AU2003262346B2 - Electrical switching system - Google Patents

Description

19-NOV-2003(WED) 14:24 MA Martin Associates 1 9NOV200(WE) 1:24 MA artn &Assciaes(FAX)61 2 9453 3659 P. 008/033 3672.3.doQ Electrical switching system Technical-Field This invention relates to lighting circuits and more particularly to lighting circuits used fo r interior lights in cabinets, rooms and spaces that are switched in response s to movement of a wing, door or other similar structure.

Backeround Art It is desirable to provide lighting for cabinets and other closed spaces, such as pantries and wardrobes that "automatically" turn on and off when a door or similar structure is opened and closed. In existing installations, a micro switch is mounted la on part of the fixed structure. Thu micro switch has a movable element that contacts a door when in a closed position. When the door is opened the movable element moves, opening or closing a circuit and activating one or more lights.

The use of micro switches has a number of disadvantages. Both the switch itself and its associated wiring are mounted on the surface of the structure and are thus is visible, which to some people is unsightly. The movable elements in micro switches only move a smalJ distance between the on and off positions. As such, both the micro switch and the door, or similar structure, that the moving element contacts needs to be accurately positioned. Failure to accurately mount the two components together will result in malfunction of the switching of the light.

Further, any small change in relative positions over time may result in incorrect operation of the circuit and more particularly the failure to cause the light to be turned off.

Disclosure of the Invention In an attempt to overcome or ameliorate at least one of the disadvantages of existing contact type switch systems, embodiments of the invention utilize proximity type switches that change stare due to the proximity or otherwise of two COMS ID No: SMBI-00500631 Received by IP AUStralia: Time 14:32 Date 2003-11-19 @3-FEB-2006(FRT) 11:36. 61 2 9453 3659(F )6 294365P.6/1 (FAX)81 2 9453 3659 P.006/018 IND 3672-.4c 0 2 components to each other, rather than contact between two components. In preferred embodiments those proximity type switches are magnetic ally activated, o with one of the components preferably being a permanent magnet mounted on die door or moving wing and the switch itself being a magnetically activated reed NO 5 switch or I-Tall Efflect device.

Cl Since the two components, of each switch need not contact each other it is then Cl possible to embed one or both of the components within the relevant structures, o rather than having the components surface mounted. Thus, for exatmple, a cabinet 0 may have a reed switch embedded within the carcass and a permanent magnet lo embedded within the door, so providing an invisible switching system.

Accordingly, in another form- the invention provides an enclosure having a concealed switching circuit and a method of forming, creating, fabricating or otherwise manufaicturing an enclosure wit a concealed switching system.

Embodiments of die invention also provide circuitry that switches the light(s) on and off in response to input from a proximity t~rpc switch. In preferred forms of the invention the circuitry provides an override function which will turn a light off after a predetermined time despite no change in the input from the proximity switch, such as when the door has been left open.

In one broad form the invention provides an electrical lighting circuit responsive to 2o movement of a wing relative to a fixed structure, the wing including a tag, the circuit including: a proximity sensor mounted on or in the structure that has first and second states, wherein the sensor has a first state and a second state and an output connected to one or more lights, wherein the output is on when the sensor is in one of said first and second states and off when the sensor is in the other of said first and second states, and COMB ID Na:SBMI-02567519 Received by IP Australia: Time 11:38 Date 2006-02-03 03-FEB-2006(FRI) 11:36 61 2 9453 3859 (FAX)61 2 9453 3659 P.007/018 Va I 3672-3.dW ._wherein the sensor changes from the First to the second state when the separation Sof the tag from the sensor increases from less than a first predetermined distance to o more than the first predetermined distance and the sensor changes from the second to the first state when the separation of the tag from the sensor decreases from N s more than a second predetermined distance to less than the second predetermined Sdistance, said first and second predetermined distances being significantly IN different, and Swherein at least one of the sensor and the tag are substantially hidden to an average r-iunaided eye of an average human.

The sensor is preferably responsive to a magnetic field but may be responsive to electromagnetic radiation. The sensor may be selected from a group including a reed switch, a Hall Effect switch and a Hall Effect sensor. The tag is preferably a magnet.

The sensor may transmit electromagnetic radiation and the tag may transmit electromagnetic radiation. The tag may transmit electromagnetic radiation in response to receiving electromagnetic radiation from the sensor. The sensor may be responsive to a signal transmitted by the tag.

