GB2266801A

GB2266801A - Intrusion detection and alarm system

Info

Publication number: GB2266801A
Application number: GB9209915A
Authority: GB
Inventors: Philip Arthur Atkinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-05-08
Filing date: 1992-05-08
Publication date: 1993-11-10
Also published as: GB9209915D0

Abstract

The system includes at least one proximity sensor (2) for detecting the presence of an intruder within a predetermined area, such as a car display area, means in the form of a pulse timer (1) for monitoring the or each proximity sensor (2) to determine if an intruder has entered into the predetermined area and for generating a pulse in response to the detection of an intruder within the predetermined area, and means in the form of a timer (3) for activating a first alarm signal (5) such as one or more floodlights in response to a first pulse from the monitoring means. A counter (4) is provided for activating a second alarm signal (7) in response to receiving a user-selectable number of pulses from the pulse timer (1). The timer (3) also resets the control system a predetermined period following the first pulse from the pulse timer (1). <IMAGE>

Description

SECURITY CONTROL SYSTEM The present invention relates to a security control system which may be used, for example, to warn-off an intruder into a protected area under the control of the system or to warn that an area under the control of the system is not secure.

Security control systems that are intended to warn-off intruders are known. US-A4 897 630, for example, describes an alarm system for detecting, signalling and reporting the occurrence of a penetration towards or unauthorised entry into a defined area. The alarm system includes means for generating vocal speech warning or alarm signals for the purpose of drawing attention to the fact that an unauthorised penetration or entry event has been sensed. The system has a degree of flexibility in that it permits the user to select various operating modes and report options, but the flexibility is severely limited, for example inasmuch as the detection of each event moves the system to a higher level of warning or alarm signal.

It is an object of the present invention to provide a security control system which provides greater flexibility in operation.

According to the present invention there is provided a security control system for use with at least one proximity sensor for detecting the presence of an intruder within a predetermined area, which system comprises: means for monitoring a proximity sensor to determine if an intruder has entered into the predetermined area and for generating a pulse in response to the detection of an intruder within the predetermined area; means for activating a first alarm signal in response to a first pulse from the monitoring means; a counter for activating a second alarm signal in response to receiving a userselectable number of pulses; and timer means for resetting the control system a predetermined period following the first pulse from the monitoring means.

The security control system may include a further counter permitting the second alarm signal to be activated a user-selectable number of times, and means for activating a third alarm signal in response to the further counter exceeding the userselectable number of activations of the second alarm signal.

The monitoring means may incorporate a user-selectable timer for determining a time interval at which the proximity sensor is monitored.

The timer means for resetting the control system may incorporate a user-selectable timer for determining the time interval at which the control system is reset.

The first alarm signal may be in the form of one or more floodlights to illuminate the protected area.

The second alarm signal may be in the form of a verbal message.

The third alarm signal may be in the form of a further verbal message and/or a radio paging device and/or a digital communication system and/or an external alarm sounder optionally with a blue stroboscopic light..

The security control system may include means for determining if an access to or within the protected area is unsecured. The system may include means for issuing a verbal message if the access is unsecured, or remains unsecured for a predetermined time.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawing which is a block diagram of an electrical circuit of one embodiment of a security control system according to the present invention.

The security control system shown in the Figure comprises a monitoring means in the form of a pulse timer 1 the input of which is connected to receive an output from one or more proximity detectors 2, only one of which is shown in the Figure. The proximity detector 2 may be, for example, a passive infra-red detector. Such detectors are readily available and can be provided with different lenses to give different area coverage. The pulse timer 1 is capable of monitoring the output of the detector 2 over a range of time intervals selectable by the user of the system, for example in the range from 1 second to 1 minute.

Outputs from the pulse timer are connected to a main timer 3 and to a first counter 4. Once the main timer has been activated, an output from the main timer 3 is connected to a first alarm 5 which is conveniently in the form of one or more floodlights that illuminate the area to be protected. In this way it is unnecessary to provide permanent night-time illumination for the area to be protected, with consequent cost savings. The main timer 3 also determines the overall time within which the detection sequence is to be completed. However, the overall time can be selected by the user of the control system, up to a maximum of, say, 10 minutes. If the detection sequence is not completed within the overall time selected the main timer generates a reset signal which is transmitted to the pulse timer 1, the first counter 4, and to a second counter 6.

An output from the first counter 4 is connected to a second alarm 7 which can conveniently be in the form of a digital speech synthesizer connected to a loudspeaker system for issuing a verbal message so as to give the intruder the impression that he is being watched. A further output from the first counter 4 is connected to the second counter 6.

An output from the second counter 6 is connected to a third alarm system 8 which can conveniently incorporate one or more of a number of alarm devices such as a further verbal message, a radio paging device, a digital communication system for alerting a central monitoring station or an external alarm sounder with a blue stroboscopic light.

