APPARATUS

TECHNICAL FIELD

The present disclosure relates to a system and method for monitoring a vehicle-mounted device or apparatus, such as a spare wheel. More particularly, but not exclusively, the present disclosure relates to an anti-theft system and method for monitoring for a spare wheel disposed on a vehicle. At least in certain embodiments, an alert may be generated as a deterrent from unauthorised removal or theft of the spare wheel.

BACKGROUND

It is well known to provide a vehicle with a spare wheel. The spare wheel is typically used in the event of a puncture or other damage to one of the vehicle wheels. The spare wheel may be located inside the vehicle, for example in an aperture formed in a floor of a loadspace. Alternatively, the spare wheel may be located externally of the vehicle, for example mounted to a rear closure member or in a carrier supported under the vehicle. It is known to provide a mechanical lock to secure the spare wheel to the vehicle. For example, one or more locking wheel nut may be used to secure the spare wheel. It would be desirable to provide improved security measures to protect the spare wheel from theft.

At least in certain embodiments, the present invention seeks to address or overcome the problems associated with prior art systems.

SUMMARY OF THE INVENTION

Aspects of the present invention relate to a system for detecting removal of a vehicle-mounted device or apparatus, such as a spare wheel; a vehicle; and a method as claimed in the appended claims.

According to a further aspect of the present invention there is provided a system for detecting removal of a vehicle-mounted device or apparatus from a vehicle, the system comprising: a first sensor for detecting the absence of the vehicle-mounted device or apparatus, the first sensor being configured to output a first signal when the vehicle-mounted device or apparatus is absent; a transmitter for transmitting a wireless signal to a receiver in the vehicle; and a control unit comprising one or more controller configured to: receive the first signal from the first sensor; and output a first alert signal in dependence on receipt of the first signal from the first sensor.

The system is configured to monitor the presence or absence of a spare wheel, or other vehicle-mounted device or apparatus. In the event that the spare wheel, device or apparatus is removed, the system generates the first alert signal. The first alert signal may be transmitted as a wireless signal to the receiver in the vehicle. The vehicle may generate an alarm or notification in dependence on receipt of the first alert signal. At least in certain embodiments, the vehicle may generate an alert when the spare wheel, device or apparatus is removed. The system may thereby function as an anti-theft device. At least in certain embodiments, the system can protect against unauthorised removal of the spare wheel, device or apparatus.

The system may be an anti-theft system for monitoring a spare wheel of a vehicle. Alternatively, the vehicle-mounted device or apparatus may be one of a storage container, a roof box; a bicycle, a surfboard, a kayak, a charging cable, a ladder, a tool box, a catalytic converter or other vehicle component or a traction battery. The system may comprise or consist of one or more spare wheel (or other device or apparatus) detector. The (spare wheel) detector may be configured to detect the presence or absence of the spare wheel, or other device or apparatus. In the following paragraphs, reference is made to the removal of a spare wheel specifically, but it will be appreciated that the term and feature of the “spare wheel” may be replaced as appropriate with “vehicle-mounted device or apparatus”.

The one or more controller may comprise at least one electronic processor having an electrical input for receiving the first signal from the first sensor, and at least one electronic processor having at least one output for outputting the first alert signal. At least one memory device may be electrically coupled to the at least one electronic processor and having instructions stored therein. The at least one electronic processor may be configured to access the at least one memory device and execute the instructions therein so as to control the output of the first alert signal.

The first sensor may comprise a first switch configured to be actuated by the spare wheel. The first switch may be actuated when the spare wheel is present. The first switch may, for example, comprise a tactile switch (also known as a Tact switch).

The first switch may be configured to be released when the spare wheel is removed. The release of the first switch may cause the first signal to be output to the processor. The first switch may comprise a normally-closed switch which is in a closed state when the spare wheel is absent and is actuated to an open state when the spare wheel is present. The first sensor may determine that the spare wheel is absent when the first switch is in the closed state. The actuation of the first switch may comprise opening the first switch (thereby breaking or interrupting the electrical circuit). The removal of the spare wheel may release the first switch, thereby allowing the first switch to return to the normally-closed state. The absence of the spare may thereby close the first switch (completing the electrical circuit). The first sensor may determine that the spare wheel is present when the first switch is in the open state.

