| This article outlines the basic steps in designing an alarm system. Obviously no two properties are exactly alike and neither are two peoples perceived security requirements.
Introduction
There are three main parts to any alarm system whether Hard-Wired or Wireless:
- Detectors
- Signalling device(s)
- Control Panel
Hard-Wired or Wireless?
In relatively low security requirement situations wireless alarms are adequate but where a higher level of security is required then hard-wired alarm systems should be fitted. Hard wired systems are more difficult to install and cannot be installed as neatly as a wireless system, but wireless alarm systems cost around three times as much as hard-wired systems. The choice is yours.
Choosing The Equipment
There is a lot of alarm equipment available from various sources - DIY stores tend to supply the basic end of the market whereas the professional quality equipment is available through alarm installation companies or via the internet using websites like ours. We only supply professional quality equipment and we also ensure that equipment is compatible. In general, hard-wired equipment is fully compatible e.g. any PIR or Sounder can be connected to any Control Panel; wireless systems are not cross compatible on frequency or manufacturer - equipment needs to be from the same manufacturer and operate on the same frequency.
Control Panels
Control Panels are the heart of the system and incorporate a multitude of features - refer to the Control Panel's description for its associated features. All Control Panels have basic features as follows;
- Multiple detection zones (usually 8 on basic models) for the connection of detectors. Note; the number of zones available does not limit the number of detectors on the system as multiple detectors can be connected to one zone. The zones are usually programmable to be of a certain type, e.g. timed entry/exit, fire.
- Global tamper circuit - a closed circuit loop which is wired through all the devices on the system. Separate tamper circuits are usually provided for the SAB sounder and RKPs.
- Back-up battery connections. Alarm systems must be fitted with a rechargeable battery. The recharging circuit is integral to the panel.
- One or more Part Set programmes, thus allowing the zones and zone types to be programmed to suit the protection required.
- Outputs for connection to an SAB sounder (see below) - except some wireless systems which have a wireless sounder.
Wireless Control Panels
Wireless control panels are almost exclusively stand-alone units and are available as basic units or with integral communicators.
Hard-wired Control Panels
Hard-wired Control Panels are available in twio main types - 'Stand-alone' and 'Blank End-station'. Both versions usually have the facility to connect extra Remote Keypads (RKPs).
Stand-alone Control Panels have an on-board key-pad and are usually installed close to the entry/exit route of the property. Blank End-stations have no on-board key-pad and are usually installed covertly (e.g. loft or airing cupboard) and are programmed and set/unset using an RKP sited near the entry/exit point(s).
Detectors
The most commonly used detectors are;
- Passive Infra-red detectors (PIRs)
- Magnetic Contacts
- Shock Sensors.
Passive Infra-red Detectors (PIRs)
PIRs are used to cover large areas with a single detector (typically 12m x 90 degrees) and are available in various versions including pet tolerant types. Another commonly used detector is the Dual Technology detector. This detector combines PIR and Microwave detection within the same unit and is controlled by a microprocessor such that both detection systems need to be triggered for an alarm to be signalled to the control panel. This arrangement helps eliminate a lot of the causes of false alarms.
Magnetic Contacts
Magnetic contacts are simple magnetic reed switches where the reed is held close circuit (non-alarm) by a magnet in close proximity. They are very reliable, easy to fit and inexpensive. They are available in various shapes and sizes to suit most situations. Their main drawback is in keeping the wiring to them neat, especially if fitted to windows. Also note that when fitted to windows, they will not detect the glass being removed from the window.
Shock Sensors
Shock sensors, also known as vibration or inertia sensors, are designed to detect the typical frequencies generated by an attempted forced entry. They are normally used for perimeter protection and are very useful for covering windows as one detector can be used to cover a large window with several opening lights.
Signalling Devices
The most common signalling device is the external sounder. These units usually include a flashing strobe unit and status/comfort LEDs. Additional signalling devices such as Speech Diallers and internal sounders can be incorporated into the system.
Conclusion
Designing and fitting your own alarm system is relatively easy and is well within the scope of an average DIY handyperson. Just follow the simple steps,
- Decide on wireless or hard-wired.
- Choose the control panel that will suit your installation, don't forget to include a back-up battery.
- Choose the number and types of detector you want
- Choose a signalling device
- Purchase the equipment from a reputable supplier who can give technical help during the installation.
Install and programme the system to you needs. You will have full control of the system, an in-depth knowledge of how it is assembled, access to all the relvant codes and programming options and the ability to maintain and amend the system as required.
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