GB2551491A

GB2551491A - Bell box for a security alarm

Info

Publication number: GB2551491A
Application number: GB1610458.0A
Authority: GB
Inventors: O'connell Michael; Galbraith Colin; David Green Jonathan
Original assignee: Orisec Ltd
Current assignee: Orisec Ltd
Priority date: 2016-06-15
Filing date: 2016-06-15
Publication date: 2017-12-27
Anticipated expiration: 2036-06-15
Also published as: GB201610458D0; GB2551491B

Abstract

An alarm bell box 1 having a housing 24, a light emitting module 25 and an adjustment module 27 where the brightness or intensity of the emitted light 26 is varied by the adjustment module. The adjustment module 27 can be a processor 32 which receives a signal from an input device 12 to change between at least two modes. The at least two modes relate to different intensities of emitted light. In one embodiment, the adjustment module may operate in a first mode or a second mode depending on the state of a switch 12 upon powerup. In the first mode, the brightness of the light emitting module may be adjusted. The switch 12 can be an anti-tamper switch. The alarm bell box may also have a memory 30 to store the modes which can be in a predetermined sequence.

Description

Bell Box For A Security Alarm

The present invention relates to a bell box for a security alarm. In particular, it relates to a bell box for a security alarm that is provided with an illumination mechanism.

Many intruder alarm systems comprise at least one bell box (also known as “external sounders” or “warning devices”), which is typically disposed on an external wall of a property that comprises the alarm system. Such bell boxes may contain audio and visual signalling devices, such as an alarm sounder or bell and a strobe light which may be activated if there is an attempted break in at the property. Bell boxes can play an important role in an intruder alarm installation because they indicate to the outside world, and therefore any potential intruders, that the property is protected by an alarm system. The bell box can therefore act as a deterrent to potential intruders.

Bell boxes may include means to illuminate the bell box. This may be used, for example, when it is dark outside. This illumination feature has two purposes. First, it clearly highlights to any potential intruders that the property is alarmed even during darkness. Second, the bell box can be personalised with details of the alarm installer, for example it may have a name, logo or the like. The illumination feature can therefore provide enhanced brand visibility for the installer.

It may be desirable to provide an alternative box for a security alarm which at least partially addresses one or more of the problems of the prior art, whether identified herein or elsewhere.

According to a first aspect of the invention there is provided an alarm bell box comprising: a housing; a light-emitting module disposed in the housing and operable to emit light; and an adjustment module operable to provide a control signal to the light-emitting module; wherein the light-emitting module is configured such that upon receipt of a control signal from the adjustment module a brightness of the light emitted by the light-emitting module is adjusted.

The alarm bell box according to the first aspect of the invention is advantageous because it allows a user (for example an installer of an alarm system) to control the brightness of the light emitting module. This allows the bell box to be installed in a plurality of different environments where, in general, different requirements may be imposed on the brightness of light emitted by the bell box. For example, it may allow the bell box to be used both in commercial and residential environments.

The first aspect of the invention may be of particular benefit if the bell box is to be installed in an environment where it is desirable for the brightness of light emitted by the bell box to be within a particular range. For example, if the bell box is used as part of a residential installation (where, for example, the bell box may be attached to an external wall of a house) it may be desirable for the brightness to be below a particular level so as to ensure that it does not cause annoyance to neighbours or contravene local light pollution or planning regulations or bylaws.

The light-emitting module may comprise a processor (for example a microcontroller) and one or more light emitting diodes (LEDs). The adjustment module may comprise a processor (for example a microcontroller). The light-emitting module and the adjustment module may share a common processor.

The housing may comprise a back plate and a cover which cooperate to define an internal volume. At least a portion of the cover may be translucent.

It will be appreciated that the light-emitting module may comprise one or more LEDs and for such embodiments the brightness may be a time averaged or perceived brightness. Emission of light from the LEDs brightness may be controlled by any suitable means, for example the control may be achieved by electronics, which may include a microcontroller, and which produces a pulse width modulated (PWM) control signal that is provided to the LEDs. For example, the LEDs may be pulsed using an appropriate control signal, at a sufficiently high frequency that the individual pulses cannot be distinguished by the human eye. The perceived brightness by, for example, the human eye is effectively a time averaged brightness which is dependent on the duty cycle of the control signal. The brightness can be controlled by controlling the duty cycle of the control signal. For example, the frequency of the pulsed control signal may remain fixed and the width of the pulses may be varied.

