Arduino Soil Moisture Sensor Circuit – Connection Diagram Now that we have a complete understanding of how a Soil Moisture sensor works, we can connect all the required wires to the Arduino UNO board.

This is a very simple circuit diagram. The output of the turbidity sensor is analog so that connected to Arduino's A0 pin, I2C LCD connected to I2C pins of Arduino that is SCL to A5 and SDA to A4.