I added a PIC and LCD to my basic radiation detector and can now display total counts over time(up to 24 hours) or Counts/Sec and relative gamma strike energy level. The energy level varies as every gamma strike does not dislodge the maximum possible number of charge carriers. I take the maximum value registered every second and display. On average various materials indicate different levels, providing a crude detection signature. Besides the LCD display, this circuit has a sample and hold circuit which is connected to the PIC ADC module and also tied a another PIC I/O pin which switches from tristate to pulled low to reset the sample/hold circuit. The maximum sample rate is 13500 samples/per sec.
Link to Schematic:
https://circuitsaladdotcom.files.wordpress.com/2013/01/dsp_geiger.gif
Link to Video Demo:
Link to Code and pcb files:
https://www.adrive.com/public/yrjs3G/DSP%20GEIGER%20COUNTER.zip
Circuit Salad 
Any code available for the PIC?
I have code I developed using MikroC. I can post it but I don’t think I commented it very well , etc..let me look it over, and clean it up and I will try and post it in the next couple days.
Hi, Ray!
Can You send me the source code?
How the circuit works at low activity gamma environment /near background level/?
In Your oppinion: can i use the CHARGE TIME
MEASUREMENT UNIT (CTMU)??
or may be dsPIC required for more simple front-end?
Thanks, with regards:
Peter
I will put a link to the source code(in the the next day or so). However this code is not well commented and hastily written so it may be a little difficult to get much from it. It was written with MikroC.
With regard to background radiation…. The device can detect about a 50 KeV gamma ray or larger. It doesn’t matter what the source. Some background radiation is very high energy some is low. The background radiation generates a low number of strikes but usually high enough energy to be detected.
Not clear on what you are trying to simplify? The PIC I am using is way overkill for the application. I am using it to do an ADC sample, then clear the sample and hold circuit and then simply drive an LCD. The ADC resolution is more than sufficient so not sure what a CTMU does for you or a more advanced micro.
If your intention is to somehow make more precise measurements, I think you will see little benefit
Just put up a new post with links to the code..its good for thirty days
I try to make a PIN dtetctor circuit nowadays.
In my opinion the ctmu measures the PIN’s virtual capacity change due to charge change.
It’s only an idea, i never use the CTMU yet. I just started to read about ctmu, and thought: its very interesting, but i have’nt enough time.
……….
“Links to the code”????
yes neat idea
Sorry , i had a problem about the file link, but works now …thanks!
Is it posted? If so where? I have MikroC and would look forward to trying it.
can you email me your code I would like to try it?
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Still looking for the code – any help would be appreciated.
I sent it to you in an email and then sent you another email asking if you got a my code? I got no response so I figured I was bothering you
Never received either of the e-mails. Sometimes Earthlink unneccasarily blocks emails and doesn’t let me know. If you don’t mind sending it again I would appreciate it, and no it wouldn’t have been a bother, and I will stay subscribed. Thanks
okay will send today (monday 29th)
I’ve given up.
I sent you a test email yesterday – you have not responded – I assume you did not get it?
I received it but since it said you where to send it yesterday I felt no need to reply.
I sent you the files – you don’t respond to my emails – they show they are sent? No one else has any trouble – I do this all the time- I don’t know what to say?
Hello, where can i download the sourcecode? can youi send it to me please? thanks!
https://www.adrive.com/public/yrjs3G/DSP%20GEIGER%20COUNTER.zip
please kindly forward the source code to my email. thank you
here is a link..my code works fine but is not commented well ..so sorry about that…it was compiled in MikroC
https://www.adrive.com/public/yrjs3G/DSP%20GEIGER%20COUNTER.zip