Raindrop Sensor HL-01 is a rain detection module with two parts.
first part is a printed circuit board that has a network of copper paths.
The second part is a converts analog output to digital output. The sensitivity of the sensor is adjusted using the potentiometer on the board.

Features:

• High quality FR-04 dual sided material, ultra area 5.0 x 4.0cm. Nickel-plated surface, with antioxidant, electrical conductivity, and superior lifetime performance
• Comparator output, clear signal, and nice waves, powerful driver over 15mA
• Equipped with potentiometer to adjust the sensitivity
• Working voltage: 3.3V~5V
• Output method: Digital switch output (0 / 1) and analog AO voltage output
• Easy installation with fixed screw hole
• PCB size: 3.2cm x 1.4cm
• Uses wide voltage and LM393 comparator
• When connected to a 5V supply power lights, no water droplets on sensor board , DO output is high; Switch lights off, drop a drop of water, DO output is low, the switch indicator light.
• Clean the water droplets, returned to output high state.
• AO analog output connects to the microcontroller AD port to detect drops in the above rainfall size.
• DO TTL digital outputs connects to the microcontroller to detect whether there is rain.