ALARMS FORGOLFBAGS ANDTHELIKE

This invention relates to alarms, particularly alarms suitable for use in protecting a readily-portable item of sports equipment such as a bag of golf clubs. As aspects of the invention are directed to the protection of sports equipment and especially golf clubs, the invention has particular advantages in those applications. However, in its broadest sense, the invention is not limited to the protection of sports equipment but can protect other items of personal property against theft and tampering.

Theft of valuable sports equipment such as golf clubs is a huge problem. An ordinary set of golf clubs can be worth well over US$2000, with some individual clubs of that set such as drivers and putters costing in excess of US$500. Yet, once stolen, clubs can easily be sold on without trace, for example via an internet auction, because they rarely have any security marking such as serial numbers. Even where serial numbers have been tried on golf clubs, they have been found to be ineffective to deter theft.

In the US alone, it is estimated that golf clubs to a value of more than US$10OM are stolen every year. The cost of theft goes beyond the monetary value of the lost clubs: players develop a feel for playing with a particular set of clubs that may be difficult to reproduce with a new set, especially if their clubs are customised. There is also the issue of delay: a customised set of clubs may take several weeks to replace, during which time a player must either refrain from playing golf or use clubs that are not ideal. Clearly, the player's enjoyment and form may suffer during that period.

A set of golf clubs in a bag is inherently portable and so can easily be picked up and carried off by a thief, who needs only to wear golfing attire to blend in on a golf course. Prominent branding on the bag and the club heads tells a thief which sets of clubs are more valuable than others, and which sets are therefore most worth stealing.

Numerous opportunities for theft are available to a thief before and after a round of golf, especially when players are in the clubhouse or the pro shop and their clubs are left outside in accordance with typical rules. Even when players have returned their clubs to their cars or lockers after a round before retiring to the clubhouse for

refreshments, their cars or lockers can be broken into in the knowledge that clubs are likely to be inside. Security in golf club car parks and changing rooms is rarely effective to prevent such theft.

It is known to secure a golf bag with a lanyard that may be threaded around a fixture such as a fencepost and secured with a lock. However, such fixtures are rarely available when needed and a lanyard presents little obstacle to a suitably-equipped and determined thief.

Alarm systems have been proposed for golf bags. Numerous patent proposals have been made in this field although such systems are not in widespread use. Examples are US Patent Nos. 5,877,686 to Ibey et al and 6,696,950 to Adolphson. Both propose alarm systems comprising two main components, namely a base unit and a remote transceiver. The base unit is associated with a golf bag, the unit having a sensor such as a switch that is sensitive to movement of the bag or to the weight of the bag being lifted from the ground. When thus triggered, the base unit generates an alarm signal that may also be transmitted to the transceiver carried by a user who is remote from the bag. The user may also employ the transceiver to control the base unit remotely, particularly to arm and deactivate the base unit without having to touch the protected golf bag and hence without risking a false alarm due to movement of the bag.

Whilst alarm systems like those proposed by Ibey et al and Adolphson are beneficial in theory, they are unsatisfactory in practice. As Ibey et al notes, prior systems are not capable of distinguishing between illegitimate movements of a golf bag caused by theft and legitimate movements due to other causes. Legitimate movements of a golf bag include movements due to the wind, due to someone accidentally bumping against the bag, or even due to a user picking up the bag while forgetting that the alarm is set. As a result, false alarms are common.

False alarms are inconvenient as they may require a user to check a protected golf bag unnecessarily, possibly walking some distance on each occasion from wherever the user happens to be in relation to the bag. If there are numerous false alarms, they increase the risk that the user or bystanders will ignore a genuine alarm. False alarms

are also embarrassing, particularly in an environment in which etiquette is important. Where false alarms occur, users are tempted to switch off an alarm system; this, of course, defeats its purpose.