The system may comprise a first flexible membrane extending over the first switch. The first flexible membrane may be waterproof. The first flexible membrane may reduce or prevent ingress of moisture or liquid.

The system may comprise a second sensor for detecting displacement of the system relative to the vehicle. The second sensor may be provided to detect tampering or removal. For example, the second sensor may detect that the system is being removed from the vehicle.

The first and second sensor may be disposed on opposing sides of the system. For example, the first sensor may be provided on a first side; and the second sensor may be provided on a second side.

The second sensor may output a second signal in dependence on a determination that the system has been displaced away from the vehicle. The one or more controller may be configured to output a second alert signal in dependence on receipt of the second signal from the second sensor.

The second sensor may comprise a second switch configured to be actuated to an open state when the system is mounted to the vehicle and biased towards a closed state when the system is spaced apart from the vehicle. The second switch may, for example, comprise a tactile switch (also known as a Tact switch). The release of the first switch may cause the first signal to be output to the processor. The second switch may comprise a normally-closed switch.

The system may comprise a second flexible membrane extending over the second switch. The second flexible membrane may be waterproof. The second flexible membrane may reduce or prevent ingress of moisture or liquid. The processor may be configured to generate the first alert signal for a predetermined time period.

The system may comprise a casing for mounting the system to the vehicle. The casing could be configured to mount the system to the spare wheel, for example removably mounted to a sidewall of the spare wheel. Alternatively, the casing may be mounted to the vehicle, for example to a wheel carrier or a vehicle body.

The system may comprise an on-board battery for powering the control unit.

According to a further aspect of the present invention there is provided a vehicle comprising a system as described herein. The system may be mounted to the vehicle body.

According to a further aspect of the present invention there is provided a vehicle for operation in conjunction with the system described herein. The vehicle may comprise a receiver for receiving one or more alert signal transmitted by the system. The vehicle may be configured to activate an alarm in dependence on receipt of said one or more signal. The vehicle may be configured to activate the alarm if the one or more signal is received while the alarm is armed.

The vehicle may be configured to activate the alarm system of the vehicle if the alarm system is armed at the time that said one or more signal is received.

The vehicle may be configured to inhibit activation of the alarm system if a portable device is detected within a predetermined range of the vehicle.

The vehicle may be configured to inhibit activation of the alarm system if an authorisation is received from a portable device.

According to a further aspect of the present invention there is provided a method of generating an alert to indicate that a vehicle-mounted device or apparatus has been removed from a vehicle, the method comprising: using a first sensor to detect a presence or an absence of the vehicle-mounted device or apparatus, the first sensor being configured to generate a first alert signal in dependence on identification that the vehicle-mounted device or apparatus is absent; transmitting the first alert signal as a wireless signal to a receiver in the vehicle; receiving the first alert signal in the vehicle; and activating one or more vehicle systems in dependence on the first alert signal. According to a further aspect of the present invention there is provided a non-transitory computer-readable medium having a set of instructions stored therein which, when executed, cause a processor to perform the method described herein.

Any control unit or controller described herein may suitably comprise a computational device having one or more electronic processors. The system may comprise a single control unit or electronic controller or alternatively different functions of the controller may be embodied in, or hosted in, different control units or controllers. As used herein the term “controller” or “control unit” will be understood to include both a single control unit or controller and a plurality of control units or controllers collectively operating to provide any stated control functionality. To configure a controller or control unit, a suitable set of instructions may be provided which, when executed, cause said control unit or computational device to implement the control techniques specified herein. The set of instructions may suitably be embedded in said one or more electronic processors. Alternatively, the set of instructions may be provided as software saved on one or more memory associated with said controller to be executed on said computational device. The control unit or controller may be implemented in software run on one or more processors. One or more other control unit or controller may be implemented in software run on one or more processors, optionally the same one or more processors as the first controller. Other suitable arrangements may also be used.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the present invention will now be described, by way of example only, with reference to the accompanying figures, in which:

