How A DIY Home Security Alarm
Protects The Perimeter

Home security alarm.

A home security alarm can help you establish the second layer of protection. This can be done by setting up your perimeter security. If done right, this will better able you to effectively monitor and safeguard the exterior boundaries of your home.

In the home security and protection industry, this type of alarm is also commonly referred to as a perimeter alarm.

(Click on the link to see all four layers of protection).

What is perimeter security, and more importantly, how does it work? Think of your alarm system as an electrical circuit that surrounds your home. The picture below shows that the switch on the left is in the horizontal position across both of its pins, allowing current to pass across it.

Alarm circuit.

As long as your alarm circuit remains in tact (like the switch on the left) the electricity in that circuit will continue to flows all the way around your home. An alarm system is nothing more than hardware components that are connected together to establish an electrical circuit around the perimeter of your home.


Window sensor.

Door And Window Sensors – Home security alarm systems are able to establish an electrical circuit around an entire home's perimeter. This is possible because of each installed door sensor and window sensor. Like in the switch above, the electric current flows across the two sensors.

In a hardwired DIY alarm system, the electric circuit is created using wired door and window sensors.The wires power the sensors and directly connect them to the security control panel.

In a wireless DIY alarm system, the circuit is created using wireless door and window sensors that run on batteries and use radio frequency signals to communicate with the security control panel. Hybrid systems use a combination of both.


Home burglary prevention.

How Home Security Alarms Work - How do these electrical circuit home security alarms work? How do they help prevent break-ins? Simple. Think about every time you want to turn on the lights on in a room. You simply flick the wall switch and the lights are on.

With a home security alarm, the switch is turned on when someone tries to break into a home by forcing open a door or a window. The break-in interrupts the magnetic connection between the two sensors that are attached to that door or window. That action interrupts the flow of electricity of the entire perimeter alarm which triggers the alarm’s siren.

That’s the basic idea behind it. Depending on the perimeter alarm’s design, the electrical circuit can be classified as either a closed circuit system or an open circuit system.

Alarm system circuit.

Closed Circuit Systems - An easy way to understand a closed circuit system is to imagine someone closing all their doors and windows and arming their home alarm system. At this point the circuit is considered to be closed (or complete).

Electrical current will loop continuously around this closed circuit from beginning to end, across all sensors, as long as all the doors and windows remain shut.

Broken circuit.


The moment a door or window is forced open, the sensors get separated. The closed circuit is now broken (or open) and the electricity stops flowing. This trips the perimeter alarm’s siren, causing it to sound.



Open Circuit Systems - An open circuit system works differently. When all the doors and windows are closed and the alarm is armed, the circuit is considered open. The moment a door or window is forced open, the sensors are separated and the circuit becomes closed or complete triggering the siren to soundly.

Which is better?

Burglars can easily disable wired open circuit systems. All they have to do is prevent the circuit from closing by cutting the right wires in hardwired systems. The circuit remains open, the alarm is not tripped, the siren does not sound. Generally speaking, open circuit home burglar alarms may not be your best choice.

In a closed circuit system, the control panel handles the triggering and sounding of the alarm. A wired control panel is usually installed in a closet or in the basement hidden away from sight, where it will be difficult for a burglar to find and tamper with. The siren will sound, and scare off the burglar and keep sounding until it is reset.

DIY closed circuit systems are generally a better choice when considering a perimeter home security alarm. They make for better perimeter security. The underlying design of a perimeter alarm starts to get a little more sophisticated when we add more components to better protect our homes.

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The Ultimate Guide
To Home Security

by Daniel Berg

The Ultimate Guide To Home Security

How to protect your
home and family.


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