A typical alarm security system is composed of four major units – a central control system (panel), Sensors, Anunciators, Central Monitoring System. Out these four units, the former three are most important and are indispensable for any alarm system to work.
Central Control System: It is the main control panel where all the processing takes place and hence should be kept at a safe location. It is connected to input detection devices and out put anunciators. In case of any alarm event the detestation devices send the signals to control panel and then the panel on the basis of programming done by user, process these signals and if required send an alert signal to activate the anunciators and alert the central monitoring system.
Types of Detection Devices:
- Magnetic Door Contact: – is most widely used the detection device for safeguarding the entries through doors and windows of
the house. It consists of a switch, and a magnet, where magnetic field helps in maintaining the electrical contact of the switch, the moment magnetic field is removed the electrical contact also is broken resulting in an alarm event. The device is installed at frame and shutter of a door or a window, the moment the door is opened, magnet moves away from the switch and the electrical contact is broken because of the removal of the magnetic field.
- Glass Break Sensor: – They are installed at outer periphery of the house at window glasses, sometimes even inside the house if percentage of the glass used in windows, doors is high. Such sensors majorly use two kinds of technologies to detect the glass break. First is through Shock wave, where as when some one tries to break the glass or make hole in the glass through some cutter, the detector senses the same by its vibrations. The limitation of such sensors is that they have to be installed at the glass itself through some adhesives.
Another technology, through the the detection is done, is by sound discrimination. Sensors identify the sound of the glass break and detect the same. Here although there is an advantage that the at a time more than one glasses can also be protected by install ting the sensors in the midway on the wall, but there is a limitation that it may give false alarms on some other sounds well like that of wind chimes. Hence it is always best to use the detectors which detect the glass break only when both the events of vibration and sound happen.
- Motions Sensors:- They are the most critical part of any security systems as they play an important role when an intruder ahs already crossed all the security measures outside and at the periphery and is now inside the house. Most commonly used Motion sensor today is Passive Infra Red Sensors (PIR Sensors), which detect the movements of an intruder by the slight changes in temperature due to infra red radiations.
Anunciators and CMS:- These can be categorised as output devices of Central Control System, since the panel after getting the signals of alarm event from its input devices, activates its anunciators which are generally hooters, alarms etc. At the same time if there is a provision of sending the pre-recorded messaged to some of the numbers, it also send these messages so that proper and timely action can be taken. These pre-recorded messages can be of neighbours, police stations or CMS (Central Monitoring Station). There are certain companies which provide the services of monitoring the Alarm Security Systems and are capable enough to take suitable action in case of any alarm event/emergency.