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1. We get back in touch
A member of our team will quickly get back to you to discuss your enquiry in more detail.
2. Free site visit
If it will help decide on the best way to proceed with your enquiry, one of our team will make a free visit to your premises to assess your requirements.
3. Free quotation
We’ll send you a free quotation for the work, and because we always aim to beat other quotes, you can be sure it will be very competitive.
4. We carry out the work
We'll send an engineer to carry out the work as soon as we can. This will be very soon for maintenance and fire extinguishers, and a few weeks for full alarm systems.

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How Do Intruder Alarms Work?

How Do Intruder Alarms Work?

Intruder alarms are among the most effective tools in the fight against crime. Not only do they react by creating a loud noise when detecting someone – while hopefully scaring them off and/or drawing the attention of neighbours and passers-by in the process – but when combined with a security system monitoring service, they can also ensure the police attend the incident considerably faster than would otherwise be the case.

There are a number of different types of intruder alarms available to suit different premises and individual security needs and budgets. But how do these various systems work and why are some better suited to certain premises than others?

The Scutum South East team is here to tell you all you need to know.

How do intruder alarms work

Motion Detector Systems

One of the most common solutions in both domestic and commercial security set-ups, motion detector systems work simply by picking up on the presence of someone in the room or area in which they have been placed. But what is it exactly that they are detecting?

There are actually two main kinds of motion detectors. One sends out ultrasonic sound waves that bounce back from objects to the source. If these sound waves are disrupted by a moving object, the alarm is triggered. However, there is a risk with this type of alarm that it can be set off by a family pet, while dogs may get stressed by the sound itself.

The more pet-friendly alternative looks for infrared energy, which all mammals give off in the form of heat. When an increase is detected, the alarm is triggered – this system can (and usually is!) set so that the small increases in infrared energy given off by cats, dogs and other household pets are disregarded.

Glass-Break Sensor Alarm Systems

Motion detectors work by picking up on the presence of someone already inside a premises, but a glass-break sensor alarm system can potentially stop them in their tracks earlier. Quite simply, they pick up on the sound or vibration associated with the glass in a window being shattered. If the windows at your premises are particularly vulnerable to those trying to force entry, this is a sensible solution.

The advantage of this type of alarm is that it can be kept on permanently, whereas motion detectors need to be turned off when people are about. That makes it more convenient if you have a remote part of your site or premises that is only accessed occasionally and you don’t want to go to the trouble of turning motion sensors on and off each time someone goes in.

Perimeter Alarm Systems

Not everything of interest to intruders is necessarily inside a building, so picking up on their presence as they try to enter the site as a whole can be extremely beneficial in many circumstances. 

Perimeter alarm systems work by having detectors attached to a perimeter fence or boundary that react when someone tries to scale it. This is usually managed by using cable sensors, fibre optics or an accelerometer to pick up on any vibrations. 

These sensors can work on most types of perimeter fencing. They can also usually tell exactly where on the perimeter any break-in is being attempted, allowing security to deal with the situation promptly.

Wireless Intruder Alarm Systems

Many traditional hardwired intruder alarm systems run entirely on electricity, but wireless systems are becoming an increasingly popular alternative. That’s because they are much quicker, cheaper and less disruptive to install, and are far easier to move or add to subsequently if required. 

With the vast majority of commercial premises likely to have a Wi-Fi system already in place, wireless intruder alarm systems are easy to install and get working. They can even usually be operated and monitored remotely via an app on your smartphone or laptop. 

Here at Scutum South East, we can make a free visit to your commercial premises to assess your security needs and work with you to find the system that best protects your site and meets your budget. And don’t forget that we always aim to beat any other quote you get, so you’re not just getting the benefit of our years of industry experience and expertise – you’re also getting the best possible value too.

Get in touch today to find out more or to ask for your free site visit and free quotation.


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About Scutum South East

Scutum South East is a leading expert in fire safety and security solutions for businesses and organisations located across South East England, including London and Surrey.

From fire alarms, fire extinguishers and fire risk assessments to access control, CCTV and intruder alarm systems – and a lot more besides – we offer a comprehensive range of products and services designed to keep you, your business and your staff and visitors safe.

With decades of industry experience to call on, we’re proud to hold accreditations from leading trade associations and bodies such as British Approvals for Fire Equipment (BAFE), the British Fire Consortium, the Fire Industry Association (FIA) and Security Systems and Alarms Inspection Board (SSAIB).

If you’d like to find out more about Scutum South East, get in touch with our friendly team or explore our products and services on our site.


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