GB2389436A

GB2389436A - Wireless remote control

Info

Publication number: GB2389436A
Application number: GB0211958A
Authority: GB
Inventors: Simon Peter Fisher
Original assignee: SWITCHFORWARD Ltd
Current assignee: SWITCHFORWARD Ltd
Priority date: 2002-05-24
Filing date: 2002-05-24
Publication date: 2003-12-10
Also published as: GB0211958D0

Abstract

A wireless remote control system is used to switch electrical apparatus on and off. When a controller is operated it transmits a control signal in a burst 30 and a duplicate 32 a period P of 2s later. The time between the burst 30 and the duplicate 32 is divided into eight time slots and three repeaters are assigned individual time slots T1, T2 and T4 in which they retransmit as indicated at 34, 38 and 42 respectively. Any signal received less than P after the control signal 30 is ignored. The repeaters also repeat signals they receive at regular but mutually different intervals as indicated at 36, 40 and 44.

Description

- 1 WIRELESS REMOTE CONTROL

This invention concerns wireless remote control, especially but not exclusively for remotely switching electrical apparatus on and off as and when required. Many premises, such as factories, shops and offices, contain electrical apparatus which needs to be on for only a portion of each day. A cold drinks dispenser in a factory, for instance, needs to be on (co'ling the drinks it contains) during the hours when the factory is in an open state - that is, when staff are 10 working on the premises, but such a cold drinks dispenser does not need to be on when the factory is in a closed state - that is, when it is unoccupied, say at night.

The same applies, of course, to hot drinks dispensers and a wide range of other apparatus including air conditioning units, space heaters, water heaters, fans, lights and so forth.

15 Our copending International Patent Application No P(:T/GB01/01777 concctns a system for controlling electrical apparatus remotely, which system comprises register means for registering whether a building containing the apparatus is in an open state or a closed state, a controller operatively associated with the register means to transmit a control signal representing said state of the 20 building, and a receiver remote from the controller for receiving the control signal, wherein the receiver includes a switch operable by the control signal to switch the .. . ...

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- 2 apparatus on and off alternatively according to whether the control signal represents the open or the closed state of the building.

It is preferred to use wireless transmission in a system of this kind, and it is an object of the present invention to provide improved reliability of wireless 5 transmission in this and other remote control systems.

Thus according to the invention there is provided a wireless remote control system in which a control signal is transmitted once, again after a period and repetitively at intervals, wherein each said interval is longer than said period.

Duplicating the control signal by transmitting it again after a period makes it 10 likely to be responded to (by whatever apparatus is to be controlled) even in the presence of interference. The repetition of the transmission continually counteracts any tendency for the controlled apparatus to come out of its intended setting. And by having the repetition interval longer than the initial duplication time - say 200s or more compared with say 2s - there is no repetition before the duplication, 15 ensuring that the intended control signal takes control rather than a repetition which may be erroneous from interference or as left over from an earlier control signal. The system may include a first transmitter which is operable to transmit the control signal once and operative automatically to transmit the control signal again 20 after said period and then repetitively.

Alternatively the system may include a first transmitter which is operable to transit the control signal once and operative automatically to transmit the control ... ...

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- 3 signal again after said period and a second transmitter which is operative automatically to transmit the control signal repetitively.

This latter system may comprise a repeater wherein the second transmitter is associated with a receiver and operative automatically to retransmit a control signal 5 received by said receiver. The first such retransmission is preferably within a time after its receipt which is less than the duplication period.

There may be one or more further transmitters each including a transmitter associated with a receiver and operative automatically to retransmit a control signal received by that receiver. Preferably with this arrangement the time for 10 retransmission is divided into a plurality of time slots and each repeater retransmits the received control signal in a said time slot allocated to that repeater. Preferably the number of time slots is a power of two and the repeaters are respectively allocated the first, second, fourth and so forth time slots immediately following receipt of a control signal, being ordinal powers of two up to said number. And to 15 overcome the possibility of a chain reaction of repeater operation, it is preferred that the or each repeater is so arranged that when it receives a control signal it will not retransmit any other control signal it receives within a consecutive tune thererafter at least equal to the duplication period.

Preferably the repetition interval of the or each repeater is adjustable. Then 20 the repeaters may be assigned different intervals, eg a first may have an interval of about 200s, a second may have an interval of about 220s and a third may have an interval of about 240s.

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- 4 - Other aspects of the invention will be apparent from the following description, which is made by way of example only with reference to the

accompanying schematic drawings in which Figure 1 illustrates a wireless remote control system embodying the invention 5 as used to control a plurality of electrical socket outlets; Figure 2 illustrates the operation of the wireless remote control system ot Figure 1; and Figure 3 illustrates different modes of operation of the system of Figure 1.