The circuit may include a control unit that receives an input from the sensor and controls the output in response thereto.

The control unit may include a timer operative to turn the output off after a predetermined time irrespective of the state of the sensor. The predetermined time is preferably about 60 minutes. The circuit may include a switch for selectively enabling and disabling the control unit.

The first predetermined distance is preferably from about 25 mm to about 30 mm and the second predetermined distance is preferably about 50 mm.

The wing may have a closed position and preferably the first predetermined distance is selected and the tag positioned so the sensor is in the first state when COMS ID No: SBMI-02567519 Received by IPAustralia: Time 11:38 Date 2006-02-03 19-NOV-2003(WED) 14:25 MA Martin Associates 19-NV-203(ED)14:5 MAMarin Asocites(FAX)61 2 9453 3659 P. 009/033 3672-3.d"- 4 the wing is less than about 25 mm from the closed position.

Preferably the second predetermined distance is selected and the tag positioned so the sensor is in the second state when the wing is more than about 50 mmn from the closed position.

s Tn another broad form the invention provides a wing for an electrical lighting circuit responsive to movement of the wing relative to a fixed structure, the wing including a tag, the circuit including a proximity sensor mourned on or in the structure that has first and second states, dependent on the location of the tag relative to the sensor, wherein the tag is hidden or substantially hidden to an lo average unaided eye of an average human.

Preferably the tag is embedded in the wing and more preferably the tag is located in a recess in a surface of the base layer of the wing.

The wing may include a base layer and the tag is preferably sandwiched between the base layer and at least one layer of material.

1s The at least one layer of material is preferably selected from a group including paint, laminate, wood, plywood, chipboard, fibreboard, including medium density fibreboard. The tag is preferably a magnet.

The sensor may transmit electromagnetic radiation and the tag may transmit electromagnetic radiation. The tag may transmit electromagnetic radiation in 2o response to receiving electromagnetic radiation from the sensor.

In a further broad form, the invention provides an installation utilising the wing or the electrical circuit as described.

In yet another broad form, the invention provides a method of forming a wing for an electrical lighting circuit responsive to movement of the wing relative to a fixed structure, the wing including a tag, the circuit including a proximity sensor mounted on or in the structure that has first and second states, dependent on the COMS ID No: SMBI-00500631 Received by IP Australia: Time (I-lm) 14:32 Date (Y-M-ci) 2003-1 1-19 19-NOV-2003(WED) 14:25 MA Martin Associates (FAX)61 2 9458 3659 P. 010/033 location of the tag relative to the sensor, the method including: providing a base layer, positioning the tag ofl or in the base layer, and covering the tag with at least one layer of material to render the tag hidden or substantially hidden to an average unaided eye of an average hunman.

The method may include providing a recess in a surface of the base layer and positioning the tag includes positioning the tag in the recess.

The method preferably also includes securing the tag in the recess prior to covering the tag. This may include adhering the tag to the base layer.

The method preferably includes covering the tag with at least one layer of material includes covering the tag with at least one layer of material selected from a group including paint, laminate, wood, plywood, chipboard, fibreboard, including medium density fibreboard, Thc invention will be understood better from the following description of nonisr limiting embodiments of the invention and the drawings.

Brief Deskcription of the Drawings Figure 1 shows a sectional plan view of a first switch configuration for a cabinet according to an embodiment of the invention.

figure 2 shows a schematic cross sectional elevation view of an installation utilising an embodiment of the invention.

Figure 3 shows a circuit diagram of an embodiment of the invention.

Figure 4 shows a flow diagram of the process steps executed by a microcontroller of the control circuit of a preferred embodiment invention.

COMS ID No: SMBI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-2003(WED) 14:25 MA Martin Associates (FAX)61 2 9453 3659P.1/3 3672-1doe 6 Figure 5 shows a sectional plan view of a second switch configuration for a rebated door according to an embodiment of the invention.

Figure 6 shows a schematic cross sectional elevation view of an alternative installation utilising an embodiment of the invention.

s Figure 7 shows a schematic cross sectional elevation view of another alternative installation utilising an embodiment of the invention.

Best Mode of Carring out the juvention Referring to figures i to 4 there is shown a cabinet 10 having a shell or carcass 12 and a movable door 14 that opens and closes access to the front 16 of the cabinet ia 10, As seen in figure 1, the cabinet includes a panel 13 and the door overlaps the panel and the carcase 12. The carcase 12, panel 13 and door 14 are typically constructed of 18 mm thick medium density fibreboard (N41F) or chipboard which is laminated with a decorative laminate.

