Author Topic: Interface Geiger counter  (Read 1636 times)

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Offline @rt

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Interface Geiger counter
« on: January 20, 2016, 04:17:34 pm »
Hi Guys,
I have an early 60’s Geiger counter, and would like to interface it to a micro through it’s headphone socket if possible.
When connected to a scope, I see a negative going signal, but there appears to be a pair of negative peaks for every count.
Has anyone interfaced to these, and is it usual to divide the total count by the micro by 2 to get a result?
Cheers, Art.
 

Offline vindoline

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Re: Interface Geiger counter
« Reply #1 on: January 21, 2016, 03:52:39 pm »
I believe that the pulse sensing is generally taken right off the Geiger tube. See, for example,  http://www.techlib.com/science/geiger.html and https://sites.google.com/site/diygeigercounter/circuit-description. You might be able to clean up the headphone "click" with a Schmitt trigger and use that, but you will have to experiment with your setup. Good luck!
 

Offline m98

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Re: Interface Geiger counter
« Reply #2 on: January 21, 2016, 08:51:20 pm »
Well, no need for external Schmitt-Triggers, because an digital input of a uC already has one.
Could you show a picture of the generated waveform? Maybe there's just some ringing, which can easily be filtered away with a low-pass filter.
« Last Edit: January 21, 2016, 11:01:15 pm by m98 »
 

Offline MartinX

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Re: Interface Geiger counter
« Reply #3 on: January 21, 2016, 10:41:20 pm »
The output is for a headphone so some load may be required, did you measure with the scope probe as the only load on the output? If so try to load it down with a resistor. If the headphones were in place when you measured it may be the headphones themselves created some kickback , try replacing them with a resistor.
 


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