this is also quite small for capture.
The modern equivalent is to use a big diode such as a PIN diode [wikipedia.org]. These can be quite large, but also expensive for the hobbyist.
A GM tube has a capture area which is the cross sectional area of the tube. These can be made quite large; and as a result can be made quite sensitive to the amount of radiation flux in the area. Hobbyists can also make their own tubes with enormous capture areas - it's not very difficult.
Large diodes are available for detecting radiation, but a GM tube is simple and can be easily made with a very large capture aperture. Also, GM tube their capture efficiency (the percent of radiation that gets in which is is actually detected) can be higher than the diode solution.
(*) There's capture aperture and detection efficiency. GM tubes have an efficiency of about 10%, meaning that only 10% of the radiation that gets into the tube is detected. Diodes have similar efficiencies [carroll-ramsey.com], depending on the photon energy and thickness of the silicon die.
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Are there any issues with silicon solar cells that make them (protected against visible light, obviously) unsuitable? Compared to power silicon or anything for computation you can get enormous area for relatively little money.
Re:Better solutions (Score:4, Informative)
Are there any issues with silicon solar cells that make them (protected against visible light, obviously) unsuitable? Compared to power silicon or anything for computation you can get enormous area for relatively little money.
Huh. I hadn't thought of that. A quick google search shows that solar cells can be used [nih.gov] as radiation detectors, and they generally have large capture areas. I'll have to try this out.
This [montana.edu] looks like a good background document for detecting radiation using semiconductors.
This [wikipedia.org] is the type of amplifier you need as a 1st stage in your detector, should you want to build your own. (Google "Charge Amplifier" for more info.)
The radiation comes in as quick pulses (3 us or so in my circuits), so normal incident light shouldn't interfere with the detection. You could perhaps get both power and detection from the same cell.
I've been interested in detecting not only the radiation, but the direction it came from. A 3-d array of detectors with an incidence/correlation circuit can give a general idea of the direction of the source, relative to the detector. I haven't done this yet due to the complexity and expense of the detectors, but solar cells being cheap and easily available I might just try this out. Hmmm...
Thanks for the suggestion.
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I'm thinking by analogy to the approach for making 'white' LEDs: the output of the LED alone is atrociously unsuitable, so you add a phosphor blob that absorbs some of the output and emits at enough other energy levels to fill in something resembling actual white light.
Would a silicon detector, with a layer of scintillation materia
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Don't worry, in 2015 Slashdot will finally stop using Flash video. They're switching to RealVideo.
geiger counters vs. survey meters (Score:3)
Geiger counters are great for prospecting for uranium or looking for any residual contamination after being in a hot site. However, they will be easily overloaded in a nuclear disaster area and could even give a very low rad reading while you are getting a maiming or lethal dose. What you need is called a "survey meter', and they do NOT work on the same principles as a G-M tube. But I daresay this guy will need a different type of electronics to make a survey meter that could be dropped in, your normal SOC and microprocessors will go apeshit in a rad environment
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Absolutey false, stop spreading nonsense you made up between your ears. You don't know how a G-M tube works, it does NOT output current proportional to events or energy. When saturated it will "fire" at a very slow rate, and moreover have a drastically shortened lifespan.
What would you shield with, an absurd amount of lead? Nonsense, instead rad hardened electronics should be ( and ARE) used.
A G-M detector wouldn't be able to detect neutrons, without a huge "rem ball", yet another reason a G-M based detec
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your normal SOC and microprocessors will go apeshit in a rad environment
And why you would lead shield the SOC heavily.
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the amount of shielding needed would make device bulky and/or heavy, that's why special rad hardened electronics are instead used for such things
Nothing new, original or really low cost (Score:1)
Also his microcontroller memory most probably will fail on serious radiation, and if not stop working, then may give invalid data.
I understand detecting alpha particles in the tin can over FET transistor can be MUCH cheaper than those (but more for alpha, again), and similar original ideas.
link to video that works? (Score:2)
Doesn't work on android tablet, who still uses flash anyhow?