GB2480741A

GB2480741A - An alarm for alerting a person to the theft of a trailer

Info

Publication number: GB2480741A
Application number: GB1108292A
Authority: GB
Inventors: Darryl Dawson
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-05-28
Filing date: 2011-05-18
Publication date: 2011-11-30
Anticipated expiration: 2031-05-18
Also published as: GB201108292D0; GB201008940D0; GB2480741B; GB2480675A

Abstract

Apparatus for alerting a person to the theft of a trailer 101 for transporting animals, comprising an alarm unit 102 for attaching to a trailer and at least one environmental sensor (313, 314, figure 3). The alarm unit comprises a processing system (506, figure 5), a motion sensor (501) to provide a motion output signal indicative of motion of the alarm unit, and a transmitter (507) for transmitting a signal. The at least one environmental sensor provides at least one environmental output signal indicative of an environmental variable within a trailer, for example sound or temperature. The processing system monitors both the motion output signal and at least one environmental output signal and identifies an alarm condition when either output signal exceeds a threshold. The transmitter transmits a signal when an alarm condition is identified. The signal may be a pager message sent to a pager receiver housed within a hand-held alarm activation unit 106, or said signal may be a GSM message sent via a telephone network to a corresponding GSM device. The unit may also comprise a GPS system for tracking the unit and thus the trailer.

Description

I

An Alarm

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for alerting a person to the theft of a trailer for transporting animals, and to a method of attaching an apparatus to a trailer.

2. Description of the Related Art

Alarm systems are commonly used to protect a valuable asset, especially if the asset is movable, such as a vehicle or a trailer. Many vehicles now are installed with alarms that detect forced entry, which is a prerequisite for being able to move the vehicle. A trailer, on the other hand, does not need to be entered in order to be moved. Whilst tow bars installed on vehicles may include locking mechanisms, they are easy to circumvent for an accomplished thief, or are simply not used by an owner. A problem is therefore encountered when one wishes to ensure that a thief will be deterred from stealing an unattended trailer, but will also be notified if such an event takes place.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided an apparatus for alerting a person to the theft of a trailer according to claim 1.

According to a second aspect of the present invention, there is provided a method of attaching an apparatus to a trailer according to claim 19.

According to a third aspect of the present invention, there is provided a trailer according to claim 21.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Figure 1 shows a horse trailer 101 and apparatus 102; Figures 2A and 2B show apparatus 102 in further detail; Figure 3 shows apparatus 102 in an alternative orientation; Figure 4 shows a method of attaching apparatus 102 to horse trailer 101; Figure 5 shows components that make up apparatus in accordance with an embodiment of the present invention; Figure 6 shows processes carried out by a processing system 506; Figure 7 details steps carried out during monitoring of output data; Figure 8 shows output shock data from a shock sensor 511; Figure 9 details steps carried out in Figure 6 upon output data; Figure 10 details steps carried out in Figure 6 when an alarm flag is set; Figure 11 shows an activation device 106; Figure 12 shows a complementary GSM device 1201; and Figure 13 shows the tracking of alarm unit 102.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 A trailer 101 is shown in Figure 1. In this particular example, trailer 101 is a horsebox suitable for transporting animals of the equine variety. In other examples, trailer 101 is another type of trailer for transporting other kinds of animals, such as cattle or sheep. Alternatively, trailer 101 is another type of trailer, such as a heavy goods vehicle (HGV) trailer.

Attached to trailer 101 is an alarm unit 102, for alerting a person 103 to the theft of trailer 101. Alarm unit 102 includes sensors (not shown in Figure 1) that are sensitive to tilting about an axis, such as movement indicated by arrow 104, acceleration along an axis, indicated by arrow 105, and high impulse motion caused by a shock upon the alarm unit 102. The sensors are configured to provide output signals indicative of motion of the alarm unit 102.

