GB2515090A

GB2515090A - A cabinet alarm system and method

Info

Publication number: GB2515090A
Application number: GB1310600.0A
Authority: GB
Inventors: Peter John Jones
Original assignee: XTRA SENSE Ltd
Current assignee: XTRA SENSE Ltd
Priority date: 2013-06-13
Filing date: 2013-06-13
Publication date: 2014-12-17
Also published as: GB201310600D0; EP2814011B1; EP2814011A1

Abstract

A cabinet alarm system is adapted to distinguish the sounds and forces of a genuine malicious attack on a cabinet from normal environmental forces and sounds to which the cabinet is routinely subjected. The alarm system comprises a timer; and at least a first and second sensor, each sensor being adapted to sense different physical inputs; and a means to trigger an alert in the successive events of: a first sensed input exceeding a first input threshold during a first time period, and after a predetermined time interval subsequent to the first time period, a second sensed input exceeds a second input threshold. The first sensor may be an acoustic noise sensor. The second sensor may be a conducted noise sensor or a thermal rate sensor. A third distortion force strain sensor may be included in the system. The acoustic noise sensor is suited to detect noise produced by a rotary grinder, a rotary cutter, and a cutting torch. The alert may be an audible or visual alarm at the cabinet itself. Alternatively, the alert may be communicated to a remote device.

Description

A Cabinet Alarm System and Method

Field of the Invention

This invention relates generally to cabinet alarm systems and methods. More s particularly this invention relates to security alarm systems and methods whereby an alert is provided only if the cabinet is subject to attack.

Background

Ticket and other vending machines are placed at locations to enable automated customer transactions and they are increasingly appearing for example at bus, tram and train stations, car parks, shopping centres and high streets.

As these machines are designed to enable automated transactions, they are typically provided at locations which may not be supervised or at least not supervised all of the time. As a consequence, machines are vulnerable to attack and vandalism, and there is a requirement to provide electronic alarms to detect inappropriate and * damaging behavior which risks the loss of the machine contents (such as money or * stock) and non-availability for use as well as expensive repairs to the cabinets or *: even complete loss due to the entire removal of the cabinets.

The nature of attacks on such machines can be divided in to the different Types of attack as follows.

Type 1 -Low impact frustration attacks where ingress is not the objective, and no damage is caused to the cabinet.

Type 2 -Vandalism where physical damaged is caused to the cabinet.

Type 3 -Concerted attempts to gain access and rob the contents.

Type 3 attacks will include: a) Use of an Oxy-acetylene or Plasma torch welding apparatus to cut holes.

b) Use of an Angle Grinder or mechanical cutter, either electrical or petrol driven, to cut holes.

c) Use of a Sledge Hammer or Lump Rammer and wrecking bar' lever to attempt to open the door.

d) Use of a vehicle or similar means to ram the machine or pull it off its mountings.

It is desirable to monitor machines to detect the occurrence of an attack and to differentiate between different types of attack. For example, a Type 1 low impact frustration attack may require one type of action; whereas a Type 2 vandalism or Type 3 attempted access attack would need different responses to be initiated.

The cabinets associated with vending and ticket machines are noticeably thinner and more flexible than a standard safe. Furthermore these cabinets are located in public areas and exposed to potentially extreme weather conditions.

One issue when monitoring a cabinet is determining when an event is a genuine attack rather than something created by a normal environmental condition, and to identify the action required by the nature of the event. This also has to be done in noisy and busy environments, such as might be found on the platform of a railway is station, where the alarm is to be fitted to a Ticket vending machine.

Prior Art * * .

Security devices and methods which could be applicable to cabinets exist. A few relevant examples are: * * * * ** UK Patent Application GB-A-2306035 for a Differential Weight Security System by Williams and Jones, *** * o UK Patent GB-B-23601 19 for Sensor Systems by Williams, Jones, and Rutcheson, S.....

UK Patent GB-B-2466721 for a Security System by Jones, EP Patent Application EP-A2-1 981010 for a Method of Detecting Lock Bumping by Smith, and FR Patent Application FR-A1-2687240 for Sispositif de protection detectant Ia solicitation du mecanisme dune fermeture et generant un signal d'information, d'aleert ou d'alarme.