The adjustment module may be switchable between at least two operational modes. The at least two operational modes may comprise: a first mode wherein the adjustment module is operable to produce and send the control signal to the light-emitting module and a second mode wherein the adjustment module is operable to produce and send a signal for another purpose.

For example, when in the second mode the adjustment module may be operable to produce and send a signal to another device.

The adjustment module may generally operate in the second mode. The second mode may therefore be referred to as the nominal mode. When it is desired to adjust the brightness of the light-emitting module, the adjustment module may be switched to the first mode. When the brightness of the light-emitting module has been adjusted, the adjustment module may be switched back to the second mode.

An advantage of such an arrangement is that one or more existing components can be used for brightness control without requiring any additional components, which would add cost to the bell box.

The adjustment mechanism may, for example, be switched to the first mode when the alarm system switches to a safe mode (often referred to in art as “engineer hold off mode”).

The adjustment module may be configured to switch between the first and second modes in response to a mode control signal.

The mode control signal may be received on a mode control terminal or pin. For example, if a first voltage is supplied to the mode control terminal or pin (for example 0 V) then the adjustment module may operate in the first mode and if a second voltage is supplied to the mode control terminal or pin (for example 12 V) then the adjustment module may operate in the second mode.

The mode control signal may be supplied by a control panel or the like to which the bell box is connected. In order for a user (for example an installer) to control the mode control signal that is sent from a control panel to the bell box, it may be necessary to enter an authentication code (for example an engineer’s code).

The adjustment module may comprise a switch and, upon power up of the alarm bell box the operational mode of the adjustment module may be dependent on a state of the switch.

For example, if on power up the switch is open (closed) the adjustment module may operate in the first mode whereas if on power up the switch is closed (open) the adjustment module may operate in the second mode.

This may allow an installer to automatically place the adjustment module in the first mode so that the brightness can be adjusted or not as desired upon power up of the alarm bell box.

The adjustment module may be configured to switch from the first mode to the second modes upon actuation of the switch from a first state to a second state. For example, the adjustment module may be configured to switch from the first mode to the second modes upon actuation of the switch from a first state to a second state for a predetermined time period. That is, if the state of the switch upon power up is such that the adjustment module automatically enters the first mode (for example the switch is open), changing the state of the switch (i.e. closing the switch) may switch the adjustment module to the second mode.

The adjustment module may comprise an input device arranged to receive an input signal. This allows a user to input a signal so as to control the brightness.

The input device may comprise a switch disposed in the housing.

With such an arrangement a user (for example an alarm system installer) can use the switch to adjust the brightness of the light-emitting module. Since the switch is disposed in the housing, a first advantage of such an arrangement is that the brightness level can be controlled locally and it may therefore be easy for a user to visually monitor the brightness level while it is being adjusted. A second advantage of this arrangement is that because the brightness is adjusted locally at the bell box, the bell box may be connected to any make of alarm control panel. That is, no modification to other parts of the alarm system (for example the control panel or wireless or physical connection between the control panel and the bell box) is necessary. Advantageously, this allows the bell box according to be more flexible and allows the bell box to be retrofit to existing systems if desired.

The switch may be a micro-switch. The switch may be an anti-tamper switch. That is, when the adjustment module is in the second mode the anti-tamper switch may be operable to produce and send a signal to one or more audio or visual indicator devices (for example piezo sounders or strobe lights) and/or a control panel.

The input signal may be received by actuation of the switch. For example, moving the switch from a closed state to an open state may generate a signal. Different input signals may be generated by moving the switch between the closed state and the open state by a different number of times.

The switch may be biased into one position (for example an open state). Each time the switch is closed, the brightness may be adjusted.

Additionally or alternatively, the input device may comprise an input terminal or pin. By controlling for example a voltage of the input terminal or pin, different brightness levels can be selected. The voltage supplied to the input terminal or pin may be controlled, for example, by a control panel or the like.

The light-emitting module may be configured to emit light while the adjustment module is operating in the second mode. Advantageously, this allows the light to be visually inspected while the brightness is being adjusted.

