Rain sensor, motor vehicle and method for detecting the intensity of precipitation

The sensor (3) has square-shaped transmitting elements emitting electromagnetic radiation. A receptor element receives a part of the emitted radiation. A control and evaluating device actuates the transmitting elements and determines upon on the received radiation. One of the transmitting elements is formed as photon detectors. The control and evaluating device transmits the radiation through the transmission element operated as a radiation receiver. The transmitting elements are arranged around the receptor element. An independent claim is also included for a method for determining intensity of precipitation on a transparent disk of a motor car.