Method of light intensity automatic regulation wherein after the device is connected to the power system parameters of minimum voltage values are set so that the electronic control system remains in standby mode, and the motion and dusk sensors are in standby mode, and those sensors are synchronized with the electronic control system, then to the electronic control system the value of input signal is entered which is generated by the motion sensor at which the operating cycle of the device is started, and also the value of the output signal generated by the dusk sensor whereupon voltage supplied to the light source increases, up to the maximum value, sources of light display 100% illumination intensity, the illumination time after which voltage supplied to the light source decreases to the minimum value as a result of which the source of light does not illuminate and the device goes into standby mode.