Simply, it’s an Arduino library for communicating with Modbus slaves over RS232/485 via RTU (remote terminal unit) protocol. In conclusion, the Modbus 2-channel 5V relay module is a very useful device ...

The hardware is consists of an Arduino microcontroller (here an Arduino Uno R3) and a pre-wired soil moisture sensor module. The soil moisture sensor module , built around the LM393 comparator, gives ...