Summary of the Invention

The approach of the current invention to distinguish a genuine attack from something created by a normal environmental condition is to use at least two separate technologies, generating separate responses to an attack, to raise the confidence level of a genuine event to a point where it needs to be acted upon. The present invention takes advantage of existing technology and combines it together in a novel and inventive way with other signal processing methods to detect attacks on cabinets such as ticket machines and vending machines.

In this specification acoustic noise' means noise travelling through air. An acoustic noise sensor is in contact with air and senses that noise in that air through that contact with that air.

In this specification conducted noise' means noise travelling through the structure of a cabinet. A conducted noise sensor is in contact with the cabinet and senses that noise in the structure of the cabinet through that contact with the cabinet.

is In this specification distortion' means strain in the cabinet. A distortion sensor' detects strain in the cabinet. A force applied to the cabinet causes strain in the cabinet. The distortion sensor senses this force by detecting the strain this force causes. * *

In this specification a thermal rate sensor is a timer combined with a thermometer * * sensitive to the temperature of air nearby the thermometer. The thermal rate sensor : detects the time rate of change of the air temperature.

Preferably a thermal rate sensor comprises a thermometer located inside the cabinet to detect the temperature of air inside the cabinet.

In a first aspect of the invention there is an alarm for providing an alert in response to a malicious attack, the alarm comprises: a timer; and at least a first and a second sensor, each sensor is adapted to sense different physical inputs; and a means to trigger an alert in the successive events of: a first sensed input exceeding a first input threshold during a first time period, and after a predetermined time interval subsequent to said first time period, a second sensed input exceeds a second input threshold.

Preferably the first sensor is an acoustic noise sensor that detects an acoustic noise input, and the second sensor is a thermal rate sensor comprising the timer combined with a thermometer that detects the time rate of change of air temperature; and the events are: (i) acoustic noise exceeding respective a first acoustic noise threshold during the first time period; and after the predetermined time interval, (ii)time rate of change of air temperature exceeding a time rate of change of temperature threshold.

Preferably the first sensor is an acoustic noise sensor that detects an acoustic noise input and the second sensor is a conducted noise sensor that detects a conducted noise input; and the events are: (i) acoustic noise during the first time period exceeding a second acoustic noise threshold; and within the predetermined time interval, (ii) conducted noise exceeding a first conducted noise threshold.

Preferably the first sensor is a conducted noise sensor that detects a conducted noise input, and the second sensor is a distortion sensor that detects a force input; and the events are: (i) conducted noise exceeding a second conducted noise threshold during the first time period; and after the predetermined time interval, (ii) force exceeding a first force input threshold. es

Preferably the first sensor is an acoustic noise sensor that detects an acoustic noise input, and the second sensor is a distortion sensor that detects a force input; and the events are: (i) acoustic noise exceeding a third acoustic noise threshold during the first time period; and after the predetermined time interval, (ii) force exceeding a second force threshold.

Preferably the first sensor is a distortion sensor that detects a force input in conjunction with time counted by the timer, and the events are: (i) time rate of change of force input exceeding respective a first time rate of change of force threshold during the first time period; and within the predetermined time interval, (ii) the force exceeding a fourth force threshold.

Preferably the alarm comprises a third sensor adapted to sense a third physical input different than the first and second sensed inputs; and a means to trigger an alert in the successive events of: the first and the second sensed inputs exceeding respective first and second input thresholds during the first time period, and after the predetermined time interval subsequent to said first time period, the third sensed input exceeds the third input threshold.

