A sensor device including a source for electromagnetic radiation, a receiver and a control device, the control device being designed for emitting electromagnetic radiation by means of the source and for determining a distance that is covered by the electromagnetic radiation emitted by the source from a reflection surface of an object to the receiver, doing so by evaluating a propagation time of the radiation or a phase of an oscillation modulated onto the radiation. According to the invention, the control device provides an economy mode in which the power of the source is lower in a prescribed time interval by comparison with a normal object detection mode, means being provided to ensure switching back into the normal object detection mode in the event of a predefined object situation.