Figure 1 shows a schematic representation of a vehicle incorporating an anti-theft system for detecting removal of a spare wheel from a vehicle in accordance with an embodiment of the present invention; Figure 2 shows a rear elevation of the vehicle shown in Figure 1 ;

Figure 3 shows a schematic representation of a vehicle controller for the anti-theft system shown in Figure 1 ;

Figure 4 shows a plan elevation of a spare wheel detector for use in the ant-theft system shown in Figure 1 ;

Figure 5 shows a side elevation of the spare wheel detector shown in Figure 4;

Figure 6 shows a schematic representation of a detector controller for generating an alert signal for transmission to the vehicle controller; and

Figure 7 shows a block diagram representing operation of the system according to an embodiment of the present invention.

DETAILED DESCRIPTION

An anti-theft system 1 for monitoring a spare wheel 3 in accordance with an embodiment of the present invention will now be described with reference to the accompanying figures. The spare wheel 3 is disposed on a vehicle 5. The vehicle 5 may, for example, be a road vehicle, such as an automobile, a utility vehicle or a sports utility vehicle. The spare wheel 3 in the present embodiment is disposed externally of the vehicle 5, but it will be understood that the system 1 could be used for a spare wheel 3 provided inside the vehicle 5, for example in an aperture formed in the load space to receive the spare wheel 3. As described herein, the system 1 functions as an anti-theft device for generating a signal in dependence on a determination that the spare wheel 3 has been removed from the vehicle 5. At least in certain embodiments, the system 1 may also generate an alert in the event that tampering is detected.

As shown in Figures 1 and 2, the vehicle 5 comprises a vehicle body 7 having a cabin 9 and a load space 1 1 . The vehicle 5 comprises four (4) wheels W-n having like configurations. The spare wheel 3 is provided as a replacement for one of the wheels W-n, for example in the event of a puncture. A rear closure member 13 is provided at the rear of the vehicle 5 for closing the load space 11. The rear closure member 13 in the present embodiment is sideopening and is pivotally mounted top and bottom to the vehicle body 7 by upper and lower hinge assemblies 15, 17. A wheel carrier 19 is disposed on the rear closure member 13. The wheel carrier 19 comprises a support frame F fixedly mounted to the rear closure member 13 and arranged to support the spare wheel 3. As shown in Figure 1 , the wheel carrier 19 is arranged to support the spare wheel 3 externally of the vehicle 5, i.e. outside of the cabin 9 and the load space 1 1. The wheel carrier assembly 19 typically comprises a mechanical locking mechanism for securing the spare wheel 3 to the wheel carrier 19. The vehicle 5 comprises a vehicle control unit 20. As shown in Figure 3, the vehicle control unit 20 comprises one or more vehicle controller 21. The one or more vehicle controller 21 each comprise at least one first electronic processor 23 and a system memory 25. A set of computational instructions is stored on the system memory 25. The at least one electronic processor 23 has an electrical input 23A; and at least one electrical output 23B. The one or more vehicle controller 21 is operable to generate an alert signal AS-n. The alert signal AS-n is configured to control one or more vehicle systems to generate an alert. The alert signal AS- n may, for example, activate an alarm system (denoted generally by the reference numeral 29) to generate an audible alert and/or a visible alert. Alternatively, or in addition, the alert signal AS-n may be output by the controller 21 to a vehicle communication system (denoted generally by the reference numeral 31 ). The vehicle communication system 31 may be configured to transmit the alert signal AS-n over a communication network, such as a cellular data communication network. The alert signal AS-n may be transmitted to a vehicle monitoring centre disposed remote from the vehicle 5.