Preferably the first sensor is an acoustic noise sensor that detects an acoustic noise input, the second sensor is a conducted noise sensor that detects a conducted noise input, and the third sensor is a distortion sensor that detects a force input; and the events are: (i) acoustic noise and conducted noise during the first time period exceeding respective first acoustic noise and first conducted noise thresholds; and after the predetermined time interval, is (ii) force exceeding a first force input threshold, or (i) conducted noise exceeding a second conducted noise threshold during the first time period; and after the predetermined time interval, (ii) force exceeding a second force input threshold, or (i) acoustic noise exceeding a second acoustic noise threshold during the first time * . * .* period; and after the predetermined time interval, (ii) force exceeding a third force threshold, * *. or (i) time rate of change of force exceeding a time rate of change of force threshold during the first time period; and after the predetermined time interval, (ii) force exceeding a fourth force threshold. *.** *****

* Preferably the first acoustic noise threshold is different than the second acoustic noise threshold. Preferably the first conductive noise threshold is different than the second conductive noise threshold. Preferably, the first, second, third, and fourth force thresholds are different from each other.

However in certain cases the acoustic noise thresholds are the same, the conductive noise thresholds are the same, and particular force thresholds are the same.

Advantageously this means that the cabinet alarrh can be customized to trigger the alert upon an attack by a particular type of tool or combination of tools.

Preferably any or all the acoustic noise thresholds, the conductive noise thresholds, and the force thresholds can all be set by a user either before the alarm is installed in the cabinet or after the alarm is installed in the cabinet or both before and after by a S local user or a remote user.

Preferably the first sensor is an acoustic noise sensor that detects acoustic noise in the frequency range produced by a rotary grinder or cutter, and acoustic noise in the frequency range produced by a cutting torch, and acoustic noise produced by metal io on metal impact and noise in the air inside the cabinet.

Preferably the second sensor is a conducted noise sensor that detects conducted noise transferred from a noise generating device to the cabinet by direct contact between the noise generating device and the cabinet. Preferably it is detected by frequency range of conducted noise due to metal on metal impact and produced by a rotary grinder and cutter.

Preferably once the alert is provided it continues while the first sensed input exceeds the first input threshold and the second sensed input exceeds the second input threshold. * * * .

* Preferably in configurations of the cabinet alarm that comprise an acoustic sensor, * the cabinet alarm further comprises a sound recording device arranged to record : s. acoustic noise immediately before, during, and after the events which trigger the *. .* alarm.

Preferably the cabinet alarm comprises a sensor signal recording and/or transmitting *5** device to record and/or transmit signals produced by any of the sensor immediately before, during and/or an attack on the cabinet.

Advantageously by monitoring the events in this fashion the alarm is provided and the acoustic noise is recorded in the event of a malicious attack designed to damage or gain entry to the cabinet.

Advantageously by monitoring the events in this fashion the alarm is only provided and the acoustic noise is only recorded in the event of a malicious attack designed to damage or gain entry to the cabinet.

Advantageously the cabinet alarm is adapted to provide no alert when a cabinet is subject to routine noise and handling.

Preferably the alarm only provides an alert when a particular sequence of events occurs indicative of an attack on the cabinet.

Preferably the cabinet alarm comprises an acoustic noise sensor arranged to detect noise that travels through at least one air path between the noise generating device and the acoustic noise sensor, and a conducted noise sensor arranged to detect noise that travels through the cabinet directly to the conducted noise sensor; whereby the cabinet alarm provides the alert only after the conducted noise sensor detects noise above a conducted noise threshold at the same time or at a predetermined time after the acoustic noise sensor detects noise above an acoustic noise threshold.

Preferably once the alert is provided it continues until the events that initiated the alarm stop or an acknowledgement of the alert is provided back to the cabinet alarm or for a predetermined time after the alert is first provided. Preferably the predetermined time is set by the alarm user.

Preferably the cabinet alarm provides an alert in response to the occurrence of an attack event which causes major distortion of the structure of the cabinet without the 0.

generation of significant noise. 0*000 * 0

In order that the present invention may be well understood, it is further explained, by way of examples, by the following description, to be read in conjunction with the appended drawings, in which:

Brief Description of the Figures 0***

Figure 1 is a cabinet comprising a door that swings on hinges.

Figure 2 is a time trace of noise detected by an acoustic noise sensor and a conductive noise sensor before and during an attack on a cabinet by a mechanical grinder or mechanical cutter.

