WO2007052034A1

WO2007052034A1 - Control of electrical devices

Info

Publication number: WO2007052034A1
Application number: PCT/GB2006/004100
Authority: WO
Inventors: Steven Thomas Barson
Original assignee: Steven Thomas Barson
Priority date: 2005-11-03
Filing date: 2006-11-03
Publication date: 2007-05-10
Also published as: GB0522448D0; GB2432028A

Abstract

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.

Description

Title: Control of Electrical Devices

Description 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 PIR 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 and/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 for controlling an electrical device according to whether or not the location is occupied. The signal for controlling an electrical device may operate switching means for switching an electrical circuit, e.g. a lighting circuit in which the apparatus is provided. Alternatively or additionally a signal may be provided for causing switching of another circuit or part of a circuit, which may be at another position.

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.

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. A light switch for controlling at least the main installed lighting in a room usually is provided on a wall immediately adjacent the doorway, such wall being either that in which the door is provided or, if the doorway is adjacent a comer of the room, a wall extending generally at right angles to the wall in which the door is provided. In the former case, adjacent sensing elements in the apparatus may have directing devices providing respective fields of sensitivity which extend obliquely of the doorway just inside the room, so as to be able to respond to movement of a person in the normal area and in the normal directions used for entry to or exit from the room.

In the case of an apparatus provided on a wall extending generally at right angles to a wall in which the door is provided, the sensing elements may have their directing devices arranged for their fields of sensitivity to extend generally parallel to one another and to the wall in which the door is provided, just inside the door.

Apparatus according to 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 a 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 pull-cord 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.

When used as a replacement for an existing light switch, apparatus in accordance with the invention may control the light or lights in the room which previously were operated by the existing light switch. Usually, this will comprise one or more ceiling and/or wall-mounted lights. The apparatus may provide for control of further lights or other electrical appliances by including transmitting means for emitting a signal or signals to control other switching devices. Such transmitting means may emit a radio signal or signals which is received by the further switching device(s).

For example, there is available a so-called remote control socket which is able to be plugged into a conventional electrical outlet and itself has a socket outlet into which a light or other electrical appliance may be plugged. A radio receiver is incorporated, responsive to a control signal emitted by a remote control unit, enabling a user to switch the electrical appliance on or off without having to operate a switch physically located on the appliance or socket outlet. Apparatus in accordance with the invention may be able to transmit signals to control one or more of such remote control sockets.

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 reengaged 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 light off.

An override device may also be used to switch lights on, and analogously to its use to switch lights off, it may comprise a switch which either adds one to the occupancy of the location in question, to cause the apparatus to switch on, or a switch may completely override the apparatus in accordance with the invention. An audible or other signal may be emitted when a person 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 after a small time delay, e.g. 5 seconds. If the indication of 0 occupancy is incorrect, a person leaving the location could operate the override switch to add 1 to the occupancy, so the lights will not be switched off.

Frequently it is the case that a location may have more than a single entrance/exit. To ensure that persons entering or leaving the room or other location are detected and taking into account when determining lights or other electrical appliance(s) are to be switched on or off, the invention provides that these may be at least one further apparatus including means for detecting entries and exits of a person or persons to or from the location, and means for transmitting a signal to the first apparatus, to be counted together with the entries and exits detected by the first detecting means, to determine whether there is any occupation of the location.

Such a further apparatus may take the form of a "slave" unit which can be mounted in relation to a further entry/exit point for the location.

Such a "slave" unit may comprise sensing elements arranged generally as in the first detecting means, together with means which detects the order in which motion in the respective regions is sensed to indicate whether a person is entering or exiting the location, and cause a signal to be transmitted, e.g. by radio, according to whether the occupancy of the location is increased or decreased.

Such a "slave" unit may be battery powered since there may be no source of electrical power at the position where it is to be located. If passive infrared motion sensing elements are used, these have a low electrical consumption when no movement is sensed, and since a radio signal is required to be transmitted to the first detecting means only upon sensing of movement, a life of a year or more can be expected to be achieved by primary or rechargeable batteries of a size able to be accommodated in a typical "light switch" housing, before replacement or recharging is required.

