Hardware

https://docs.sixfab.com/docs/raspberry-pi-4g-lte-cellular-modem-kit-intoduction

Software

The program consists of several scripts:

init_environment.sh Shell script that sets up the environment and dependencies required for the other scripts to function properly.

set_up_data_over_qmi.sh Shell script that sets up a data connection over QMI interface so that RPi can connect to the internet using a SIM card.

start_gnss_stream.py Python3 script that sends the required AT commands to the Telit module in order to configure and start the GNSS stream.

stop_gnss_stream.py Python3 script that sends the required AT commands to the module in order to stop the GNSS stream and reset GNSS parameters.

gnss_to_mqtt.py Python3 script that reads GNSS data from the ttyUSB1 serial port, parses the raw values and publishes the extracted information to the MQTT broker.

add_startup_job.sh Shell script that sets up the cron job which automates script execution on RPi startup for headless GNSS data streaming to the MQTT broker.

remove_startup_job.sh Shell script that cancels the cron job so that the scripts are not run on RPi startup and stops GNSS data streaming.

clear_log.sh Helper script which clears the telit.log file located in the RPi user home directory.

How to use

All the scripts should be run as current user (without sudo). There is no need to invoke sh or python3 when running them, since they all contain the appropriate shebang (#!/bin/sh for shell scripts and #!/usr/bin/env python3 for Python3 scripts).

Setting up a new RPi:

To set up a new RPi environment for GNSS data streaming:

1. Run the init_environment.sh script.
2. Check the APN parameters in the apn_params.json file (currently set to T-Mobile Internet) and after that run the set_up_data_over_qmi.sh script.
3. Check the MQTT parameters in the mqtt_params.json file and device parameters in the device_params.json file before proceeding.

Manual execution:

To start the GNSS data streaming:

1. Run the start_gnss_stream.py script.
2. Run the gnss_to_mqtt.py script.

To stop the GNSS data streaming:

1. Stop the execution of gnss_to_mqtt.py with Ctrl+C.
2. Run the stop_gnss_stream.py script.

Automated execution on the Raspberry Pi startup:

To set up the cron job which starts the GNSS data streaming when the RPi is powered up:

1. Run the add_startup_job.sh script.
2. Restart the RPi for the scripts to start executing.

To cancel the cron job and stop GNSS data streaming:

1. Run the remove_startup_job.sh script.

In the automated execution mode, all the script outputs (stdout and stderr) are logged to telit.log file which is located in the RPi user home directory. The log is cleared on restart.