Apparatus and method for detecting the presence of a mobile device in a room, the apparatus having a device control unit for controlling a target device, a mobile device for controlling a target device, a signal source for emitting a pilot signal, a signal receiver for receiving a room signal caused by the pilot signal, the signal receiver arranged in the vicinity of the mobile device and outputting a measurement signal in response to the room signal, a signal control unit for controlling the signal source, the signal control unit controlling the signal source based on an actual value signal obtained from the measurement signal in such a manner that the actual value signal approaches a predefinable target value signal over time, and the device control unit configured to control the target device by means of the mobile device on the basis of whether the approach has taken place.
