Mightyohm Geiger Counter & Raspberry Pi

Support forum for the mightyohm.com Geiger Counter.
http://mightyohm.com/geiger
jetson
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Mightyohm Geiger Counter & Raspberry Pi

Postby jetson » Mon Nov 24, 2014 9:35 pm

BIG thanks to Chankly for doing all the heavy lifting in this forum post.
viewtopic.php?f=15&t=3504

I was able to get my Mightyohm Geiger counter to send serial data to my Raspberry Pi and post history graphs of radiation measurements via a web server. The Raspberry Pi can power the Geiger counter if you remove the batteries. Here are the steps I took:
1. Disable the Raspberry serial port to prevent Linux from using it as a console:
sudo raspi-config

2. Connect the Geiger counter to the Raspberry Pi (Remove Geiger Counter batteries before connecting power)
Mightyohm Geiger counter ----------------Raspberry Pi
Serial---pin 1 black triangle----------------Pin 6 Ground
----------pin 4--------------------------------Pin 8 Transmit Data
----------pin 5--------------------------------Pin 10 Receive Data
Pulse----pin 1 black triangle---------------Pin 14 Ground
----------pin 3--------------------------------Pin 1 3.3v

3. Test that the Raspberry Pi is receiving data from the Geiger Counter:
sudo apt-get install minicom
minicom -b 9600 -o -D /dev/ttyAMA0

4. Read Chankly's entire thread, download the archive and follow the instructions for setting up everything. Remember your Geiger counter is on ttyAMA0
viewtopic.php?f=15&t=3504

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mightyohm
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Re: Mightyohm Geiger Counter & Raspberry Pi

Postby mightyohm » Wed Nov 26, 2014 8:40 am

Cool, thanks for sharing!

confusedspanner
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Re: Mightyohm Geiger Counter & Raspberry Pi

Postby confusedspanner » Wed Nov 11, 2015 1:41 am

Any tips for how to connect the geiger counter to the raspberry PI to access the raw counts? E.g. not through the serial port.

I would like to use the PI to read in the raw counts and bypass the Tiny chip completely if possible.

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mightyohm
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Re: Mightyohm Geiger Counter & Raspberry Pi

Postby mightyohm » Sun Nov 15, 2015 5:46 pm

I wouldn't recommend bypassing the AVR entirely because it does some signal conditioning on the pulse from the geiger tube.

The kit outputs a 3V pulse on header J6 pin 2 every time there is an impulse detected from the geiger tube. You should be able to connect this pin (and ground) to the pi and use that to collect counts on the pi, bypassing the serial connection entirely.

Schematics for the geiger counter kit are here:
http://mightyohm.com/files/geiger/geige ... edR5R6.png

J6 is drawn to the right of the MCU.

confusedspanner
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Re: Mightyohm Geiger Counter & Raspberry Pi

Postby confusedspanner » Mon Nov 16, 2015 12:41 am

Great,

Thanks for the info. I'll give it a go and post the results!

confusedspanner
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Re: Mightyohm Geiger Counter & Raspberry Pi

Postby confusedspanner » Mon Nov 16, 2015 10:26 am

Actually another question for you

Is there a theoretical limit on how many counts per minute the circuit can manage?

E.g. is 200,000 counts per minute possible? We are going to be using this against a caesium 137 source (for measuring the density of the material going through a pipe).

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mightyohm
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Re: Mightyohm Geiger Counter & Raspberry Pi

Postby mightyohm » Sat Nov 21, 2015 10:54 pm

The theoretical maximum is 65535 * 60 or over 3 million CPM. In reality the tube will probably saturate before then. I've seen some pretty high counts when testing radium sources, so I think 200k CPM is possible but may be close to saturation. The symptom of saturation is that the CPM will start dropping above a certain radiation level, so keep an eye out for this.

MatejKovacic
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Re: Mightyohm Geiger Counter & Raspberry Pi

Postby MatejKovacic » Fri Jan 06, 2017 12:46 pm

Hi,

I have connected Raspberry3 to Geiger counter as you described, but when I connect RPi to a power, it doesn't power up.

However, if i disconnect PIN 1 (3.3 V), then it powers up and I can ssh to it. Then of course, I cannot get any reading via minicom..

Please note that I have removed batteries from Geiger counter.

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mightyohm
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Re: Mightyohm Geiger Counter & Raspberry Pi

Postby mightyohm » Sun Jan 08, 2017 11:56 pm

Check if pin 1 is shorted to ground, or if you have pin 1 and 3 swapped.


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