In addition to the presence of sensors configured to provide output signals indicative of motion of the alarm unit 102, alarm unit 102 also includes at least one environmental sensor which, in an embodiment, includes environmental sensors sensitive to temperature and sound levels in trailer 101. Further, an activation device 106 is shown, and is manually portable by a person 103.

Activation device 106 is suitable for activating alarm unit 102.

Figures 2A and 2B Alarm unit 102 is shown in an enlarged view in Figure 2A. Alarm unit 102 comprises a rigid housing 201. In an embodiment, rigid housing 201 is fabricated from a radio-transparent material in order that an antenna may be enclosed within rigid housing 201. Preferably, rigid housing 201 is fabricated from polycarbonate, although any other similar plastics material that provides good mechanical strength and good antenna performance may be used. In alternative embodiments, an antenna is located outside rigid housing 201. In this case, the rigid housing 201 is fabricated from a metallic material, such as stainless steel.

Activation device 106 is shown in greater detail in Figure 2B. Activation device 106 includes a housing 202, in which a pager receiver (not shown) is housed, along with a transmission unit (not shown). On the exterior of housing 202 are placed a first button 203 for activating alarm unit 102 by instructing the transmission unit to emit an activation signal. Additionally, a button 204 is provided for disabling alarm unit 102 by instructing the transmission unit to broadcast a deactivation signal. In the present embodiment, buttons 203 and 204 are separate. However, in an alternative embodiment a single button replaces the function of buttons 203 and 204 by broadcasting an activation signal when it is first pressed, and broadcasting a deactivation signal on a subsequent press. A visual display unit 205 is also positioned on the exterior of housing 202. Visual display unit 205 is suitable for displaying a message encoded within a pager signal received by the pager unit within activation device 106, and in the present embodiment comprises a liquid crystal display.

Figure 3 Components that make up apparatus in accordance with an embodiment of the present invention are shown in Figure 3. Housing 201 includes on its rear four threaded elements 301 through 304 for receiving threaded bolts such as bolt 305. The provision of threaded elements 301 through 304, in combination with bolts such as bolt 305, allow alarm 302 to be attached to trailer 101. This process is described further with reference to Figure 4.

Alarm unit 102 further comprises a power supply unit, such as battery 310, for providing electrical power to further components housed within housing 201. Further components include a siren 311, which may emit a high volume sound, and a tamper switch 312. Processing and control of these components is achieved by the provision of a printed circuit board including a processing system, a plurality of motion sensors, and connections to at least one environmental sensor, such as a temperature sensor 321 and a microphone 322 configured to be positioned inside trailer 101, along with radio devices. The components and how they interact will be further described with reference to Figure 5.

Figure 4 The process of attaching alarm unit 102 to an outside surface 401 of trailer 102 is described in Figure 4.

Holes 402 through 405 are drilled in outside surface 401 at locations corresponding to the position of threaded elements 301 through 304 on alarm unit 102. Thus, bolts such as bolt 305, may be passed through holes 402 through 405 in the direction of arrow 406 and tightened within threaded elements 301 through 304. Thus, alarm unit 102 is attached to trailer 101 with no means of attachment visible from the outside.

Thus, a method of attaching an alarm such as alarm unit 102 to the outside surface of a trailer such as trailer 101 with a set of bolts such as bolt 305 is provided.

In addition, in this embodiment a further hole 407 is drilled to allow the passage of connections from at least one environmental sensor to the alarm unit 102, such as temperature sensor 321 and microphone 322.

Alternatively, the at least one environmental sensor could be housed within the alarm unit 102 and the alarm unit attached within the trailer so as to not be visible at all from the outside of a trailer.

Figure 5 A block diagram is shown in Figure 5, representing the components located within and connected to alarm unit 102 as previously described with reference to Figuie 3. Alarm unit 102 includes a siren 311, a tamper switch 312, a printed circuit board 313 and an external environmental sensors 320, such as temperature sensor 321 and microphone 322. On activation, siren 311 emits a sound of magnitude 120dB. Tamper switch 312 includes a spring-loaded push switch, which, on release, causes an internal circuit to be broken.