Located withiin a roof panel 18 of the cabinet 10 is a lamp 20, which illuminates is the interior space 22 of the cabinet. More than one lamp 20 may be provided for each interior space 22. The lamp 20 is preferably a low-voltage light, such as a 12 V halogen light commonly used in household installations, but other types of lights and different voltages may be used. Low-voltage lights arc preferred for safety reasons, size and power.

The cabinet: 10 has a space 24 above the roof panel 18 into which the lamp protrudes. The side walls 26 and a front panel 28 hide the space 24 from the front and sides of the cabinet Located within the space 24 is a control unit 30, shown in more detail in figure 4, which controls the operation of the lamp 20. The control unit 30 receives power via a 12 V AC supply 32, typically provided by a conventional transformner or an electronic switching transformer, which converts mains voltage to a 12 V AC supply. Depending on the power required and number of lights in each cabinet, a single t-ansfonner may supply multiple cabinets or each COMS ID No: SMBI-00500631 Received by IP Australia: Time (I-tm) 14:32 Date 2003-11-19 19-NOV-2003(WEO) 14:26 MA Martin Associates (FAX)61 2 9453 3659 R 012/033 36723.dpc cabinet may have one or more trainsformers. If desired the transformer(s) may be located within the space 24.

The control unit 30 receives an input from a proximity sensor 34 via wires 36. As best seen in Figure 2, the proximity sensdr 34 is preferably embedded in one of the s side walls 26, adjacent the front of 16 of the cabinet. The wires 36 leading from the sensor 34 to the control unit 30 are also preferably embedded in the wall 26 and so neither the sensor 34 nor wires 36 are visible to the user. The proximity sensor 34 opens and closes a circuit depending on the proximity of a complementary tag 38.

The tag 38 is located on or in the door 14. The tag 38 is also preferably embedded io in the door and so is not visible to the end user.

The tag is preferably hidden or substantially hidden from the average eye of the average human. This may be achieved by covering the tag with one or more layers of material or by locating the tag in a recess, or both. When the tag is covered with one or more materials, these may include paint, lamninate, wood, plywood.

chipboard, fibreboard, including medium, density fibreboard or any other suitable material.

Embedding of the components in the structure of the cabinet is not as critical but does provide an invisible switch and hides any unsightly components from the user. Hiding the components also means that damage to the components is less 2o likely to occur. For example, wires are not exposed and so cannot be accidentally pulled or abraded.

The sensor 34 is preferably a magnetically operated reed switch, in which the switch is normally open in the absence of a magnetic field and closed in the presence of a magnetic field. The tag 3 8 is a permanent magnet and so when the 2s door is closed or almost closed, the tag's magnetic field causes the reed switch Co close and the lamp 20 to be turned off by-the control unit 30. When the door is fully or partially open and the magnetic tag 38 is out of range of the sensor 34, the light is turned on by the control unit 30. It will be appreciated that by use of a COMS ID No: SMBI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-2003(WED) 14:26 MA Martin Associates (FAX)61 2 9453 3659 P. 013/033 34672.3.doe 8 different control unit 30 or a different program in the control unit 30, the lamnp may be caused to turn on when the sensor circuit is closed and to turn off when the sensor circuit is open. Thus, if desired, a reed switch that is closed in the absence of a magnetic field may be used.

s The reed switch 34 and magnet 38 both have a body that is about 9.5 mm in diameter and about 20 to 25 mm in length. Thus both the reed switch 34 and magnet 38 may be located lengthways in a MDF panel, as shown in figure 1. MDF panels are typically manufactured to size in a bare state and then covered with a decorative lamninate or finish. In the prefq~rrcd embodiments suitable recesses and passageways are formed in the MDF panels when in the bare state. The magnet 38, reed switch 34 and associated wires 36 are positioned in the respective recesses and secured with adhesive, fasteners and/or suitable plugs inserted into the recesses. The panels are then coated, laminated or otherwise finished so that the reed switch and magnet are bidden from view. The wires 36 obviously exit the 16 relative panel but this may be at a location where they are not visible in the finished product The recess for the magnet may be formed by drilling a blind bore 17 in the free end 19 of the door panel. Alternatively a channel may be cut in a side wall 21 of the door panel. The recess for the reed switch and wire may be forned by drilling a bore lengthwise along the panel 13. Alternatively a channel may be cut in the hidden face 23 of the panel 26. When assembled, the face 23 opposes the sidewall 26 and so any channel formed in the face 23 is hidden.

