Author Topic: EEVblog #776 - World's Smallest Digital Dosimeter  (Read 39515 times)

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Offline dmg

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #25 on: August 06, 2015, 11:06:08 am »
Well, I'm building one or two of these I'm amazed of the PSU design, very nicely done. I've already ordered all the components. For your reference on things I've found difficult to get:

I'm 99% sure that these are the cases:
http://www.aliexpress.com/item/plastic-case-small-6-pcs-49-27-18mm-electronic-project-box-electronic-case-abs-swith-housing/32219511996.html
It has the exact inside dimensions and looks very similar on the outside.

This is the only source I've found for screens:
http://www.aliexpress.com/item/Original-LCD-screen-digitizer-display-Second-External-LCD-For-Nokia-2760-Mobile-Phone-Repair-replacement-Tools/1822978844.html

As for the vibration motors the ebay seller listed on the motor parameters ( ebay store 4hobbyde) seems not to be carrying them, but no worries, I'm 99% sure they are these:
http://www.ebay.com/itm/231218458556?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

SBM-10 tubes are readily available on ebay from lots of sellers, no problem there.


As for the rest of the electronic components all of them are readily available on digikey and mouser. Well, there are no matching tactile switches on mouser but those can be found on ebay for dirt cheap (the model listed on the BOM is from a russian store but it's standard. So is the orange LED, any 1206 orange led will do). It gets cheaper on mouser. Only things I've found are that:

- ATB322515-0110 transformers are out of stock everywhere until september 2015, but you can get ATB322524-0110 which seems to be fully compatible, just a bit taller (same series, same datasheet, higher current rating)

-ABM7-8.000MHZ-D2Y-T has a unique footprint and there are literally no other crystals on that size and frequency anywhere. They are out of stock until late october 2015 in mouser and digikey, thankfully they're in stock at farnell and I had to make an order there anyway. I've ordered extra in the case anyone needs. I was about to change the crystal for something in 5032 package which is more readily available but I had already ordered the PCB's. Elecrow seems to be happy so far with the gerbers. Looking at the design rules and browsing the PCB it seems that the tolerances are within the capabilities of all 6mil/6mil chinese manufacturers.
 
Total cost ordering in 1's is about 60€. If anyone is interested I can share a cart for digikey/mouser with everything you need in exact quantity (once you stockpile about 8 large boxes full of leftover SMD's you start seeing the value of ordering just two damn 0603 resitors even if that's more expensive than ordering 25 or 50 as you did when your room had more space)

I've ordered six cases and I have a milling machine that can do plastic. I only plan on building two of these and once I get the milling machine set up right I might machine all six cases so I might offer them here if anyone is interested. I plan on using a CD as a source for polycarbonate windows.

I'll tell you how it goes when It's built. Very nice project.

« Last Edit: August 06, 2015, 11:15:44 am by dmg »
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #26 on: August 06, 2015, 11:32:16 am »
Display - Last time i buy here, but it expensive.
Case - I use this, but you is very similar.
Transformer -  ATB322524-0110, yes, it will be work fine.
Crystal - yeah.. its very rare thing.... But i buy it on Farnell.

Ordered 6 case is good idea, because it need complicated milling like this and this. It make by the hands with Dremel and "file" in first prototype. Last versions fully doing on CNC machine.
« Last Edit: August 06, 2015, 11:47:35 am by shodan@micron »
 

Offline dmg

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #27 on: August 06, 2015, 11:48:15 am »
Display - Last time i buy here, but it expencive.
Case - I use this, but you is very similar.
Transformer -  ATB322524-0110, yes, it will be work fine.
Crystal - yeah.. its very rare thing.... But i buy it on Farnell.

Thank you very much, I'm pretty sure that my case is exactly that one. I've seen the exact same model I ordered listed elsewhere with the same dimensions as yours (in my link the case is listed with a height of 18mm but I've see it listed as 14mm with the exact same part number. You know, chinese millimeters aren't always as everywhere else's millimeters).

