Home Security Guide
Our goal is an informed user
Can I design my own security system?
Once you decide your personal tolerance of risk versus what you are willing to pay for the Peace of Mind you seek you should have a good idea of what you will need to configure your security system. Basic security system design involves common sense, knowledge of the premises to be protected and some knowledge of how the components and sensors operate. These paragraphs are not intended to make someone an expert but to provide enough information to understand the basic concepts and to assess the overall appropriateness of a proposal you may be asked to consider by a service provider. The expertise comes into the selection of specific sensors, how to use devices to avoid false alarms, and the installation challenges that the specific location presents.
Let's take the most frequently chosen scenario that fits the risk profile, lifestyle, and budget of the average home or business owner. Later we'll discuss full perimeter systems and the so called "free" security system.
Each entrance from the exterior requires a sensor. Window sensors have largely been supplanted by motion sensors in the configuration of a typical security system although they are often used on basement windows.
State of the art motion sensors strategically located on basement and ground levels provide interior detection. Ideally you want a motion sensor to activate before an intruder has fully entered the premises. If this is not practical you have to assess the path an intruder would have to take from the point of entry and intercept his movement before he can reach the persons and assets you are trying to protect. The number of motion sensors you require will depend on the floor plan of the premises. If you are concerned about "home invasion" or having an intruder sneak up on you will require more than this to have the peace of mind you seek. A full perimeter security system may address some of these concerns but such decisions require more than can be briefly covered here.
A keypad to enter arm/disarm codes must be placed close to the
Full perimeter security system
Perimeter security systems were state of the art before the advent of motion sensors when security systems were the domain of the wealthy beyond the reach of just about everyone. The design was simple. Place a sensor at every door and window that would activate when it was opened thus triggering the alarm.
Of course if the intruder cuts through the glass without being heard the security is defeated. Today a glass break sensor, essentially a sensitive microphone that listens for specific sound frequencies of breaking glass or splintering wood is placed within earshot of the window. Alternatively one can place a shock sensor or "bug" on the window frame or glass that will activate if the window is broken or entry is attempted. This type of sensor can be susceptible to triggering from innocent sources of vibration so it is important to select one that has acceptable immunity to false alarm and alarm response protocol should be designed to avert unnecessary dispatches.
If every opening is protected in this way it should provide sufficient protection without the use of motion sensors unless perimeter sensors that are susceptible to false alarms have been used. In such cases the use of the additional motion sensor is intended to provide some measure of confirmation that an alarm from a sensor susceptible to false alarm is cause for concern. By counting the number of sensors required to cover all vulnerable openings one can see how costly such a system can be. Sometimes a middle ground can be found between a full perimeter system and the common variety using motion sensors.
entrance. Since you want to delay the triggering of the alarm just long
enough to enter the premises and disarm the system the keypad must be
close at hand. More than one keypad may be required if a second
frequently used entrance is some distance from the first.
what other conditions such as fire, toxic gases, loss of heating or
refrigeration, plumbing failure, etc. are a concern.