A universal self-contained proximity sensor for attachment to any night-vision device that does not have such a sensor or for replacement of the existing sensor. The proposed sensor has a cable with a connection cap that connects terminal contacts of the sensor with the master battery of the night-vision device and can be mechanically connected to the master-battery compartment of the night-vision device by replacing the existing cap of mastery-battery compartment. The sensor can be attached to any selected area on the surface of the night-vision device by means of tiny hooks and loops known under trademark Velcro®. This attachment is carried out with the use of two parts, one of which is adhesively attached to the substrate of the sensor and the other to the housing of the night-vision device, while both parts engage through the aforementioned tiny hooks and loops.