HiLetgo 3pcs LM393 Rain Drops Sensor Weather Moisture Monitor Sensor Humidity Sensitivity Module Nickeled Plate 3.3-5V for Arduino The sensor uses high quality FR-04 double-sided materials, large area of 5.0 * 4.0CM, and nickel-plated surface, with oxidation resistance, conductivity, and life expectancy superior performance Comparator output, the signal clean, good waveform, strong driving ability, more than 15mA The raindrop board and the control board are separate, easy to lead the line TTL level output, TTL output valid signal is low. Drive capacity of about 100MA, direct drive relays, buzzers, small fans, and so on. Adjust sensitivity by potentiometer