5 Whenever a user wishes to move a golf bag that is protected by an alarm, it is necessary to deactivate the alarm before moving the bag and, in most cases, to re-set the alarm after the bag has been moved. This is the case even when the user wishes to move the bag over a very short distance, as when shifting the bag in a locker to reach something behind, or when lifting the bag into a car. hi each case, moving a

10 protected golf bag requires the user to locate the transceiver about their person, for example in a pocket, to press a deactivate button on the transceiver, to put the transceiver down or back into their pocket, to move the bag and then to repeat the process of finding the transceiver and then replacing it after pressing an activate button on the transceiver. There is a risk during this process that the user will put

15 down or drop the transceiver somewhere where it cannot easily be found. More likely, a user will not bother to set the alarm when leaving their golf bag unattended for a short while, for example when visiting a pro shop to make some minor purchase. An opportunist thief will relish such a situation.

20 The alarm system disclosed by Adolphson contemplates a permanent or semipermanent installation of alarm components in a golf bag. This introduces problems of compatibility with various bags when the components are designed to be retrofitted, and increases the cost of a bag when the components are built in. It also makes it difficult or impossible to use the alarm system on different bags, or in contexts

25 other than the protection of golf clubs.

In contrast, Ibey et al proposes a motion-sensing tilt-switch alarm base unit that fits within a typical pocket of a golf bag. This is better than Adolphson in the above respects but Ibey et al contemplates that the base unit should be secured within the

30 pocket and provides means for attachment. This is inconvenient and, moreover,

- *.. implies that the orientation of the base unit is crucial, as indeed the use of a tilt switch would suggest. A golf bag may lie in various orientations when at rest, fox, example: on its end when on a buggy, in a rack or locker; inclined on a fold-out stand when placed on the ground in use; or substantially horizontal when placed in a car. It

is impractical for an alarm system to be unable to cope with all of these orientations, and worse still for the alarm to be triggered whenever the bag is moved from one such orientation to another. It is also noted that the end-mounted weight sensor of Adolphson could not cope with all of these orientations.

Another problem is that pocket space must be available in a golf bag if an alarm system is to rely upon that pocket space to accommodate a base unit. Indeed, some golf club carriers have no pockets at all, instead relying upon a skeletal frame with holes for clubs, golf balls, tees and so on. One such golf club carrier is marketed under the trade mark 'A Frame' by the English company A Frame Golf Limited, whose website is at www.aframegolf.com. Such a carrier has no means for attaching a base unit of the type contemplated by Ibey et al; moreover, it cannot be adapted with a weight sensor in the manner of Adolphson.

It is against this background that the present invention has been devised.

In one sense, the invention resides in a hand-portable alarm base unit for protecting a golf bag or a golf club holder, wherein the unit has a substantially spherical shell and can fit into a ball pocket or ball holder of the golf bag or golf club holder. The shell suitably has an external diameter of between 40mm and 50mm, more preferably between 42mm and 47mm, and yet more preferably between 42mm and 44mm.

Elegantly, the shell may comprise first and second parts that are moveable with respect to each another, and contains switch means responsive to said movement to operate alarm circuitry in the base unit. Consequently, the invention may also be expressed as a hand-portable alarm base unit, wherein the unit has a shell comprising first and second parts that are moveable with respect to each another, the shell containing switch means responsive to said movement of the parts to operate alarm circuitry also contained in the shell.

The first and second parts of the shell are suitably moveable between positions representing different operative states of the base unit. For example, a first position represents on and a second position represents off. In a third, non-operative position, the parts of the shell may be separated. Co-operable indicia on the respective parts of

the shell, such as an arrow on one part and respective words on the other part, suitably align to indicate each operative position. To give positive confirmation of position by a click and by feel, it is preferred that detents resiliently bias the parts of the shell into each position.

The movement between the positions is preferably relative angular movement between the parts of the shell. For example, the first and second parts of the shell may be substantially hemispherical and may be in sliding contact.

When the parts of the shell are in and between the operative positions, it is preferred that inwardly-facing lugs of the first part of the shell engage under an overhang formation associated with the second part of the shell. The overhang formation may be defined by an insert attached to the second part of the shell, and may be spaced outwardly with respect to an open side of the second part of the shell. The overhang formation may, for example, be an edge region of a platform, in which case the platform suitably has peripheral notches or cut-outs for permitting the lugs to pass under the edge region of the platform when the parts of the shell are brought together.

