This practical module is able to sense the presence of water. It is contactless because there is no sensing element that makes physical contact with the water. The sensor is even able to detect the presence of water through small thicknesses of plastic, glass, ceramic, and other non-metallic materials.
The sensor features a built-in red indicator LED that lights up when water is detected and the detection signal will output a high signal when water is present. The polarity of the detection signal can be changed by grounding the black wire, which will change the detection signal type to an active low signal. The sensor's sensitivity can be adjusted by opening the top cover and turning the blue potentiometer.