Rain Sensor Module

This type of sensor detects the presence of rain by measuring changes in conductivity when it comes into contact with water.

Simple sensors use two conducting tracks placed close together but without touching. When water bridges the gap, it creates an electrical connection. This change in conductivity is detected and processed.

A standard measurement board with an LM393 comparator is often used. This allows for both analog and digital readings. The analog output provides a value from 0 (fully soaked) to 1023 (fully dry). The digital output triggers when the humidity exceeds a set threshold, adjustable via a potentiometer.  

While the analog signal can be read, it lacks the precision to accurately measure the amount of rainfall. Therefore, the rain sensor primarily indicates the presence or absence of rain.