General scheme of the watering control system is shown below:
Code to program transmitter and receiver arduino microcontrollers are available in sensors directory.
The wiring scheme for the receiver module is as follows:
When compared with the receiver module, the wiring scheme of the soil humidity module has additionally (i) an external power supply, (ii) a voltage divider plugged to the analog pin (to measure the voltage of the battery), and (iii) the soil humidity sensor.
The sensor_listener.service script should be placed in the /etc/systemd/system folder.