| A home alarm system is an integral part of a | | | | of breaking of glass windows or doors. These |
| complete home security system. A good home alarm | | | | detectors have highly attuned audio sensors that can |
| is a deterrent to would-be thieves, but it is also a | | | | distinguish the sound of an object striking glass and |
| mechanism by which to slow them down and lower | | | | the sound of glass breaking that immediately follows. |
| the possibility that they make of with your things in | | | | Generally one device is sufficient to cover one room. |
| the event of a break-in. | | | | Passive Infrared Sensors use advanced technology |
| Perhaps the most crucial element of a home alarm is | | | | to detect the presence of an intruder by identifying |
| the sensor. These can sense activity in and around | | | | changes in air temperature due to body heat. |
| the house by taking various observations and relaying | | | | Ultrasonic sensors send out sound waves which are |
| them back to a central control panel. Understanding | | | | returned to the sensor. Movement in the room will |
| the different types of sensors and their different | | | | alter the pattern of waves returning to the sensor |
| functions is an important step in planning your own | | | | and trigger the alarm. The sound waves sent out by |
| home security system. What follows is a brief primer | | | | ultrasonic sensors can be moved by strong air |
| on the basic types of sensors available to | | | | currents, such as those from a heating and cooling |
| homeowners. | | | | system, so a careful assessment of the air currents |
| Magnetic Detectors are commonly used for windows | | | | in the space should be made before installation. |
| and doors and are composed of two magnetic | | | | Microwave sensors operate similarly to ultrasonic |
| elements, one on the window or door frame and the | | | | ones, but use microwave radio waves instead of |
| other on the window or door itself. When the door | | | | sound waves. These waves are not affected by air |
| or window is opened, the elements are separated | | | | currents and can thus be used as an alternative to |
| and, if the system is armed, an alarm is triggered. A | | | | ultrasonic systems in rooms with powerful air con or |
| sensor such as this would not trigger the alarm | | | | heating units. Microwave radio waves are powerful, |
| system if a thief broke the window and entered | | | | however, and may trigger alarms due to movement |
| without separating the elements. | | | | detected beyond the boundary you have chosen. As |
| Pressure Sensors can add an extra layer of security | | | | such, careful assessment and consultation with a |
| to window entrances. Mats with pressure sensitive | | | | professional is advisable if using such a system. |
| elements are placed beneath carpet or other flooring | | | | Photo-Electric Sensors are composed of a light |
| at the base of the window. When the system is | | | | source such as a laser and a sensor that receives it. |
| armed, the weight of a person on the hidden mat will | | | | If movement in the path of the light source prevents |
| trigger an alarm. | | | | it from reaching the receiving sensor, the alarm will |
| Glass breakage detectors use highly developed | | | | be triggered. |
| acoustic technology to trigger an alarm on detection | | | | |