The release of the push switch indicates removal of alarm unit 102 from outside surface 401 of trailer 101, and thus an alarm is raised.

Printed circuit board 313 includes a motion sensor 501 comprising an accelerometer 502 and a tilt switch 503. Accelerometer 502 is sensitive to low magnitude accelerations (below 10 m.s2) along an axis, whilst tilt switch 503 is sensitive to motion causing motion around a defined axis. Motion sensor 501 may include up to three accelerometers, and three tilt switches, thus providing motion detection in six degrees of freedom. Motion sensor 501 is thus configured to output a first output signal indicative of motion upon detection of motion of the alarm unit 102.

In this embodiment, printed circuit board 313 further includes a shock sensor 504, which is sensitive to high magnitude accelerations (above 30 m.& 2) Shock sensor 504 is thus configured to output a shock output signal indicative of a high impulse motion upon detection of a high impulse motion, such as that generated by an impact causing an acceleration of over 30 m.s2.

In alternative embodiments, alarm unit 102 is provided without shock sensor 504 to provide a cheaper alternative for customers.

The first output signal from motion sensor 501 and the shock output signal from shock sensor 504 (when present) are stored in memory 505.

Memory 505 may be non-volatile flash memory, or a higher performance random access memory. Output data from motion sensor 501 and 504 that has been stored in memory 505 is therefore able to be read by a processing system 506. Processing system 506 is configured to monitor the motion and shock output signals and identify an alarm condition when the motion and shock output signals exceed a motion or a shock threshold respectively.

Operations carried out by processing system 506 on output motion data from motion sensor 501 and output shock data from shock sensor 504 are described further with reference to Figures 6 through 10.

In the present embodiment, the motion output signal from motion sensor 501 and the shock output signal from shock sensor 504 are provided constantly, and comprise digital samples. Thus, processing system 506 constantly monitors the output signals and responds to them according to pre-configured rules. Alternatively, motion sensor 501 and shock sensor 504 may provide analogue signals that are converted to digital samples by an analogue-to-digital converter. It is envisaged, however, that in alternative embodiments motion sensor 501 and shock sensor 504 are configured to only output signals that instruct the processor to raise an alarm, and are themselves able to monitor and process input motion and shock.

Further, in this embodiment, at least one environmental sensors (shown in box 320) are provided and are configured to provided processing system 306 with at least one type of environmental data. Given that animals are often kept in trailers for substantial periods of time, either during transit or when an owner is pursuing other activities, it has been recognised that sensing of temperature increases within the trailer or high levels of noise within the trailer provide security against what can on occasions evolve into fatal circumstances. An increase in temperature above a certain level, or a decrease below a certain level within the trailer may indicate that a contained animal may soon experience discomfort, whilst a high level of noise may indicate that a contained animal is experiencing distress.

Thus, in this embodiment, a first environmental sensor comprises temperature sensor 321, which writes output temperature data concerning the current temperature within the trailer to memory 505. Additionally, a second environmental sensor comprises a microphone 322 which writes output sound data to memory 505. The processing by processing system 506 of output temperature data and output sound data stored in memory 505 will be described further with reference to Figures 6, 7 and 10.

In the embodiments shown in the Figures, environmental sensors such as temperature sensor 321 and microphone 322 are shown as being wired to alarm unit 102. It is possible, however, that in alternative arrangements that the environmental sensors include radio devices that provide processing system 506 with their environmental data using a wireless protocol such as ZigBee (RTM) or Bluetooth (RTM).

In a similar way to the motion output signals and the shock output signals described above, the environmental output data produced by the at least one environmental sensor is provided constantly, and comprises digital samples. Thus, processing system 506 constantly monitors the at least one environmental output data and responds to it according to pre-configured rules. Alternatively, the at least one environmental sensor may provide analogue signals that are converted to digital samples by an analogue-to-digital converter.

