Cut Through the Confusion: Understanding Home Security Sensors

A home security system is made up of several components working together to provide the overall security you, as the homeowner, desire.  One of the key components is the sensors that trigger the system, which in turn alerts you of a problem. 

The brains of the system is the central control panel or keypad.  When triggered, it will provide audible (siren) and possibly visible (flashing strobe) alerts or may, if so designed, place a phone call to pre-programmed number (your cell phone, the police department, etc.).  It is the job of the sensors to tell the brains that the alerts should be activated and when they should be activated. 

Most sensors are intended to provide immediate alerts when triggered.  Some are delayed.  For instance the main door used for entry into the house will have a delayed trigger, allowing family members time to disable the alarm when entering the home.  The number of delayed sensors should be kept to a minimum because they can work in the burglar’s favor too. 

The common sensors are of several types.
    * Door sensor
    * Window sensor
    * Motion sensor
    * Carbon monoxide detector
    * Smoke detector

Door Sensor
These sensors create a circuit when the door is closed.  One part is attached to the door and one part is installed on the door frame.  The circuit is broken when the door is opened and the alarm is triggered.  Some systems allow for these sensors to be set to give a chime at anytime the door is opened during routine use in addition to the alarm when the system is set to do so.

Window Sensor
These work on the very same principle as the door sensor.  An alternative is an impact sensor (also called a glass break sensor) that is triggered by impact to the window.

Motion Sensor
These sensors are able to detect movement and/or body heat.  They can be set in interior rooms of the home or at exterior entry points.  There is the capability of adjusting sensitivity of these devices so that small house pets won’t trigger the system.  Delays are commonly used with these sensors to allow time to disable the alarm for regular entry into the home or a family member up moving about the house at night. 

Carbon Monoxide Detector
These sensors detect a build up of toxic gases, particularly carbon monoxide.  These should be used where gas powered appliances are present.  Carbon monoxide is colorless and odorless… and deadly. 

Smoke Detector
Many homes are already equipped with independent, battery-operated smoke detectors.  As a part of a home security system, these devices not only alert the occupants of the home of the presence of smoke, but can also be programmed to automatically call the local fire department when triggered.