GB2202982A

GB2202982A - Improvements in or relating to alarm systems

Info

Publication number: GB2202982A
Application number: GB08707393A
Authority: GB
Inventors: John Alfred Mercer; Paul Ian Mercer
Original assignee: MERCER ENERGY CONSERVATION COM
Current assignee: MERCER ENERGY CONSERVATION COM
Priority date: 1987-03-27
Filing date: 1987-03-27
Publication date: 1988-10-05
Also published as: GB8707393D0

Abstract

An alarm system for use on a building includes sensors for detecting the presence of an intruder prior to or at least during entry of the intruder into the building, visual or audible alarms, and a control unit actuated by the sensors to control operation of the alarms so that occupancy of the building is simulated. The alarms may include internal lights of the building and acoustic apparatus such as tape players, radios and televisions. The lights may be turned on in a given sequence eg bedroom lights, followed by ground floor lights. A tape player may be used to produce the sound of a barking dog. A switch may be provided to enable the conditions and functions of the system to be preset according to the conditions appertaining at a particular time e.g. day or night, building occupied or unoccupied. The switch may be manually operable or automatically operable e.g. in response to ambient light. <IMAGE>

Description

"Improvements in or relating to alarm systems" This invention relates to alarm systems and more particularly, but not exclusively, to an alarm system for use on domestic premises.

Conventional domestic alarm systems normally only detect the presence of an intruder once the intruder has gained access into the building but the present invention is particularly concerned with alarm systems in which the presence of an intruder is detected prior to or at least during entry into the building.

According to this invention, an alarm system for use on a building comprises one or more sensors for detecting the presence of an intruder prior to or at least during entry of the intruder into the building, at least one visual or audible alarm, and a control unit actuated by the or each sensor to control operation of the or each visual or audible alarm, wherein the control unit includes means for simulating occupancy of the building.

Preferably, the means for simulating occupancy of the building comprises one or more timers or time delay circuits for actuation of a visual alarm in two or more spaced-apart locations orzonesofthe building at predetermined intervals of time after activation of a sensor in order to simulate movement of an occupant between said locations or zones.

Preferably, also, the or each visual alarm comprises one or more of the conventional interior lights in the building.

Alternatively, the or each timer or time -delay circuit may be adapted to actuate one or more audible alarms to simulate occupancy of the building at a predetermined interval of time after activation of a sensor.

Preferably, the audible alarm may comprise a tape or tape cassette player, a radio, a television, or the like.

Preferably, also, the control unit is adapted to de-activate the visual or audible alarms at predetermined periods after the or each sensor indicates that the intruder is no longer being detected.

The visual or audible alarms are, preferably, de-activated in a sequence which is the reverse of their sequence of activation.

A preferred embodiment of this invention will now be described, by way of example only, with reference to the accompanying drawings of which: Figure 1 is a block circuit diagram of an alarm system; and Figure 2 is a flow diagram of the functions of the system.

Referring now to the drawings, an alarm system for use on a domestic building comprises sensors 10 for detecting the presence of an intruder prior to entry of the intruder into the building. Although any suitable type of sensor could be used, it has been found that sensors of the passive infra-red type are particularly effective.

Each of the sensors 10 is connected to a control unit 12. The control unit 12 is connected to and controls the operation of an interior audible alarm 14, which may be mounted in the control unit 12 itself; exterior lights 16; interior lights 18 in a first location or zone of the building, for example on the first floor of the building; interior lights 20 in a second location or zone of the building, for example on the ground floor of the building; and one or more other visual or audible alarms 22.

It will be appreciated that the control unit 12 can be arranged to control the operation of interior lights in more than two locations or zones of the building according to the size and lay out of the building and the alarms 22 may comprise a tape or tape cassette player, a radio, a television, or the like.

The control unit 12 is also provided with timers or time delay circuits for initiating operation of the alarm 14; lights 16, 18, and 20; and alarms 22 at predetermined times after one or more of the sensors 10 have been actuated by an intruder approaching the building. The timers or time delay.circuits are particularly arranged to control the actuation of the lights 18 and 20 in different zones of or locations in the building to simulate the effect of an occupant being aroused and moving around the building.

The control unit 12 is also provided with manually operable switch means to enable the conditions and functions of the alarm system to be preset according to the conditions appertaining at any particular time.

