How Does A Burglar Alarm Use Sensors?
There are several components that make up a burglar alarm security system. There
is the main control panel, alarm bell box or siren and sensors. The main control
panel is the "electronic brain" that gets information from its sensors, processes
this information then makes a decision as to the next course of action, and this
of course could be sounding the siren. But how does the control panel get the information
from the sensors and what in fact do the sensors do?
Alarm sensors are essentially monitoring devices and there are many different types
of sensors that monitor different things. Some are electronic and some are mechanical
in operation. The most common burglar alarm sensor that you will find in virtually
all alarm systems is the door/window sensor. These sensors are typically mechanical
in operation and use a magnet to make or break an internal contact inside the sensors
to detect if a door or widow is open or closed. The burglar alarm control panel
monitors the signal from the sensor to determine if the contact is made or broken.
When arming the system the door sensor contact should be made. Once armed, if the
contact is broken the control panel will be notified and the alarm will sound. However,
the sensor may be identified as a entry/exit door sensor. In this case there will
be a delay before the alarm will sound. This delay is to allow the home owner to
enter the property and disarm the alarm without setting off the siren.
Another common type of alarm sensor is the PIR (passive infrared) sensor. This detects
movement within a room by monitoring changes in heat directly in front of the sensor
and will trigger if a rapid change in heat occurs such as someone walking in front
of it. It does not detect a very gradual change in heat such as steady ambient temperature
change over a few minutes so a false alarm will not occur.
There are window/door shock sensors that are installed directly onto a window or
a door. These sensors are designed to detect a burglar’s attempt to smash into the
property via vibration detection.
Some alarm systems allow the addition of safety sensors such as smoke or carbon
monoxide detection. These sensors are well worth installing as they could save your
life.
A burglar alarm system simply cannot function without one of more sensors. The sensors
are essentially the eyes and ears of the burglar alarm system that supplies information
allowing the control panel to make a decision whether to trigger the siren.