The lugs preferably slide on respective tracks communicating with the cut-outs of the platform. Those tracks may include ramps that are inclined to draw the parts of the shell together as the lugs move away from the cut-outs along the tracks. The tracks ^' and the lugs suitably have resiliently co-operable detent formations defining the respective positions as aforesaid. ,

The platform suitably supports circuitry in the second part of the shell, and may have a recess, facing the circuitry to give clearance for components of that circuitry. For example, the platform may support a printed circuit board that carries the circuitry, the printed circuit board being supported between the platform and the second part of the shell.

The circuitry may include an antenna in the second part of the shell, in which case it is advantageous if the unit is counterweighted such that its, centre of gravity lies in the first part of the shell. Elegantly, the unit maybe counterweighted by a power cell

in the first part of the shell, remote from an equator of the shell. This helps to orient the antenna upwardly to the benefit of RF transmission and reception.

More specifically, a power cell holder associated with the second part of the shell preferably extends into a void within the first part of the shell. The power cell holder may be arranged such that the first part of the shell presses a power cell into contact with terminals in the power cell holder when the first and second parts of the shell are brought together. In that case, one of the terminals of the power cell holder may act resiliently through the power cell to bias the lugs of the first part of the shell against the overhang formation associated with the second part of the shell.

It is highly advantageous that the base unit can be armed irrespective of its orientation. This ensures that when the base unit has been placed ready for use, for example in a pocket of a golf bag, the alarm can be armed no matter whether the bag is vertically on its end in a buggy or locker, inclined on a stand during a round, or horizontal in a car.

The unit of the invention preferably accommodates one or more of the following components within the shell: an alarm sounder; an RF transmitter for transmitting an alarm state to a remote unit; and an RF receiver for receiving commands remote unit. Thus, the invention extends to an alarm system comprising the base unit of the invention and a remote unit having an RF transmitter capable of controlling the base unit by RF transmission of commands. The remote unit may further include an RF receiver for receiving RF signals from the base unit. The invention also extends to an alarm system comprising the base unit of the invention and a remote unit having an RF receiver for receiving RF signals from the base unit. The remote unit may further include an RF transmitter capable of controlling the base unit by RF transmission of commands.

In each case, the remote unit suitably includes a controller responsive to an alarm signal from the base unit to put the remote unit into an alarm state. In the alarm state, the remote unit may vibrate, emit an alarm sound and/or produce a visual display.

The invention also encompasses a base unit for an alarm system, the unit comprising: a motion sensor; and a controller responsive to signals from the motion sensor and being programmed to: (a) in response to movement sensed by the motion sensor, (i) produce a first alarm signal; and (ii) start a count-down timer set to time a count- down period; and (b) in response to continuation of said movement after expiry of the count-down period, (iii) produce a second alarm signal that preferably results in a substantially louder alarm sound than is generated by the first alarm signal. In this way, a relatively quiet warning can be given that the full alarm is about to go off, while a protected golf bag or the like is being moved a short distance without the alarm being disarmed.

In response to termination of movement before expiry of the count-down period, the controller suitably re-sets the count-down timer to reinstate the count-down period and ceases to produce the first alarm signal.

The controller may have memory that stores a threshold value and may be programmed to compare the signal from the motion sensor with the threshold value and only to respond to movement sensed by the motion sensor if the signal exceeds the threshold value. This helps to guard against false alarms caused by prevailing conditions such as the wind. The threshold value may be determined by sampling the signal from the motion sensor as the alarm system is being set. .

The invention therefore also extends to a base unit for an alarm system, the unit comprising: a motion sensor; a memory for storing a threshold value; and a controller responsive to signals from the motion sensor and being programmed to, in response to movement sensed by the motion sensor: (i) retrieve the stored threshold value from the memory; (ii) compare the signal received from the motion sensor with the threshold value; and, if the signal received from the motion sensor exceeds the threshold value, (iii) produce an alarm signal.

