Intrusion & Hold-up Alarm System Design

Intruder alarm systems detect unauthorised entry to specific areas or properties. These ‘properties’ can be residential houses, apartments, retail spaces or commercial buildings, and quite often extend beyond a building’s physical structure to protect open areas including perimeter fence lines.

Any indication of an ‘intrusion’ sends an alert to the property owner, immediately triggering an external audible siren of different tones to alert others to the intrusion. This external deterrent exceeds 110 decibels and is usually accompanied by a strobe light to visually indicate the property being attacked.

Larger scale systems can be monitored by certified Alarm Receiving Centres (ARC), such as ‘Redcare’. Upon any alarm activation the ARC calls in a local mobile response team to investigate.

An intruder alarm system is comprised of detectors, control panels and communication devices. Detectors identify and react to specific occurrences including movement, shock, vibration, heat and flood. 

There are a number of different types of detectors available depending on the desired function, such as:

• Passive infrared (PIR) - detects movement using heat sensors.
• Dual technology - uses combined infrared and microwave technology to reduce false alarms.
• Magnetic door contacts - detect the opening of doors and windows.
• Glass breaks - listen to specific ‘noise’ of breaking glass.
• Shock sensors - detect an ‘attack’ on a door or window.
• Water leak sensors - detect moisture at specific points.

The control panel is the heart of the system and all detectors are connected to it. The panel analyses and actions signals from detectors following an alarm ‘set’ control from a user keypad.

System keypads come in different forms and provide an instant system status, removing the need for networks, computers or specialised software. Users can log on to the system via the keypad and access status reports on alarms, detectors, zones and entry/exit times of users.