Rain sensor, in particular for a vehicle with a windscreen wiper device and method of controlling a windscreen wiper device

Rain sensor (10), especially for a motor vehicle, with a windscreen wiper system, has a measurement element (12) whose sensitivity can be set by a control unit (16). The control unit receives a signal (v) that is characteristic of the motor vehicle velocity. When the velocity is low, the control unit increases the sensitivity (E) of the measurement element. An Independent claim is made for a method for controlling a motor vehicle rain sensor in which sensor sensitivity is controlled by a control unit dependent on the vehicle velocity.