The reed switch and the permanent magnet used in the preferred embodiment have characteristics that result in the reed switch closing when the gap between the 2.9 sensor 34 and the tag 38 is about 25 mm to about 30 mm and opening when the gap between the sensor 34 and the tag 38 is about 50 mm. The tag 38 and the reed switch 34 are located about 15 mm from each other when the door 14 is fully closed so the separation of the two components is well within the make and break ranges. Thus a slight misalignment of the two parts will not cause a malthnction of COMS ID No: SMVBi-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-2003(WED) 14:26 MA Martin Associates (FAX)61 2 9453 3659 PR014/033 367 -3.&oc 9 the switching apparatus. Since Opening of the senso r turns on the light, the tag 3 8 needs to be moved to be more than 50 mm from the sensor before the light turns on and to be moved to be less than 25 to 30 mm from the sensor before the light turns off. Wit a separation of the two parts of about 15 mm when the door is fully s closed, the light will not turn on if the door opens a few mm and similarly will be turned off if the door is not fully closed. This is significant with cabinets where the doors are secured with screw adjustable hinges; frequently the hinge adjustment screws become loose and the door does not hang as when originally installed. It will be appreciated that these make and break values are not critical to the working io of the invention and different combinations of sensor and tag may have different make and break values.

Because the switching of the light occurs without requiring contact of the sensor and a. tag, thei manner in which the door opens is not significant. Thus the door may have a hinged, sliding, bifold, uplift or any other opening action, so long as is the tag and sensor are positioned so that sufficient separation occurs when the door opens to turn the light on and off.

WhilIst a magnetically operated reed switch is the preferr ed sensor, other magnetically operated sensors may be used, such as Hall Effect switches and sensors. Magnetic operation is preferred as permanent magnets are readily available and inexpensive. However, this is not to preclude other forms of proximity sensors having modes of operaton which do not rely on magnetic fields.

The reed switch used in the preferred embodiments has a load current in the order of 30 milliamps maximum. However, a 12 V DC 20 W halogen lamp draws slightly less than two amps. As such, the sensor cannot directly switch the lamp and must be used to operate a switching circuit, such as a relay. It will be appreciated, however, that if the sensor has a sufficiently high current capacity it may directly switch the lamp 20 without the use of the control unit 30. It will also be appreciated that the sensor 34 may have an insufficient current capacity to directly operate a relay or other lamp switching circuit that switches the lamp COMS ID No: SMBI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-2003(WED) 14:26 MA Martin Associates (FAX)61 2 9453 3659 P. 015/033 3672.3,doe current and an intermediate circuit may be required to amplify the signal from the sensor before operating a relay or the like, In the preferred embodiments of the invention the sensor 34 provides an input to a control unit 30, which in turn switches the lamp on and off via a relay. The s preferred switching circuit is shown in figure 3. The control unit 30 receives a 12 V AC supply at 32. A diode bridge 40 comprised of diodes D 1 to D 4 rectifiers this to 12 V DC. This in turn is smoothed via capacitors C 1 to C 4 indicated by numeral 41. A voltage regulator 42 then regulates the voltage to +5V DC, at pin 3, indicated by numeral 44, relative to pin 2, indicated by numeral 46.

lo Power is supplied to the sensor 34 via line 48 and ajumper block 52 and to a microcontroller 54 via line 56. The microcontroller 54 is preferably a PICAXE 08 microcontroller, which may be custom programmed. The program flow diagram is shown in Figure 5 and the program code is shown later in the description.

The sensor 34 connects to the microcontroller 54 via line 50. A 1 kQ resistor 58 is is located in series with the sensor 34 whilst a 10 kW resistor 60 is connected between line 50 and ground line 63. Thus, when the sensor 34 is closed, pin 3 of the microcontroller 54, indicated by numeral 44, will be at about 4.5 V, due to the voltage splitting effect of the resistors 58 and 60. When the sensor 34 is open, resistor 60 allows the voltage at pin 3 to drain to ground.

2o The microcontroller 54 has an output 62, at pin 0 on the chip, which is connected to the base input of a power transistor 64, which in turn is connected to a relay 66.

