Video Alarms - What Are They Needed For?

It is not nice to wake up and find a stranger at home, is it? Normally intruders would prefer to visit when nobody is home, unless they find it so easy that they cannot resist the temptation to enter. That is why it would be wise to set up a home surveillance system.

Is there anything that could be done to intercept home intrusions? Many options are available, like keeping a dog that is expected to bark in a threatening way. But a dog needs constant loving care besides daily provisions, so that it may not be the easiest solution.

There are also different electronic gadgets that can perform some actions intended to scare the intruder, like triggering a powerful siren, alert a guard post or the police station, or flooding the place with lights.

These gadgets, known as Video Alarms, are sensors connected to a control unit, which operates a signal that initiates the required action. The function of specific types may be performed in different ways.

Alarms exploit one or more physical principles, like the emission of thermal radiation by any living body, or the interruption of invisible infrared rays by an opaque mass, or electrical circuits broken by forcing a door or a window open, or even the detection of vibrations in a normally quiet environment.

One popular unobtrusive Video Alarm used in connection with home surveillance is the Passive Infra Red (PIR) detector, designed to react to a slight temperature change (from human presence) in the controlled area.

Software programs called motion detectors or image processors monitor certain areas of an image taken by a surveillance camera and trigger an alarm upon detecting a change, interpreted as a movement, in the scene observed.

This way they may start the video recorder, so that whatever comes in the field of view of one or more cameras of a surveillance system is immediately recorded for later review. The same signal may initiate sending images and messages by e-mail on the Internet if instructed to do so.

In some cases other security sensors could be integrated in the same system to take care of the risks of fire, flooding, gas accumulation and additional dangers.

"False Positives" or the triggering of an alarm when in fact there should be no reason to do so are a known hindrance that certain alarms may be prone to. More serious problems could be incurred by “False Negatives” or the absence of an alarm when a system overlooks real and dangerous events.

Therefore some redundancy should be designed into the system, as is usually done for higher end applications.

The justification of the expenses involved in implementing an integrated multi function system capable of alerting about different threats or risks depends on the importance and the value of the object under surveillance.

Specialized companies offer home surveillance service in exchange for a long time contract, where they absorb all the cost of equipment and installation, while charging a recurring service fee.

In conclusion one should note that any security system however simple and imperfect is better than no surveillance at all.

Article Source: http://www.content.onlypunjab.com

Elia Levi is a retired engineer. He built a website to assist with a step-by-step Guide to understand, design, select and set up, all by yourself the best and least expensive Surveillance System for your Home Security. Read more on the subject of this article at www.1st-diy-home-surveillance-guide.com/ Video-alarms.html

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