In order that this invention may be more readily understood, reference will no w _; foe made, by way of example, to the accompanying drawings in which:

Figure 1 is a perspective view of a base unit in the general form of a golf ball and a remote transceiver in the form of a key fob;

Figure 2 is a perspective view of the ball and fob of Figure 1, showing the ball in an exploded view;

Figure 3 is a perspective view of an insert within the ball, evident in the exploded view of the ball in Figure 2;

Figure 4 is a perspective view of the insert of Figure 3 in a second orientation;

Figure 5 is a perspective view of the insert of Figure 3, in a third orientation;

Figure 6 is a perspective view of the insert of Figure 3, in a fourth orientation;

Figure 7 is a block diagram of the main electronic components of the ball and fob of Figure 1;

Figure 8 is a block diagram of a microcontroller and radio frequency integrated circuit evident in Figure 7; and

Figure 9 is a flow chart illustrating the operation of the ball and fob.

Referring firstly to Figure 1, a base unit 10 is in the general form of a golf ball and a remote transceiver 12 is in the form of a key fob. Both of those components are of injection-moulded plastics construction. Either or both of those components may be coated externally with a rubberised layer for a resilient external finish, for example by over-moulding. A resilient external finish is good for grip in a user's hand and is pleasing to the touch while helping to protect the component from damage in use. Also, when applied to the base unit 10, a resilient external finish helps the base unit 10 to fit within and grip the periphery of the golf ball holes of an 'A Frame'-type carrier.

The base unit 10 comprises a generally spherical hollow shell divided into two hemispheres 14, 16 that meet at an equator 18 where the hemispheres 14, 16 are in mutual sliding contact. Each hemisphere 14, 16 has a dimpled outer surface such that the shell emulates a golf ball, except that one of the hemispheres 14 (uppermost in Figure 1) has a circular non-dimpled area 20 at its apex remote from the equator 18. The area 20 may have one or more apertures (not shown) that penetrate the shell for emitting sound from an alarm sounder within the base unit 10.

The external diameter of the base unit 10 approximates to that of a standard golf ball, whose usual diameter is 42.67mm (1.68 inches). It is, however, acceptable for the external diameter of the base unit 10 to be slightly larger than that.

The transceiver 12 has a hollow casing 22 that is generally ellipsoidal save for a slightly concave elliptical button 24 on one face and an elliptical flat area on the opposite face, not visible in Figure 1. The flat area is apt to carry a decal for promotional branding. The casing 22 divides into two halves along a junction 26 extending around the periphery of the casing 22, where the halves clip together. A coin, knife or screwdriver may be used to prise the halves of the casing 22 apart for replacement of a power cell (not shown) within.

A hole 28 penetrates the casing 22 near one end to accommodate an optional split ring 30 whereby the transceiver 12 can be used as a key fob. A translucent window 32 near the other end of the casing 22 displays light from LEDs behind the window, within the casing 22.

In the exploded view of Figure 2, the base unit 10 has been inverted so that the hemisphere 16 is uppermost. Here, it will be apparent that the hollow interior of the base unit 10 contains an insert 34 that is attached by two diametrically-opposed screws 36 (one of which is shown) into corresponding holes (not shown) in the interior of the hemisphere 16. The insert 34 supports a PCB 38 inside that hemisphere 16. The key components and functionality of the PCB 38 will be described later.

The other hemisphere 14 of the base unit 10 has a stepped inner rim 40 around its open face. The rim 40 supports inwardly-facing diametrically-opposed lugs 42, 44. One of the lugs 42 has a leg 46 that projects orthogonally from the inner end of the lug 42, beyond the open face of the hemisphere 14. Each lug 42, 44 has a small protrusion (not shown) on its underside, facing into the interior of the hemisphere 14.

Figures 3 to 6 of the drawings show the insert 34 in isolation. The insert 34 is a plastics injection moulding that comprises a generally circular platform 48 for supporting the PCB 38 shown in Figure 2. The diameter of the platform 48 is slightly smaller than the internal diameter of the hemispheres 14, 16.

A tubular power cell holder 50 extends orthogonally from the centre of the platform 48. A power cell (not shown) is inserted into the open end of the holder 50 where it makes contact with terminals (not shown) within the holder 50 that are connected to the PCB 38. One of those terminals faces outwardly toward the open end of the holder 50 and is resilient for contact with the negative end terminal of the power cell. The other terminal extends along the inner side of the holder 50 for sliding contact with the positive side terminal of the power cell.