The relay 66 receives unregulated DC voltage via line 68. When pin 0 is placed at a higher voltage by the microcontroller 54, the transistor 64 starts conducting, allowing relay 66 to energise and in turn changing the switching state of the relay contacts 70, which receives AC current from input 32 via lines 72 and 74. The relay contacts 70 output to the lamp 20 via connection block 76.

If desired the relay 66 may be replaced by the power transistor 64 alone or by a separate power transistor. However, any transistors would need to have sufficient COMS iD No: SMBI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-2003(WED) 14:27 MA Martin Associates (FAX)o1 2 9453 3659 P.010/033 3672-3.&c I1 current capacity but more importantly the supply to the lamp would need to be rectified and so require a larger capacity rectifying circuit. In addition the rectifier would drop about 1.2 V when a current of about 4 A were drawn, generating about 4.8W, which would require a large heatsink. Further, the power transistor would also drop about 1.2 V, so requiring a large heatsink. In addition there would be a total voltage drop of about 2.4 V so any lamp would not run at full power. Of course one could have a higher voltage supply so the voltage at the lamp would be 12 V, but this would require non standard transformers and would not avoid the heat generated by the rectifier and the power transistor.

A further alternative is to replace the relay with mosfet based solid state controller.

The advantage of such controllers is that they have a very low voltage drop (and hence power dissipation) when on and may be used to control AC circuits. A further advantage is the ability to provide a "soft" start by ramping up the voltage when the door is opened and the lamp first turned on.

1s The program code of' the microcontroller 54 is shown below. Execution of the code shown below results in the flow diagram shown in figure 4 being followed.

start: 'test relay and lamp, 3 seconds on, then off high 0 pause 3000 low 0 main: 'wait for door to open, if door opens input on pin 3 goes low, 'pause 100, delay for switch bounce bO =0 bl =0 pause 100 low 0 if pin3 0 then timer goto main timer. 'energise relay and 60 minute time delay COMS ID No: SMSI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-2003(WED) 14:27 MA Martin Associates (FAX)61 2 9453 3659 P. 017/033 3('72,3.doc 12 'b minutes, combination ofbl x pause period milliseconds 'pause is in milliseconds high 0 forb0=l Sforbl=1to240 pause 250 if pin3 1 then main next bl next bO goto rlyoff rlyoff: 'de-energise relay and wait for door to close if pin4 1 then rlyon low 0 ifpin3 1 then main goto rlyoff rlyon: 'keep relay energised until door is closed high 0 if pin3 1 then main goto rlyon In use, assume the door 14 of the cabinet is closed and no power is supplied to the system. Assume power is then provided. When power is first supplied to the microcontroller 54, the programme first sets the voltage at pin 0, 62, to be high for 3 seconds, irrespective of any other input. This causes transistor 64 and relay 66 to turn on and turn on lamp 20. This serves to indicate that the lamp 20 and relay 66 are operational. If the lamp 20 fails to illuminate at start-up this indicates a relay malfunction or a light failure is likely, When the door is closed, the sensor 34 is closed and so pin 3, 44, of the microcontroller 54 is set to a high voltage. After testing the relay, the program checks the voltage at pin 3 and if high sets the voltage at output pin 0 to 0V or a COMS ID No: SMBI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-203(NED) 14:27 MA Martin Associates (FAX)61 2 9453 3659 P. 018/033 13 low-voltage which is insufficient to cause the transistor 64 to conduct. Thus the transistor 64 is off; the relay 66 is also off and so the lamp 20 is not turned on. The door 14 is then opened and the sensor 34 also opens, so causing pin 3 to drop to OV. The microcontroller 54 reacts to this by setting the voltage at pin 0 to a high voltage, turning transistor 64 on, relay 66 on and the light is turned on. When the door is closed the permanent magnet located in the door causes the sensor 34 to close, resulting in a high voltage at pin 3, 44. This results in the voltage at pin 0, 62, dropping to zero, turning the transistor 64 off, de-energizing the relay 66 and turning the lamp 20 off.

lo Whilst a programmable microcontroller is preferred, it will be appreciated that other forms of switching circuitry may be used that Ias the same overall effect.