 By the way, is there anything else I need to know before building the 4.06 version? I've seen that the design is mostly the same as 4.04 except for a 1.6ohm ferrite which is now a 22 ohm resistor and an extra mosfet at the HV power supply. Will it work with the current firmware? I've also read in your blog something about some resin that you applied to the positive terminal of the geiger tube but later you had to scrape off the PCB but I didn't understand very well. Could you explain? I have a friend who speaks russian and could help but she's on holiday.

EDIT: I have a CNC milling machine. The window for the screen and the holes for the buttons are easy to make but the USB micro hole will require a custom tool to support the case in a vertical position. I hope the plastic is ABS or something easy to machine. I'll make a 3D model of the enclosure when it arrives and hopefully I'll get it right before the 6th trial.
« Last Edit: August 06, 2015, 11:55:44 am by dmg »
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #28 on: August 06, 2015, 12:24:37 pm »
Oh... resin this is most complicated thing!
I will try to explain.

My design is based on the ultra-low leakage on HV side.
For this i tested many-many different components on different manufacture and select that diodes and capacitors witch have low leakage. It should be understood very clearly. It means replace component on HV with analogs are not allowed in most cases.

About resin... The decrease in current consumption I was so successful that mosisture level in atmosphere is now be critical to current consumption.
In high moisture level it be high current consumption and battery discharging is faster. I do not like it, although in most cases it is not critical.
So then i try epoxy coating HV area.
But is be big problem.... many epoxy whitch i use shows increase leakage, if compared it to clear HV area.

Dave version as you can see, not coated by epoxy, because it need to be very cleary the PCB layout for video.

This is no critical. Device balanced by current to compensate lekage by mosisture.
Find a high-quality resin is very difficult .... if you are not ready for experimentation, I recommend not use the epoxy resin!

UPDATE it also means, PCB need to be cleared very good with ultrasonic. And i recomend use very good flux(absolutely non conductive), like as Nordson EFD FluxPlus 6-411

I am so sorry, i speak English is very bad, but i hope you understand me.

About 4.04 -> 4.06 change, yes, is little different PCB layout and replace some component on pump side.
Firmware for version 4.02, can be installed on all 4.** generation PCB.

Remember, first you need load bootloader! (DFU.BIN) After that you need upload .DFU firmware via STM DfuSe tool via USB
« Last Edit: August 06, 2015, 12:39:10 pm by shodan@micron »
 

Offline axel15

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #29 on: August 06, 2015, 06:15:42 pm »
Well, I tried to recompile English translated Win-software, but too many 3rd party version depended files required.

Axel.
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #30 on: August 06, 2015, 06:21:22 pm »
Just install Delphi JCL
« Last Edit: August 06, 2015, 06:24:08 pm by shodan@micron »
 

Offline axel15

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #31 on: August 06, 2015, 09:29:30 pm »
Just install Delphi JCL

That was obvious. But besides Jedi there are some missing properties (modified std Classes?), missing VCL(s) (at least MyTray), version conflict between Jedi and zlib object files (or pngimage-source... can't say), modified or updated Indy... etc etc.
Anyway: too many conflicts between my D7 and dosi-win software.

If it were only changing some texts and recompile I would do that. Investigating and reverse engineering goes beyond my economical effort in this case...

Axel.
 

Offline dmg

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #32 on: August 06, 2015, 09:36:10 pm »
Oh... resin this is most complicated thing!
I will try to explain.

My design is based on the ultra-low leakage on HV side.
For this i tested many-many different components on different manufacture and select that diodes and capacitors witch have low leakage. It should be understood very clearly. It means replace component on HV with analogs are not allowed in most cases.

About resin... The decrease in current consumption I was so successful that mosisture level in atmosphere is now be critical to current consumption.
In high moisture level it be high current consumption and battery discharging is faster. I do not like it, although in most cases it is not critical.

[...]


I was kind of expecting this, thankfully all the components in the HV section are easily available in exact part number, so no problems there. That HV power supply design is a masterpiece. I also have an ultrasound cleaner, but is it OK to clean the board with the SBM-10 installed or do I have to clean it before installation? I'm concerned about vacuum seals potentially cracking due to vibration. I'm no expert on HV/humidity barrier coatings but there are people in my company who are, I'm gonna ask them to see what can be done.

