EEVblog #776 - World's Smallest Digital Dosimeter

[callipso]

I have 6 spare PCB's. Let me know if anyone wants one.

I could also give some away within the european region.

Cheers
Rubi

Ooh, do you have any left?

[dmg]

Today I got the screen and assembled the tube. I've set the pump to 8T (it was the default value). It always reads 0 uR/h... I think the tube is broken... Any extra things to do?

EDIT: it says BAT= 3.8V, 3V = 3.08V HV=360V

imp/min = 34

[dmg]

My meter measures 308V at HV cap. If i touch with something metalic the uR/h jump a lot and the alarm sounds. I've reset it and now it says between 130 and 172 imp/min but still 0uR/h

By the way how do I wake it up? when it goes to sleep I can only turn it back on by connecting the USB. If I touch the buttons nothing happens.

[dmg]

I've increased pump voltage to 410 V and I measure 350V at HV cap. My meter is very bad, I'll try at work tomorrow.

Yes, uR/H goes up and the line moves right, that works well.


Here are the pictures, hope they are high resolution enough.





BTW I think it's been working for some time because it was measuring steady 15uR/h, but I moved it to test the HV cap and now it reads 0 uR/h again....

[dmg]

Well, looks like the first geiger tube I used was bad as it was working intermitently and required higher than normal voltage for starting counting. It was also somewhat insensitive. I've swapped it for the other sensor I had and now I think my UltraMicron is 100% working.

I've popped the bad tube open to see what's inside and what was the source of the rattling noise it had. Turns out there was nothing broken inside. The tube has three main parts, the outer can, an inner tube and a glass insulator that caps the inner tube. That glass insulator is loose and it doesn't seem to have any glue residue nor any other evidence suggesting that this came loose, it was just manufactured like that so the rattling noise is perfectly normal.

Here are some pictures (sorry for the very bad focusing, for some reason my phone had a very hard time focusing on the thing....):

[JackM]

I've popped the bad tube open to see what's inside and what was the source of the rattling noise it had. Turns out there was nothing broken inside. The tube has three main parts, the outer can, an inner tube and a glass insulator that caps the inner tube. That glass insulator is loose and it doesn't seem to have any glue residue nor any other evidence suggesting that this came loose, it was just manufactured like that so the rattling noise is perfectly normal.

Thanks for the interesting dissection photos! Pretty simple device when you get down to it.

[NO_name]

solder it quickly, otherwise and you will have chance to make such photos

[dmg]

I made my first attempt to build the case today. It went relatively OK. For anyone that wants to machine a case like this note that they are made of a very easy to machine plastic. It has to be some sort of ABS with tons of fillers that make it hard-ish and resistant to temperature. It won't easily melt and clog your tool. I've been able to machine it at 10k RPM with a 4-flute 1mm end mill that I normaly use for fiberglass laminates and hard stuff using water as lubricant and the results are good enough for the pourpose. All the mills I have for cutting plastics turned out to be too short for the job.



It's still missing the butons and the scren guard, I plan on making the screen guard out of machined polycarbonate from a CD and I'll try to mill the buttons in acrylic. But well, everything fits!

[Rubi]

Sorry I was on vacation, yes I have one left, pm me your address.

Cheers
Michael

I have 6 spare PCB's. Let me know if anyone wants one.

I could also give some away within the european region.

Cheers
Rubi

Ooh, do you have any left?

[NO_name]

Good job, I already have tested it.

[JackM]

Also i be forced to delete all sourcecode of firmware and PC Software in public repository. I afraid it be steal my project.

Now i provide only "compiled binary firmware".
Without license on it, work almost all features, except new.

That's too bad to hear
I was still planning on making one of these dosimeters of my own and even possibly contributing to the project.

[dmg]

Why building one when you can build two?

Both are now working, I need to machine a new case for the second one and re-clean it a little bit. The one in the case has a rattling tube, the other has a non-rattling tube. I've checked them for a while and they correlate very well, not only do they stay at almost the same radiation level but they do track each other very well too, if one starts reading higher the other follows the trend very soon. This mostly confirms that indeed I have the radiation record of all microns currently registered within the monitoring system and that the tubes are consistent with each other. Next step is finding something radioactive to test them, maybe I'll hide one of these inside the pile of bananas at the supermarket...