The vehicle 5 is configured to communicate with one or more portable device 33 to provide remote access to the cabin 9 and/or a start-up procedure for the vehicle 5. The device 33 functions as an electronic key and may, for example, be in the form of a key fob. The vehicle 3 comprises a vehicle transceiver 35 for transmitting and receiving a wireless radio frequency (RF) signal. The vehicle transceiver 35 in the present embodiment is an ultra-wideband transceiver. In a variant, the vehicle transceiver 29 may be Low Frequency (LF) transceiver or an Ultra High Frequency (UHF) transceiver. The vehicle transceiver 35 is configured to communicate with the device 33. The vehicle transceiver 35 is connected to at least one antenna 37 for transmitting and receiving a wireless radio frequency (RF) signal. In the illustrated arrangement, the vehicle transceiver 35 is connected to an antenna 37 disposed on the vehicle 3. The vehicle transceiver 35 is in communication with the one or more vehicle controller 21 . The signals received by the vehicle transceiver 35 are communicated to the one or more vehicle controller 21. The vehicle transceiver 35 may form part of the vehicle communication system 31 . Alternatively, the vehicle transceiver 35 may be separate from (i.e. independent of) the vehicle communication system 31. In a variant, the device 33 may comprise a cellular telephone or other electronic device configured to function as an electronic key.

As shown schematically in Figure 1 , the system 1 comprises a spare wheel detector 41 for detecting the presence or absence of the spare wheel 3. As described herein, the spare wheel detector 41 is configured to identify removal of the spare wheel 3. The spare wheel detector 41 is operative to activate an alert in dependence on identification of the removal of the spare wheel 3. A first change from the spare wheel 3 being present to the spare wheel 3 being absent corresponds to a removal of the spare wheel 3. By identifying this change in state, the spare wheel detector 41 can determine that the spare wheel 3 has been removed. The spare wheel detector 41 may optionally be configured to identify that the spare wheel 3 has been replaced. A second change from the spare wheel 3 being absent to the spare wheel 3 corresponds to the spare wheel 3 being replaced. By identifying this change in state, the spare wheel detector 41 can determine that the spare wheel 3 has been replaced.

The anti-theft system 1 comprises one or more spare wheel detectors 41 for detecting the presence or absence of the spare wheel 3. Schematic representations of the spare wheel detector 41 are shown in Figures 4 and 5. The spare wheel detector 41 comprises a housing 43, a printed circuit board (PCB) 45, a first sensor 47, a second sensor 49, a detector control unit 51 , a detector transmitter 53 and an on-board battery 55. The detector control unit 51 is mounted on the circuit board 45 which is located in the housing 43. The printed circuit board 45 is double-sided in the present embodiment. The first and second sensors 47, 49 are disposed on opposing sides of the circuit board 45. In the arrangement illustrated in Figure 3, the first sensor 47 is oriented upwardly and the second sensor 47 is oriented downwardly. The spare wheel detector 41 comprises a first flexible membrane 57 to cover the first sensor 47; and a second flexible membrane 59 to cover the second sensor 49. The first and second flexible membranes 57, 59 at least substantially seal the housing 43 to reduce or prevent the ingress of moisture or contaminants. The housing 43 in the present embodiment is generally circular in plan form and comprises opposing first and second mounting lugs 61 A, 61 B. The first and second mounting lugs 61 A, 61 B comprise apertures for receiving mechanical fasteners 63A, 63B for mounting the spare wheel detector 41 to the vehicle body 7.

The first sensor 47 is configured to detect the presence (or absence) of the spare wheel 3. By detecting a change in state, the first sensor 47 can identify when the spare wheel 3 is removed. The first sensor 47 in the present embodiment comprises a first switch. The first switch comprises a first actuator 48 which is moveable between a first position and a second position. The first actuator 48 may, for example, comprise a plunger or other actuating member. When the first actuator 48 is in the first position, the first switch is in an open state in which an electrical circuit is interrupted. When the first actuator 48 is in the second position, the first switch is in a closed state in which the electrical circuit is complete. A first spring biasing element is provided for biasing the first actuator 48 towards one of the first position and the second position. In the present embodiment, the first switch is a normally-closed switch. The first actuator 48 is spring biased towards the first position in which the first switch is in a closed state and the electrical circuit is complete. The first actuator 48 is extended in the second position and at least partially retracted in the first position. The spare wheel detector 41 is mounted to the vehicle body such that the first sensor 47 faces outwardly. The spare wheel detector 41 is positioned such that, when fitted, the spare wheel 3 applies a load to the first sensor 47 to overcome the spring bias and displace the first actuator 48 to the first position (thereby breaking the electrical circuit). When the spare wheel 3 is removed, the load is removed from the first sensor 47 and the first actuator 48 is biased towards the second position under the action of the first spring biasing element (thereby completing the electrical circuit). It will be understood, therefore, that the first sensor 47 is operable to detect the presence or absence of the spare wheel 3. A first member may be provided to protect the first sensor 47. The first member may function as a stop or travel limiter to limit displacement of the first actuator 48.