In response to the processing by processing system 506 on output motion data, output shock data, output temperature data and output sound data, processing system 506 is arranged to instruct a transmitter 507 to emit radio signals to complementary devices. In this respect, transmitter 507 includes a pager unit 508 and a GSM unit 509.

Pager unit 508 is configured to operate on the 433MHz or the 2.4GHz bands, and has an effective range of between 600 to 800 metres line-of-sight.

Thus, when a person 103 in possession of activation device 106 is in the vicinity of alarm unit 102, they are able to receive a pager message transmitted by pager unit 508 where it is displayed by visual display unit 205. Such a message may alert them to an alarm being raised.

GSM unit 509 is configured to communicate with a telephony network using the GSM system. In order to achieve this, OSM unit 509 comprises a housing for receiving a SIM card 510 to allow the GSM unit 509 to identify itself to a telephony network. The presence of GSM unit 509 allows transmitter 507 to transmit an SMS message to a complimentary GSM device, alerting a person 103 to the fact that an alarm has been raised.

In addition, the provision of GSM unit 509 and microphone 314 allows for the broadcast to a user of a complimentary GSM device with a transmission of the detected sound within trailer 102.

Printed circuit board 313 further comprises a receiver 511 configured to activate processing system 506 on receipt of an activation signal emitted by activation unit 106. Printed circuit board 313 also includes a GPS unit 512 to allow tracking of the alarm unit 102 and thus trailer ioi. on activation, GPS unit 512 ascertains its co-ordinates by triangulation from GPS satellites, and then transmits its position data along with a unique identifier to a tracking service provider (not shown).

Figure 6 Procedures undertaken by processing system 506 are illustrated in Figure 6. At step 601 processing system 506 is activated in response to receiver 511 receiving an activation signal from activation unit 106. At step 102, processing system 506 begins monitoring the output data from motion sensor 501, shock sensor 504, temperature sensor 313 and microphone 314 that has been stored in memory 505. At step 603, processing system 506 enters a state of alert triggered by a motion threshold, a shock threshold, a temperature threshold or a sound level threshold being exceeded. At step 604 a question is asked as to whether an alarm flag has been set during the state of alert. If the alarm flag has not been set, this question will thus be answered in the negative and processing system 506 will return to step 602 whereupon it continues to monitor sensor output. If the question at step 604 is answered in the affirmative, processing system 506 will enter an alarm condition at step 605.

Figure 7 Figure 7 details step 602 carried out by processing system 506.

At step 701, processing system 506 reads output data from motion sensor 501 that has been stored in memory 505. At step 702, a question is asked as to whether a pre-set motion threshold has been exceeded, and if this question is answered in the affirmative, processing system proceeds to step 709. If this question is answered in the negative, processing system 506 continues to step 703. The provision of the threshold allows processing system 506 to negate effects of noise in motion sensor 501, low level motion due to ground vibration or movement of trailer 101 due to wind, for example.

At step 703, processing system 506 reads output data from shock sensor 504 from memory 505. At step 704, a question is asked as to whether the shock threshold has been exceeded, and if this question is answered in the affirmative, processing system proceeds to step 709. If this question is answered in the negative, processing system 506 returns to step 701. As with step 702, the provision of a shock threshold allows for processing system 506 to negate noise and other false-positives from the shock sensor 504.

At step 709, a siren flag is set which will cause processing system 506 to instruct siren 311 to sound. This process will be described further with reference to Figure 10.

If the questions asked at 702 and 704 are answered in the negative, then control proceeds to step 705 where output temperature data from temperature sensor 313 is read from memory. At step 706, a question is asked as to whether the output temperature data exceeds a pre-set threshold, and if answered in the affirmative then control proceeds to step 603. If answered in the negative, to the effect that the temperature level within trailer 102 is below or above an acceptable level, then at step 707 output sound data is read from memory. The output sound data is analysed by processing system 506, and thus at step 708 a question is asked as to whether the level of sound detected by microphone 314 is above a certain level. If answered in the negative, then control returns to step 701. If answered in the affirmative, then control proceeds to step 603, and step 602 is complete.