Figure 3 is a time trace of noise detected by an acoustic noise sensor and temperature of the air inside a cabinet before and during an attack on the cabinet by a hot gas or plasma cutting torch. &

Detailed Description of Preferred Embodiments of the Invention Figure 1 illustrates a cabinet 10 comprising a door 15 that swings on hinges 16.

The cabinet 70 is supported above, and spaced apart from, a base 20 by four supports 31, 32, 33, and 34 (not shown). Due to the supports holding the cabinet above the base there is a gap, or spacing, 40 between the bottom of the cabinet and the base. The gap allows the cabinet to move on the supports if an external force is applied to the cabinet without the cabinet contacting the base.

There is a microphone 50 inside the cabinet to detect noise that travels through the air inside the cabinet before reaching the microphone. The microphone is an acoustic noise sensor.

There is a temperature sensor 60 inside the cabinet to detect the temperature of the air inside the cabinet. The temperature sensor 60 is combined with a clock (not shown) to create a temperature rate of change sensor to detect the time rate of change of air temperature inside the cabinet.

is There is a conducted noise sensor 70 fixed to the cabinet. **

There is a distortion sensor 80 fixed to the cabinet which distortion sensor detects

S fl.*.

* distortion of the base of the cabinet due to a force applied to the exterior of the , *"* cabinet.

The supports 31, 32, 33, and 34, and gap 40 give freedom for the base to distort *; 20 under an applied force. S...

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* The present invention combines noise detection, force detection, and heat detection technologies. By identifying the signal characteristics for the acoustic noise and br the conducted noise and structural deformation generated by different types of attack on the cabinet, some, or all of these signals may be interpreted by a control microprocessor to determine the type of attack.

For example, if a wrecking bar is hammered in to the door opening to provide purchase for levering the cabinet door open, there will be characteristic acoustic signals and very large short duration conducted noise signals from the hammer blows followed by a deformation of the structure as levering is commenced. A refinement of this process is to count the number of hammer blows such that a minimum number will be required to be registered before the alarm is triggered by the subsequent levering.

s In the case of attacks by hot gas and angle grinder I cutters, it is typical for the cuffing apparatus to be started and run for a few seconds prior to its being introduced to the cabinet to be cut and, naturally enough, for this noise to continue during the cutting process.

In the case of the angle-grinder I cutter, this will generate a large conducted noise level as soon as the cuffing blade is touched on to the cabinet and if this is preceded or accompanied by a suitable acoustic noise then a serious attack is confirmed.

Figure 2 illustrates a typical time trace of noise detected by the acoustic noise sensor and the conducted noise sensor 70 before and during an attack by a grinder. The time trace is a plot of the acoustic noise signal produced by the acoustic noise sensor 50 and on the same graph a plot of the conducted noise signal produced by the conducted noise sensor 70. "

* * Almost always just before a perpetrator of an attack on a cabinet actually attacks a cabinet with a grinder or power cutter, they switch the device on. Grinders usually : * comprise a rotary cutting blade driven by a loud series electric motor or a loud compressed air motor. The loud noise is transmitted through the air inside and outside the cabinet and it is received and detected by the acoustic noise sensor. b* ö

Preferably the acoustic noise sensor is fixed inside the cabinet. This location prevents the perpetrator from covering the acoustic noise sensor with a device to muffle the noise.

Figure 2 shows the rise in the time trace of noise detected by the acoustic noise sensor when the grinder is switched on. The level of noise produced by grinder rises above the acoustic noise threshold as illustrated.

Almost always just after the perpetrator of an attack on a cabinet turns on a grinder, they begin to cut through the cabinet by bringing the culling blade into contact with the cabinet. The cutting blade imparts vibrations to the cabinet which is transmitted through the walls of the cabinet directly from the grinder to the conductive noise sensor which detects the conducted noise.

As illustrated in Figure 2 the conducted noise imparted to the cabinet by the grinder is above the conducted noise threshold after the grinder contacts the cabinet. Thus the conducted noise rises above the conducted noise threshold within a very short time after the acoustic noise rises above the acoustic noise threshold. This very short time is usually between a fraction of second and several seconds. Most often it is between half a second and two seconds.

