GB2432028A

GB2432028A - Controlling electrical devices on the basis of occupancy

Info

Publication number: GB2432028A
Application number: GB0522448A
Authority: GB
Inventors: Steven Thomas Barson
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-03
Filing date: 2005-11-03
Publication date: 2007-05-09
Also published as: WO2007052034A1; GB0522448D0

Abstract

A method for controlling operation of an electrical device in dependence upon whether or not a location is occupied by at least one person, comprising detecting entries and exits of a person or persons to and from the location; counting the detected entries and exits to determine whether there is any occupation of the location; and providing a signal to control an electrical device according to whether or not the location is occupied.

Description

Title: Control of Electrical Devices DescriDtion of Invention This

invention relates to a method of, and apparatus for, controlling operation of an electrical device or devices depending on whether or not a location, for example a room, is occupied by one or more persons.

The invention has been devised in relation to the control of electric lighting in a room or other location depending on whether the room is occupied by one or more persons.

It is known to control a light or lights by using a motion sensor. For example so-called security lights or courtesy lights may use a motion sensor of the passive infra-red (PIR) type to sense motion within the area covered by the sensor, and switch a light or lights on for a predetermined length of time. After that time has elapsed with no further detection of motion, the light is switched off. The motion sensors for such operation often have a detector for the level of ambient light to protect the light from being switched on during daylight times, and may have an overriding switch device for enabling the light to be switched on whether or not any motion is detected or when required for testing purposes.

It would be desirable if lighting in a room, for example, were able to be switched on automatically when the room is occupied, but switched off when the room is unoccupied, as an energy-saving measure and for convenience.

The well known FIR motion sensor device as described above is not suitable for this purpose, because it will only keep the lighting switched on for the predetermined period of time, and if the occupant of the room does not move before that time has expired, or is out of the line of sight of the sensor, the light will be switched off. In many cases lighting will require to be kept switched on even though the occupant of a room does not move sufficiently to be detected by the motor sensor. On the other hand, if, in an attempt to overcome this problem, the light is set to be switched on for a relatively long time, this is wasteful of energy since the occupant's leaving the room will cause the light to be switched on and remain so long after the room has become unoccupied. This type of device can also be activated by large pets.

It is broadly the object of the present invention to provide for control of an electrical device or devices, which may be lighting or may be other things as described hereafter, in a way which overcomes or reduces these disadvantages.

According to one aspect of the invention, we provide a method for controlling operation of an electrical device in dependence upon whether or not a location is occupied by at least one person, comprising: detecting entries and exits of a person or persons to and from the location; counting the detected entries and exits to determine whether there is any occupation of the location; and providing a signal to control an electrical device according to whether or not the location is occupied.

According to another aspect of the invention, we provide apparatus for controlling operation of an electrical device in dependence upon whether or not a location is occupied by at least one person, comprising: means for detecting entries and exits of a person or persons to and from the location; means for counting the detected entries and exits to determine whether there is any occupation of the location; and means for providing a signal to control an electrical device according to whether or not the location is occupied.

The entries and exits of a person or persons relative to the location may be detected by sensing the presence of the person or persons in at least one entrance/exit part of the location, and determining the direction of movement of each person sensed as occupying the entrance/exit part(s).

The direction of movement of a person in an entrance/exit part of the location may be determined by sensing motion in adjacent regions of the entry/exit part, the regions being positioned so that when motion is sensed in one region followed by the other the order in which the respective motions in the regions are sensed will indicate whether a person is moving in the direction to enter or exit from the location. The regions may be spaced from other another or may overlap.

In the case where the entrance/exit part of the location is a doorway rather than an elongate passage which must be travelled by person entering or leaving the location, overlapping or very closely adjacent regions in the vicinity of the doorway would be appropriate.

If a location has more than one entrance/exit part, it would be necessary to detect entries and exits of persons at all such parts and provide for communication of detected entries and exits to the counting means of the apparatus.

Motion in the entry/exit part(s) may conveniently be sensed by infra-red motion sensing elements, positioned so as to be able to sense motion in the required regions. If such sensing elements are mounted adjacent one another, suitable directing devices such as Fresnel lenses may be arranged to ensure that they respond to motion in the required regions. Means for detecting the order in which motion in the regions is sensed indicates whether a person is entering or exiting the location.

Apparatus for carrying out the method of the invention requires the provision of a suitable counting circuit to count the entries to and exits from the location, and to give a signal when the status of the location changes from being unoccupied to occupied and vice versa.

An electrical device which may be controlled in accordance with the invention may be lighting equipment. A signal provided in accordance with the invention may control the lighting equipment so that when the location is unoccupied the light will be off, whilst when it is detected that the location is occupied by one or more persons the light is switched on.

In typical operation of the invention, in relation to a light in a room, from a starting condition when the room is empty and the light off, detection of a person's entering the room will be identified as a room occupancy of +1, causing the light to be switched on. If a second person enters the room, the room occupancy will be +2 and the light will remain on. When one person leaves the room it will reduce the occupancy to +1 at which the light will remain on, but when the second person leaves the room the occupancy will be reduced to 0 and the light switched off.