Figure 8 In the event that the questions asked at step 702 and 704 are answered in the affirmative, processing system 506 enters a state of alert at step 603. If the motion threshold, a temperature threshold or a sound level threshold was exceeded, and thus the question asked at either step 702, 706 or 708 was answered in the affirmative, then an alarm flag is immediately set. Thus, the question asked at step 604 is answered in the affirmative and an alarm condition is identified at step 605.

However, if the question asked at step 702 was answered in the negative, whilst the question asked at step 704 is answered in the affirmative, this indicates that output shock data was the trigger for entering the state of alert at step 603. Further conditions must be met in order for an alarm condition to be identified. This is in order to negate effects from noise, local vibration and wind causing false-positive shock data to be transferred into memory.

Figure 8 shows an example timeline of events having taken place to cause shock data to be output by the shock sensor. Output shock data 801 is graphed with respect to advancing time, and may rise above a pre-determined threshold level 802.

At time to, output shock data 801 rises above the threshold 802, and thus causes processing system 506 to enter a state of alert. At this point a time limit is set to last for a period tilmit, and a timer is started. In the present embodiment of the invention, tljmjt is equal to two minutes. Receipt of the shock data at time to causes a counter to be incremented by 1. Thus at time to, the shock count is equal to 1. A period t1 elapses, after which output shock data again exceeds threshold 802. This causes the counter to be incremented by another unit, and thus the counter now registers 2. In order to negate wind, noise and vibration effects, it is specified that shock data must exceed the threshold 802 at a higher frequency of occurrence than a prescribed limit. In the present example, the count must reach the prescribed limit of 3 within period tljmjt.

As shown in the Figure, no further output data is received that exceeds the threshold 802 within tilmit. However, we must also account for the fact that the shock data received at t1 may be interpreted as an initial shock and thus the time limit is extended by a period of t1. Thus the timer is scheduled to last for a duration of tljmjt+tl. Accordingly, the count is reduced by 1. As shown, at time t2 and time t3, further output shock data is received that exceeds threshold 802. Thus, there have been 3 instances where output shock data rises above threshold 802 within a period tilmit, starting from t1. Accordingly, an alarm flag is set as the requirements for the alarm condition have been met.

Figure 9 Processes carried out at step 603 are detailed in Figure 9. At step 901, a question is asked as to whether the trigger for the state of alert to be raised was motion data, temperature data or sound data. If the question is answered in the affirmative, processing system 506 proceeds to step 914, where an alarm flag is set.

If the question asked at step 901 is answered in the negative, a counter is set at 1 at step 902. At step 903, the time limit is set to a period timit. At step 904, the timer is started, and at step 905, output shock data is read from memory. At step 906, a question is asked as to whether the shock threshold has been exceeded. If the question asked at step 906 is answered in the negative, processing system advances to step 910. If the question asked at step 906 is answered in the affirmative, processing system 506 advances to step 907 where the time of the output shock data exceeding the threshold is logged as t, where S is an integer representing the shock number. At step 908, the counter is incremented by 1. At step 909, a question is asked as to whether the counter is now equal to 3, and if answered in the affirmative, processing system 506 advances to step 914 where an alarm flag is set. If the question asked at step 909 is answered in the negative, processing system advances to step 910 where a question is asked as to whether the timer has reached tljmjt. If the question asked at step 910 is answered in the negative, processing system 506 returns to step 905, whilst if it is answered in the affirmative, processing system 506 advances to step 911.

At step 911, processing system 506 subtracts 1 from the counter. At step 912, a question is asked as to whether the count is now equal to zero following the subtraction of 1 at step 911. If the question asked at step 912 is answered in the affirmative, processing system 506 advances to step 604. If the question asked at step 912 is answered in the negative, processing system 506 advances to step 913 where the time limit is set for a period equal to t logged at step 907, and then proceeds to return to step 904.