When noise is detected by the acoustic noise sensor above the acoustic noise threshold a very short time before the conducted noise sensor detects noise above the conducted noise threshold, then there is a very high likelihood that the cabinet is being attacked by a perpetrator with a grinder. So when this series of events occurs then the cabinet alarm provides an alert of the attack.

is In the case of a hot gas cutter, the acoustic noise detected prior to detecting a rapid rise in the air temperature inside the cabinet when the cuffing flame penetrates the cabinet skin can be used as confirmation of a serious attack. The level of acoustic

S

noise inside the cabinet will also amplify significantly when the cutting flame penetrates the cabinet skin, offering an alternative confirmation of a serious attack. * S. * *5S

Figure 3 is a time trace of noise detected by an acoustic noise sensor and temperature of the air inside a cabinet before and during an attack on the cabinet by a hot gas cuthng torch.

Almost always, just before a cutting torch cuts through a cabinet, the air inside the cabinet is relatively cool and quiet.

A cutting torch makes a whistling or hissing sound. Until the flame cuts through the cabinet, the sound of the cutting torch may be below the acoustic noise threshold for the cutting torch. However, as the flame cuts into the interior of the cabinet, the whistling or hissing sound of the torch is amplified inside the cabinet and is detected by the acoustic noise sensor 50 and exceeds the acoustic noise threshold.

Until the flame cuts through the cabinet the air inside the cabinet is relatively cool.

Because the air inside the cabinet is in an enclosed space, immediately after the torch flame cuts through the cabinet to the interior the temperature of the air begins to rise quickly. Advantageously the rate of temperature rise of this air is much higher s when it is due to a torch flame in the interior of the cabinet than sunlight shining on the outside of the cabinet. Therefore a time trace of the temperature detected by the temperature sensor 60 inside the cabinet that rises faster than the temperature rise rate threshold is an indicator that a flame of a cutting torch has cut into the cabinet.

This is illustrated in Figure 3 by the time trace of the temperature of the air detected by the temperature sensor 60 inside the cabinet.

When the cabinet alarm detects acoustic noise and temperature changes over time as illustrated in Figure 3, there is a high probability that a perpetrator has attacked the cabinet with a hot gas cutting torch. That is the time series of events where: first, the temperature inside the cabinet is near constant or only gradually changing with is the weather or change from night to day, and the level of noise inside the cabinet is below the acoustic noise threshold for a cutting torch flame, then second, the level of noise inside the cabinet rises suddenly above the acoustic noise threshold for a * cuffing torch flame and also the rate of temperature rise in the cabinet is above the : *. temperature rise rate threshold for a culling torch flame. S...

An alternative form of attack, which may not involve significant levels of noise is to :r attempt to remove the cabinet from its mountings by ramming it or pulling it off with powerful machinery. Ticket and other vending machine cabinets will be bolted down using a number of floor bolts, usually one in each corner 31, 32, 33, and 34. Any attempt to forcibly remove the unit by ramming it or tying a strap or chain round it and pulling it with a vehicle or other device, will cause significant deformation of the cabinet. This will be detected as strain by the distortion sensor 80. Identifying suitable monitoring points and setting appropriate signal level thresholds allows genuine attacks to be distinguished from environmental events, such as strong winds. The sensitivity of detection of this deformation is enhanced when the cabinet is supported only by the bolts 31, 32, 33 and 34. A gap 40 of approximately 2mm between the floor of the cabinet and its pedestal or floor mounting is ideal so that all of the weight of the cabinet is distributed between the bolts 31, 32, 33 and 34.

By providing different outputs, the cabinet alarm can identify the likely nature of an attack to initiate suitable responses.

A further improvement of the cabinet alarm is the recording of acoustic information. A rolling 30 seconds of audio on a first in, first out basis and then freeze that recording S if a major alarm is generated for latter retrieval or sending as a file by the Internet or mobile networks.

The invention has been described by way of examples only. The invention is further made clear and further explained in the appended claims. Substitution of substantially equivalent features to those claimed may be made to without departing from the scope of the claims. * * * * * *

* .**** * *. * ** * * * ** ** **** * S.