The first detecting means may draw its electrical power supply from a lighting circuit in which it is connected. A rechargeable battery may be incorporated in the detecting means, arranged to be charged when the light(s) is on, or possibly a small quiescent current may be caused to flow through a light or lights connected in such a circuit even when switched off, to ensure the battery is kept charged. This latter possibility is not available in the case of a fluorescent light. If the battery becomes discharged, manual switching only is possible, and radio communication will not function.

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, as above described. 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

Radio communication utilised in apparatus according the invention, between the first apparatus and a further or slave unit, and between the first apparatus and one or more remotely-controlled switching devices, may be at a radio frequency and power level which is licence-exempt. It is proposed that, physically, the first or master apparatus including the detecting means, counting means, and signalling means, may be constructed on two printed circuit boards. A first printed circuit board, which is disposed immediately behind the front plate of a unit, carries the motion sensing elements, switches for manual operation of the various functions, a microcontroller, and radio transmitting and/or receiving modules. A second printed circuit board, spaced behind the first printed circuit board, would carry the means for mains electrical power switching, and a battery/charging circuit. Such ah arrangement of printed circuit boards has the advantage that for a "slave" unit, only the first printed circuit board having sensors, manually operable switches, micro-controller, and radio transmitting circuits would be required, the second printed circuit board being unnecessary.

The invention will now be described by way of example, with reference to the accompanying drawing which illustrates the principal elements of apparatus in accordance with the invention.

Referring to the drawing, this illustrates a first or "master" apparatus 10 and a second or "slave" unit 12. The apparatus 10 is a unit able to be mounted on a wall, for example, in substitution for an ordinary light switch, controlling a light (or lights) 14 for a room or other location, and receiving electrical power from a supply 16. Usually, in the case of a switch for controlling lighting in a room, the apparatus 10 would be disposed adjacent an entry/exit point such as a doorway of the room.

The apparatus 10 incorporates the operative components above described. Thus it has means for detecting entries and exits of persons to and from the location, such means preferably including infra-red motion sensing elements positioned so as to be able to sense the presence of persons in adjacent regions in the vicinity of the apparatus. Such motion sensing elements are provided behind a front plate of the unit, the front plate having a window 18 with a lens or lenses arranged so the motion sensing elements are responsive to motion in suitably positioned fields of sensitivity. Preferably the lenses are adjustable, so suitable fields of sensitivity may be set wherever the apparatus is positioned in relation to a doorway. Because the window 18 is provided on the front of the unit, the field(s) of sensitivity of the apparatus may be set, by adjustment of the lens or lenses, to extend to either side of the unit, enabling a common unit to be utilised for installation to either side of a doorway. A radio receiving circuit receives signals from the "slave" unit 12. The apparatus further includes means for counting entries and exits to determine whether the location is occupied or not, and means for giving a signal in accordance with the state of occupation of the location, to a switching means for switching the electrical power supply to the light(s) 14.

As described above, the apparatus includes manually-operable, e.g. push- button, switches 20, 22 of which the switch 20 is an increment switch for increasing by one the counted number of persons within the location. 22 is a decrement switch for decreasing to 0 the number of persons occupying the location, i.e. switching the light(s) off when required if such switching does not occur automatically. The apparatus 10 further includes a manually operable switch 24 which has three positions providing respectively for total (overriding) switching "off" of the light(s), automatic operation of the light(s) by means of the apparatus, and overriding switching "on" of the light(s). Conveniently the switch 24 may be a rocker switch, and it may have a mid position which is the overriding "off' position.

The apparatus 10 may derive its power supply for the motion sensors and associated circuitry from the electrical power supply for the light(s) 14. A rechargeable battery may be incorporated. The apparatus further includes means for transmitting a radio signal to switching devices associated with further electrical circuits, which may comprise so-called remote-controlled sockets 30, able to be plugged into conventional electrical socket outlets and themselves having socket outlets into which a light or other appliance may be plugged. Each incorporates a radio receiver responsive to a radio signal emitted by the apparatus 10. For providing overriding control of the remote control sockets 30, a further switch 26 such as a rocker switch may be provided on the apparatus 10, such further switch having, like the switch 24, three operative positions namely an overriding "off" position, an overriding "on" position, and a position in which the sockets 30 are switched automatically in accordance with the detected state of occupancy of the room or other location.

