THE CATHEDRAL CHURCH OF THE HOLY SPIRIT, GUILDFORD
SUMMER 2008A Combined Motion Detection & Personnel Panic Alarm System
Guildford Cathedral in Surrey had been searching for an effective Personnel Panic Alarm
System for the protection of their staff, comprising mostly volunteers, for about five
years. In addition, the installation of two small but valuable bronze statues in their
newly-opened Childrens Garden raised the issue of how best to sound the alarm in the event
of somebody attempting to steal them.
The solution lay in the use of the RF spectrum. The challenge was that radio waves had to
be able to travel the required distances as well as overcoming the problem of being
received through walls which are over 2 feet thick. In addition, the University of Surrey
is co-located with the Cathedral on Stag Hill, and on the roof of its main building is the
large transmitter for their campus-wide radio-based Security Systems; a potential source
of local interference which could "jam" our signals. Our project consisted of two clearly
identified elements; a Motion Detection System for the statues and a Personnel Panic Alarm
System for the current six designated areas in the Cathedral considered most "at risk".
Our solution combines both elements into one modular system.
The Motion Detection System.
A Motion Detection Sensor, which utilises a mercury "tip-over" switch, was activated, and
then placed in a small receptacle in the concrete plinth at the base of the statues.
The enclosure was then sealed to prevent dirt and water ingress, and covered with hoggin
(a stone-like material used for the statue base and footpaths). Once tilted beyond a
critical number of degrees, (which would be essential in order to extract the concrete
plinth), the circuit activates, and a radio signal is transmitted back to the System's
Receiver Panel, which is located some 30 metres away in the Sacristy. Since the sensor
only activates when tilted, any vibrations caused by children running, jumping or playing
on the statues, the plinth, or even directly above the sensor's location, would not cause
it to activate.
The signal generated by the sensor both lights the corresponding LED on the Receiver Panel,
which tells the Vergers where the incident is occurring, and also sounds a very loud
audible alarm. This can only be silenced by means of the Control Key. In addition,
the radio signal also generates a text message to the Duty Verger's pager, (or could be
to a mobile 'phone). This message tells the Verger the location of the incident, so that
the police may be summoned for assistance without further delay or the risk of personal
injury; the pager has a range of up to 4kms.
In addition, once the Motion Detection Sensor has been activated to send the radio signal,
we have also installed a volt-free relay circuit to link into the spotlight which is
focussed on the statues. Once the alarm sounds at the System Receiver Panel, the lighting
circuit is also automatically activated using this link.
Once the spotlight is automatically switched on, the appearance of the bright light
activates the recording function on the CCTV.
The Personnel Panic Alarm System.
The Personnel Panic Alarm System also lights an LED on the System Receiver Panel, sounds
an audible alarm, and simultaneously sends a text message to the Duty Verger's pager or
mobile 'phone which indicates where the incident is taking place.
There are six transmitters fitted in the Cathedral, and adjacent buildings,
located as follows:
The Dean's Secretary's Office
The Western Entrance Guides' Reception Desk
The Cathedral Bookshop
The Cathedral Office Main Reception Area
The Cathedral Gift Shop
The Stewards Station
Auxilliary
The location of the "Auxilliary" Panic Transmitter has yet to be activated, but is fully
configured and integrated into the Receiver Panel and Pager Text Transmitter database.
The Personnel Panic Alarm System transmitters are all battery-powered, whilst the
System's Receiver Panel is mains-powered. This Receiver Panel also has an on-board
UPS (Uninterruptible Power Supply), which will keep the unit working for a period of up
to 8 hours in the unlikely event of a prolonged mains power failure, or the accidental
removal of the power plug. The entire system is covered by an annual maintenance contract,
which provides for the checking and replacement of any spent batteries and a routine
re-test and commissioning of both systems.
The system is extremely cost-effective and very flexible in design, enabling us to tailor
a proposed installation to exactly match the Cathedral Administrator's precise requirements.
The entire Guildford Cathedral Motion Detection & Personnel Panic Alarm System project took
less than three man-days to install; providing Guildford with a very secure, sophisticated,
cutting-edge technology solution which affords peace of mind for its staff, worshippers
and visitors alike.