In use of the security control system according to the present invention, when the pulse timer 1 first detects a signal from the proximity detector 2 it emits a pulse to activate the main timer 3, and the main timer 3 in turn triggers the first alarm 5. The effect of this is to illuminate the area protected by the control system. The pulses from the pulse timer 1 are also transmitted to the first counter 4 which in the case of the first pulse registers a count of one.

The pulse timer 1 continues to monitor the output of the detector 2 at the end of each user-selected time interval and if a signal is detected the pulse timer transmits a further pulse. The first counter 4 counts the pulses transmitted by the pulse timer 1 up to a user-selected number in the range from, say, 2 to 10, the minimum number of two pulses being to avoid activating both the first and second alarms simultaneously.

Each time the first counter 4 registers the user-selected number of pulses, in addition to activating the second alarm 7 and issuing the stored verbal message, a pulse is sent to the second counter 6 and the first counter is reset to zero. The second counter 6 counts the pulses from the first counter 4 up to a user-selected number in the range from say 2 to 10, again the minimum number of two pulses being to avoid activating both the second and third alarms simultaneously with the first activation of the second alarm.

When the second counter 6 registers the user-selected number of pulses the third alarm system 8 is activated and, as noted above, this can take a number of forms depending on the wishes of the user of the system. At this stage it is assumed that the intruder has not been deterred by the one or more verbal messages and that further action is required to protect the property within the protected area.

As noted above, all counting operations are required to be completed within the overall time determined by the main timer 3. If not, the main timer issues a reset signal to reset the first and second counters 4 and 6, respectively, and the pulse timer 1. Thus, if the first alarm has been activated this is de-activated and all detecting and counting operations are started afresh.

The security control system according to the present invention can be used to protect many external areas, such as car display areas, builders' yards, garden centres, fish farms, scrap metal yards, aircraft hangars and the like. The combination of the multiple level of alarms, the user-selectable first and second counters and the userselectable periods for the pulse timer and the main timer impart considerable flexibility of operation making the system adaptable to widely varying requirements.

In some cases, the security control system according to the present invention may be required to detect an animal, for example, rather than a human intruder.

The combination of the user-selectable period for the pulse timer and the user-selected number for the first counter make it possible for the control system to operate in completely different modes. For example, if the time interval between detections in the pulse timer is low and the number of pulses in the first counter is high, a large number of individual movements is needed to activate the second alarm. On the other hand, if the time interval between detections in the pulse timer is high and the number of pulses in the first counter is low, then a second (or third) movement in a predetermined time of, say, 1 minute would be sufficient to activate the second alarm.

Overriding all these possibilities, to avoid unnecessary activations of the second and third alarms, is the need to complete the entire detection sequence within the overall time. However, in order to ensure that the second and third alarms will be able to function, it is important that the overall time selected by the user is greater than the time it could take for the system to complete its sequence of operations.

Clearly additional features can be incorporated into the security control system according to the present invention. One possibility with an aircraft hangar is to fit a door closure detector to the hangar doors. If the hangar doors are left open unnecessarily, even during periods when people are working in the hangar, unauthorised persons or even animals can more readily gain access to the hangar. To avoid this, the security system can at all times monitor whether the hangar door is open or closed and if the door has been left open for a predetermined time can issue a synthesized verbal warning that, if desired, can only be de-activated if the time is reset or the door closed. It will be apparent that the principle of detecting whether an access to or within the protected area is left unsecured can be extended to other applications.

Claims

1. A security control system for use with at least one proximity sensor for detecting the presence of an intruder within a predetermined area, which system comprises: means for monitoring a proximity sensor to determine if an intruder has entered into the predetermined area and for generating a pulse in response to the detection of an intruder within the predetermined area; means for activating a first alarm signal in response to a first pulse from the monitoring means; a counter for activating a second alarm signal in response to receiving a userselectable number of pulses; and timer means for resetting the control system a predetermined period following the first pulse from the monitoring means.

2. A security control system as claimed in claim 1 and including a further counter permitting the second alarm signal to be activated a user-selectable number of times, and means for activating a third alarm signal in response to the further counter exceeding the user-selectable number of activations of the second alarm signal.

3. A security control system as claimed in claim 2, wherein the third alarm signal is in the form of a further verbal message and/or a radio paging device and/or a digital communication system and/or an external alarm sounder optionally with a blue stroboscopic light..

4. A security control system as claimed in any preceding claim, wherein the monitoring means incorporates a user-selectable timer for determining a time interval at which the proximity sensor is monitored.

5. A security control system as claimed in any preceding claim, wherein the timer means for resetting the control system incorporates a user-selectable timer for determining the time interval at which the control system is reset.

6. A security control system as claimed in any preceding claim, wherein the first alarm signal is in the form of one or more floodlights to illuminate the protected area.

7. A security control system as claimed in any preceding claim, wherein the second alarm signal is in the form of a verbal message.

8. A security control system as claimed in any preceding claim and including means for determining if an access to or within the protected area is unsecured.

9. A security control system as claimed in claim 8 and including means for issuing a verbal message if the access is unsecured, or remains unsecured for a predetermined time.

10. A security control system substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.