Advantageously, the power cell holder extends far enough from the platform that when the hemispheres 14, 16 are assembled, the internal face of the hemisphere 14 bears against the exposed face of the power cell to press the power cell firmly into contact with the terminals. Moreover, by placing the weight of the power cell as far as possible from the equator 18, the centre of gravity of the base unit 10 lies in the hemisphere, 14. Thus, the base unit 10 will tend to lie with the hemisphere 14 facing down and the hemisphere 16 facing up as shown in Figure 2, whereby an ,antenna , : inside the hemisphere 16 associated with the PCB 38 is positioned to best advantage.

The platform 48 has various moulded-in formations. For example, on its side facing away from the power cell holder 50, the platform 48 has an annular rim 52 defining a circular recess 54 that allows clearance between the platform 48 and components on the PCB 38. Diametrically-opposed C-section cut-outs 56 in the outer edge of the platform 48 receive the screws 36 that attach the insert 34 to the hemisphere 16. Those screws 36 also extend through cut-outs (not shown) in the edge of the PCB 38,

which on assembly is sandwiched between the insert 34 and the hemisphere 16. The PCB 38 is supported by formations (not shown) inside the hemisphere 16 such that the PCB 38 lies substantially flush with the rim of the hemisphere 16, extending across its open face.

Each C-section cut-out 56 of the insert 34 is surrounded by a C-shaped wall 58 that projects above the platform 48 on its side facing the PCB 38. When the insert 34 is attached to the hemisphere 16 with the PCB 38 sandwiched between, the walls 58 bear against the PCB 38 such that the platform 48 stands proud of the open face of the hemisphere 16, spaced from the PCB 38. The side of the platform 48 facing away from the PCB 38 has countersunk formations corresponding with the cut-outs 56 to accommodate the heads of the screws 36.

Diametrically-opposed notches 60 in the generally circular edge of the platform 48 are dimensioned to receive the lugs 42, 44 of the hemisphere 14 when the hemispheres 14, 16 are brought together in face-to-face relation. A track 62 communicates with each notch 60 on the side of the platform 48 facing the PCB 3.8,

Both tracks 62 extend away from their associated notches 60 in the same angular direction, each track 62 and its associated notch 60 extending about 80° around the circumference of the platform 48.

As the platform 48 stands proud of the open face of the hemisphere 16, the lugs 42, 44 lie under the platform 48 when the hemispheres 14, 16 are in face-to-face sliding contact about the equator 18. Thus, when the face-to-face hemispheres 14, 16 are moved angularly in relation to each other in a twisting action, the lugs 42, 44 slide along the tracks 62 away from the notches 60 and under the overhanging edge of the platform 48. In so doing, the lugs 42, 44 engage with the platform 48 to. hold the hemispheres 14, 16 together.

More specifically, each track 62 comprises an inclined ramp 64 that, moving aw.a$. from the notch 60, slopes toward the side of the platform 48 facing the PCB and terminates in a shoulder 66. The ramps 64 draws the hemispheres 14, 16 together as the lugs 42, 44 move away from the notches 60.

Detent formations in the form of two recesses 68 are spaced along each track 62. Each recess 68 is resiliently co-operable with one of the aforementioned protrusions on the undersides of the lugs 46, 48 that face into the interior of the hemisphere 16. Click-engagement of a protrusion into a respective one of the recesses 68 defines a relative operative position of the hemispheres 14, 16. Also, in one of those positions, the lugs 42, 44 encounter the shoulders 66 to limit further relative angular movement of the hemispheres 14, 16. One operative position represents 'on' and the other represents 'off, as shown by the ON OFF indicia on the hemisphere 14 in Figure 2. Those words are spaced to correspond to the spacing between the recesses 68 of each ramp 64. An opposed arrow on the hemisphere 16 aligns with ON or OFF as appropriate to confirm to the user which position is which.

Two mutually-spaced micro-switches (not shown) extend beyond the edge of the PCB 38 on its side facing the interior of the hemisphere 16, one micro-switch being aligned with each respective recess 68 of one of the ramps 64. The leg 50 on the lug 46 bears resiliently against the micro-switches in turn as the lug 46 moves to and fro along the associated ramp 64. This opens or closes the micro-switches, causing logic circuitry on the PCB 38 to power up the base unit 10 or to power it down as may be selected by a user who moves the hemispheres 14, 16 relative to each other in a twisting action.

