The system has an optical sensor (1), peephole with optical element (2) with variable throughput and the activating light (3) emitting radiation which is detected by the optical sensor (1). The activating light (3) is connected to a switch (4) and located within range of the optical sensor (1). Within the device where it implements technological process with the light effect, detects an instruction to initiate appropriate technological processon and based on this instruction turns on the activating light (3). This will activate the optical sensor (1) by means of the activation light (3) even before the optical sensor (1) detects the luminous effect of the technological process. The activation light (3) may be as easy infrared LED. The advantage lies in the fact that the protector is not need to modified in any way, and his the reaction time can be reduced to zero, respectively we can achieve as a negative response time, when we use to darken time flowing at start of the process prior to the formation of lumin
