A new rugged rain sensor is being used to automatically close vents and windows. Hydreon Corporation of Minnesota has introduced the RG-11 Optical Rain Gauge. With the RG-11, applications such as greenhouses, agriculture, and louver vents are provided simple and effective ventilation. The ventilation is also closed properly in the event of a downpour. In some cases these systems can replace far more costly and less efficient air conditioning systems.

The RG-11 Rain Gauge is an optical sensor and is sensitive to even tiny amounts of rain. In contrast, rain sensors used in irrigation do not detect rain until several millimeters have already fallen. The RG-11 also stops sensing rain when the rain stops. It does not need to wait for the water to evaporate.

The Hydreon RG-11 is based on the same principle used in automotive windshield wiper control systems. Consequently, it is immune to external contaminants, a problem which plagues conductive rain sensors. DIP switches within the device set the sensitivity, and the RG-11 can be set to various modes of operation. The device may be set as a simple on/off "it's raining" indicator, or used to emulate a tipping bucket where qualitative measurement of rainfall rate is desired. Interfacing is through simple relay contacts. The RG-11 costs $49.00 each in quantity of three. Further information is available at www.rainsensors.com.