The second sensor 49 is configured to identify tampering or removal of the spare wheel detector 41 . By detecting the presence or absence of the vehicle body 7, the second sensor

49 can identify when the spare wheel detector 41 is dislodged or displaced relative to the vehicle body 7. Any such movement may indicate an attempt to tamper with the spare wheel detector 41 . The second sensor 49 in the present embodiment comprises a second switch. The second switch comprises a second actuator 50 which is moveable between a first position and a second position. The second actuator 50 may, for example, comprise a plunger or other moveable actuating member. When the second actuator 50 is in the first position, the second switch is in an open state in which an electrical circuit is interrupted. When the second actuator

50 is in the second position, the second switch is in a closed state in which the electrical circuit is complete. A second spring biasing element is provided for biasing the second actuator 50 towards one of the first position and the second position. In the present embodiment, the second switch is a normally-closed switch. The second actuator 50 is spring biased towards the second position in which the electrical circuit is complete. The second actuator 50 is extended in the second position and at least partially retracted in the first position. The spare wheel detector 41 is mounted to the vehicle body such that the second sensor 49 faces inwardly. The spare wheel detector 41 is mounted to the vehicle body 7 such that a force is applied to the second sensor 49 to overcome the spring bias and displace the second actuator 50 to the first position (thereby breaking the electrical circuit). Thus, mounting the spare wheel detector 41 to the vehicle body 7 displaces the second actuator 50 to the first position. If the spare wheel detector 41 is removed, the load is removed from the second sensor 49 and the second actuator 50 is biased towards the second position under the action of the second spring biasing element (thereby completing the electrical circuit). The second sensor 49 may thereby detect if the spare wheel detector 41 is removed from the vehicle body 7. Removal of the spare wheel detector 41 may indicate tampering or other unauthorised activity. Thus, the second sensor 49 can be used to generate an alert indicating tampering. A second member may be provided to protect the second sensor 49. The second member may function as a stop or travel limiter to limit displacement of the second actuator 50.

As shown in Figure 6, the detector control unit 51 comprises one or more controller 64. The one or more controller 64 comprises a detector processor 65 and a detector memory 67. The processor 65 comprises a second electronic processor having at least one electrical input 65A for receiving first and second input signals from the first and second sensors 47, 49 respectively. The processor 65 has at least one first electrical output 65B for outputting a spare wheel status signal S-1 indicating a status of the spare wheel 3, for example to indicate that the spare wheel 3 is present or is absent. The processor 65 has at least one second electrical output 71 -2 for outputting a detector status signal S-2 indicating a status of the spare wheel detector 41 , for example to indicate that the spare wheel detector 41 is mounted to the vehicle body 7 or that the spare wheel detector 41 is not mounted to the vehicle body 7. A set of computational instructions is stored in the detector memory 67. When executed, the computational instructions cause the processor 65 to implement the method(s) described herein.

The detector control unit 51 is configured to output the spare wheel status signal S-1 and/or the detector status signal S-2 to the detector transmitter 53. The detector transmitter 53 is a radio frequency (RF) transmitter and is operable to transmit the spare wheel status signal S- 1 and/or the detector status signal S-2. The detector transmitter 53 may be a Low Frequency (LF) transmitter (operating at a radio frequency (RF) in the range 30-300 kHz); or a Ultra High Frequency (UHF) transmitter (operating at a radio frequency (RF) in the range 300 megahertz (MHz) to 3 gigahertz (GHz). The detector transmitter 53 may have different operating frequencies for different territories. The detector transmitter 53 may comprise three channels having an operating frequency of 315 MHz (±17kHz); and/or three channels having an operating frequency of 433.92 MHz (±17kHz). A LF coil (not shown) may be provided on the printed circuit board 45, or optionally a 3D coil. Alternatively, or in addition, a UHF transmitting antenna pay be printed on the printed circuit board 45. In certain embodiments, the detector transmitter 53 may comprise a low energy system suitable for local (short-range) communications, for example to establish a wireless personal area network. A suitable low energy system is Bluetooth (RTM) Low Energy. The vehicle transceiver 35 may be configured to communicate with the detector control unit 51 over the low energy system.

