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How to Install an Alarm System (page 1 of 2)

Learn how to set a home security system, including motion detectors and magnetic contact detectors.

Excerpted from Do It Yourself Home Improvement

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Courtesy of DK - Do It Yourself Home Improvement © 2009 Dorling Kindersley Limited

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Intruders fear detection, making light and sound excellent deterrents to unwelcome visitors. With an increase in the availability and reliability of battery-operated alarm systems, installing them yourself is now easy and quick. This article deals with issues of security in the home as well as issues of safety.

Installing an Alarm System

The vast majority of alarm systems use sensors to detect movement or magnetic contact plates that set off the alarm when parted. The most commonly used sensors are called passive infrared detectors (PIRs), which detect the movement of a heat source. The most important thing to consider when installing alarms is the positioning of these sensors, so that they can monitor all the necessary zones in your home.

PIR Positioning Tips:

  • Know the detection range of your PIR.

  • Detection of movement across the detection arc is better than of movement toward or away from the sensor.

  • Do not position PIRs in direct sunlight or near a heat source, unless instructed to do so, or if solar power is required for operation.

  • Avoid areas of excessive vibration or where there are drafts.

  • If you live in an apartment, you may only need to consider detection around the front door area, although you may need to consider window access in ground- and first-floor dwellings.

Security House Plan

A sensor is placed at each access point to your house, which divides the area into zones. This lets you see at a glance where a zone has been breached, or where some maintenance is required. Front, back and patio doors, windows, and fire escapes should be considered, although you may decide that some windows are inaccessible. Remember that pets will have to be kept out of zones when the alarm is on unless you buy a system that can detect them by being sensitive to size. When you purchase an alarm, it is worth checking for any extra features such as a panic button, or anti-tamper safeguards for sensors and the control panel.

Typical Zone Layouts
Along with PIRs and magnetic contact plates, other less common devices are pressure pads, and vibration detectors for doors and windows.

Arming and Disarming Alarm Systems
Take time to study your instruction manual so that you fully understand how to arm and disarm the system. Large systems may allow you to alarm just some zones of the house as well as the whole house.

Wired, Part-Wired or Wireless?

Traditional alarms are hard-wired into the home's main electricity supply. However, wireless or part-wired systems are now widely available.

Wired Systems
Although these take longer to install, there is no need to worry about replacing or recharging batteries. Professional installers tend to use hard-wired alarms.

Part-Wired Systems
Some alarms require the control panel to be wired into the main electricity supply. However, many have the option to run off a built-in rechargeable battery and the panel can be removed and recharged at a power point when necessary.

Wireless Wystems
These can literally be set up in hours because there is no need for complicated cable routing and electrical connection. The PIRs, magnetic contacts for doors and windows, and the main control panel are all battery-operated, and the external bellbox is often solar-powered. The main drawback of wireless alarms is that batteries need replacing or recharging, although many systems give a prompt if maintenance is necessary.

Courtesy of © 2007 Dorling Kindersley Limited

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Excerpted from Do It Yourself Home Improvement

© Dorling Kindersley Limited 2009