The switch means can be arranged to include a switch for selecting whether day time or night time functions are to be effective, although an external ambient light sensor could be provided to automatically make this selection; a switch to select the condition of whether the building is occupied or unoccupied; and a switch to enable the external lights 16 to be brought into operation irrespective of whether a sensor 10 has been actuated.

Referring now particularly to Figure 2 of the drawings, in operation when any one of the sensors 10 is actuated by an intruder approaching the building, the interior audible alarm 14 will be immediately brought into operation. If the control unit 12 has been set to operate in a day light mode, only the alarm 14 will sound and will continue to sound until a pre-determined period of time has expired after the sensors 10 no longer detect the presence of the intruder.

In the night time mode of the system where the building occupied function has been preset on the control unit 12, the external light 16 as well as the alarm 14 will be immediately switched on when any one of the sensors 10 is actuated and will remain in operation for a predetermined period of time after the sensors 10 are de-activated.

In the night time mode of the system where the building unoccupied function has been preset on the control unit 12, in addition to operation of the alarm 14 and external lights 16; the interior lights 18 in, for example, a bedroom are switched on after a predetermined period of time has elapsed from any one of the sensors 10 being activated to simulate an occupant of the building being awakened. After a further period of time has elapsed, the interior lights 20 in, for example, a ground floor room are activated to simulate the aroused occupant moving about within the building. In addition, the other alarms 22 such as a tape recorded noise of, for example, a dog barking are actuated to further deter the intruder.

As long as the sensors 10 detect the presence of the intruder, the external lights 16 remain switched on but after a predetermined time, the interior lights 18, 20 and alarms 22 are de-activated, the lights 18, 20 being de-activated in the reverse sequence to their sequence of operation in order to simulate the disturbed occupant retiring to bed so that any watching intruder will be given the impression that the building is genuinely occupied.

When the sensors 10 no longer detect the presence of the intruder, the external lights 16 will also be switched off after a predetermined period of time and the system will be reset until one of the sensors 10 is again activated.

It will be appreciated that although this system is primarily for use with external sensors, conventional door or window sensors in the form of, for example, micro-switches or reed switches, or pressure pads, or the like could be used without departing from the scope of this invention.

Claims

1. An alarm system for use on a building, which alarm system comprises one or more sensors for detecting the presence of an intruder prior to or at least during entry of the intruder into the building, at least one visual or audible alarm, and a control unit actuated by the or each sensor, to control operation of the or each visual or audible alarm, wherein the control unit includes means for simulating occupancy of the building.

2. An alarm system according to Claim 1, wherein the means for simulating occupancy of the building comprise one or more timers or time delay circuits for actuation of a visual alarm in two or more spaced apart locations or zones of the building at predetermined intervals of time after activation of the or one of the sensor(s) in order to simulate movement of an occupant between said locations or zones.

3. An alarm system according to Claim 1 or 2, wherein the or each visual alarm comprises one or more of the conventional interior lights in the building.

4. An alarm system according to Claim 2 or Claims 2 and 3, wherein the or each time delay circuit is adapted to actuate one or more audible alarm(s) at a predetermined interval of time after activation of the or one of the sensor(s), thereby to simulate occupancy of the building.

5. An alarm system according to any of the preceding claims, having at least one audible alarm which is selected from a group comprising tape players, tape cassette players, radios, televisions and the like.

6. An alarm system according to any of the preceding claims, wherein the control unit is adapted to deactivate the or at least one of the visual or audible alarm(s) at a predetermined period after the or each sensor indicates that the intruder is no longer being detected.

7. An alarm system according to Claim 6, wherein a plurality of alarms are provided and the control unit deactivates the alarms following a sequence which is the reverse of a sequence in which the alarms were activated.

8. An alarm system according to any of the preceding claims, wherein switch means is provided to switch the control unit between at least two modes which enable the conditions and functions of the alarm system to be preset according to the conditions appertaining at any particular time.

9. An alarm system according to Claim 8, wherein said switch means is operative to select either a night time or day time mode.

10. An alarm system according to Claim 8 or 9, wherein said switch means is manually actuable.

11. An alarm system according to Claim 9, wherein, in use, said switch means is automatically actuated in response to an external ambient light sensor.

12. An alarm system according to Claim 8, 9, 10 or 11, wherein said switch means is operative to select modes representative of whether the building is occupied or unoccupied.

13. An alarm system substantially as hereinbefore described with reference to the accompanying drawings.