The light-emitting module may be configured to have a plurality of selectable modes. The brightness of the light emitted by the light-emitting module may be dependent on a current mode of the light-emitting module and adjustment of the brightness of the light emitted by the light-emitting module may be achieved by changing the current mode of the light-emitting module from one of the plurality of selectable modes to another of the plurality of selectable modes. This way, a user may be provided with a plurality (for example eight) different brightness levels and can select one as desired or required.

The control signal may comprise one or more pulses and the brightness of the light emitted by the light-emitting module may be dependent on the number of pulses.

The brightness of the light emitted by the light-emitting module may be further dependent on a default or starting brightness level or mode of the light-emitting module.

Each pulse may be generated by an actuation of the switch. Alternatively, each pulse may be input to the adjustment mechanism via an input terminal or pin.

The plurality of selectable modes of the light-emitting module may be ordered and stored in a predetermined sequence. Each pulse of the control signal may cause the mode of the light-emitting module to change from one of the plurality of selectable modes to the next one of the plurality of selectable modes in the predetermined sequence. For example, the plurality of selectable modes may be stored in order of brightness (for example from lowest to highest). A mode stored in memory (for example in a non-volatile memory) may act as a default or starting mode.

The alarm bell box may further comprise a memory, which may be configured to store the mode of the light-emitting module. The memory may comprise non-volatile memory.

The alarm bell box may further comprise a photo sensor arranged to output a light level signal indicative of an ambient light level to the light-emitting module. The light-emitting module may be configured to emit light only when the ambient light level is below a threshold.

Various aspects and features of the invention set out above or below may be combined with various other aspects and features of the invention as will be readily apparent to the skilled person.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

Figure 1 shows a back plate for a bell box according to an embodiment of the present invention.

Figure 2 shows a cover for releasable cooperation with the back plate of Figure 1;

Figure 3 shows a bell box comprising the back plate of Figure 1 connected to the cover of Figure 2 via a hinge, the cover being disposed in an open configuration; and

Figure 4A shows a lighting panel being inserted into an interior of the cover of Figure 2;

Figure 4B shows the lighting panel received in and engaged with an interior of the cover of Figure 2;

Figure 5 is a schematic representation of the bell box according to the present invention, parts of which are shown in Figures 1 to 4B;

Figure 6 is a schematic representation of a first specific embodiment of the bell box schematically shown in Figure 5; and

Figure 7 is a schematic representation of a second specific embodiment of the bell box schematically shown in Figure 5. A security alarm system may comprise, among other components, one or more bell boxes. A bell box 1 according to an embodiment of the present invention is now described with reference to Figures 1 to 5.

The bell box 1 comprises a back plate 2 and a cover 3. The back plate 2 is for attachment to a surface. In use, the bell box 1 is typically provided on an external wall of a building that is protected by the security alarm system. The back plate 2 is typically attached to a surface of the exterior wall using screws or the like, in a conventional manner. To achieve this, the back plate 2 comprises six apertures 5 that allow back plate 2 to be attached to the external surface of a building (for example a wall), in a conventional manner. Each of the six apertures 5 is provided as an elongate slot on a generally circular insert 6 which is connected to a main body of the back plate 2 such that it can rotate relative thereto. This rotation of the circular inserts 6 (relative to the back plate 2) can aid an installer since it allows a greater tolerance for the placement of holes for fixing screws (which holes may be drilled in a brick wall or the like).

Referring to Figure 3, the cover 3 is connected to the back plate 2 by a hinge such that the cover 3 can rotate relative to the back plate 2 about an axis 9. The cover 3 can rotate between an open positon (as shown in Figure 3), wherein the back plate 2 can be accessed, and a closed position. When the cover 3 is disposed in the closed position the cover 3 cooperates with the back plate 2 so as to define an internal volume. The back plate 2 and cover 3 may be considered to form a housing of the bell box 1.

When the cover 3 is disposed in the closed position the cover 3 can be fixed to the back plate 2. This fixing is achieved by way of one or more fixing members 8 such as, for example, conventional screws or bolts. For this purpose, the back plate 2 further comprises two attachment features 7 for releasable engagement with the two fixing members 8 (see Figure 2).

Each fixing member 8 is generally of the form of a bolt with a shank portion and a head portion. The shank portion is inserted into a fixing aperture in the cover 3 from an external surface 10 of the cover into the internal volume defined by the back plate 2 and the cover 3. The shank portion passes through the fixing aperture in the cover 3 and engages with one of the attachment features 7. The engagement may for example be achieved by rotation of the fixing member 8. The head portion is larger than the fixing aperture in the cover 3 and remains on an exterior of the cover 3. Optionally, the head portion may be received within a recess formed on the exterior surface 10 of the cover 3.

