This industrial-grade optical rain sensor is a rainfall sensing device intended to detect and communicate when a pre-selected rain intensity has been reached or exceeded. It uses beams of infrared light within a plastic lens about the size of a tennis ball. It is maintenance-free: with the round surface of the lens, there are no collections of debris, no moving parts to stick, or water-pathways to clog. The sensitivity levels include: Rain Drops, Very Light, Medium, and Heavy.
RG-9 Solid State Rain Sensor features an open-collector output as well as RS232 serial communications that provide more detailed data, including 8 near real-time rain intensity levels.
This is a model comparison.
More information is available in the datasheet and on the website of Hydreon.