Peephole
A peephole is a device in a door that allows someone to be seen in front of the door without having to open it.
As a so-called presence protection, the peephole increases the security of apartments because after the spy has identified a visitor , residents who are present have a better basis for decision-making as to whether they want to open the door.
In the simplest case, the peephole is a hole at eye level that is often provided with a flap to close on old doors. Better peepholes have a special wide-angle lens which, on the one hand, increases the detection angle up to 200 degrees and, on the other hand, makes it difficult to look inside from the outside.
Peepholes are particularly widespread in apartment buildings, so that today almost every apartment is equipped with them. Alternatives to the peephole are door chains or locking bars . In order to be able to identify visitors in front of the outside door of a house, intercom systems and increasingly video surveillance systems are also used.
In addition to securing living spaces, peepholes are also used:
- In prison cell doors so that guards can see prisoners without opening the cell door
- in security-relevant areas, such as access to a bank's vault , in the money transport system or at the police station
Peepholes can pose a security risk if they can be unscrewed from the outside. An opening tool can be used to operate the door handle through the hole. In addition, optical devices can be used to peer through the lens from the outside.
View through a spy to the outside
Door flap with sleeping councilor (16th century); historical museum Dinkelsbühl
Historic prison door with food flap and peephole (Austria)