In the preferred embodiment the microcontroller 54 includes a timer function, so that if the door 14 is accidentally left open or not fully closed, the light will be turned off after a predetermined time. When the voltage at pin 3 first goes low (when the door is opened) the microcontroller enters into a countdown loop, which tests the state of pin 3 periodically. In the preferred embodiment this is every 250 milliseconds. If the countdown loop reaches zero, the controller tests the state of pin 4, indicated by numeral 78. If pin 4 is at OV, then pin 0 is also set to OV, turning off the transistor 64 and hence the lamp 20. The countdown loop is set to do this after 60 minutes but the microcontroller may be programmed to do this for any period up to the maximum period possible for that microcontroller. Due to the constraints of the microcontroller used, the program runs a loop within a loop to provide a 60 minute delay. It will be appreciated that a single loop may be used if the microcontroller chosen will accommodate the desired delay with a single countdown loop. It will be appreciated that the period provided by the preferred microcontroller may be insufficient and other microcontrollers which provide a greater time may be used instead.

As mentioned above, during the countdown loop the voltage of pin 3 is tested every 250 milliseconds. If the door closes the voltage at pin 3 will go high and at COMS ID No: SMBI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-2003(ED) 14:28 MA Martin Associates (FAX)61 2 9453 3659 P.019/033 3672-3.da: 14 this point the programme exits from the countdown loop, and returns to the main program and sets the voltage of output pin 0 low, irrespective of the voltage at pin 4.

The testing of pin 4 is to enable the countdown loop to be selectively disabled by the user or installer, without needing to reprogram the microcontroller. Pin 4, 78, of the microcontroller 54 is connected via line 80 to the jumper block 52, By connecting lines 48 and 80 via ajumper on the jumper block 52, pin 4, 78, is permanently set to a high voltage. When the countdown loop tests pin 4 at the end of the countdown period, if pin 4 is at a high-voltage then pin 0 is left at a high voltage, maintaining the transistor 64, relay 66 and lamp 20 on.

The inveation is not limited to use in cabinets and may be used in conventional doorways, as shown in figure In figure 5 a door 100 is provided with a magnet 38 near its free end 102. The magnet is preferably mounted by drilling a blind bore 104 in the free end 102. The door frame 106 is provided with a reed switch 34 adjacent to where the magnet 38 is positioned when the door is closed. Preferably the reed switch 34 is mounted by drilling a counter sunk bore 108 in the rebated surface 110 through the door frame.

The wires 36 of the reed switch exit to the inner side of the frame 106 and are hidden by plaster board 112. The bores 104 and 108 may be filled with appropriate filler material before painting of the door and door frame. If the components will be left bare, plugs of the same material may be used instead. The location of the bores means that any indication of their existence is hidden when the door is closed. If the reed switch and magnet are placed near the comer of the door they are unlikely to be noticed by the casual user even if not fully hidden.

Figure 6 shows a cabinet 120 similar to that of figure 2 but in which the proximity sensor 122 is mounted in the space 124 rather than in the carcase of the cabinet. A permanent magnet 126 is mounted in the door 128 but is positioned vertically.

Since the MDF sheeting used is usually 18 mm thick the separation of the sensor COMS ID No: SMBI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19 19-NOV-2003(WED) 14:28 MA Martin Associates (FAX)61 2 9453 3859 PR020/033 3672-3,doc 122 and magnet 126 when the door is closed may be too great to use the reed switch and mnagnet combination discussed with reference to figures 1 to 3.

However, by using a stronger magnet one could use the samne reed switch.

Alternatively one could use a more sensitive sensor. The advantage of this s configuration is that the sensor does not need to be embedded in the carcase and so may be installed after manufacture of the carcase. This also enables the sensor 122 and a control unit 130 to be mounted Qu a single mounting plate 132 which may be easily installed wit some self tapping screws or the like.

Figure 7 shows a cabinet 140 having a sensor 142 that uses radio frequency electromagnetic radiation rather than magnetic fields to detect a tag 144 mounted on a door 146. The tag 144 is of the type that receives and is powered by a radio signal from the sensor 142 and transmits *a signal in response. These types of tags are commonly used in anti theft systems in shops and generally are less than I mm thick. Accordingly, the tag 144 may be mounted on the top, bottom or side of the 1ir door 146 using adhesive without the need to embed the tag in the door 146. This configuration allows both the sensor and tag to be installed after manufacture of the cabinet and door avoids the need to embed either or both components. If the top of the door will be easily seen, then mounting the tag on the bottom of the door may effectively hide the tag. Of course, if desired the tag could be embedded in the 2o door prior to application of a decorative laminate or finish.

Other ways of detecting the presence or position of' the door may be used.

