Serial port to network socket service for Raspberry Pi

The script written in Python is designed to maintain an open serial port for data retrieval and then transfer the collected data to an IPv4 address and port.

The source serial port and destination IP:port settings is obtained from the configuration file named sts.conf.

Server requirements

• Python 3.x (python --version)
• GIT client
• Python pip library manager

SETUP

Clone this project using git command line tools

git clone the_repo /home/pi/sts

Install Python libraries

Option A) By using python:

python -m pip install configParser
python -m pip install pyserial
python -m pip install RPi.GPIO

Option B) Using pip:

sudo pip install configParser
sudo pip install pyserial
sudo pip install RPi.GPIO

NOTE: Please be advised that a "sudo" installation is mandatory when running STS as a "daemon" service.

Option C) For Debian based OS it is also possible to install the dependencies using apt:

sudo apt-get update

sudo apt-get -y install python-configparser
sudo apt-get -y install python-serial
sudo apt-get -y install python-rpi.gpio

Duplicate the "sts.conf.dev" file and rename the copy as "sts.conf".

cp sts.conf.dev sts.conf

Configure the sts.conf file to indicate the appropriate IP address (and, if necessary, the serial port).

Sample configuration file

The .conf file contents should look like:

[hostinfo]
write.ip=192.168.1.103
write.port=15010
read.port=/dev/ttyACM0
read.end_char=13

NOTE: Since this code was written for a specific use case, the serial port basic configuration (9600 bauds) is currently hardcoded.

WARNING: Configure the read.end_char to the appropriate ASCII code representing the End of Transmission character (ETX) transmitted by the serial port.

Execute the tool / service

For proper functionality, a remote computer with the IP 'write.ip' should be actively listening on the designated port 'port'.

python sts.py

or

sh sts_service.sh

Optional: DAEMONIZE THE SCRIPT

sudo chmod +x sts_service.sh
sudo cp /home/pi/sts/init.d/sts /etc/init.d
sudo chmod +x /etc/init.d/sts

It is now necessary to update the .rc boot scripts to allow the sts service to be executed during system boot.

sudo update-rc.d sts defaults

Finally, and optionally, just for testing the sts service without requiring to reboot the system:

sudo systemctl daemon-reload

From now on, it is possible to control the script using:

sudo /etc/init.d/sts start
or
sudo service sts start

sudo /etc/init.d/sts stop
or
sudo service sts stop

sudo /etc/init.d/sts restart
or
sudo service sts restart

sudo /etc/init.d/sts status
or
sudo service sts status

Stopping the service manually

If it has been executed manually press *control+z*

ps aux |grep -i sts.py  (to get the process ID)
kill -9 ID

TESTING AND TROUBLESHOOTING

It is possible to conduct a test of the service by using keyboard inputs to simulate barcode scans instead of using the serial port, allowing you to verify communication with the remote socket.

python sts_keyboard.py

When the remote computer is not available or not responding, the script server_test.py emulates a socket server listening to the same port. It just dumps/echoes to the console whatever it receives.

For this testing, it is necessary to set the client (such as 'sts.py' or 'sts_keyboard.py') to point to the local IP address of 127.0.0.1.

python server_test.py