GB2310065A - Security apparatus - Google Patents

Abstract

Transmitters, attached to items (e.g. computers) to be protected, each transmit a respective coded signal (e.g. rf) to a control unit to give an alarm, if the item is moved. The control unit can be disabled from so responding. Each transmitter can be individually disabled using a respective coded key 26 (having a respective resistance or capacitance), insertion of an invalid key will also give an alarm.

Description

SECURITY APPARATUS The present invention relates to a security apparatus. It finds particular application in protecting an area in which a plurality of discrete units of equipment are kept. For example, the equipment may be personal computers (PC), or display stock of electronic consumer goods, or the like.

Theft of or from personal computers is a growing problem. Often the target for thieves is components within the computer, usually the memory chips. This is because the value per unit weight of a computer memory chip is extremely high in relation to most articles. It is not unknown for thieves to enter premises, open computers and remove the memory chips. They then depart with the chips, leaving the rest of the computer behind.

Alarm systems for PCs exist, by these generally protect the computer itself. Examples are shown in W094/16420 and W094/01843. Such devices will not protect the memory chips, since the thieves in this instance do not remove the computer.

Usually, an office containing PCs or a retail establishment containing displays of consumer electronic goods will protect the area with a general burglar alarm. This will often employ a PIR sensor covering the relevant area which will detect movement of hot objects such as people. However, in an office environment the alarm must be deactivated if a person somewhere in the building is working late. Thus, thieves could enter another part of the building unbeknown to the person present. Alternatively, the presence of patrolling security guards will mean that the alarm system must be disabled.

It is possible for thieves to enter one floor of an office whilst security guards are patrolling another floor and to have completed their task and to have left before security guards reach the relevant floor.

In a retail environment, the presence of customers means that a PIR sensor is inappropriate. However, it is still necessary to detect the attempted removal of a display item whilst allowing access thereto for inspection purposes.

The present invention provides, in its first aspect, a security apparatus comprising a control unit associated with a receiver unit and an attentiondiverting means, and at least one transmitter, including a motion sensor and transmitter unit, and adapted to send a signal when the motion sensor detects motion; wherein the control unit has an active state and a passive state and is adapted to locate the attention-diverting means when the receiver unit detects the signal whilst the control unit is in the active state.

Preferably, there are a plurality of transmitters, and each transmitter preferably sends out a different coded signal.

Preferably, each transmitter includes a coded disabling key.

The transmitter and receiver will ideally operate using rf signals.

Other (preferably wireless) links are however useable.

Thus, in this aspect of the invention, an individual transmitter can be attached to each item to be protected. Thus, if and when that item is moved, the transmitter sends out a signal which is received by the receiver.

If the system is activated, an alarm is triggered. For example in an office, movement of computers etc during the day will not trigger the system because although the transmitter will send a signal, the system will be deactivated. During the night, any movement of a computer will trigger the alarm. Such movement will be inevitable if a burglar is to gain access to internal components or to remove the computer itself. However, in the preferred form of the system, an individual transmitter can be disabled using the coded key, and thus the system as a whole can be armed but leaving one particular computer (for example) unaffected. Thus, an employee who is working late can do so whilst the remainder of the office is alarmed.

Also, it is possible for security guards etc to patrol the area whilst the alarm is activated so long as they do not disturb computers etc.

The attention-diverting means can be any known form of alarm signal.

A bell or siren will suffice, but this is not essential and may be replaced by a pager or auto dial system. The latter will enable action to be taken against burglars without alerting them to the fact that their presence has been discovered.

The second aspect of the invention relates in more detail to the disabling key of the first aspect. According to this aspect, the present invention provides a security device comprising a triggering means adapted to initiate an alarm signal when the device is not inhibited, an inhibition means adapted to receive a key, capable of inhibiting the system, the key comprising an electrical component being one selected from within a class of such which is a range of such components of identical characteristic but which differ in the quantum of that characteristic, the inhibition means being adapted to measure the quantum of that characteristic and compare it to a pre-set standard, the inhibiting means being adapted only to inhibit the system if a key including a component of the correct quantum is present.

As a practical matter, the correct quantum will include those within a certain error range of the pre-set standard. A suitable range of error is plus or minus 10%.

It is preferred if the system is adapted to trigger the alarm system signal if an incorrect key is inserted.

A suitable electrical component is a resistor or capacitor, preferably a resistor. Suitable values of resistance are those from 1 kQ and 10 kQ.

Thus, a cheap and simple key is provided, but which is still able to include a wide range of coded values. In addition, such a key can easily be read by an electronic circuit.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying Figures, in which; Figure 1 is a schematic side view of the transmitter unit of the present invention attached to an article to be protected; Figure 2 is a schematic illustration of the circuitry within the transmitter unit of Figure 1; Figure 3 is a schematic illustration of the receiver and control unit; and Figure 4 is a schematic illustration of an alternative arrangement: Figure 1 shows a transmitter unit 10 attached to a device 1 2 which is to be protected. The transmitter unit 10 is attached, in this case, by a strip 14 of double sided sticky tape. However, this could be replaced by hook and loop fastening (Velcro TM) or epoxy resin. It will be noted, for reasons that will be apparent later, that a firm anchoring is not necessary.

On the exterior face of the transmitter 10 is a socket 1 6 for receiving a key and an-indicator light 18.

Figure 2 shows the electronics, in schematic form, of the transmitter 10 of Figure 1. A transmitter device 20 is arranged to supply an rf signal to an aerial 22. Associated with the transmitter unit 20 is a tilt/tremble detector 24 which has an indicator light 18 (Figure 1) when a tilt/tremble sensor 24 is activated, it illuminates the LED 18.