Detection may be based on change in capacitance or inductance. A capacitance based sensor, simnilar to that used in stud finders, that detects the change in dielectric constant as the door opens and closes may be used. In an inductance based system a piece of metal, such as steel, may be inserted in the door and switching of the lamp occurs based on the change in inductance detected.

It will be apparent to those skcilled in the art that many obvious modifications and variations may be made to the embodiments described herein without departing from the spirit or scope of the invention.

COMS ID No: SMBI-00500631 Received by IP Australia: Time 14:32 Date 2003-11-19

Claims (11)

1. 03-FEB-2006(FRI) I11:36 61 2 9453 3659 (FAX)61 2 9453 3659 P. 008/018 I D3 6 r2 -3 .d w ~0 C'q 16 The claims defining the Invention are as rollows o 1. An electrical lighting circuit responsive to movement of a wing relative to a fixed structure, the wing including a tag, the circuit including: a proximity sensor mounted on or in the structure that has first and second states, wherein the sensor has a first state and a second state nand 0 0'q an output connected to one or more lights, wherein the output is on when the sensor is in one of said first and second states and off when the sensor is in the other of said first and second states, and lo wherein the sensor changes from ile first to the second state when the separation of the tag From the sensor increases from less than a first predetermined distance to more than the first predetermined distance and the sensor changes from the second to the first state when the separation of the tag from the sensor decreases from more than a second predetermined distance to less than the second predetermined is distance, said first and second predetermined distances being significantly different, and wherein at least one of the sensorand the tag is substantially bidden to an average unaided eye of an average human or the location of at least one of the sensor and the tag is substantially hidden to an average unaided eye of an average human. 2. The circuit of claim I wherein the sensor is responsive to a change in a magnetic field, capacitance or inductance. COMS ID No: SBMI-02567519 Received by IP Australia: Time 11:38 Date 2006-02-03 03-FEB-2006(FRI) 11:37 61 2 9453 3859 (FAX)61 2 9453 3659 P.009/018 Cl 17 3. The circuit orany one of the preceding claims wherein the sensor is selected from a group including a reed switch, a Hall Effect switch and a Hall Effect sensor.
2. 4. The circuit of any one of the preceding claims wherein the tag is a magnet. IND 5. The circuit of claim I wherein the sensor is responsive to electromagnetic e radiation.
3. 6. The circuit of claim 5 wherein the sensor transmits electromagnetic oradiation.
4. 7. The circuit of claim 5 or claim 6 wherein the tag transmits electromagnetic radiation.
5. 8. The circuit of claim 7 wherein the tag transmits electromagnetic radiation in response to receiving clectromagnetic radiation from the sensor.
6. 9. The circuit of any one of the preceding claims wherein the sensor is responsive to a signal transmitted by the tag. The circuit of any one of the preceding claims including a control unit that is receives an input from the sensor and controls the output in response thereto.
7. 11. The circuit of claim 10 wherein the control unit includes a timer operative to turn the output off after a predetermined time irrespective of the state of the sensor.
8. 12. The circuit of claim 10 wherein the predetermined time is about 60 minutes.
9. 13. The circuit of claim 11 or claim 12 including a switch for selectively enabling and disabling the control unit
10. 14. The circuit of any one of the preceding claims wherein the first predetermined distance is from about 25 mm to about 30 mm. The circuit of any one of the preceding claims wherein the second COMS ID No: SBMI-02567519 Received by IP Australia: Time 11:38 Date 2006-02-03 03-MAR-2006(FRI) 11:40 61 2 9453 3659 (FAX)61 2 9453 3659 P. 005/006
11. 3672-3.doc 18 predetermined distance is about 50 mm. 16. The circuit of any one of the preceding claims wherein the wing has a closed position and the first predetermined distance is selected and the tag positioned so the sensor is in the first state when the wing is less than about 25 mm s from the closed position. 17. The circuit of any one of the preceding claims wherein the wing has a closed position and the second predetermined distance is selected and the tag positioned so the sensor is in the second state when the wing is more than about mm from the closed position. o1 18. An electrical circuit substantially as herein described with reference to the drawings. 19. An installation substantially as herein described with reference to the drawings. Dated 3 March 2006 Paul Sydney Young by his Patent Attorneys M A MARTIN ASSOCIATES COMS ID No: SBMI-02855888 Received by IP Australia: Time 11:39 Date 2006-03-03