The user can replace a power cell held in the power cell holder 50 simply by twisting the hemispheres 14, 16 until the lugs 46, 48 align with, and so can be withdrawn through, the notches 60. The hemispheres 14, 16 then readily come apart, exposing the open end of the power cell holder 50 for power cell replacement. As the outwardly-facing terminal of the power cell holder 50 bears resiliently against the negative end terminal of the power cell, that terminal may push the power cell slightly out of the power cell holder 50 for ease of replacement.

Moreover, as the internal face of the hemisphere 14 bears against the exposed face of the power cell when the hemispheres 14, 16 are assembled, the resilient outwardly- facing terminal of the power cell holder 50 may act on the hemisphere 14 through the power cell. This presses the hemisphere 14 outwardly and hence biases the lugs 46, 48 against the tracks 62 defined by the edge of the platform 48.

Moving on now to Figure 7 of the drawings, this shows the main electronic components of the base unit 10 and remote transceiver 12. Some of those components appear in both the base unit 10 and the remote transceiver 12 as will now be described.

The base unit 10 and remote transceiver 12 each carry a microcontroller and radio frequency integrated circuit (RF IC) 70 which will be described in greater detail below with reference to Figure 8. Microcontroller/RF ICs suitable for use in the invention are supplied by the English company Harrison-Croft Limited, whose website is at www.harrison-croft.com, under their serial numbers GBLl 403130B and GBL1403130F.

The microcontroller/RF ICs 70 of the base unit 10 and the remote transceiver 12 communicate with each other wirelessly via respective antennas 72. The antenna.72 of the base unit 10 is suitably located in the void inside the hemisphere 16 that is defined by the PCB 38 lying across the open side of the hemisphere 16. Two-way data communication between the microcontroller/RF ICs 70 may be effected via the licensed free 433MHz band.

A respective cell 74 powers each of the microcontroller/RF ICs 70 of the base unit 10

-V- and the remote transceiver 12. The cell 74 of the base unit 10 is inserted into the open end of the tubular power cell holder 50 of the insert 34 as aforesaid. It is envisaged that standard user-replaceable lithium cells may be used and could have a life of several months, for example six months to a year, when the base unit 10 is armed.

Respective EEPROMs 76 provide non-volatile storage of configuration data for the microcontroller/RF ICs 70.

A dual-axis accelerometer 78 sends a signal to the microcontroller/RF IC 70 of the base unit 10, that signal being a changing voltage level relative to the supply voltage. The signal varies in accordance with any acceleration the base unit 10 may

experience in use. The signal is measured by the microcontroller/RF IC 70 against a threshold level to determine whether an alarm condition exists.

An accelerometer 78 suitable for use in the invention is supplied by Analog Devices, Inc. of Massachusetts USA under the serial number ADXL322. The website of Analog Devices, Inc. is at www.analog.com.

An alarm condition is signalled to the user and to passers-by by sounders 80 in the base unit 10 and the remote transceiver 12, one sounder 80 being driven by each microcontroller/RF IC 70. The microcontroller/RF IC 70 of the remote transceiver 12 additionally drives a vibrator 82 to alert the user by vibrating the remote transceiver 12 when there is an alarm condition.

The aforementioned button 24 operates a switch 84 that controls the microcontroller/RF IC 70 of the remote transceiver 12. That microcontroller/RF IC 70 drives three LEDs 86, 88, 90 being red, green and blue respectively. The LEDs 86, 88, 90 are disposed behind the window 32 in the casing 22 of the transceiver 12.

Figure 8 of the drawings shows the general internal layout of each microcontroller/RF IC 70. A microprocessor 92 takes timing input from a clock 94 and is in two-way data communication with an RF module 96 associated with an antenna 72, with volatile memory 98 and with an VO port 100 having I/O pins 102.

Each microcontroller/RF IC 70 communicates with other paired microcontrollers of the same type and allows remote control and monitoring of the VO port 100 using the RF module 96.

