GB2233789A

GB2233789A - Electronic security apparatus

Info

Publication number: GB2233789A
Application number: GB8910232A
Authority: GB
Inventors: Gordon Thomas Dale-Smith
Original assignee: DOLPHIN HITEC Ltd
Current assignee: DOLPHIN HITEC Ltd
Priority date: 1989-05-04
Filing date: 1989-05-04
Publication date: 1991-01-16
Also published as: GB8910232D0

Abstract

An ambient light sensor 6 is used to provide a "darkness" signal in response to which a number is randomly selected from a pseudo-random sequence generated by microprocessor 1. The selected number serves as basis for selection of a programme (held in EPROM 4) of actuation signals (to switch on lights or other devices so as to simulate occupancy of a building) supplied by circuits 9. Times used in the programmes depend on the selected pseudo-random number. A switch 5 can be provided for manual selection of consecutively run programme portions. A TEST mode may be provided in which programmes are run in accelerated fashion. <IMAGE>

Description

ELECTRONIC SECURITY APPARATUS This invention relates to electronic security apparatus and in particular to such apparatus for use in buildings to provide indications of activity of occupants (who may not be present) to external observers who may intend to effect unlawful entry.

There are known devices which can provide timed activation of electrical appliances in buildings such as lights, radios and tape recorders in order to provide an appearance of activity and presence of occupants to discourage unlawful intruders. However, such known devices generally suffer the disadvantage that even if relatively complex they exhibit a detectable pattern of activity which can indicate to an observer that the building is unoccupied.

According to one aspect of this invention there is provided electronic security apparatus comprising means for supplying a timing signal, in dependence on the occurrence of one or more events, to means for generating a pseudo-random number sequence and for selecting the current pseudo-random number in dependence on said timing signal, and means for providing a programme of actuation signals dependent on said selected pseudo-random number.

Preferably said means for supplying the timing signal comprises an ambient light level detector arranged for producing said timing signal when the ambient light level falls below a predetermined value. Alternatively the timing signal may be produced on the passage of a predetermined time period and/or the sensing of some other physical quantity.

Advantageously a microprocessor may be provided for said number sequence generation and selection and for determining said programmes. It may be arranged that the selected pseudo-random number is used in the programme to vary one or more times associated with said actuation signals.

Advantageously, means may be provided to enable pre-selection of one or more programme portions to be run in sequence, the selected pseudo-random number being used in one or more of the pre-selected programme portions.

Means may be provided for pre-selecting operating modes involving respectively different rates of occurrence of the actuation signals.

Conveniently the apparatus may include means for selecting a TEST mode in which pre-selected programme portions can be run at an accelerated rate to check the operation of the apparatus.

The apparatus may be combined with an alarm system arranged to detect and indicate unlawful intrusion and/or fire.

According to another aspect of this invention there is provided a system for building security comprising apparatus according to said one aspect arranged for operating a plurality of lights in respective time patterns dependent on said programmes.

Advantageously the system may include means for operating window curtains in response to said actuation signals. Further household devices such as radios, television sets and tape recorders may also be operated by means of said actuation signals.

Embodiments of this invention will now be described, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a block circuit diagram of electronic security apparatus embodying this invention; Figs. 2 and 3 are block circuit diagrams of respective building security systems incorporating the apparatus shown in Fig.

1; Fig. 4 is a flow diagram of the daily operational cycle of the apparatus shown in Fig. 1; and Fig. 5 is a table of various programme portions which can be pre-selected in the apparatus shown in Fig. 1.

Referring to Fig. 1, electronic security apparatus comprises an R6501Q single-chip microprocessor sold by Rockwell International and a power supply 2 to be connected to a mains supply and controlled by means of an ON/OFF switch 3.

The microprocessor 1 has an associated EPROM 4 containing various hour-long programme portions which can be pre-selected for consecutive running by means of a selection switch 5 for selecting the number of hours duration for a complete switching programme to be provided by the apparatus An ambient light sensor 6 is provided outside main control unit 7 containing the microprocessor and is connected via an analogue-to-digital converter 8 to the microprocessor 1 so as to provide a timing signal for the latter indicating that darkness has fallen so that lights in the building can be switched on in a time pattern determined by the pre-selected programme portions. The microprocessor 1 has outputs for actuation signals connected via power control circuits 9 to lights (not shown in Fig. 1) in the building.