Figure 10 In the event that the question asked at step 604 is answered in the affirmative, processing system 506 proceeds to step 605 by identifying an alarm condition. Steps carried out at step 605 are detailed in Figure 10. At step 1001, a question is asked as to whether a GSM network is present. Thus, processing system 506 polls GSM unit 509 for network connectivity. If the question asked at step 1001 is answered in the affirmative, processing system 506 instructs GSM unit 509 to send an SMS message alerting a person to the alarm condition. If the question asked at step 1001 is answered in the negative, processing system 506 proceeds to step 1003.

At step 1003, a question is asked as to whether paging has been specified by a user. If answered in the affirmative, processing system 506 proceeds to step 1004 where it instructs pager unit 508 to emit a pager signal containing a pager message to activation device 106. If the question asked at step 1003 is answered in the negative, processing system 506 proceeds straight to step 1005, where GPS unit 512 is activated and begins broadcasting GPS co-ordinates of the alarm unit 102. At step 1006, a question is asked as to whether the siren flag was set at step 709, and if not, then control proceeds to step 1013. If answered in the affirmative, then control proceeds to step 1007, where processing system 506 instructs the siren to emitasound.

At step 1007, a question is asked as to whether an instruction to silence, indicated by the receipt of a disarming signal from activation unit 106, has been received. If answered in the affirmative, processing system 506 instructs the siren to stop sounding at step 1008, and then switches itself off at step 1009. If the question asked at step 1007 is answered in the negative, processing system 506 advances to step 1010, where a question is asked as to whether the siren has sounded for more than a predetermined amount of time. If the question asked at step 1010 is answered in the affirmative, processing system 506 returns to step 1007. If the question asked at step 1010 is answered in the negative, processing system 506 advances to step 1011, where it instructs the siren to stop sounding, and instructs GPS unit 512 to continue transmitting GPS co-ordinates at step 1012.

Figure 11 The activation device 106 is shown in Figure 11. As a result of processing having taken place with reference to Figure 10, activation unit 106 receives a pager message, and proceeds to display the contents of the message 1101 on visual display device 205.

Figure 12 A complementary GSM device 1201 comprising a mobile telephone 1201 is shown in Figure 11. As a result of an SMS message being transmitted by alarm 102 at step 1002, complementary GSM device 1201 receives the SMS message which alerts a user, such as person 102, to the identification of an alarm condition.

Figure 13 A computer system 1301 running a mapping utility software is shown in Figure 13. The mapping utility application is configured to display a map 1302 of a geographical region and also, on receipt of GPS co-ordinates, to plot a position 1303 on the map representing those co-ordinates.

In the event that the instruction to silence was not received at step 1007, GPS unit 512 continues to broadcast GPS co-ordinates. The location of alarm unit 102, and thus trailer 101, is able to be tracked via the mapping utility software.

