APRS Geiger Counter

I'm not the first one, won't be the last. The mightyOhm gieger counter has serial output. I figured it would be kinda cool to show background radiation in my home and push to APRS IS. You can see my notes aren't the perfect how to. I cover 2 approaches as well as notes soing the fail from me working while a bit tired.

Link to the APRS telemetry graphs. https://aprs.fi/telemetry/a/ne6rd-11

So now 2 working aproaches.

Current states 11/22/2020

I flushed out send.py using the APRS python library. runing via cron once an hour.

Dire Wolf - First Pass

I made a pass using Dire Wolf. Problem is since this is in my house I did not feel the need to pass the packets over the air. Just run an igate and send the data.

Dire Wolf seems to have a lot of overhead. Configure a CBEACON with an infocmd option that called a python script to read the board. Granted, the raspberry pi has nothing else to do. Truthfuly, working on this initially at 3AM, this did not GROK until the next day. Thought it could not be done. When tired, go to bed. I might have done this. Still might to publish another approach.

I found his bash script that uses ncat to send the packets: https://s55ma.radioamater.si/2017/07/27/send-aprs-objects-or-telemetry-via-bash/

Seems workable, but I tend to not use bash as a programming language. I use it as a wrapper to setup environments for python.

So other than getting the packes generated while I was playing, Dire Wolf got me no where.

Dire Wolf Pass 2

Took about an hour. You will see geiger_reading.py is called from a CBEACON. For notw it will create /var/run/geiger to hold the latest seq number. Need a better place for the file so direwolf does not have to be run as root.

Once I get the geiger counter assembled I will add the code to read the data.

##Python APRS library Ran these 2 commands and I was in business:

• sudo apt-get install python3-pip
• sudo pip3 install aprs

The issue with this library is even though a version 7 makes it look mature, the code might be abandoned. Found a couple of obvious errors in the initial readme.

The calls for the TCP class takes bytes, not strings. So b"foo" or FOVAR.encode('utf-8') is your friend.

Some setup notes

Using the Raspberry Pi OS Lite Image

• apt-get install git python3
• git clone git@github.com:mpechner/online_geiger.git
• sudo apt-get install python3-pip
• sudo pip3 install aprs pyserial

MightyOhm Wiring to Raspberrypi

http://mightyohm.com/forum/viewtopic.php?t=4524 Pin marked 'blk' on the ftdi pins is pin1

6 pin serial
MO   Pi
1....6
4....8
5...10

Power Mighty Ohm from Pi. Make sure you remove the batteries.

3 pin pulse
MO    Pi
1....1 3.3v
3....14 gnd

https://mightyohm.com/blog/products/geiger-counter/usage-instructions/

CSV lines; CPS, #####, CPM, #####, uSv/hr, ###.##, SLOW|FAST|INST

I am posting "uSv/hr"

Current State as of now and future plans

Since I do not have the board soldered yet, there is not imput. Send.py just sends a fixed set of packets. Will eventually be a cron job reading the board and sending the packets.

Coming Thanksgiving 2020

References

• Dire Wolf user guide https://github.com/wb2osz/direwolf/blob/master/doc/User-Guide.pdf
• Dire Wolf Repo git clone git@github.com:wb2osz/direwolf.git
• APRS Passcode Generator https://apps.magicbug.co.uk/passcode/
• Dire Wolf Telemetery https://github.com/wb2osz/direwolf/blob/master/doc/APRS-Telemetry-Toolkit.pdf
• APRS Website http://www.aprs.org/
• APRS Reference http://www.aprs.org/doc/APRS101.PDF
• APRS BASH https://s55ma.radioamater.si/2017/07/27/send-aprs-objects-or-telemetry-via-bash/
• Enable Serial https://pimylifeup.com/raspberry-pi-serial/