|Input voltage||\( 5-35 VDC \)|
Uses IR light sensors to detect rain falling on its curved plastic lens, and
can detect rain very fast. The sensor communicates over a serial UART
connection, and pulls a pin
HIGH when rain is detected.
The specific model that I am using (RG-9) is designed for "is it raining now?" use cases.
The Hydreon RG-9 Solid State Rain Sensor is a rainfall sensing device intended to detect and communicate when a pre-selected rain intensity has been reached or exceeded. The RG-9 is rugged, reliable, and maintenance-free.
The RG-9 uses beams of infrared light within a plastic lens about the size of a tennis ball. The round surface of the lens discourages collection of debris, and the RG-9 has no moving parts to stick, and no water-pathways to clog.1
It's faster at detecting current rain than a "tipping-bucket" style sensor, more local and accurate than weather APIs. Combining local sensors and weather APIs may be useful.
Home Assistant forum thread: Hydreon RG-15 rain sensor
Home Assistant forum thread, posts from janick