Referring finally to Figure 9 of the drawings, this flow chart outlines the operation of the system in two stages, the first stage being the steps up to arming and the second stage being the steps involved when an alarm condition arises. The system also requires that the microcontroller/RF ICs 70 of the base unit 10 and the transceiver 12 must firstly be paired, which process will be described later.

In essence, the first stage begins when the button 24 on the transceiver 12 is pressed and the base unit 10 is on. A press of the button 24 initialises communications

between the base unit 10 and the transceiver 12 such that when the base unit 10 is on, the transceiver 12 commands the base unit 10 to calibrate the accelerometer 78 and then to become armed.

More specifically, the state of the base unit (ball) 10 is firstly queried at 104. The base unit 10 is powered up by turning the hemispheres 14, 16 relative to each other into the ON position, whereupon the base unit 10 can be placed into a pocket or other ball holder of a golf bag or golf club carrier that is to be protected by the alarm system. When the base unit 10 has been powered up and placed in this way, the state of the button 24 of the transceiver (fob) 12 is queried at 106. When the button 24 is pressed for a period of more than, say, three seconds, the system is turned on at 108. The blue LED 90 of the transceiver 12 then flashes once at 110 and the red LED 86 of the transceiver 12 begins flashing at 112, for example once every four seconds. One or both of the sounders 80 of the base unit 10 and the transceiver 12 may also emit a confirmatory sound at this point.

When the system is on, a press of the button 24 of the transceiver 12 at 114 causes the base unit 10 to sample the signal from the accelerometer 78 to calibrate the accelerometer 78 at 116. This establishes the prevailing level of background motion by virtue of movement of the base unit (ball) 10 over a brief period at 118 until the base unit 10 stops moving. The level of background motion is then recorded in the memory 98 of the microcontroller/RF IC 70 in the base unit 10 and a previous activation value is modified to reflect this level to give a new activation value. In this way, movement of the base unit due to prevailing conditions such as wind gusts can be ignored by the system, reducing the frequency of false alarms.

Once the accelerometer 78 has been calibrated in this way, the system enters the armed state at 120 whereupon the blue LED 90 of the transceiver 12 again flashes once at 122 and the green LED 88 of the transceiver 12 begins flashing at 124, for example once every four seconds. Again, one or both of the sounders 80 of the base unit 10 and the transceiver 12 may also emit a confirmatory sound such as a beep -at this point.

Moving on now to the second stage of the flow chart, if the base unit (ball) 10 experiences movement at 126 in excess of the new activation value, the microcontroller/RF IC 70 of the base unit 10 will output a quiet chirping or ticking sound at 128 via the associated sounder 80 and will also start a count-down timer at 130 by counting pulses of the clock 94. During this brief period of motion, the chirping or ticking sound warns anyone nearby that the device is an alarm and that the golf bag is protected.

If movement of the base unit 10 in excess of the new activation value ceases before a predetermined period has elapsed, the timer is reset, the quiet chirping or ticking sound ceases, and the base unit 10 remains in the armed state. A predetermined period of, say, three seconds is shown in the example at 132 but other periods such as five or seven seconds can be used instead.

This relatively quiet initial warning will be effective whether the person moving the bag is the legitimate user of the system or a potential thief. Yet, the sound is not lqucl enough to disturb fellow golfers unduly.

If the person moving the bag is the legitimate user, the user will be reminded to disarm the alarm before moving the bag any appreciable distance and especially before walking off with it. Nevertheless, the user will be able briefly and repeatedly to adjust the position of the bag without having to take the laborious steps of disarming and re-arming the alarm on each occasion. This convenience encourages the user to use the alarm and hence for the user's belongings to enjoy its protection.

Conversely, if the person moving the bag is a potential thief, the thief will be encouraged quickly to put down the bag and escape or move on to easier pickings before a full-loudness alarm goes off. Of course, a potential thief behaving in this way may arouse suspicion and so would be more likely to be apprehended or, at least, deterred.

If movement of the base unit 10 in excess of the new activation value occurs for a predetermined period greater than, say, three seconds in the example shown, the system enters an alarm state at 134. Here, the microcontroller/(RF IC 70 of the base

unit 10 will output a loud oscillating alarm sound via the associated sounder 80. The microcontroller/RF IC 70 of the base unit 10 will also transmit an alarm signal to the corresponding microcontroller/RF IC 70 of the transceiver 12, via their respective antennas 72. The transceiver 12 will then use its sounder 80, LEDs 86, 88, 90 and/or vibrator 82, or a combination thereof, to alert a user who is carrying the transceiver 12, usually in a pocket.

