Correctly selected door eye - protection of the apartment from intruders

It's unpleasant when you call at your door, and you are completely unaware of who is on her side. You can call yourself anything, introduce yourself - anyone. The voice can be faked. Only with my own eyes, seeing the otherworldly visitor, you can open the door. In the Middle Ages, there was an observation slot for this, like a loophole. Today - the peephole. However, the eye of the eye is a big strife.

First of all, it is necessary to determine the viewing angle of the eye. If it is not enough, one of the intruders can simply sit down - and now he is not visible, and the second one rings at the door, with a "trusting person" (two unfamiliar men at the door are always suspicious than one).

Therefore, the optimal viewing angle of the door eye begins at 180 degrees. Security experts advise choosing 200 degrees - due to the fact that at the edges of the view this angle gives less distortion. In this case, it will be possible to consider the entire visitor, down to the shoes on his legs.

The material from which the peephole is made, too, is of no small importance. Immediately and forever goodbye to plastic: cheap, but inefficient. Electrified plastic, like a magnet, attracts dust to itself, and after a while, the optical properties of plastic slowly but inevitably deteriorate. It is better to put once, but "for centuries". Then pay attention to the union of metal and glass, optical or spectacled. Only the metal should have a coating, so as not to darken with time.

Another important security detail associated with the door eye is the curtain that covers it from the inside. The fact is that the door peephole itself is able to give out the criminal, at home the owners or not, by changing the lighting in his lens. However, if you first bring your face closer to the eyepiece, and then open the curtain, the lens that remains outside will remain dark. For effective operation, the shutter must tightly cover the opening of the eyepiece, and when opening, do not make a single sound.

Of course, there can be no question of any kind of silence if there is a child left at home. After all, in order to look at the peephole, he first needs to bring him into the hallway chair, and then climb it. The problem is solved by a more complex, but also a safe device of the periscope type. In this case, the ocular eyelet is located at the level of child growth.

The last of the considered optical options, the most suitable for both adults and children, is the door-peephole. The eyepiece is replaced with a frosted glass, which, as on the screen, is projected the entire surveyed area in front of the door. The image on the screen is perfectly visible from 1.5-2 meters.

Approximately from the middle of 90th years of the last century in Russia electronic devices which earlier established only on protected objects began to spread actively. They made it unnecessary to go into the hallway on the doorbell. In fact, if the digital camera is looking at the peephole, just look at the screen of the computer to which it is connected. Or the camera can generally be located on the landing to look at it all (and not one if desired). And if you add an infrared lamp, then a twisted light bulb for criminals will not help. Added microphones and speakers will allow to negotiate with the visitor / s, without departing again from the computer, with which you can also videotape in any case to conduct ...

In doing so, however, do not forget that the stairwell is a common use area, and it is illegal to keep a hidden picture on it.