It will be based on this one, that can run from a 9V battery:
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But... it should be much smaller, more sensitive, not so obvious in the supermarket, etc etc
Starting wth a more sensitive and much smaller GM tube, the SI29-BG, eBay item number: 190928106922, 19$75 + 9$ shipping, I tested a better HV section:
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that is a 160 mAh LiPoly at 4 V, and a conrad.nl 1:10 audio transformer, driven by the PIC output in the above diagram. I have 1.2 kHz pulse rate, and at a pulse width 10/255 with no load get >= 400 V DC, with a current consumption of 1.5 mA (makes 100 hours). When the GM tube would be saturated (nuclear war, 10 MOhm load) it needs a PWM width of about 35/255 to get the 400V, and draws about 5.6 mA. I see 70 V Vce peaks on the driving BC548, a bit much... and of course that audio transformer is used out of spec. But this is very small, the HV cap is the biggest part. There will be a 120MOhm feedback voltage sensor resistor divider. But the LCD module did not fit the box I had in mind, so I was looking for smaller LCD, and found eBay item number: 360695746942 at 5$46. Nice and small, and here is how to drive it:
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Then I was looking for an old Nokia phone to build it in, or an old Nokia phone with this display to build it in, (I actually have one, but hey, lets keep it in one piece) but found this solar powered flashlight, FM radio, and mobile phone charger for only 10$ or so: eBay item number: 370856410707 I have orered that, and will try to put the GM tube, PIC, and Nokia LCD in it... So now we can, even if society completely collapses, as is near on the US west coast, still check our fish and chips for dangerous radiation, even if there is no more electrickity.
So, these thing may or may not arrive (YMMV with ebay), but so far there is a plan. Will it work? We will see.
I may still go for the phone idea too, once could add a GPS module too and logging to see _where_ your got that radiation over dose. But of course this first, those GPS sats will be shot down anyways by the Chinese perhaps, they have tested that. It would be to their advantage as their GPS BALDU? system is coming on line and free for anyone to use, sort of competition (to GPS), now imagine...
On a sunny day (Tue, 07 Jan 2014 11:51:12 -0500) it happened Neon John wrote in :
Read the datasheet, it is 360 to 440, nominal 400V.
I have a small 500V stabilizer tube from an old mil Geiger unit, the same one I took the probe and pot core from. The PIC micro controller in that project uses the hardware comparator to bang teh drive pulse on and off, I will probably make this one with PID control. It is indeed important to stabilize teh voltage. BTW in my case you can set the voltage via RS232, look at this menu: # ptlrc -d /dev/ttyUSB0 -b 19200 Panteltje ptlrc-0.7 using device /dev/ttyUSB0 Escape exits.
Clock cal 255
18:27 PR2 reload 101 Softstart speed 10 UGM select 7 PWMmax. 35 PWM 35 Ubat 9.6 V UGM 480 V Accumulated ticks 18 not saving dose Alarm off
And that is via the LAN, the counter is far away!
I just restarted it so I could show this, normally the output of /dev/ttyUSB0 goes to a log file, via grep cpm. cpm 18:6 7 cpm 18:7 3 cpm 18:8 7 cpm 18:9 4 cpm 18:10 4 cpm 18:11 7 cpm 18:12 7 cpm 18:13 5 cpm 18:14 7 cpm 18:15 3 cpm 18:16 11 cpm 18:17 7 cpm 18:18 6 cpm 18:19 6 cpm 18:20 4 cpm 18:21 5 cpm 18:22 4 cpm 18:23 3 cpm 18:24 7 cpm 18:25 7 cpm 18:26 4 cpm 18:27 9
No much here, this is a 1r/h tube in the probe.
This is help menu: RS232 commands: A alarm at 100 mR on, LED and beep off. a alarm off, LED and beep on. B LCD backlight on. b LCD backlight off. C flash clock separator. c do not flash clock separator. GnnnENTER sets clock calibration, timer1 reload low byte, default 175. HnnENTER sets hour, range 0-24. h prints help. K save accumulated dose in EEPROM every minute (use if no battery backup). k do not save accumulated dose in EEPROM. MnnENTER sets minute, range 0-59. PnnnENTER sets maximum PWM value, range 0 to 100. R reset accumulated exposure counter. S sets soft start speed, range 1-15. s prints status: time, local/remote voltage control, max. pwm, pwm, battery voltage, GM tube voltage, accumulated ticks. UnnnENTER selects output voltage, range 0-31, set for 475 V. v prints version number. All settings except time and debug are maintained after a power down. cpm 18:28 11 Accumulated ticks 22
-------------------------------
Did you look at my 'probe'? It has a closeable metal window:
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It is specified at 1 tick per second background (60 cpm), I do not see the point of exceeding the tube specs, it is way more sensitive than most other ones.
Nice.
There are small Russian pancakes [:-)] on ebay, but those are still big,
Yes, that is cool, for that reason I have ordered some of these:
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(ebat item 160784342887) You cannot go wrong for 2$69, note the cool POTENTIOMETER in the earbuds cable.. Will need some art to get the stuff in there, It almost look too innocent, but should not cause panic, If I can fit the tube and electronics I may do some more.
I have some radium watch hands, Mine are not very active, do not glow in the dark either, bad buy,
When I worked with the centrifuges anyways _that_ was really dangerous :-)
On a sunny day (Wed, 08 Jan 2014 07:54:51 +1000) it happened Adrian Jansen wrote in :
When I had the TV shop we once bought some mechanical cash 'calculators' from the "domeinen" (Dutch military surplus auction). Sold some of them for export to Turkey IRC as those were used on the markets there where there is no 'trickity.