The invention is especially but not necessarily exclusively directed towards 10 the remote control of electrical apparatus, for instance to switch such apparatus off when not required so as to reduce the power consumed thereby. As described more fully in our copending International Patent Application No PCT/GBO1/01777, this may be effected by connecting the apparatus to its power supply by way of a I socket including a wireless receiver responsive to a transmitted control signal to 15 switch a relay in the power line on and off altematively.

Referring then to Figure 1, this illustrates one such use of the invention. In Figure 1 a compound shown in broken lines at 10 has a number of buildings 12, as in a factory or barracks. Each building 12 contains a number of units 14 of electrical apparatus which are required to be on only when the building is in use.

20 Thus each unit 14 is connected to its power supply by way of a socket (not shown) including a remotely controlled relay as indicated above, and a controller 16 is ... ...

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operated to transmit control signals to switch the apparatus on and off as appropriate. When the controller 16 is operated, for ON or OFF as the case may be, it transmits a corresponding signal a first time and then again after a period P of 2s.

5 Duplicating the signal again in this way means that it will be received, and responded to, by the socket receivers even if the first transmission is blocked or distorted by transient interference. The controller 16 is also arranged to transmit the control signal repetitively at regular intervals of 200s, to ensure that the sockets are constantly reinstructed as to their intended setting.

10 The controller 16 is fixed, so it can readily be supplied with mains power to enable indefinite repetition of the control signal. (Also, as described in our International Patent Application No PCT/GB01/01777, such a fixed controller may be operated automatically through connection to an intruder alarm, the controlled apparatus being switched on or off as required whenever the alarm is 15 armed and disarmed). However, as will now be described in more detail, there are many situations in which it is convenient to have a portable controller, with battery power which could be rapidly depleted by extensive repetition.

Suppose the compound 10 is patrolled at night by a security guard who perceives, during his round, that certain items of apparatus 14 have been left on 20 although Be buildings t2 are unoccupied. If he has access to the buildings 14 he can perhaps go into them and turn things off. Rut he may not be able - or authorised - to enter some or all of the buildings 14, he may not know what should I.. . .. -. À

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- 6 be off and what should be on, and in any event the job may be unduly time-

consuming. 111 these problems may be overcome by providing the guard with a portable, hand-held, controller 18. If he sees or suspects that some apparatus 14 has been left on erroneously, he simply presses an OFF button on the controller 18: 5 and all apparatus connected to a controllable socket will automatically be switched off. This portable controller 18 duplicates the initial transmission of the control signal but to preserve its battery life it does not provide the repetition required to make sure the controlled sockets do not come out of their intended setting. Instead 10 this is provided by a mains-powered repeater 20 which receives the control signal i from the controller 18, retransmits it and then repeats it at regular intervals of 200s.

Now another function of the duplicated initial transmission from the controller 18 may be noted. Once the remote control system is set up, the repeater 20 will be continually transmitting a control signal, for ON or for OFF. When the 15 controller 18 is operated to change the setting, from ON to OFI; or mee versa, its first-time transmission may coincide with a contrary signal from the repeater 20, blocking the intended change or at least making it uncertain. Automatically transmitting the intended control signal again avoids this, because the 2s duplication period is quite different from the 200s repetition interval.

20 The repeater 20 also provides an additional function, now to be described. I The transmission power of a wireless remote control system is limited, usually by regulation, and this in turn curbs its range. And especially with limited power, Me ......

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reach of the system may be restricted by structural or topographical features. lN repeater may be used to extend both range and reach. Thus, for instance, if transmission of a control signal from the controller 18 is not picked up throughout the compound 10, its retransmission from the repeater 20 may fill in the blank area.

5 A site survey may show the need for further repeaters, and Figure 1 shows a system having a second repeater 22 and a third repeater 24 as well the first repeater 20. Having a number of repeaters suitably located also ensures that one of them will pick up the initial transmission from a portable controller 18 wherever this is taken within the compound 10.

10 Referring now to Figure 2, this shows how transmissions from the controller 18 and the first, second and third repeaters 20, 22 and 24 are timed. When the controller 18 is operated it transmits a control signal a first time as indicated at 30 and again a period P later as indicated at 32, thereby providing the duplicated initial transmission described above. The period P is of 2s duration, and the time between 15 signals 30 and 32 (which, as can be seen from Figure 2, is less than the period P by an amount equal to the temporal length of a signal) is divided into eight equal time slots T: to To. When the first repeater 20 receives the control signal it retransmits it in time slot To, ie the first of the eight time slots, as indicated at 34. The repeater 20 then repeats its transmission after 200s, as indicated at 36, and thereafter at 200s 20 intervals. AI1 the repeaters have different allocated time slots and repetition intervals. Thus the second repeater 22 retransmits in time slot T. as indicated at 38 and repeats the retransmission after 220s as indicated at 40; and the third repeater 1.. ......