Claims

Claims 1. Apparatus for alerting a person to the theft of a trailer for transporting animals, comprising an alarm unit for attaching to a trailer and at least one environmental sensor, where said alarm unit comprises: a processing system, a motion sensor configured to provide a motion output signal indicative of motion of said alarm unit, and a transmitter for transmitting a signal; and said at least one environmental sensor is configured to provide at least one environmental output signal indicative of an environmental variable within a trailer; wherein: said processing system is configured to monitor said motion output signal and identify an alarm condition when said motion output signal exceeds a motion threshold; and said processing system is configured to monitor said at least one environmental output signal and identify an alarm condition when said at least one environmental output signal exceeds an environmental threshold; and said transmitter is configured to transmit a signal when an alarm condition is identified.
2. The apparatus of claim 1, wherein said at least one environmental sensor includes a temperature sensor configured to provide an environmental output signal indicative of the temperature within said trailer.
3. The apparatus of claim 1 or claim 2, wherein said at least one environmental sensor includes a microphone configured to provide an output signal representing sounds sensed within said trailer.
4. The apparatus of any of claims 1 to 3, further comprising a shock sensor configured to provide a shock output signal indicative of detection of a high impulse motion, wherein said processing system is configured to monitor said shock output signal from said shock sensor, and identify an alarm condition when said shock output signal exceeds a shock threshold at a higher frequency of occurrence than a prescribed limit
5. The apparatus of any of claims 1 to 4, further comprising an activation device including a manually operable button, wherein: said activation device emits an activation signal on manual operation of said button; and said alarm unit further comprises a receiver configured to activate said processing device on receiving said activation signal.
6. The apparatus of any of claims 1 to 5, wherein said motion sensor comprises an accelerometer configured to output data upon acceleration along at least one axis.
7. The apparatus of any of claims 1 to 6, wherein said motion sensor comprises a tilt switch configured to output data upon motion around a defined axis.
8. The apparatus of any of claims I to 7, wherein said alarm unit further comprises a tamper switch configured to output an alarm signal upon detection of tampering of said apparatus.
9. The apparatus of claim 8, wherein said processing system identifies an alarm condition in the presence of output data from said tamper switch.
10. The apparatus of any of claims I to 9, wherein said alarm unit further comprises a siren that emits sound when said alarm condition is identified.
11. The apparatus of any of claims 1 to 10, wherein said transmitter comprises a GSM unit configured to communicate with a telephony network using the GSM system.
12. The apparatus of claim 11, wherein said processing device provides said third output signal from said microphone to said GSM unit for transmission to a complementary GSM device.
13. The apparatus of claim 11 or claim 12, wherein said GSM unit transmits an SMS message to a complementary GSM device upon the identification of said alarm condition.
14. The apparatus of any of claims 1 to 13, wherein said transmitter comprises a pager transmitter configured to transmit a pager signal upon the identification of said alarm condition.
15. The apparatus of claim 14, wherein said activation device further comprises a pager receiver for receiving said pager signal, and a visual display unit configured to display the contents of said pager signal.
16. The apparatus of any of claims I to 15, further comprising a GPS unit to allow tracking of said alarm, and thus said trailer.
17. The apparatus any of claims 1 to 16, wherein said alarm unit includes rigid housing, said rigid housing including threaded elements to enable attachment to said trailer using a set of threaded bolts.
18. The apparatus of claim 17, wherein said threaded elements are positioned on the inside of said rigid housing, such that they are not visible when said alarm unit is attached to a trailer.
19. A method of attaching the apparatus according to any of claims 1 to 18 to a trailer, comprising attaching the apparatus to a trailer with a set of bolts.
20. The method of claim 17, wherein said apparatus is attached to an outside surface of said trailer.
21. A trailer including an alarm unit and at least one environmental sensor, where said alarm unit comprises: a processing system, a motion sensor configured to provide a motion output signal indicative of motion of said alarm unit, and a transmitter for transmitting a signal; and said at least one environmental sensor is configured to provide at least one environmental output signal indicative of an environmental variable within a trailer; wherein: said processing system is configured to monitor said motion output signal and identify an alarm condition when said motion output signal exceeds a motion threshold; and said processing system is configured to monitor said at least one environmental output signal and identify an alarm condition when said at least one environmental output signal exceeds an environmental threshold; and said transmitter is configured to transmit a signal when an alarm condition is identified.
22. The trailer of claim 21, wherein the alarm unit is attached to the outside of said trailer.
23. The trailer of claim 22, wherein the alarm unit is attached to the inside of said trailer.
24. Apparatus for alerting a person to the theft of a trailer substantially as herein described with reference to the accompanying Figures.
25. A method of attaching an apparatus according to any of claims 1 to 18 to a trailer substantially as herein described with reference to the accompanying Figures.