The battery 55 is provided to provide power for the spare wheel detector 41 . The battery 55 may be a coin cell which may, for example, provide sufficient power for operation over at least 5 years or 10 years. The spare wheel status signal S-1 and/or the detector status signal S-2 are transmitted as one or more wireless signal to the vehicle transceiver 35. To comply with RF regulations and to reduce battery drain during servicing, the spare wheel status signal S- 1 and/or the detector status signal S-2 are transmitted for a predetermined time period, for example 5 seconds or 10 seconds. Alternatively, or in addition, the spare wheel detector 41 - 1 may be electrically connected to a vehicle power source, such as a vehicle battery. The battery 55 may be used as a back-up power source, for example to trigger an alert if the road wheel detector 41 -n is disconnected from the vehicle power source. Alternatively, the battery 55 could be omitted from the spare wheel detector 41 .

The vehicle transceiver 35 receives the spare wheel status signal S-1 and/or the detector status signal S-2. The vehicle controller 21 processes the spare wheel status signal S-1 to determine the status of the spare wheel 3. If the security alarm is armed on the vehicle 5 at the time that the spare wheel 3 is removed, the vehicle controller 21 generates the alert signal AS-n to activate the alarm system 29. The vehicle controller 21 processes the detector status signal S-2 to determine the status of the spare wheel detector 41 . If the vehicle controller 21 determines that the spare wheel detector 41 has been partially or completely removed, the alert signal AS-n is generated and output to activate the alarm system 29. The alarm system 29 may be disarmed by an authorised user, for example using the device 33 to reset the alarm system 29. In the absence of any such override signal, the alarm system 29 remains armed to alert third persons to the potential theft of the spare wheel 3.

The spare wheel detector 41 is disposed on the wheel carrier 19. Locating the spare wheel detector 41 on the wheel carrier 19 (or the vehicle body 7) causes the second actuator 50 to be depressed. The second sensor 49 is thereby displaced to an open state in which the electrical circuit is interrupted. The first sensor 47 is biased towards the closed state under the action of the spring biasing element. The operation of the spare wheel detector 41 will now be described with reference to a block diagram 100 shown in Figure 7. The spare wheel 3 is initially located in the wheel carrier 19 (BLOCK 105). The spare wheel 3 engages the first sensor 47 and causes the first actuator 48 to be depressed (BLOCK 110). The first sensor 47 is thereby displaced to an open state in which the electrical circuit is interrupted. The detector control unit 51 detects that the first sensor 47 is in the open state and determines that the spare wheel 3 is disposed on the wheel carrier 19 (BLOCK 1 15). If the spare wheel 3 is removed from the wheel carrier 19, the first actuator 48 of the first sensor 47 is displaced to the closed state by the spring biasing element. The detector control unit 51 detects that the first sensor 47 is in the closed state and determines that the spare wheel 3 has been removed from the wheel carrier 19 (BLOCK 120). The detector control unit 51 transmits the spare wheel status signal S-1 to the vehicle controller 21 as a wireless signal (BLOCK 125). The detector control unit 51 determines that the spare wheel 3 is absent and performs a check to determine if the alarm system 29 of the vehicle 5 is armed (BLOCK 130). If the alarm system 29 is armed, detector control unit 51 outputs the alert signal AS-n to the alarm system 29 (BLOCK 135). The alarm system 29 is activated to provide a visible and/or audible alert indicating that the spare wheel 3 has been removed (BLOCK 140). The device 33 can be actuated to disarm the alarm system 29 (BLOCK 145).