The internal volume defined by the back plate 2 and the cover 3 houses internal components of the bell box 1. Such internal components are typically attached to the back plate 2. As can be seen in Figures 1 and 3, in the example embodiment the following are attached to the back plate 2: two piezo sounders 11, a micro-switch 12 and a compartment 13 for housing control electronics (not shown). The compartment 13 may also house a battery arranged to provide power to the control electronics. The control electronics are connected to the micro-switch 12 and the two piezo sounders 11. The control electronics are also connected to one or more other components of the security alarm, for example a control panel, which is typically internal to a building to which the bell box is attached. The compartment 13 may also house a visual signalling device (for example a strobe light), which may be connected to the control electronics.

The micro-switch 12 acts as an anti-tamper switch. To achieve this, the micro-switch 12 comprises an actuator lever 14 which is forced closed when the cover 3 of the bell box is disposed in the closed position. The micro-switch 12 is biased open such that it is arranged to spring open when the cover 3 moves towards the open position.

The bell box further comprises a lighting panel 15. The lighting panel 15 is of the form of a generally flat, thin panel. A size and shape of the lighting panel 15 generally match those of a front face of the bell box 1. As shown in Figures 4A and 4B, the lighting panel 15 is connected to an interior surface 16 of the cover 3 by way of fixing features 17, 18. To achieve this connection, the lighting panel 15 may be inserted into an internal space of the cover 3 at an angle to the interior surface 16 such that a leading edge 19 of the lighting panel 15 engages with first fixing features 17 provided on one side of the cover 3. This is illustrated in Figure 4A, which shows the lighting panel 15 being inserted into the internal space of the cover 3 generally along arrow 20 at an angle of around 40° to the interior surface 16. Once the leading edge 19 of the lighting panel 15 engages with the first fixing features 17 an opposed or trailing edge 21 is pushed towards the interior surface 16 of the cover 3 until the lighting panel 15 is generally parallel to the interior surface 16. This is illustrated in Figure 4B, which shows the trailing edge 21 being pushed towards the interior surface 16 of the cover 3 generally along arrow 22. When the lighting panel 15 is generally parallel to the interior surface 16, the trailing edge 21 of the lighting panel 15 engages with second fixing features 18. The lighting panel is then retained generally parallel to the interior surface 16 of the cover 3 by first and second fixing features 17, 18.

In use, the lighting panel 15 is operable to emit light. In particular, the lighting panel 15 is operable to emit light generally uniformly from a surface of the lighting panel 15 which, in use, is disposed adjacent to the interior surface 16 of the cover 3. The light is emitted in a direction that is generally perpendicular to said surface of the lighting panel 15.

In use, the lighting panel 15 is electrically connected to control electronics, which may be disposed within the compartment 13. This electrical connection is achieved via a wire 23. By sending a suitable control signal to the lighting panel 15 via wire 23, the emission of light from the lighting panel may be controlled remotely.

The lighting panel 15 may comprise a plurality of light-emitting diodes (LEDs) disposed along one edge of the lighting panel 15. The plurality of LEDs may all be connected to the wire 23. For example, the LEDs may be mounted on a generally strip shaped printed circuit board (PCB) that extends along the edge of the lighting panel 15. The connection of each of the LEDs to the wire 23 may be via said PCB. Each of the LEDs may be arranged to emit light in a direction generally parallel to a plane of the lighting panel 15. The lighting panel 15 may be considered to form a waveguide and the light emitted by the LEDs may be transmitted to an opposite edge of the lighting panel 15 to the LEDs by total internal reflection. The lighting panel 15 is further provided with a plurality of light directing features that are arranged to direct a portion of light propagating through the plane of the lighting panel 15 out of the lighting panel 15 in a direction that is generally perpendicular to the plane of the lighting panel 15. The plurality of light directing features is arranged such that light is emitted generally uniformly from a surface of the lighting panel 15.

At least a portion of the cover 3 is formed from a transparent or translucent material. The light emitted by the lighting panel 15 is transmitted by such portions of the cover 3. The effect is that when light is emitted by the lighting panel 15, the bell box 1 appears to be illuminated from within its interior volume.