The transceiver 12 will continue to alert the user in this manner even if the base unit 10 is found and disabled. The discreet yet robust design of the base unit 10 and the facility to stow the base unit 10 out of sight makes it unlikely that the base unit 10 could be found or disabled, at least not in time to prevent the user being alerted via the transceiver 12 once the duration of movement exceeds the predetermined period.

The alarm state continues while the state of the button 24 of the transceiver (fob) 12 is queried at 136. When the button 24 is pressed, the system reverts to the armed state at 120 so that the various alarm signals via the sounders 80, LEDs 86, 88, 90 and/or vibrator 82 will cease.

When the system is in the armed state and the base unit (ball) 10 is not moving, the state of button 24 of the transceiver (fob) 12 is queried at 138. When the button 24 is pressed, the system reverts to the 'on' state at 108 and therefore is disarmed, readyitø be armed again upon a further press of the button 24 after calibration of the accelerometer 78 at 116 as aforesaid. When disarmed, the blue LED 90 may flash once, the sounder 80 of the transceiver may output a distinctive sound such as a double beep and the red LED 86 will thereafter flash once every four seconds to indicate the 'on' state as before.

To turn the system off, the hemispheres 14, 16 of the base unit 10 are turned to the OFF position whereupon the red LED 86 of the transceiver 12 will stop flashing to indicate that the system is inactive.

Before the alarm system can be used, the microcontroller/RF ICs 70 of the base unit 10 and the transceiver 12 must firstly be paired as mentioned above to allow

communication between those devices without interference from corresponding devices of similar alarm systems close by.

To pair previously unpaired devices, the hemispheres 14, 16 of the base unit 10 are turned to the ON position, whereupon the button 24 of the transceiver 12 is depressed for a period longer than, say, three seconds. At this point a unique number, for example one of over 18 billion unique numbers, is generated by one of the devices 10, 12 and transmitted to the other device 10, 12. That number is used by the paired devices 10, 12 to allow exclusive communication between them without interference from in-range devices on the same radio band. A code-hopping facility is also possible for added security. The blue LED 90 of the transceiver 12 turns on until the devices have paired, whereupon pairing is indicated by all three LEDs 86, 88, 90 turning on in turn and the vibrator 82 pulsing three times.

By repeating this pairing operation, it is possible to pair one or more further base units 10 to one transceiver 12 or to pair one or more further transceivers 12 to one base unit 10.

Many variations are possible within the inventive concept. For example, means may be provided to locate the base unit 10 if lost but in range. This may be achieved by pressing the button 24 of the transceiver 12 for a relatively long period, for example greater than five or ten seconds. If in range, the base unit 10 will then, output an oscillating sound until the button 24 is released, helping the user to locate the base unit 10. It is also possible to locate the transceiver 12 using the base unit 10, for example by turning the hemispheres 14, 16 of the base unit lO to a position between the ON and OFF positions. With suitable switching, the base unit 10 may theft ' transmit an alarm signal to the transceiver 12 which will respond by activating its sounder 80, the LEDs 86, 88, 90, the vibrator 82 or any combination thereof

If the transceiver 12 is carried out of range from the base unit 10 within an initial period after the system has been armed, then the transceiver 12 may provide an indication of this using the sounder 80, the LEDs 86, 88, 90, the vibrator 82, or, any, combination thereof. For example, once the transceiver 12 goes out of range of the base unit 10, the sounder 80 of the transceiver 12 may beep periodically and the red

and green LEDs 86, 88 may flash in alternating fashion. That alert may be cancelled by pressing the button 24 of the transceiver 12, whereupon the sounder 80 of the transceiver 12 may beep when the transceiver 12 is back in range of the base unit 10.

An indication may also be given to a user that the base unit 10 or the transceiver 12 are getting low on power. In that case, one or more of the LEDs 86, 88, 90 may, for example, double-flash when the system is in the armed or disarmed state.