If the spare wheel detector 41 is removed from the wheel carrier 19, the second actuator 50 of the second sensor 49 is displaced to the closed state by the spring biasing element. The detector control unit 51 detects that the second sensor 49 is in the closed state and determines that the spare wheel detector 41 has been removed (partially or completely) from the wheel carrier 19 (BLOCK 150). The detector control unit 51 transmits the detector status signal S-2 to the vehicle controller 21 (BLOCK 155). The vehicle controller 21 identifies tampering with the spare wheel detector 41 and performs a check to determine if the alarm system 29 of the vehicle 5 is armed (BLOCK 130). If the alarm system 29 is armed, the detector control unit 51 outputs the alert signal AS-n to the alarm system 29 (BLOCK 135). The alarm system 29 is activated to provide a visible and/or audible alert indicating that the spare wheel 3 has been removed (BLOCK 140). The device 33 can be actuated to disarm the alarm system 29 (BLOCK 145).

The vehicle transceiver 35 and/or the detector control unit 51 may be configured to communicate with the device 33 in dependence on a determination that either the spare wheel 3 has been removed and/or the spare wheel detector 41 has been removed. The vehicle transceiver 35 and/or the detector control unit 51 may be configured to transmit a polling signal to initiate communication with the device 33. The spare wheel status signal S-1 and/or the detector status signal S-2 may be transmitted directly to the device 33 by the detector control unit 51 , or indirectly to the device 33 by the vehicle transceiver 35. In dependence on receipt of the spare wheel status signal S-1 and/or the detector status signal S-2, the device 33 may generate an alert or notification for a user. The device 33 may optionally request a user input, for example to authorise the removal of the spare wheel 3 or the spare wheel detector 41 . The vehicle controller 21 may inhibit generation of an alert if an authorisation is received. This may be appropriate to enable servicing of the vehicle 3. Alternatively, or in addition, the vehicle controller 21 may inhibit generation of an alert if the device 33 is detected. The vehicle controller 21 may inhibit generation of an alert if the device 33 is detected within a predetermined range of the vehicle 3. Alternatively, or in addition, the transmission of the spare wheel status signal S-1 and/or the detector status signal S-2 may be inhibited if the detector control unit 51 establishes communication with the device 33. If the device 33 is within range and communication is established, the generation of an alert may be inhibited. A time period for establishing communication with the device 33 may be predefined.

In a variant, a wired connection could be implemented between the spare wheel detector 41 and the vehicle controller. The spare wheel status signal S-1 and/or the detector status signal S-2 could be sent to the vehicle controller over a wired connection. The spare wheel detector 41 may comprise one or more tamper detection devices, such as the second actuator 50 which is displaced to the closed state if the spare wheel detector 41 is displaced relative to the wheel carrier 19. Alternatively, or in addition, the vehicle controller 21 may periodically communicate with the spare wheel detector 41 to ensure that it is still operational.

It will be appreciated that various modifications may be made to the embodiment(s) described herein without departing from the scope of the appended claims. The embodiment comprises first and second sensors 47, 49 which are in the form of mechanical switches. It will be understood that a different type of sensor may be employed to detect the presence or absence of the spare wheel 3. Similarly, a different type of sensor may be used to detect tampering or removal of the spare wheel detector 41 .

The system 1 described herein could be configured as a general-purpose alert system. For example, the system 1 could be used to detect the presence or absence of other devices or apparatus removably mounted to the vehicle 5. The detector 41 -1 could be used to generate an alert in dependence on detecting removal from the vehicle of one or more of the following: a storage container, such as a roof box; a bicycle; a surfboard; a kayak; a charging cable (for connecting the vehicle to an electrical power supply to charge an on-board battery). The device or apparatus could also be a ladder, a tool box, a catalytic converter or other (removable) vehicle component, or a traction battery. The detector 41 -1 could be fastened to the vehicle 5. Alternatively, the detector 41 -1 could be removably mounted to the vehicle 5, for example using a suction cup or a magnetic mounting device. An alarm may be triggered if the detector 41 -1 determines that the device or apparatus has been removed from the vehicle 5.