I've had a lot of fun building these, It's hard to find great self-contained and useful proyects that are worth building in these days of arduinos, and this is also a very good lesson on low power electronics and power converters.

[SeanB]

Big bulk pack of gas mantles will work well as a test source. The cheaper the better, just buy a big pack of the cheapest ones, which will have enough Sr in them to register above your background levels.

If you have piped natural gas that is also slightly radioactive from Radon inside it.

[apis]

This is indeed a cool project.

I'm sorry if this is a stupid question but why is the isolation so important on the HV side, is it to save battery power or is it because the detection circuit is so sensitive?

(And system shock was a good game  )

[frank_gamefreak]

Hello,
can I buy the UltraMicron somewhere?
I am very interested in the data the device provides.
But unfortunately I lack the knowledge to build the device.

I want the end of my trip to Japan Blog restart. Of course, the data would be very intresting by fukushima.
Thank you very much

[frank_gamefreak]

Dear frank, unfortunately i do not sell it now.
Just because i have no time for it.

No problem, maybe someone else can help me in this forum?

By the way, is this (https://oshpark.com/shared_projects/sQYExg6e) the new one?

[frank_gamefreak]

I can understand you well, you want that is not stolen your idea. I have but the problem that for me knowledge, technique and skill is lacking .
Moreover, I think that is not "selling" here. I pay the material and working time for only one device.
And I can imagine to donate to you, even if someone else is solder for me.

But please answer my second question, is this (https://oshpark.com/shared_projects/sQYExg6e) the new one?

[frank_gamefreak]

"I pay the material and working time for only one device." - that is also selling.

It's like giving a beer to a good friend for his help or is it also selling for you? I don't say bring it on the market...

It project i made for hobbyists who like build some devices by itself.

And I'm a hobbyist how likes to make something with the data provided by the device.
But I'm not good at suche things like soldering, because of my shaky hands. I've been just not steady enough.

You have the opinion because I'm not good enough in dealing with the soldering iron, I may not have the hardware?
This contradicts the open source idea completely. I do not know what you want to achieve with it.

[osiixy]

This is just a hint for your clue.

You see, you are the one who killed your own project,
why would anyone be part of it?

You own it, you sell it or just let it die peacefully,
there is not much reason to contribute with you.

This gadget just faintly more than a proprietary stuff,
so you are the one who needs to decide how to treat it.

If you stick to it so hard and also want to share it with others
someway do everything by yourself.
(Arrange the mass production, retailing and selling).

OR just simply amuse yourself and few of your fellas.

[osiixy]

Be happy with yourself, your attitude and few of your friends.

I will do the same with my "solder iron", what is working, even if you "do not see".

[frank_gamefreak]

I do not see hobbyst here, it is sad for me... i see only "I CAN'T" "I WANT BUY" "MASS PRODUCTION"....
No hobbyists... almost nobody!

Okay my hobby is not make new hardware that is true, but my hobby is big data.
I'm working on projekts like loklak.org or yacy, why is using data no hobby?

And I want to contribute to you.

[frank_gamefreak]

Why you give yourself then the effort to create a possibility to load the data to the PC?
I do not get the idea

[osiixy]

I do not see hobbyst here, it is sad for me... i see only "I CAN'T" "I WANT BUY" "MASS PRODUCTION"....
No hobbyists... almost nobody!

Okay my hobby is not make new hardware that is true, but my hobby is big data.
I'm working on projekts like loklak.org or yacy, why is using data no hobby?

And I want to contribute to you.

It has been revealed: "So this project is not for you. Sorry!
" , do not worry it is not for me either and many other "inferior ones", even if I am able to assemble it.

[frank_gamefreak]

If you think I'm not the person for your device... help me to finde a divce which i can use without you.
Noone will earn money with the data on a travel blog but I can show that japan is safe to travel.
I love Japan.

[Someone]

If you think I'm not the person for your device... help me to finde a divce which i can use without you.
Noone will earn money with the data on a travel blog but I can show that japan is safe to travel.
I love Japan.

Just measuring external count rates does not provide the complete picture, ingestion/inhalation of alpha emitters is possibly the biggest risk after an accident and very hard to measure with compact or cheap equipment.