Thanks again
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #33 on: August 06, 2015, 09:38:44 pm »
Its compiled by RAD studio XE6 with JCL, noting else!

You dont need make anything, in this week i added language selector to this software.
 

Offline axel15

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #34 on: August 06, 2015, 09:42:52 pm »
Its compiled by RAD studio XE6 with JCL, noting else!

You dont need make anything, in this week i added language selector to this software.

That is very good - and the only thing I was going to do anyway.

Axel.
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #35 on: August 06, 2015, 09:51:35 pm »
dmg - you must clean PCB without buttons, display and SBM-10, all other components must be installed.
Sometime quarz crystals has died in ultrasound, do not use much power ultrasonic clear.

Ah! and... soldering SBM-10 to PCB "sensor contact" must be very qickly. I heatup PCB pad, touch solder to PCB until it touch SBM-10 contact, and move out soldering Iron quickly. Because sbm-10 central pin is sensitive to heat.

UPDATE You can see here, solder just little touch sensor. I not soldered it fully.
« Last Edit: August 06, 2015, 09:56:11 pm by shodan@micron »
 


Offline Rubi

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #37 on: August 06, 2015, 09:58:10 pm »
Hi Shodan!

I recommend use Seeedstudio, because it have better "Annular Ring" PCB limitations.

First thank you very much for this great project!

Seeedstudio is also great, esp. when you want to build more than one unit, but I recently prefer oshpark because of the default golden coating , at seed this would cost an extra 20$.

On another great russian project i built recently I had to use dirty pcbs which were extremly cheap and also very good quality but it nearly took two months to get to me.
http://dirtypcbs.com/view.php?share=6586&accesskey=cad38a0e9484b06ec39b33055847b133

Cheers
Michael



 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #38 on: August 07, 2015, 04:48:03 am »
I added English version of software to testing branch.
After 2-3 weeks it be released with new firmware. Now it testings....
« Last Edit: August 07, 2015, 05:02:29 am by shodan@micron »
 

Offline VK3DRB

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #39 on: August 08, 2015, 06:59:13 pm »
What the country of Japan needs is a tool to detect radioactive trace elements in their food. Invent that and you will become very wealthy. In the meantime, many Japanese are buying foreign fish because they do not trust the stuff from local waters.
« Last Edit: August 08, 2015, 10:52:00 pm by VK3DRB »
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #40 on: August 08, 2015, 11:25:27 pm »
For food needs Alpha + Beta + Gamma sensitive detector.
SBM-10 not sensitive to Alpha and soft Beta. Only hard Beta + Gamma.
 

Offline Skibane

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #41 on: August 09, 2015, 02:14:09 pm »
"World's Smallest"?

Not sure about that...



 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #42 on: August 09, 2015, 02:16:54 pm »
SIZE: 7.6 x 5.4 x 1.7 cm (3.0 x 2.1 x 0.69 in.) (H x W x D)
WEIGHT: 144 g (5.1 oz), including batteries
:-DD


My device is 18.2 gramm  49*27*14mm.
Yes i know, it is really insane size, but is real.  :box:

Believe me, i don't see dosimeter smaller my.
I see many small devices, but it need PC or smartphone for displaying data. It increase size to smartphone dimension.
Also i see devices without displays(sound or led indications) which smaller, but it can't displayed dose, or do it very-very poor(unusable).

My friend MadOrc make dosimeter called "Nanit" link
It has very close to me, but is bigger and poor functionality. Also it more cheap component price.
We started development at same time, and share ideas between with each other. Because that, this is very similar devices.
« Last Edit: August 09, 2015, 03:36:12 pm by shodan@micron »
 

Offline drago

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #43 on: August 09, 2015, 11:29:28 pm »
Awsome project!
I like the clean design especially the high voltage converter but also other features:
 • user interface
 • Nokia display
 • USB ESD protection
 • cute vibration motor
 • digital design

Thanks for sharing this as an open source.
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #44 on: August 10, 2015, 04:09:19 pm »
I added English translation to "Micron monitoring system" link
« Last Edit: August 10, 2015, 04:11:42 pm by shodan@micron »
 