The "slave" unit 12 is able to be mounted in a position adjacent another point of entry to or exit from the location. Like the apparatus 10, it incorporates motion sensors whose field of sensitivity is determined by a lens or lenses 32 in a window in a front plate of the unit, and a circuit which, from the order in which the sensing elements respond to movement, determines whether a person is entering or leaving the location. It also includes manually operable increment and decrement switches 34, 36 respectively. A radio transmitter circuit transmits signals to the main apparatus 10 in accordance with detected or manually-input increments or decrements in the location's occupancy, to be counted by the counting circuit in the apparatus 10 in addition to the changes in occupancy detected by the sensors at the unit 10. If a location has more than two entry/exit points, additional "slave" units 12 may be provided.

The slave unit 12 may incorporate a battery, primary or rechargeable so that it can operate independently of any mains electrical power supply.

Since communication between one or more slave units 12 and the main apparatus 10 is by radio transmission, suitable means may be provided for setting the apparatus, e.g. by adjusting the frequency or some other characteristic of radio transmissions, so that transmissions in one location are not interfered with by transmissions from another location, e.g. a different room in a building or adjacent building. It is well known for such provision to be made in apparatus involving radio transmissions.

Further features may be provided. For example, a hand-held remote control unit may enable the apparatus to be operated by a person in the location but remote from the main or a slave unit.

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 performing 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

1. 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.

2. Apparatus according to claim 1 wherein the signal operates switching means for switching an electrical circuit in which the apparatus is provided.

3. Apparatus according to claim 1 or claim 2 wherein a signal is provided for causing switching of a circuit at another position.

4. Apparatus according to claim 3 wherein said signal for causing switching at another position is a radio signal transmitted by the apparatus.

5. Apparatus according to claim 3 or claim 4 further comprising at least one socket adaptor including a receiver for said signal.

6. Apparatus according to any one of preceding claims 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 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.

9. Apparatus according to claim 8 comprising sensing elements mounted adjacent one another and directing devices arranged so that they are responsive to motion in the required regions.

10. Apparatus according to any one of the preceding claims 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.

11. Apparatus according to claim 10 wherein the overriding device is operable to provide signals, representing entries or exits, to the means for counting the entries and exits.

12. Apparatus according to any one of the preceding claims adapted to control lighting in the location.

13. Apparatus according to claim 12 provided in a unit able to be mounted in replacement for a conventional light switch.

14. Apparatus according to claim 12 or claim 13 further comprising means for detecting a level of ambient light in the location and for controlling the operation of the apparatus in accordance therewith.

15. Apparatus according to any one of the preceding claims further comprising means for providing an audible or visible signal when it is detected that the occupancy of the location is reduced to zero.

16. Apparatus according to claim 15 comprising means providing a time delay, after provision of the signal, before a signal is provided to cause switch- off of the electrical device.

17. Apparatus according to any one of the preceding claims, which derives its electrical power supply from an electrical circuit in which it is connected.

18. Apparatus according to claim 17, incorporating electrical storage means, charged from the electrical power supply.

19. Apparatus according to any one of the preceding claims, further comprising at least one further apparatus including means for detecting entries and exits of a person or persons to and from the location, and means for transmitting signals indicative of such entries and exits to the first apparatus at which the entries and exits are counted with those detected by the first detecting means.

20. Apparatus according to claim 19 wherein the signals from the further apparatus are transmitted by radio.

21. Apparatus according to claim 19 or claim 20 wherein the further apparatus incorporates at least one battery for supplying it with electrical power.

22. Apparatus for controlling operation of an electrical device, substantially as hereinbefore described with reference to any or as shown in the accompanying drawing.

23. A room having apparatus according to any one of the preceding claims for controlling at least one light in the room.

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