In Figure 2, a key 26 comprising an electrical resistor is inserted into the socket 1 6. The resistance is measured by the test unit 28. The test unit 28 is connected to the transmitter 20 via two control lines. One control line 30 is activated if a key 26 is of the correct resistance, whilst the other control line 32 is activated if a key 26 is of an incorrect resistance. Neither control line is activated if no key is inserted.

The transmitter unit 20 is configured so as to send a predetermined rf signal in either of the following situation; when the tilt/tremble detector 24 is activated and the control line 30 is not activated (no key present), or the control line 22 is activated (incorrect key) regardless of the state of the tilt/tremble detector 24.

The tilt/tremble detector 24 will be triggered if the transmitter 10 is removed against the strip 14 of sticky tape or hook and loop fastening.

Thus, firm anchoring such as epoxy resin is not strictly necessary as this form of tampering is detected automatically.

Not shown in Figure 2 is an external power supply for the transmitter.

This includes a step-down transformer converted to the mains power and a rectified and smoother to provide a regulated low voltage DC supply to the transmitter via a jack socket. The transmitter also includes an internal battery back-up in the form of rechargeable cells maintained in a charged state by a trickle charger powered by the external power supply. Should the mains power fail, the battery can supply sufficient power to run the transmitter for approximately five hours.

In this embodiment, a number of transmitters according to Figure 2 are provided. Each is coded with a unique rf signal, so that each transmitter can be identified from its signal.

Figure 3 shows in schematic form the electronics of the remainder of the system. An aerial 34 and associated receiver unit 36 receive unit signals from transmitter unit 20. Any signals received are decoded to identify the individual transmitter, and an identification of that transmitter is passed to a control device 38 via a bus 40. The control device 38 has an associated on/off switch (not shown). This switch may be key-activated or keypad controlled for additional security. If a transmitter identification message is received by the control unit 38 when the system is switched on, a sounder 42 is activated, in this embodiment.

The sounder 42 can, of course, be replaced by a bell, an auto dial system, or a pager system.

The control unit 38 can, if desired, be integrated within a general alarm system for the building.

Thus, this invention allows the system as a whole to be armed and thus protect the majority of the components, but simultaneously allows individual items to be dis-armed, allowing their use. It also allows personnel to approach closely the items, so long as they do not disturb them. If the tilt/tremble sensor 24 is made relatively insensitive, this should allow customers to inspect items on sale, but should trigger the system should the customer attempt to steal the items. In these circumstances, a firmer anchoring 14 such as epoxy resin may be desirable, depending on the chosen sensitivity of the sensor 24.

Figure 4 shows an alternative arrangement according to the present invention. A plurality of computers 50, in this case six, each include a motion sensor as described above. A key is provided for each computer 50 which is arranged to disable the motion sensor as above. The six motion sensors are connected by wires 52 in a 'daisy chain' formation ending with a transmitter 54, also as set out above.

This single transmitter 54 is adapted to send, when triggerred, an rf signal 56 as above to a receiver unit 58. This decodes the rf signal 56 and sends a signal to the building alarm 62 via a wire link 60. If the building alarm 62 is set, the alarm will then be triggerred. The receiver 58 can if desired be integrated into the alarm 62, as shown by alternative transmission path 64.

Thus, according to this alternative, groups of computers or the like can be protected by a single transmitter. This multiplies the numbers of computers that can be protected with a limited number of transmitter codes or frequencies, at the expense of less accuracy in determining which computer was disturbed.

It will of course be appreciated by those skilled in the art that the above described embodiments are purely illustrative of the present invention, and many modifications may be made without departing from the scope of the invention. For example, the radio frequency signal could be replaced with an alternative wireless link such as microwave, IR or ultrasound link.

Claims (11)

1. A security apparatus comprising a control unit associated with a receiver unit and an attention-diverting means, and at least one transmitter including a motion sensor and transmitter unit and adapted to send a signal when the motion sensor detects motion; wherein the control unit has an active state and a passive state and is adapted to activate the attention-diverting means when the receiver unit detects the signal whilst the control unit is in the active state.

2. A security apparatus according to claim 1 wherein there are a plurality of transmitters.

3. A security apparatus according to claim 2 wherein each transmitter sends out a different coded signal.

4. A security apparatus according to any preceding claim wherein the or each transmitter includes a coded disabling key.

5. A security apparatus comprising; a triggering means adapted to initiate an alarm signal when the device is not inhibited, an inhibition means adapted to receive a key, capable of inhibiting the system, the key comprising an electrical component being one selected from within a class of such which is a range of such components of identical characteristic but which differ in the quantum of that characteristic, the inhibition means being adapted to measure the quantum of that characteristic and compare it to a pre set standard, the inhibiting means being adapted only to inhibit the system if a key including a component of the correct quantum is present.

6. A security apparatus according to claim 5 wherein the correct quantum includes those within a pre-set error range of the pre-set standard.

7. A security apparatus according to claim 6 wherein the range of error is plus or minus 10%.

8. A security apparatus according to any one of claims 5 to 7 being adapted to trigger the alarm system signal if an incorrect key is inserted.

9. A security apparatus according to any one of claims 5 to 8 wherein the electrical component is a resistor or capacitor.

1 0. A security apparatus according to claim 9 wherein the electrical component is a resistor of resistance between 1 kn and 10 kQ.

11. A security apparatus substantially as any one described herein with reference to the accompanying drawings.