Electronic device to a single mounted passive infrared on adjustable motorized mobile support that has the task to sound the atmosphere where is istallato, to the aim to maintain in ON rel?the single actuator in presence of persons, after the first income, even if pieces of real estate inside of the same atmosphere. The mounted passive infrared on the device oriented on the income of the premises, will send in ON, to the first income, control logic that will activate the movement of the sensor and rel?the actuator. The system will remain active until there will be presence of persons and when the last person exits carries itself in state of OFF in real time. Dispositive saying concurs a electric power saving with all the advantages offers from the automatism.