Schematic is simple:
I write a sketch for this who can download from my channel Github !
Eatch soil sensor is powered few seconds when measure humidity after that is powerred off (tens of seconds):
- first sensor powered:
- second sensor is powered:
- third sensor is powered:
- fourth sensor is powered:
You can see two movies:
- soil moisture control in 4 zones using Arduino
Because are 2 version of relay module:
- with normal control when if you give 5V at input module relay relay is energized and coil is powered, normal open contact is close
- with negative control (inversed control) when give 5V at input module realy is cut the power at coil, normal open contact is open ...
So, I put a jumper for easy use of relay modules, when jumper is open (in air) it use normal control and when jumper is close it use negative control.
Schematic is simple just add jumper:
and must use sketch named lcd1602_i2c_soilhumidity_ver4.ino !