The present invention relates to a rain sensor that adaptively functions in a variety of different modes when deployed on vehicle windows of different thicknesses and compositions. The arrangement of multiple lens segments and reflecting surfaces in a nonsequential configuration allows utilization of a greater proportion of light rays from the at least two emitters. Further, a greater portion of the light rays emitted by the at least two emitters is captured by the lens segments and reflectors arranged about at least two detectors, and directed to the detectors. Connection to analytical circuitry then allows interpretation of electrical signals, which in turn control, for example, window wiper systems.