The Most Reliable and Rugged Rain Gauge
The Hydreon Optical Rain Gauge is a reliable and cost-effective choice for precipitation measurement, outputting both rain accumulation and intensity. The sensor package is about the size of a tennis ball and completely sealed from the environment. A built-in mounting arm allows for convenient mounting to weather station masts, buildings, and other infrastructure.
The RG-11 senses water hitting its outside surface using beams of infrared light, modeling the principle used in automotive rain-sensing windshield wiper controls. The optical gauge bounces the infrared beams within the sensor lens, and as rain drops hit the surface, the infrared light escapes through. Changes in the intensity of the infrared beams during rainfall are directly correlated with the size of the rain drop. The system automatically compensates for condensation and very small drops; it can detect rain drops less than a half millimeter in size!
The Optical Rain Gauge has multiple settings, including the “tipping bucket mode.” By counting each individual droplet and noting its size, the optical gauge correlates the data to that of a tipping bucket. In many applications, the RG-11 may be directly wired in to replace a tipping bucket.
The RG-11 also has a function referred to as “it’s raining” mode, used to trigger applications that must be notified immediately once rainfall begins or precipitation hits a specific threshold. This is ideal for wet weather notification systems or for triggering samplers and other monitoring instruments. A built-in DIP switch allows the user to switch to the mode of operation best suited for the applicaton.
The optical sensing technology overcomes many of the shortcomings of conventional tipping bucket rain gauges. The sensor works in mobile environments, there is no collecting funnel to clog with leaves, and the round shape makes it essentially self-cleaning. While the sensor is not as accurate as a tipping bucket rain gauge, the low cost ($99) and compact size of the RG-11 makes it ideal for wet weather notification systems or remote rain gauges where periodic maintenance is not possible.