How to make intruder alarm with own hands

How to make intruder alarm with own hands

How to secure own apartment or the house against undesirable invasion of guests? At first sight it can seem quite difficult occupation as the embodiment of the idea requires the modern expensive equipment. However quite really to make the simple alarm system with own hands.

There is such small thing as the sound alarm system, otherwise, the switch piezoelectric. This small device weighs only 80 grams, in its device there is nothing difficult at all therefore it can be applied in protection of the possession.

Noise level which makes this device is 110 decibels. For those who does not know, such indicators are equal to noise of the engine of the jet plane. In other words, it is very loud. The principle of work of intruder alarm consists in the following: the terminal switch is installed at outer door, it will be either mechanical, or magnetic, but it is necessary that there was well closed contact. This element will perform function of the annunciator which reacts to opening of door.

In or outside of the room the siren is established, it is better to place it in protective cage. It is also necessary to walk on elements of connections by the two-conductor cable. Power supply is connected to the lowering transformer 220 in 12 volts. At the closed door the normally closed contact of the switch works so that through it there passes current which feeds the device. The signal in such situation is not given therefore the siren does not work.

When opening door there is rupture of chain which feeds the device therefore contacts of power supply of the alarm system become isolated. The device begins to make loud sounds. If the thief makes the way to the house where the alarm system very loudly sounds, it will draw attention of neighbors and people around that very much will frighten ill-wishers. If around nobody is not present, then the siren sound all the same will not allow malefactors to be in the room as sound almost intolerable and it it is necessary to leave the building quickly long.

Thus the simplest security system looks. Even if the integrity of cable which goes from the terminal switch of the relay, system will be broken will work all the same. If there is power outage in all building, such intruder alarm will be useless.

Of course, it is impossible to call this system completely effective, but it will be suitable for the small country house. Besides installation does not demand certain skills, it is only enough to know elementary things and to be able to put them into practice.

Author: «MirrorInfo» Dream Team