I also tried to repair one, hundreds of levers and washers on the table later ... I could not put it back together again... For me, 'tronics is easier.
I have a Ludlum model 3. I don't have it in front of me, but it is the kind with the tube and rotatable gamma shield. Looks like this:
What does the pancake detector do differently?
Sources aren't as easy to get these days. Ebay doesn't seem to have radioactive rocks for sale anymore. I have a chunk of uramium glass rock (stored in the well ventilated garage) I got from ebay and a bit of uranium glass tubing I found at a flea market. Ebay does sell uranium glass and Fiestaware. But all the sources are gone.
Some of the Primus lantern mantles are radioactive. Hard to find though.
I'll keep an eye out for an orphaned Ludlum pancake sensor, but they don't appear to be mylar covered. [Orphaned as in no companion meter.]
I know spots that read 100uR/h on the cylindrical tube. That is about the hottest I ever ran into just in the field. This is out by Kelbaker in the Mojave, a well known location for uranium. I didn't have my gieger counter with me when I was at the waste pit near Moab. That might be hotter. But that is behind a fence. [Not much of a fence. ;-0)
I have a UV flashlight, so I can find rocks that glow green, similar to the uranium glass, but most of time they aren't that hot. And lots of stuff glows green, including scorpions.
It could be a California thing, but none of the lantern mantles at Wally World are hot. But I wll check next time I am in Nevada or Arizona.
Orange fiestaware is amazing. That they still sell on ebay, they just don't talk about the radiation.
I think you can buy those from McMaster-Carr... (TIG General purpose) But the McC web site is having issues.... either that or the NSA is interupting my search.
I wonder guys why don't you just buy a REAL radioactive isotope source? They are definitely more expensive than a single _OLD_ mantle (new ones are not made with thorium salts any more) but they don't cost a fortune either.
There are several places that sell _LEGAL_ sources to general public. Something like Cs-137 with it's beta/gamma would've been sufficient for a geiger counter enthusiast...
Here is one of such places:
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Usual disclaimer -- I'm not affiliated with them (and with any other such businesses,) just using standard sources for playing with my own geigers...
And BTW, most of those russian commonplace counters (SI-29, SBM-20 etc) _DO_ have ~400V working voltage that is in the middle of their plateau. They never lied in their datasheets :)
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It will be based on this one, that can run from a 9V battery:
formatting link
But... it should be much smaller, more sensitive, not so obvious in the supermarket, etc etc
Starting wth a more sensitive and much smaller GM tube, the SI29-BG, eBay item number: 190928106922, 19$75 + 9$ shipping, I tested a better HV section:
formatting link
that is a 160 mAh LiPoly at 4 V, and a conrad.nl 1:10 audio transformer, driven by the PIC output in the above diagram. I have 1.2 kHz pulse rate, and at a pulse width 10/255 with no load get >=
400 V DC, with a current consumption of 1.5 mA (makes 100 hours). When the GM tube would be saturated (nuclear war, 10 MOhm load) it needs a PWM width of about 35/255 to get the 400V, and draws about 5.6 mA. I see 70 V Vce peaks on the driving BC548, a bit much... and of course that audio transformer is used out of spec. But this is very small, the HV cap is the biggest part. There will be a 120MOhm feedback voltage sensor resistor divider. But the LCD module did not fit the box I had in mind, so I was looking for smaller LCD, and found eBay item number: 360695746942 at 5$46. Nice and small, and here is how to drive it:
formatting link
Then I was looking for an old Nokia phone to build it in, or an old Nokia phone with this display to build it in, (I actually have one, but hey, lets keep it in one piece) but found this solar powered flashlight, FM radio, and mobile phone charger for only 10$ or so: eBay item number: 370856410707 I have orered that, and will try to put the GM tube, PIC, and Nokia LCD in it... So now we can, even if society completely collapses, as is near on the US west coast, still check our fish and chips for dangerous radiation, even if there is no more electrickity.
So, these thing may or may not arrive (YMMV with ebay), but so far there is a plan. Will it work? We will see.
I may still go for the phone idea too, once could add a GPS module too and logging to see _where_ your got that radiation over dose. But of course this first, those GPS sats will be shot down anyways by the Chinese perhaps, they have tested that. It would be to their advantage as their GPS BALDU? system is coming on line and free for anyone to use, sort of competition (to GPS), now imagine...
If the disaster has already happened, did you hear the boom or see the mushroom cloud? Just use your 5 senses.
Not quite sure what Shaun is saying, but there are now dangerous levels of radiation on beaches in California that have finally made it there from the Fukushima incident in Japan. Looks extremely serious. Your gizmo may well come in useful for checking tuna and other seafood.
Hmm, much more "dangerous" in the mountains of Colarado than the beaches of California. I'm not concerned about either. Radiation is a part of life, it's a shame that most people are so worried about it.
On a sunny day (Sun, 12 Jan 2014 18:45:27 -0800 (PST)) it happened George Herold wrote in :
Now explain that to the people who lost their homes and land in Japan. And Fuckupshima is just starting up... Why do you not go and help them clean up the mess?
I am all for nuclear power, but the one who designed Fuckupshima had some wires lose.
Anyways, it is GOOD to have test equipment, it ALWAYS is a help, even to _prevent_ paranoia.
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