Figure 5 is a schematic illustration of the bell box 1 according to the present invention. As described above, the bell box 1 comprises a housing 24 (formed by back plate 2 and cover 3). The bell box 1 further comprises a light-emitting module 25 disposed in the housing 24 and operable to emit light 26. The light-emitting module 25 may comprise the lighting panel 15 described above and a suitable processor. The bell box 1 further comprises an adjustment module 27. The adjustment module 27 is operable to provide a control signal 28 to the light-emitting module 25. The light-emitting module 25 is configured such that upon receipt of a control signal 28 from the adjustment module 27 a brightness of the light 26 emitted by the light-emitting module 25 is adjusted.

Various different embodiments of the bell box 1 illustrated schematically in Figure 5 are now described by way of example. A first embodiment of a bell box 1 according to the present invention is shown in Figure 6.

The light-emitting module 25 comprises the lighting panel 15 described above, a processor 29 and a memory 30. The processor 29 may form part of the lighting panel 15. For example, the processor may be disposed on the PCB to which the LEDs are attached. Additionally or alternatively, the processor 29 may be disposed within compartment 13. The processor 29 is operable to read from and to write to the memory 30. The memory 30 may comprise a non-volatile memory.

As shown in Figure 6, in this embodiment the micro-switch 12 forms part of the adjustment module 27. The adjustment module 27 further comprises a processor 31.

In Figure 6, each of the light-emitting module 25 and the adjustment module 27 are shown as comprising a processor 29, 31 respectively. In practice, the functionality of two processors 29, 31 may be provided by two separate processors. Alternatively, the functionality of two processors 29, 31 may be provided by a single processor, as indicated by dashed line 32. The processors 29, 31 may for example comprise a central processing unit (CPU), a microcontroller and/or a programmable logic device, such as, a field-programmable gate array (FPGA).

The micro-switch 12 may be considered to be an input device that is arranged to receive an input signal (for example by manual actuation of the micro-switch). Since the micro-switch 12 is disposed in the housing 24 formed by the back plate 2 and the cover 3, this embodiment allows the brightness level of the light-emitting module 25 to be controlled locally. This may allow a user to visually monitor the brightness level while it is being adjusted. Furthermore, because the brightness is adjusted locally at the bell box 1, the bell box may be connected 1 to any make of alarm control panel. That is, no modification to other parts of the alarm system (for example the control panel or wireless or physical connection between the control panel and the bell box) is necessary. Advantageously, this allows the bell box 1 to be more flexible and allows the bell box 1 to be retrofit to existing systems if desired.

As described above the micro-switch switch 12 acts as an anti-tamper switch. Therefore, during normal operation of the bell box 1, the micro-switch provides antitamper detection for the bell box 1. Flowever, during installation or maintenance of the bell box 1, the anti-tamper function may be disabled (for example by entering an engineer’s code into a control panel) such that the micro-switch 12 would otherwise be redundant. Therefore, in order for the micro-switch 12 to form part of the adjustment module 27, the adjustment module 27 is switchable between a first operational mode and a second operational mode. When in the first operational mode the adjustment module 27 is operable to produce and send the control signal 28 to the light-emitting module 25.

The adjustment module 27 generally operates in the second operational mode, which may be referred to as the nominal mode. When operating in the second operational mode, the micro-switch 12 acts as an anti-tamper switch and the processor 31 is operable to produce and send a control signal 33 for an alarm indicator 34. The alarm indicator 34 may comprise the piezo sounders 11 and/or a strobe light 35. The microswitch 12 is operable to produce a signal 36 indicative of its state (i.e. whether it is open or closed). When operating in the second operational mode, this signal 36 may be received by the processor 31 which is operable to control operation of the piezo sounders 11 and/or the strobe light 35 in dependence thereon (via signal 33). For example, if the micro-switch 12 is closed, the processor does not actuate the piezo sounders 11 or the strobe light 35 whereas if the micro-switch 12 is open, the processor actuates the piezo sounders 11 and the strobe light 35.

When it is desired to adjust the brightness of the light-emitting module 25, the adjustment module 27 can be switched to the first operational mode. In this embodiment, this may be achieved in one of two ways, as now described.