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- 8 24 retransmits in time slot T4 as indicated at 42 and repeats the retransmission after 240s as indicated at 44. The repeaters are all of the same design, and these adjustments are made by altering the position of a link in the circuitry thereof.

To prevent a chain reaction of repeaters triggering one another, each 5 repeater is arranged so that it will not respond to any control signal received sooner than P after another control signal. Thus, referring to Figure 2, if the second repeater 22 receives the transmission 30 from the controller 18, it will not respond to the retransmission 34 from the first repeater 20. In other words, the second repeater 22 will be caused by its receipt of the signal 30 to retransmit in time slot T2 10 (the second slot after 30) as indicated at 38, but it will not be caused by its receipt of the retransmitted signal 34 to retransmit in time slot T3 (the second slot after 34).

Similarly, if the third repeater 24 receives the transmission 30 from the controller 18, it will retransmit it in tone slot T4 (the fourth time slot after 30) as indicated at 42, but not in time slot T5 (the fourth time slot after 34) or in time slot T6 (the 15 fourth time slot after 38).

The overall effect of the receipt and retransmission pattern shown in Figure 2 is that the hrst repeater 20 has taken command of the system. However many over modes of operation are possible.

First, it is to be understood that the system will operate in substantially the 20 same way as described with reference to Figure 2 if the repeaters 20, 22 and 24 miss the first-time transmission 30 and respond instead when the control signal is transmitted again, in which case the time slots T. to TO follow the transniission 32 ., .. .. ..

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- 9 - and the repeater 20 retransmits in the first time slot after the transmission 32, and so forth.

Quite different modes of operation occur when one repeater picks up a transmission from the controller 18 but one or both of the other repeaters do not.

5 Two examples are shown in Figure 3.

In Example A of Figure 3 the transmission of a control signal from the controller 18 is received satisfactorily only by the third repeater 24. Then the third repeater 24 retransmits the control signal in its allocated time slot T4, as indicated at 50. The retransmission 50 is picked up by the first repeater 20 and the second 10 repeater 22, and they themselves retransmit in tune slots T5 and T6 respectively, as indicated at 59 ant] 54.

In Example B the transmission from the controller 18 is received satisfactorily only by the first repeater 20, which retransmits the control signal in its allocated time slot To, as indicated at 60. The retransmission 60 is then picked up by 15 the Bird repeater 24, and this retransmits it in time slot Ts (the fourth time slot after 60) as indicated at 62. Finally the retransmission 62 is picked up by the second repeater 22, and this retransmits it in time slot T7 (the second time slot after 62) as indicated at 64.

Those skilled in the science will now appreciate that the system of the 20 invention will operate without either a chain reaction or (except for the possible coincidence of a new transmission with a preset retransmission or repetition) any overlapping, and that any such coincidental overlapping is dealt with by duplication ......

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- 10 of the initial signal. It is also to be noted that the system is arranged so that the temporal length of each retransmission is at most equal to a time slot, so that no retransmission will spread from its allocated time slot into adjoining orne slots. (In fact, each signal whether initial, duplication, retransmission or repetition - is in 5 the form of a burst shorter than a time slot).

It having been established that the invention provides a simple and effective wireless remote control system which is reliable in conveying control signals, robust against interference and maintains the intended setting of equipment controlled by the system, some additional features of the invention not detailed in the drawings 10 will now be discussed.

The system uses radio communication at 433.92 MHz approved under the MPT1360 standard in force - at least throughout Europe - for telecommand systems. The system employs off-the-shelf radio modules to approved under standard EN 300-220-1, which are widely available. The modules work to quasi 15 FM, which is better than AM in terms of range and resistance to interference.

Systems for most if not all applications can be assembled by combining portable controllers, fixed controllers, repeaters and switching receivers.

The portable controller includes a transmitter module powered by a PP3 battery. It has two buttons, for ON and OFF respectively. When either button is 20 pressed the transmitter transmits a corresponding control signal, in two identical bursts separated by 2s. An LED associated with each button flashes when the button is pressed, to show its operation. The LEDs also indicate any decline in .. . .. ..

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- 11 battery power, by flashing erratically, although in normal use (say up to ten operations per day) the battery life should be as long as its shelf life.

The fixed controller includes a transmitter module powered from the mains by way of a 12V dc transformer. It incorporates a three-way security keyswitch for 5 manual operation, the keyswitch being movable against spring bias to either ON or OFF position and, when released, returning to a neutral position in which it delivers a corresponding repetition. The Fred controller is also operable automatically through a feed from an intruder alarm which switches the fixed controller from ON to OFF or vice versa whenever the alarm is armed or disarmed 10 (ie whenever the site of the system is vacated or recentered). LEDs show the operation, and remain illuminated to show the ON or MULE; setting of the system.