Apparatus in accordance with the invention may be provided with a means for detecting a level of ambient light, e.g. daylight, in the location, and if there is sufficient ambient light it will not be necessary to switch on the controlled lighting in the location. Movement of persons into and out of the location when there is sufficient ambient light need not be counted, or preferably the method of counting entries and exits relative to the location is continued even if there is sufficient ambient light, so that if the location is occupied and the ambient light level drops, the controlled lighting can be switched on.

Apparatus in accordance with the invention may be incorporated in a unit able to be mounted in replacement for a conventional light switch. Light switches are nearly always positioned by the entrance/exit of a room, so are conveniently positioned to be able to detect person's entering and leaving the room, It is relatively simple to remove an existing light switch and replace it by an apparatus in accordance with the invention. Further, as a result of the height at which light switches usually are mounted on walls (or on the ceiling in the case of a pullcord operated switch for use in a bathroom for example), it is relatively easy to set the apparatus so as to be able to detect the movement of persons including children but not domestic pets.

An override facility is preferably provided so that control of the electrical device can be effected otherwise than as a result of the counting process for determining whether or not the location is occupied. For example, in the case of a bedroom, lighting may be required to be switched off even when the room is occupied.

To this end, a switch may be provided which is operable to decrease the number of persons counted as occupying the location to 0. Alternatively, the apparatus according to the invention may be disengaged completely until re-engaged by further operation of a switch. In the latter case, a light in a bedroom, for example, would not automatically be switched on when another person enters the room some time after a first person has switched the lights off.

An override device may also be used to switch lights on, and analogously to its use to switch lights off, it may either add one to the occupancy of the location in question or completely override the apparatus in accordance with the invention.

An audible or other signal may be emitted when a person is leaving the location has reduced the occupancy thereof to 0. This would indicate to the last person leaving a room for example that the room has now been classified as empty and the lights will be switched off. If the indication of 0 occupancy is incorrect, a person leaving the location could operate the override.

Although described herein primarily in relation to the control of lighting, the invention may also be useful for use in controlling other electrical devices e.g. by causing one or more electrical power outlets to be switched on or off, or by putting electrical appliances into a "stand-by" or "sleep" mode. A separate detector for room occupancy may be used for this purpose, or a device used for lighting control could send an electrical signal to cause further switching devices to be operated on electrical socket outlets or appliances. Yet a further possibility is that the invention may be used in association with telecommunications equipment, for example, for indicating to a telephone apparatus in which room a calling signal should be given in a premises having a number of rooms with calling signals When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for pertorming the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

Claims 1. A method for controlling operation of an electrical device in

dependence upon whether or not a location is occupied by at least one person, comprising: detecting entries and exits of a person or persons to and from the location; counting the detected entries and exits to determine whether there is any occupation of the location; and providing a signal to control an electrical device according to whether or not the location is occupied.

2. A method according to claim 1 wherein the entries and exits of a person or persons are detected by sensing the presence of the person or persons in at least one entrance/exit part of the location, and determining the direction of movement of each person sensed as occupying the entrance/exit part(s).

3. A method according to claim 2 wherein the direction of movement of a person in an entrance/exit part of the location is determined by sensing motion in adjacent regions of the entry/exit part, and detecting the order in which motion in the regions is detected to indicate whether a person is entering or exiting the location.

4. A method according to claim 3 wherein the motion is sensed by infra-red motion sensing elements.

5. Apparatus for controlling operation of an electrical device in dependence upon whether or not a location is occupied by at least one person, comprising: means for detecting entries and exits of a person or persons to and from the location; means for counting the detected entries and exits to determine whether there is any occupation of the location; and means for providing a signal to control the electrical device according to whether or not the location is occupied.

6. Apparatus according to claim 5 wherein the means for detecting entries and exits comprises means for sensing the presence of a person or persons in at least one entrance/exit part of the location, and means for determining the direction of movement of each person sensed as occupying the entrance/exit part(s).

7. Apparatus according to claim 6 comprising means for sensing motion in adjacent regions of the entry/exit part, and means for detecting the order in which the motion in the regions is sensed to indicate whether a person is entering or exiting the location.

8. Apparatus according to claim 7 wherein the regions are spaced from one another.

9. Apparatus according to claim 7 wherein the regions overlap one another.

10. Apparatus according to any one of claims 5 to 9 wherein motion in the entry/exit part is detected by infra-red motion sensing elements arranged so as to be able to sense motion in the required regions.

11. Apparatus according to claim 10 comprising sensing elements mounted adjacent one another and directing devices arranged so that they are responsive to motion in the required regions.

12. Apparatus according to any one of claims 5 to 11 further comprising an overriding device so that the electrical device can be controlled otherwise than by counting entries and exits to and from the location.

13. Apparatus according to claim 12 wherein the overriding device provides signals representing entries or exits to the means for counting the entries and exits.

14. Apparatus according to any one of claims 5 to 13 adapted to control lighting in the location.

15. Apparatus according to claim 14 provided in a unit able to be mounted in replacement for a conventional light switch.

16. Apparatus according to claim 14 or claim 15 further comprising means for detecting a level of ambience light in the location and for controlling the operation of the apparatus in accordance therewith.

17. A method, or apparatus, for controlling operation of an electrical device in dependence upon whether or not a location is occupied by at least one person, substantially as hereinbefore described.

18. A method, or apparatus, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

19. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.