Upon power up of the alarm bell box the operational mode of the adjustment module is dependent on the state of the micro-switch 12. For example, if on power up the microswitch 12 is open the adjustment module 27 may operate in the first operational mode whereas if on power up the micro-switch is closed the adjustment module may operate in the second operational mode. This allows an installer to automatically place the adjustment module 27 in the first operational mode so that the brightness of light-emitting module 25 can be adjusted upon installation. The installer can, for example, power up the bell box 1 with the cover 3 disposed in the open position (as in Figure 3) so that micro-switch 12 is open. This provides a first way of placing the adjustment module 27 in the first operational mode.

Additionally or alternatively, the adjustment mechanism 27 may comprise a mode control pin or terminal 37, which may provide a mode control signal 38 to the processor 31. The mode control pin 37 may be connected to a control panel of an alarm system to which the bell box is connected. The mode control signal 38 may therefore be supplied by a said control panel. If a first voltage is supplied to the mode control pin (for example 0 V) then the adjustment module 27 may operate in the first operational mode and if a second voltage is supplied to the mode control pin 37 (for example 12 V) then the adjustment module 27 may operate in the second operational mode.

In order for a user (for example an installer) to control the mode control signal 38 that is sent from a control panel to the bell box 1, it may be necessary to enter an authentication code (for example an engineer’s code). The adjustment module 27 may be switched to the first operational mode when the alarm system switches to a safe mode (often referred to in art as “engineer hold off mode”).

The provision of a suitable mode control signal 38 to the processor 31 via the mode control pin 37 therefore provides a second way of placing the adjustment module 27 in the first operational mode. Once the adjustment module 27 has been thus placed in the first operational mode, the cover 3 can be moved from the closed positon to the open position without actuating the alarm indicator 34.

The bell box 1 is configured such that the light-emitting module 25 continuously emits light while the adjustment module 27 is operating in the second operational mode. Advantageously, this allows the light 26 to be visually inspected while the brightness is being adjusted.

Once the adjustment module 27 is in the first operation mode, the brightness of the light-emitting module can be adjusted. In this embodiment, this adjustment is achieved using the micro-switch 12 as an input device of the adjustment module 27.

An input signal may be received by the adjustment module 27 by actuation of the micro-switch 12. For example, moving the micro-switch 27 from a closed state to an open state may generate a signal. This is illustrated in the insert of Figure 3, which shows that the actuator lever 14 of the micro-switch 12 may be used to open and close the micro-switch 12 as generally indicated by arrow 39. A user can depress the actuator lever 14 to close the micro-switch 12. Since the micro-switch 12 is biased open, subsequently releasing the actuator lever 14 causes the micro-switch 12 to automatically spring open.

The signal input by a user using micro-switch 12 may be generally of the form of one or more pulses. For example, the micro-switch 12 may be connected in series with a resistor (not shown) between a power supply and ground (i.e. a reference voltage). Each time the micro-switch 12 is actuated, for example by pressing and releasing the actuator lever 14, the micro-switch 12 is turned on and off once. This generates a voltage pulse at a node between the micro-switch 12 and the resistor. Furthermore, a current pulse is generated in the current flowing through the micro-switch. The processor 31 is operable to monitor each actuation of the micro-switch 12, for example by detecting the voltage or current pulses generated thereby. The processor 31 may be operable to count the number of actuations of micro-switch 12. Upon receipt of such a pulse, the processor 31 may send a control signal 28 to the processor 29 of the light-emitting module 25. Different input signals may be generated by actuating the micro-switch a different number of times. Each time the micro-switch 12 is closed, the brightness of the light-emitting module 25 may be adjusted.

The light-emitting module 25 is configured to have a plurality of selectable modes. The brightness of the light 26 emitted by the light-emitting module 25 is dependent on a current mode of the light-emitting module 25. Upon receipt of control signal 28, adjustment of the brightness of the light emitted by the light-emitting module 25 is achieved by changing the current mode of the light-emitting module 25 from one of the plurality of selectable modes to another of the plurality of selectable modes. This way, a user may be provided with a plurality (for example eight) different brightness levels and can select one as desired or required.

The control signal 28 may comprise one or more pulses. Each pulse may be transmitted or generated by the processor 31 of the adjustment module 27 upon receipt of a pulse from micro-switch 12. The brightness of the light 26 emitted by the light-emitting module 25 is further dependent on a default or starting brightness level or mode of the light-emitting module 25.

