Burglar Alarms and Home Security

Archive for December, 2007

Everybody knows how to make burglar alarms. At one time or another, you may have made a crude alarm fashioned out of stringed tin cans and laid it out on your hedges that line the perimeter of your farm to alert you on unwanted intruders. Or maybe you might have tied a fish line on the door of your tool shed and stringed this up all the way to your bedroom and tied the other end to your alarm clock to ensnare the thief who steals your garden tools. Perhaps you may have even set up a wind chime below the window sill of your teen-aged daughter’s bedroom to catch her sneaking out at night.

Well, anybody can fashion crude burglar alarms from household odds and ends, but how will you react when your little son comes up to you to help him out on his science project and asks, “do you know how to make burglar alarms?” Surely, you wouldn’t want him to submit stringed tin cans for his science project, would you?

Actually, you don’t have to be a rocket scientist to know how to make burglar alarms. Behind the sleek impressive plastic and metal casing of these little home security devices are just three simple components that make up the core of the burglar alarm—a switch or electric terminals, a ringer or buzzer and a power source or a battery.

Before you can start working on your son’s science project, you must first learn how to make burglar alarms yourself. The first thing you need to do is to understand the operating concept of a burglar alarm.

An electrically operated burglar alarm is basically a buzzer that is wired to a power source, like a battery, for instance. If the terminals, which comprise the positive and negative ends of the wire, get in contact with each other, the circuitry is said to be completed and electricity will flow into the buzzer causing it to sound off. This can be likened to flicking a light switch in your room to turn on the light bulb.

To start your lesson on how to make burglar alarms, you will need a buzzer, one D size battery, a length of insulated wire, one piece of wooden or plastic cloths line clip, a fish line, duct tape and a piece of sturdy card board.

First, fashion a switch by coiling one end of a length of wire on the jaw of the clip and coil another length on the opposite jaw. Insert the card board between the jaws so that the wires don’t come into contact. Then, connect the other end of the wire to one terminal of the buzzer and fasten with the tape the other end of the wire to the positive terminal of the battery. Using another length of wire, connect the negative battery terminal to the remaining terminal of the buzzer. Punch a hole on the card board and using the fish line, tie this to a doorknob. Once you open the door, the card board will be pulled out of the clip and the circuitry will be completed and cause the buzzer to sound off.

Now that you know how to make burglar alarms, you are all set to help your son with his science project.

Tags: Home Protection, Alarm, Burglar Alarms, Security, Home Security, Burglaries

A simple electric circuit built into an entry way is what makes a basic burglar alarm work. The electricity in a burglar alarm circuit starts to flow when a channel is provided between two points of opposite charges. By either opening or closing the circuit, the electricity is turned on or off. Electrically operated appliances are turned on or off by flicking the switch. A burglar alarm sounds off when its sensors detect intrusion into an entry point of a house like a window or a door.

A burglar alarm circuit can be classified into two general categories. The first is the closed-circuit system which means that the circuit is close when the entry way like a door is shut and that the electricity continues to flow as long as the door remains shut. The alarm is trigger off the moment the door is opened and the electrical circuit is cut off. The second is the open-circuit system which basically switches on the electricity by completing the circuit once the door is opened. A burglar alarm circuit of the open-system type can easily be rendered inutile by any intruder by cutting the connecting wires that is why closed-circuit systems are generally the better choice.

There are many ways of building a burglar alarm circuit into an entry way. A simple device makes use of an electromagnetic switch that is turned on and triggers the alarm once the door or window is opened. Another simple switch is a button that is positioned between the door and the door jamb. The alarms does not sound off for so long as the door or window is close, but once it is opened the button is released and sounds off the alarm. These switches are flawed in the sense that the burglar can turn off the alarm by merely closing the door or window.

The effective burglar alarm circuit incorporates a control box that monitors the electrical circuits positioned in various entry points. Once it detects a change in the electrical circuits it sounds off the alarm continuously until the homeowner types in the security code on the control box keypad. Often times, these control boxes are hidden from view so that the intruder will not be able to find and disable it. A burglar alarm circuit in modern systems makes use of thin foil wires that run through window panes, metal strip triggers underneath mats and carpeting and other innovative high-tech triggers like motion detectors and infra-red sensors.

Tags: Burglaries, Security, Home Security, Alarm Systems, Crime Prevention, Alarm