A switch 10 is connected to the microprocessor to enable selection of a TEST mode in which the programme is accelerated by a factor of 60.

Referring to Fig. 2, there is shown a building security system in which the control unit 7 has its actuation signal outputs connected via ceiling fittings 11 to four lights 12 in different rooms 13,14,15,16 in the building, e.g. the kitchen, hall, bedroom and lounge of a house.

Referring to Fig. 3, there is shown an alternative form of building security system in which the control unit 7 has its actuation signal outputs connected via respective wall sockets 110 to electric lights 111 in rooms 130,140,150,160.

Referring to Figs. 4 and 5, it is illustrated how, once the apparatus has been switched on and has gone through a setting-up routine, it proceeds to generate a sequence of pseudo-random numbers and the occurrence of the "darkness" signal from the ambient light sensor 6 causes selection of the current random number for use in the selected hour-long programme portions which are included in dependence on the setting of switch 5. When the light-switching programme has been completed, the apparatus waits for one hour before either continuing with pseudo-random number generation (if darkness has lifted) or starts another cycle of waiting for a further hour.

Selection of the TEST mode causes the selected programme to be run at 60 times normal speed.

Advantageously the system may include means for operating window curtains in response to said actuation signals Further household devices such as radios, television sets and tape recorders may also be operated by means of said actuation signals.

ACTIVE - Average of 10 switch actions per hour NORMAL - Average of 5 switch actions per hour SEDENTARY - Average of 3 switch actions per hour The apparatus may be combined with an alarm system arranged to detect and indicate unlawful intrusion and/or fire.

Thus the apparatus described above provides a pattern of light switching and possibly switching of other devices in dependence on the actual daylight level rather than on a preset time and varies the pattern on a daily basis using the change in selected pseudo-random number to reduce the likelihood that an outside observer will detect that the appearance of activity in the building is being contrived automatically rather than being the result of the activity of occupants in the building.

Instead of the switch 5 described above, a three-position switch may be arranged to provide three alternative time periods for the programme. The three possible time periods may be related to seasons of the year and may comprise ranges as: POSITION SEASON PROGRAMME DURATION 1 Summer 2-4 hours 2 Autumn/Spring 4-6 hours 3 Winter 6-8 hours The actual programme duration in the selected range may be selected in dependence on the pseudo-random number selected.

Claims

CLAIMS:

1. Electronic security apparatus comprising means for supplying a timing signal, in dependence on the occurrence of one or more events, to means for generating a pseudo-random number sequence and for selecting the current pseudo-random number in dependence on said timing signal, and means for providing a programme of actuation signals dependent on said selected pseudo-random number.

2. Apparatus according to claim 1, wherein the timing signal is produced on the passage of a predetermined time period and/or the sensing of some physical quantity.

3. Apparatus according to claim 2, wherein said means for supplying the timing signal comprises an ambient light level detector arranged for producing said timing signal when the ambient light level falls below a predetermined value.

4. Apparatus according to any one of the preceding claims, wherein a microprocessor is provided for said number sequence generation and selection and for determining said programmes.

5. Apparatus according to claim 4, wherein the selected pseudo-random number is used in the programme to vary one or more times associated with said actuation signals.

6. Apparatus according to any one of the preceding claims, wherein means are provided to enable pre-selection of one or more programme portions to be run in sequence, the selected pseudo-random number being used in one or more of the pre-selected programme portions.

7. Apparatus according to any one of the preceding claims, wherein means are provided for pre-selecting operating modes involving respective different rates of occurrence of the actuation signals.

8. Apparatus according to any one of the preceding claims, wherein means are provided for selecting a TEST mode in which pre-selected programme portions can be run at an accelerated rate to check the operation of the apparatus.

9. Apparatus according to any one of the preceding claims and combined with an alarm system arranged to detect and indicate unlawful intrusion and/or fire.

10. A system for building security comprising apparatus according to any one of the preceding claims and arranged for operating a plurality of lights in respective time patterns dependent on said programmes.

11. A system according to claim 10, wherein means are provided for operating window curtains in response to said actuation signals.

12. A system according to claim 10 or claim 11, wherein means are provided for operating a radio and/or a television set and/or a sound reproduction system by means of said actuation signals.

13. Electronic security apparatus substantially as described herein with reference to the accompanying drawings.

14. A system for building security substantially as described herein with reference to the accompanying drawings.