The plurality of selectable modes of the light-emitting module 25 are ordered and stored in a predetermined sequence. Each pulse of the control signal 28 causes the mode of the light-emitting module 25 to change from one of the plurality of selectable modes to the next one of the plurality of selectable modes in the predetermined sequence. For example, the plurality of selectable modes may be stored in order of brightness (for example from lowest to highest). A mode stored in the memory 30 (which may, for example, be a non-volatile memory) may act as a default or starting mode. In this way, each actuation of the micro-switch 12 causes the brightness of the lighting panel 15 to cycle up (or down) to a next brightness level in sequence until the maximum (or minimum) level is achieved. A subsequent actuation of the micro-switch 12 causes the brightness to wrap around to a minimum (or maximum) level.

When the brightness of the light-emitting module 25 has been adjusted, the adjustment module may be switched back to the second operational mode. This may be achieved by placing the cover 3 in the closed position such that the micro-switch 12 is closed for a predetermined time period (for example 5 seconds). As the adjustment module 27 enters the second operational mode, the currently selected mode of the light-emitting module 25 is stored in the memory 30 by processor 29.

As explained above, this embodiment of the invention utilises the anti-tamper microswitch 12 when it would otherwise be redundant. An advantage of such an arrangement is that one or more existing components (i.e. the micro-switch) can be used for brightness control without requiring any additional components, which would add cost to the bell box 1 and may require additional space on a printed circuit board. A second embodiment of a bell box 1 according to the present invention is shown in Figure 7. The second embodiment of a bell box 1 as shown in Figure 7 shares common features with the first embodiment of a bell box 1 as shown in Figure 6. Features that are common to the first embodiment as shown in Figure 6 and the second embodiment as shown in Figure 7 have the same reference numerals. In the following only the differences between the first and second embodiments will be described in detail.

As shown in Figure 7, in place of the micro-switch 12 the adjustment module 27 comprises a second input terminal or pin 40. The second input pin 40 may be considered to be an input device of the adjustment module 27 that is arranged to receive an input signal (for example from a control panel to which the bell box is attached).

As with the first embodiment described above, in the second embodiment, the adjustment module 27 is switchable between a first operational mode and a second operational mode. When in the first operational mode the adjustment module 27 is operable to produce and send the control signal 28 to the light-emitting module 25 for brightness control. When operating in the second operational mode, the adjustment module 27 is operable to produce and send a second control signal 41 to the light-emitting module 25. The second input pin 40 is operable to produce a signal 42 which is received by the processor 31. In turn, the processor is operable to receive the signal 42 from the second input pin 40 and to output either the control signal 28 or the second control signal 41 to the light-emitting module 25, depending on an operational mode of the adjustment module 27.

The second input control pin 40 may be connected to a control panel of an alarm system to which the bell box is connected. The signal 42 may therefore be supplied by a said control panel. The second input control pin may be a bell box light control input terminal. When the adjustment module 27 is operating in the second operational mode, if a first voltage is supplied to the second input control pin 40 (for example 12 V) then the adjustment module 27 may generate a second control signal 41 that causes the light-emitting module 25 to emit light 26. Alternatively, if a second voltage is supplied to the second input control pin 40 (for example 0 V) then the adjustment module 27 may generate a second control signal 41 that causes the light-emitting module 25 to not to emit light 26.

When it is desired to adjust the brightness of the light-emitting module 25, the adjustment module 27 can be switched to the first operational mode. In this embodiment, this may be achieved in one either of two ways described above. Alternatively, switching of the adjustment module 27 to the first operational mode may be effected upon receipt of a suitable signal by the second input control pin 40 (for example from a control panel). For example, the processor 31 may monitor the signal 42 provided by the second input control pin 40. In the event that the signal 42 is a generally static voltage level, the adjustment module 27 may operate in the second operational mode and the processor 31 may generate the second control signal 41. In the event that the signal 42 undergoes transient changes, for example, comprises one or more pulses or the like, the adjustment module 27 may operate in the first operational mode and the processor 31 may generate the control signal 28.

Similarly to the first embodiment described above, the control signal 28 that is sent to the light-emitting module for brightness control may comprise one or more pulses. The brightness of the light 26 emitted by the light-emitting module 25 may be dependent on the number of such pulses. For example, one pulse may signal that a first brightness level should be selected, two pulses may signal that a second brightness level should be selected and so on. Other protocols may alternatively me used. For example, in a manner similar to the first embodiment, each pulse in the control signal 28 may cause a brightness mode of the light-emitting module 25 to change by one mode, cycling through a predetermined sequence of brightness modes.