When the keyswitch is operated, or the intruder alarm armed or disarmed, the transmitter of the fixed controller transmits a corresponding signal, duplicated like that of the portable controller. Unlike the portable controller, the fixed controller is 15 arranged to provide repetitive transmission of the control signal at regular intervals.

The repeater includes a receiver module and a transmitter module connected thereto, each powered from the mains by way of a 12V dc transformer. The repeater retransmits a control signal received from either a portable or a fixed controller. It also retransmits a control signal received from another repeater of the 20 system, provided this is not received less than 2s after another signal.

The switching receiver includes a receiver module powered from the mains, together with a relay connected thereto. It responds to control signals received À À À À À.

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- 12 (from a portable controller, a fixed controller or a repeater) to switch a power supply on or off accordingly. The switching capacity is 1 3A resistive or 4A inductive load at 240V ac, and the switching receiver may be incoporated in a socket outlet or in an item of apparatus to be controlled, such as a machine or a 5 light socket. A randomised delay of up to 250ms is provided to effect non synchronous switching of multiple receivers, thus to avoid a surge.

During manufacture, the portable controllers, fixed controllers and repeaters are randomly assigned signature codes with enough variety (eg 1 out of 65,536) to be practically certain that neighbouring systems will not interfere with one another.

10 A set-up procedure is provided whereby one of the assigned signature codes is adopted for a given system, and also for introducing new components to an established system. These procedures are initiated by means of a special switch within the casing of a component or, in the case of the portable controller, by pressing both of its control buttons simultaneously. Those skilled in the science will 15 be readily able to devise such procedures along with modifications and adaptations of the system described.

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Claims

- 13 CLIMS 1 wireless remote control system in which a control signal is

transmitted once, again after a period and repetitively at intervals, wherein each said 5 interval is longer than said period.
2 wireless remote control system as claimed in Claim 1 including a

first transmitter which is operable to transmit the control signal once and operative automatically to transmit the control signal again after said period and then repetitively. 10
3 A wireless remote control system as claimed in Claim 1 including a first transmitter which is operable to transmit the control signal once and operative automatically to transmit the control signal again after said period and a second transmitter which is operative automatically to transmit the control signal repetitively. 15
4 A wireless remote control system as claimed in Claim 3 comprising a repeater wherein the second transmitter is associated with a receiver and operative automatically to retransmit a control signal received by said receiver.
5 wireless remote control system as claimed in Claim 4 wherein Me repeater retransmits the control signal within a time less than said period.

20
6 wireless remote control system as claimed in Claim 4 or Clang 5 comprising one or more fi - er transmitters each including a transmitter associated !!: '!

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- 14 with a receiver and operative automatically to retransmit a control signal received by that receiver.
7 A wireless remote control system as claimed in Claim 6 wherein said period tune is divided into a plurality of time slots and each repeater retransmits the 5 received control signal in a tune slot allocated to that repeater.
8 A wireless remote control system as claimed in Claim 7 wherein the number of time slots is a power of two and the repeaters are respectively allocated the first, second, fourth and so forth time slots immediately following receipt of a control signal, being ordinal powers of two up to said number.

10
9 A wireless remote control system as claimed in Claim 8 wherein the number of time slots is eight.
10 A wireless remote control system as claimed in any of Claims 4 to 9 wherein said interval of the or each repeater is adjustable.
11 A wireless remote control system as claimed in Claim 10 wherein a 15 first of said repeaters has an interval of 200s, a second of said repeaters has an interval of 220s and a third of said repeaters has an interval of 240s.
12 A wireless remote control system as claimed in any of Claims 4 to 11 wherein said period is of 2s.
13 A wireless remote control system as claimed in any of Claims 4 to 12 20 wherein the or each repeater is so arranged that when it receives a control signal it will not retransmit any other control signal it receives within a time consecutive thererafter at least equal to said period.

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- 15
14 A wireless remote control system as clanned in any preceding claim wherein the control signals are transmitted in the 433MHz band.
15 wireless remote control system as claimed in Claim 14 wherein the control signals are quasi-fin.

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16 A wireless remote control system as claimed in any of Claims 2 to 15 wherein the first transmitter is operable manually.
17 A wireless remote control system as claimed in Claim 16 wherein the first transmitter is portable.
18 A wireless remote control system as claimed in any of Claims 2 to 15 10 including register means for registering whether a building is in an open state or a closed state, wherein the first transmitter is operable automatically in response to registration of a change of said state by the register means.
19 A wireless remote control system substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

15 20 In a system for controlling electrical apparatus remotely according to International Patent Application PCT/GBO1/01777, a wireless remote control system as claimed in any preceding claim.

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