Off-grid, offline solar geiger counter using SMS to comunicate

https://radmon.org/index.php/forum/arduino/936-connecting-geiger-counter-for-arduino-and-raspberry-pi-to-radmon-org?start=0
https://www.libelium.com/wp-content/uploads/2013/02/radiation_board_eng.pdf

Hi guys,

I'm developing an automatic solar off-grid geiger dosimeter capable of sending periodic data to remote stations by using SMS messages and also able to receive commands by SMS, it will send 1 SMS every hour, 24 messages per day.
I used an old Huawei E172 3G USB GSM dongle with an Italian SIM with unlimited SMS within Europe @ 4.99 euro/month.

The advantage of using SMS is not only that it bypasses the problem of mobile internet coverage, which is not always present everywhere, but also that the SMS service is capable of working independently of the band used by the BTS (2G GSM, EDGE, 3G, 4G, 5G) and  it is quite resilient to the network congestion (in case of nuclear incident).

This device has an external GSM antenna to increase sensitivity and range, so it will be able to connect to a GSM BTS as far as 22 miles (maximum theoretical range of a BTS).

Since every message need to be  limited within 120 characters, it will send a SMS message once per hour, with 30 CPM readings inside, one reading every 2 minutes (CPM values from 0000 to 9999, 4 digits).

The device has a USB GPS receiver to get date/time in real time from GPS satellites since raspberry does not have any RTC and also to be used as a portable mobile device on my car, so it will able to send longitude and latitude position in addition to the CPM reading (e.g.: 42.63N11.51E9999 = latitude-longitude-CPM reading, 16 digits).

The next step will be to use LoRaWAN in addition to the SMS, or to further increase the connection rage, even using a CW Morse (short wave radio) for extreme coverage (hundreds or thousands miles).
 

My previous post showing my raspberry-libellum dosimeter project

https://radmon.org/index.php/forum/arduino/936-connecting-geiger-counter-for-arduino-and-raspberry-pi-to-radmon-org#4258

My solar array:

2x 100W 12V solar panels



2x MPPT solar charger (one per panel)



1x 100 Ah LiFePO4 battery

Since my raspberry dosimeter has the Raspbian Jessie OS (quite old), to send and to receive SMS I'm using "gnokii", but for newer linux releases you may use "gammu" instead.

Commands for gnokii

to check the modem: 
to check presence and number of received SMS messages:
to read the SMS message number "x" on the SIM:
[/code]
to send SMS message from file:
to send SMS message from text:
https://bends.se/?page=anteckningar/server-os/ubuntu-server/gnokii

https://wammu.eu/gammu/

Now, I'm in the process of writing the following scripts (all in Bash):

1) On the geiger dosimeter: collect CPM data, put values in a file and send it by SMS every hour to a remote raspberry device.
2) On the remote raspberry: receive the SMS, format the data received, put all values in a MySQL table for further analysis and send the 1 hour reading mean value to Radmon.
3) On the geiger dosimeter: get any new SMS received (from a list of valid senders) and convert the text into commands to launch pre-set scripts locally (e.g.: "reboot", "send real time CPM now", "send GPS position", etc.).

Note: the remote raspberry has a similar GSM dongle with a rechargeable SIM with no monthly service active since it does not have to send any SMS, just receive them (it is enough one recharge of 5 Euro per year to maintain the sim active).

As soon as the scripts will be ready I post them here.