Abstract: A device for detecting a vital parameter is described, comprising: an optoelectronic sensor arrangement for detecting the vital parameter by means of light remission at a finger, wherein the optoelectronic sensor arrangement has a first light source for generating light in a visible wavelength range, a second light source for generating light in a non-visible wavelength range and a light-sensitive element; and a controller which is implemented to switch on the second light source in temporal intervals, execute an evaluation of the light received from the light-sensitive element in the invisible wavelength range of the second light source with respect to whether a finger is applied to the optoelectronic sensor arrangement and to switch on the first light source as soon as the evaluation indicates that a finger is applied to the optoelectronic sensor arrangement.