Safecast - Kickstarter Open Source Geiger Counter

[madmacmo]

FYI - I wanted to share the unique opportunity/fund raiser offer below as I have been watching Andrew (bunnie) Huang's open source geiger counter project development with great interest for a while now (especially if anyone is already familiar with the Medcom Inspector Alert):
Safecast X Kickstarter Geiger Counter

We wanted to do something special for the Kickstarter community, who helped us get Safecast moving in the first place, and thought that a limited edition version of the geiger counter we designed, at a discounted price, would be a cool way to do that.

So here you go: a Kickstarter exclusive Safecast geiger counter. Limited clear plastic casing (like these pics), numbered edition of however many people pre-order them here. The only way ever to get this clear version is from this Kickstarter campaign. Obviously, this edition is a real working geiger counter, 100% functionally identical to the forthcoming retail release version.

The final design features include:
•LND7317 pancake tube (aka the industry standars 2" pancake sensor which measures Alpha, Beta and Gamma radiation) + iRover HV board
•STM32-based microcontroller; sufficient CPU power to digitally sign logs with a unique private key as a non-repudiation/anti-tamper measure
•450 mAh Li-poly battery
•3-axis accelerometer so sensor orientation can be recorded
•128×128 color OLED display
•6-button captouch array
•“Hold” button on the back to lock the captouch array and prevent false triggering of the power-hungry UI elements
•Lanyard attachment (important for the Japanese market)
•microusb port for charging and data upload interface, featuring an FTDI-based serial chipset capable of loading firmware into the microcontroller
•3.5mm jack capable of bidirectional audio
•Embedded hall-effect sensor (to detect attachments, e.g. for occluding alpha or beta radiation)
•Audible event notification via piezo buzzer
•Low-power visual event notification via conventional LED

All in all, this Safecast designed geiger counter will be the swiss army knife of geiger counters.

The design is completely open source (you can download the source files here), so that everyone can benefit from these updates. Medcom International, who has helped us out with hardware at every single step of this, agreed to immediately start producing our design. Without them, this would just be an idea so they deserve a lot of credit for pushing it into reality.

Right now the top of the line device that Medcom makes, the Inspector Alert, retails for about $700 {Current "Spring Sale" Price $599}. If you've been paying attention to geiger counter prices you know there are cheaper devices out there, but they are also less sensitive to some kinds of radiation. We feel that this is important and why we've standardized our measurements and devices around the 2" pancake sensor so that we can detect Alpha, Beta, and Gamma radiation. Medcom's Inspector uses this sensor, and we designed our new device around it as well. As this device is to some extent an update to the Inspector, it will have a higher retail price tag, probably closer to $800 when Medcom releases it.

Pledge $400 or More
Don't kid yourself, this is the whole reason you are even looking at this project. At this level you get ONE of the limited edition SAFECASTxKICKSTARTER geiger counters. Numbered edition of however many people choose this level. This is the *only* time and place this version will be available, and at a much lower price than the forthcoming retail version. Our way of saying THANKS!!!

Estimated Delivery: Nov 2012
This project will be funded [pledging ends] on Tuesday Jun 19, 11:44am EDT

Note for the following eBay auctions for Inspector Alerts for comparison pricing:
Inspector Alert Geiger Counter - Radiation Detector alpha, beta, gamma, X-rays - eBay BIN USD $525.00
Inspector Alert/radiation food tester/Geiger counter/ionized nuclear radiation - eBay BIN USD $750

 

[T_Warne]

Ugh! I WANT! I just built this kit for fun and now I'm hooked.

Now, how do I explain to the wife that I want to spend $400 on a new toy?

 

[TacoHerder]

I noticed that last night, but the price is out of my league. Would be nice to have when goto the beach though. See if any debri has floated my way.

 

[Seoul_lasers]

For that price I can buy a properly calibrated Gamma Scout. Wow...

When you are going to be using it for something serious, I'd stick to a calibrated counter.

Well having a look at it, I do notice that the tube is 3600CPM:1mR/hr, which kicks the crap out of LND712 which is 1000:1

 

[T_Warne]

I'm not going to be using it for anything serious ( I'm rarely serious

)

How about a link to that calibrated Gamma Scout?

 

[T_Warne]

eeewww! It looks like something from Dewalt.

"Well having a look at it, I do notice that the tube is 3600CPM:1mR/hr, which kicks the crap out of LND712 which is 1000:1"

So... the safecast has more sensitive detection?

 

[T_Warne]

This makes me want it even more ----> to design a new Geiger counter that was not only more intuitive and easier to use than the current crop, but was also sufficiently stylish so that civilians would feel natural carrying it around on a daily basis.

I want something that is easy to understand and simple to use.

I think this is an awesome idea... ( and “Run Lola Run” was a great move. )
Another whimsical thought was to build a subsystem that would play music out the audio port based upon the current radiation level — calm, ambient music in low-radiation environments escalating to death metal and the sound track of “Run Lola Run” at dangerous levels.

*** As I sit here typing this my crude little Geiger in ping ping pinging away at some uranium marbles.

 

[TacoHerder]

That sounds pretty cool actually. I want just a basic one to take with me to the beach next month. Not even sure where to begin searching.

 

[Sigurthr]

This does look pretty sweet. The best thing it has going for it is the LND7317 tube, that is for sure. Even at the reduced price I am far from being able to grab one. While it would be a big upgrade over my LND712; I just got hired at a new job and start work tomorrow, and pay could be up to 2 weeks out. My finances are a bit of a mess right now, haha, and I have other priorities - O-scope and a long list of components. Besides if I were to upgrade rad equipment, it is a scintillator that is in order, not another geiger.