Online Kleinstein

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #45 on: August 10, 2015, 06:27:28 pm »
Food testing is much more complicated. The radiation levels are much lower, so one needs quite heavy shielding.
Normaly they also use only gamma radiation, but a energy seperated cintilation detecor. The expensive part is the detector (special crystal and photomultiplier tube). The electronik can be small and cheap - though in small quatities it has a price. Even than it takes hours to get a usefull reading, unless  the radiation levels are way to high.
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #46 on: August 10, 2015, 08:42:04 pm »
Schematic for PMT can not be cheap, because it need high speed ADC with 16-24 bit accuracy + high speed RAM + high speed MCU (FPGA better) + 1-1.5 kV ultra low noise powersource. It also need 3-5 calibrated radiactive source.
It very complicated device at all.

Maybe if .... use pull pulse duration .... then it can be simple and cheap, but it can't be accuracy between energy levels.
... that device is trash....

More simple and cheap, if you use alpha-beta-gamma high sensitive sensor. It can't be very precisely, but it shows danger level contaminations.


I think this thread is not for discuss about PMT, let's not discuss them here, okay?
It is principally different devices.

As for the ultra-micron, it is designed to protect the user from dangerous gamma radiation, and is meant as a pendant for continuous wear.
In some cases, it can detect hard Beta radiations.

I never claimed that it is suitable for testing food!
But it can be detect gamma source without any problem. Also it can very good to detect Ra-226 (Beta source) (The most common, after Am-241 smoke detector) and many more. As many GM-tube based detectors.
« Last Edit: August 10, 2015, 09:19:36 pm by shodan@micron »
 

Offline dmg

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #47 on: August 11, 2015, 12:11:28 am »
Hi again, I just received the main components order but I'll take about a month to get everything else from china. I can't find a datasheet for the screen, do you have one? Could you at least tell me the main dimensions (width, length and thickness) of the screen so I can model it in 3D for the case design?

I live in a part of Spain with relatively high levels of natural radiation. Right where I live it's about 15 uR/h just in gamma radiation according to available maps, but in the mountains nearby it can go up to 30 uR/h. I plan on taking this to mountain trips and monitor the radiation.

EDIT: also, do you have a source for the button plastic keys? I've seen in your blog that you used calculator keys in previous designs but now all your cases have the same black buttons. I can't find them on ebay.
« Last Edit: August 11, 2015, 12:27:16 am by dmg »
 

Offline shodan@micron

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #48 on: August 11, 2015, 12:34:52 am »
Screen has no datasheet. Border on it have protrusion and matrix not symmetrically.
Please wait while you receive it.

Background level is similar at random value, it can be calculated only in very long period.
See graph on this page.
Normal level is 7-20 uR/h. In this range it can be vary random.

As you can see on this map it can be different within the same city/area limits.

Yes on high altitude it be higher, also it can be higher beside in deposits of granite, uranium ore, high content of Ka-40 in ground.

EDIT: Yes i use calculator CT-106 (made in China), therse buttom is transparent plastic. I deleted legend with isopropyl alcohol.
It transparent to LED light. When i charge device keys glowing!
But i think you can't find same model of calculator. I buy it on local store. You need find similar.
« Last Edit: August 11, 2015, 12:54:52 am by shodan@micron »
 

Offline dmg

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Re: EEVblog #776 - World's Smallest Digital Dosimeter
« Reply #49 on: August 11, 2015, 01:01:00 am »
Thanks, I'll get that exact calculator if possible.

Right where I live the soil is basically sand and river sediments but the mountains nearby are mostly made of granite and that's why radiation is higher than average. I hope this device can detect the extra radition.

Besides that, I think that the only potentially highly contaminated area in Spain is near a small southern town where a yankee plane accidentally dropped 4 atomic bombs in 1966 and the explosives in one of them detonated spreading plutonium over a large area. Thankfully it wasn't a nuclear explosion. They cleaned most of the stuff but as far as I know there are places that are still contaminated. I might visit that place one day.
 


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