In 1852 the American Edward Holmes invented the first electro-mechanical burglar alarm. Prior to this the family watch dog was the usual form of protection from intruders. Holmes' invention was quite simple. Trip wires were places around windows and doors. When a wire was disturbed a solenoid struck a gong, thus alerting the residents of possible danger. It was well received by the public, and was not improved upon until the next century.

There are three main components to the basic burglar alarm system: the detection device, the main control unit, and the siren or sounder. The detection device, depending on what it's set for, can monitor motion, heat, noise, shock, vibration, and smoke (if the unit is also used for smoke detection). When the device is triggered it sends the message to the main control unit, or the brain. The data is quickly analyzed and it is then determined whether or not to sound the alarm.

A wireless burglar system is relatively easy to install, and doesn't require a specialist. Every component of the wireless system contains a radio transmitter/receiver which allows the detection device to communicate with the control unit. With this setup there are no worries about running wire, the parts can be placed just about anywhere, and it is easy to add onto the system or move it around.

A monitored home security system allows the home to be protected 24 hours a day by an alarm company. When a detection device is triggered the alarm is set off and the information is sent to the alarm company monitoring the system. This gives the homeowner peace of mind when they are not at home. There is also minimal maintenance to the homeowner, as the agency hired to install and monitor your home will also ensure that the system is always operable.

Probably the easiest burglar alarm to install without a professional is a magnetic switch. They are used on doors and windows. There are two parts: the magnet and the switch. When properly installed, the magnet and switch line up on the door or window. When the connection between the two is broken (the door is opened, for example), the alarm sounds. When they are reconnected though, the alarm usually stops.

There are different reasons to have a burglar alarm, and they are no longer just for the wealthy and business owners. They are still used to protect valuables, but are also widely used to protect the family as well. Not all intruders are after monetary riches. The cost of home security systems has decreased, making them very affordable.

It is very important to choose the right burglar alarm. The money you have available to spend on an alarm, if you are able to install it yourself or need a professional to do the job, and why you need the alarm system are all key points to consider before you make a purchase. To ensure that you are completely satisfied with your choice, do some research and educate yourself on the alarms available.