It is good to see more high end detectors being designed though. Now if only they could bring the prices down a bit and properly calibrate, it would be perfect. If they can calibrate and compete price/sensitivity wise with Ludlum.. we're heading for a real up swing in the field. Prices have been insane since the Fuku. disaster.

 

[T_Warne]

Both you and Seoul_Lasers mention "Calibrate". On the kickstart page I see:

Will the device be calibrated?

Yes, this will be identical function wise to the commercial version that Medcom produces and they will calibrate everything before it ships.
Last updated: Tuesday Jun 5, 3:25pm EDT


Only 10 days left to decide if I'll pull the trigger on this.:shhh:

 

[Sigurthr]

Both you and Seoul_Lasers mention "Calibrate". On the kickstart page I see:

Will the device be calibrated?

Yes, this will be identical function wise to the commercial version that Medcom produces and they will calibrate everything before it ships.
Last updated: Tuesday Jun 5, 3:25pm EDT


Only 10 days left to decide if I'll pull the trigger on this.:shhh:

Just saying that it is calibrated does not = it truly being calibrated. Rule of thumb in the RAD industry; NEVER trust a "calibration" when the isotope being used for calibration is not given. All calibrations are relative to a particular isotope and/or photon energy level, and without knowing which isotope/eV is used and the associated energy compensation/response graph, the calibration is completely worthless.

Edit; for greater clarity and information;
Take for example a geiger counter calibrated to Cs137. This geiger counter will read accurately when exposed to a Cs137 source, but it will NOT read accurately to a U235 source or any other source which is not Cs137. Energy compensated designs help level out the response curve of the detector so that a minimal derivation factor from the primary calibration isotope is attained; it will read close to accurate for most commonly encountered isotopes.

 

[T_Warne]

Reading that makes my head hurt.

So, what you are saying is you need a device calibrated for each radioactive thing-a-ma-bob you are testing for?

This is what I have now... a kit I put together from parts. All I know is that it loves green marbles.

 

[Sigurthr]

Reading that makes my head hurt.

Awesome. That pain is your brain growing and being used. It also means I am doing it correctly.

So, what you are saying is you need a device calibrated for each radioactive thing-a-ma-bob you are testing for?

Right, but that is usually unrealistic to achieve or expect, so you include a graph with your geiger counter which allows you to correct for the fact that your geiger counter isn't calibrated for say Sr-90 or U235 or so on and so on. Of course, you would have to have an Isotope identifier (MCA) to determine what it is that you're measuring so that you know what correction factor to apply! OR you use an energy compensated probe design and then publish data on how far off from accurate your reading can be given a range of isotopes. This is what you would expect to recive with an expensive radiation detector, not a "calibrated" meter which gives meaningless numbers without the data to support it. We see enough ignorant figures being thrown around by people not trained with rad equipment.

This is what I have now... a kit I put together from parts. All I know is that it loves green marbles.

Ah, a Geiger Clicker! Ya, those are fun. Not useful for anything quantitative really, though you could pull up the datasheet on the tube and find the cpm/(R/hr) figure and sit there with a stop watch and a piece of paper and count the clicks to determine background radiation rates. I've done it before, it isn't particularly fun, haha. Those are good for determining is something is inherently radioactive or heavily contaminated (think Chernobyl level of contamination, not Fukushima/3mi island - not for use in determining if something is safe or not to eat).

 

[T_Warne]

Doesn't a Geiger counter just measure Alpha/Beta particles and Gamma rays?

Why does it matter what source it was calibrated with?
A beta particle is a beta particle, so how Xmany particles interacting with the sensor would give you an idea just how much radiation is present, no matter if it's from a whats-a-call it or a do-hickey.

 

[Sigurthr]

Doesn't a Geiger counter just measure Alpha/Beta particles and Gamma rays?

Why does it matter what source it was calibrated with?
A beta particle is a beta particle, so how Xmany particles interacting with the sensor would give you an idea just how much radiation is present, no matter if it's from a whats-a-call it or a do-hickey.

That is where your error lies. A beta particle is NOT simply a beta particle! Just like photons they come in characteristic energies, and also just like photons they interact differently with different matter depending on their characteristic energy. Every isotope (flavor of radioactive material) gives off a different and signature characteristic energy for every bit of radiation it releases. The "spectrum" of radiation from Cs137 looks and behaves different than from Cs134 or Sr-90 or anything else. That means the geiger counter sees it differently as well.

For example: with nuclear particle physics the more energy a particle has the higher it's eV (or KeV or MeV for thousands and millions of eV) rating is. This is equivalent to what we identify as wavelngth for light. Why does 280nm light burn your skin and cause cancer but 405nm light doesnt? 280nm light penetrates deeper and deposits more energy than 405nm light. The same goes for eV ratings. A 660KeV photon penetrates far deeper than the 60KeV photon (xray) from a dental x-ray machine. A lead vest stops 90% of all the 60kEv xrays at a Dr's office but it barely stops 10% of the xrays from a 600KeV isotope!

When a particle enters a geiger tube it has to strike and be stopped by some matter inside that tube to be recorded, either the gas inside or the wire or the inside surface of the shell. Below a certain energy level, usually 30KeV the geiger tube's OUTER walls stop the radiation from getting in, the result is you could be in a LETHAL radiation field of 25kEv photons or betas and the geiger counter will read ZERO radiation present. Also, at >800KeV a similar situation happens... the particles have so much energy they pass right through the entire geiger tube without being stopped and recorded at all! Again, you could be in a lethal field and never know it. Every variety of geiger tube has a different responce to different energies and you need to know it in order to determine if that zero reading on your meter is really zero, or not. This goes for all forms of radiation, but it is most pronounced with Gamma radiation (which is the hardest to shield against also).

Hope that helps you understand.

 

[T_Warne]

Your comparison with the visible spectrum really helped. Now i get it! It makes sense now.