**.*** * *

Claims

Claims: 1. An alarm for providing an alert in response to a malicious attack, the alarm comprises: a timer; and at least a first and a second sensor, each sensor is adapted S to sense different physical inputs; and a means to trigger an alert in the successive events of: a first sensed input exceeding a first input threshold during a first time period, and after a predetermined time interval subsequent to said first time period, a second sensed input exceeds a second input threshold.
2. An alarm according to claim I wherein the first sensor is an acoustic noise sensor that detects an acoustic noise input and the second sensor is a conducted noise sensor that detects a conducted noise input: and the events are: * . . * . (ii) acoustic noise exceeding a second acoustic noise threshold during the first time : ** 15 period; and after the predetermined time interval, fl0S (ii) conducted noise exceeding a first conducted noise threshold. ***
3. An alarm according to claim 1 wherein the first sensor is an acoustic noise sensor * that detects an acoustic noise input, and the second sensor is a thermal rate sensor comprising the timer combined with a thermometer that detects the time rate of change of air temperature; and the events are: (i) acoustic noise exceeding an acoustic noise threshold during the first time period; and after the predetermined time interval, (ii) time rate of change of air temperature exceeding a time rate of temperature threshold.
4. An alarm according to claim 1 comprising a third sensor adapted to sense a third physical input different than the first and second sensed inputs; and a means to trigger an alert in the successive events of: the first and the second sensed inputs exceeding respective first and second input thresholds during the first time period, s and after the predetermined time interval subsequent to said first time period, the third sensed input exceeds the third input threshold
5. An alarm according to claim 4 wherein the first sensor is an acoustic noise sensor that detects an acoustic noise input, the second sensor is a conducted noise sensor that detects a conducted noise input, and the third sensor is a distortion sensor that detects a force input; and the events are: (i) acoustic noise and conducted noise during the first time period exceeding respective first acoustic noise and first conducted noise thresholds; and after : * 15 the predetermined time interval, (ii) force exceeding a first force input threshold, Or (i) conducted noise exceeding a second conducted noise threshold during the first time period; and after the predetermined time interval, (ii) forceexceeding a second force input threshold, Or (i) acoustic noise exceeding a second acoustic noise threshold during the first time period; and after the predetermined time interval, (ii) force exceeding a third force threshold, Or (I) time rate of change of force exceeding a time rate of change of force threshold during the first time period; and after the predetermined time interval, (ii) force exceeding a fourth force threshold.
6. An alarm according to claim 5 wherein the first acoustic noise threshold is different than the second acoustic noise threshold.
7. An alarm according to claims 5 or 6 wherein the first conducted noise threshold is different than the second conducted noise threshold.
8. An alarm according to claims 5, 6, or 7 wherein the first, second, third, and fourth force thresholds are different.
9. An alarm according to any preceding claim in which the first sensor is an acoustic noise sensor that detects acoustic noise in the frequency range produced by a * rotary grinder or cutter, and acoustic noise in the frequency range produced by a cutting torch, and acoustic noise produced by metal on metal impact and noise in the air inside the cabinet.*
10. An alarm according to any preceding claim in which the second sensor is a conducted noise sensor that detects conducted noise transferred from a noise generating device to the cabinet by direct contact between the noise generating device and the cabinet.
11. An alarm according to claim 4 in which the third sensor is a distortion sensor that detects strain changes in the structure S the cabinet caused by force applied directly to the cabinet.
12. An alarm according to any preceding claim in which once the alert is provided it continues while the first sensed input exceeds its respective input threshold and the second sensed input exceeds its respective input threshold.S13. An alarm according to any proceeding claim where the means to provide an alert is suitable for connection to a wireless or a hardwired transmitter.14. An alarm according to any preceding claim wherein the predetermined time interval is substantially zero.15. A cabinet alarm according to any preceding claim in which the cabinet alarm comprises an acoustic sensor, further comprising a sound recording device arranged to record acoustic noise during the events which trigger the alarm.* .. 15 * . . **..16. A cabinet comprising an alarm according to any preceding claim. * a... **".*