An advantage of this second embodiment is that the brightness level can be adjusted remotely. For example the brightness level can be adjusted via a control panel of an alarm system to which the bell box 1 is attached, which is typically more easily accessible than the bell box 1 itself. A further advantage of this second embodiment is that it can be accomplished without adding any additional components to the bell box or control panel electronics since the second input control pin 40 may already be provided. A third embodiment of a bell box 1 according to the present invention is shown in Figure 8. The third embodiment of a bell box 1 as shown in Figure 8 shares common features with the first embodiment of a bell box 1 as shown in Figure 6. Features that are common to the first embodiment as shown in Figure 6 and the second embodiment as shown in Figure 8 have the same reference numerals. In the following only the differences between the first and second embodiments will be described in detail.

As shown in Figure 8, in place of the micro-switch 12 and input terminal 37, the adjustment module 27 comprises third and fourth control terminals or pins 43, 44. The third and fourth control pins 43, 44 may be considered to be input devices of the adjustment module 27 that are arranged to receive an input signal (for example from a control panel to which the bell box is attached).

The third control pin 43 may be connected to an output pin of the control panel of an alarm system to which the bell box is connected. The fourth control pin 44 may be connected to an input pin of the control panel of an alarm system to which the bell box is connected. The third and fourth control pins 43, 44 provide a mechanism for signals 45, 46 to be exchanged with the control panel.

The processor 31 is operable to monitor the voltage levels of the third and fourth control pins 43, 44.

The third control pin 43 may be used for signalling from the control panel to the bell box 1 that an alarm has been triggered. The processor 31 is operable to produce and send a control signal 33 for the alarm indicator 34, the control signal being dependent on the signal 45 received from the control panel. If a first voltage is supplied to the third control pin 43 (for example 0 V) then the processor 31 is operable to produce and send a control signal 33 for the alarm indicator 34 to cause the alarm indicator to activate so as to indicate the alarm has been triggered. Alternatively, if a second voltage is supplied to the third control pin 43 (for example 12 V) the processor 31 is operable to produce and send a control signal 33 for the alarm indicator 34 that does not activate the alarm indicator. By using 0 V as the first voltage and a non-zero voltage such as 12 V for the second voltage, the control signal 33 sent to the alarm indicator 34 by the processor 31 may cause the alarm indicator to activate in the event that a wire or cable connecting the control panel to the third control pin 43 is severed.

The fourth control pin 44 may be used for signalling from the bell box 1 to the control panel that the bell box 1 has been tampered with.

For example, in one embodiment, the processor 31 may be operable to produce and send a signal 46 to the control panel, the signal 46 being dependent on whether or not the bell box has been tampered with. The signal may, for example, be dependent on a state of the micro-switch 12. For example, a third voltage supplied to the fourth control pin 44 (for example 0 V) may indicate to the control panel that the bell box 1 has been tampered with whereas a fourth voltage supplied to the fourth control pin 44 (for example 12 V) may indicate to the control panel that the bell box 1 has not been tampered with. In this way, the processor 31 can control the voltage of the control pin 44 via signal 46. By using Ο V as the third voltage and a non-zero voltage such as 12 V for the fourth voltage, the control panel may determine that the bell box 1 has been tampered with in the event that a wire or cable connecting the control panel to the fourth control pin 44 is severed.

Alternatively, in another embodiment, the processor 31 may be operable to control the voltage of the control pin 44 in combination with a power supply in the control panel, as now described with reference to Figure 9. The fourth control pin 44, which is part of the bell box 1, may be connected to a fifth voltage 48 (for example 0 V) via a relay switch 47. The relay switch 47 may be provided within the processor 31 or external thereto. In turn, the fourth control pin 44 may be connected, for example via a wire 49, to a pin 50 in the control panel 51. The pin 50 in the control panel 51 is also connected via a pull up resistor 52 to a sixth voltage 53 (for example 5 V).

In the event that no tampering of the bell box 1 has been detected, the processor 31 may be operable to close the relay switch 47. With the relay switch 47 closed, the fourth control pin 44 is held at the fifth voltage 48 and therefore the pin 50 in the control panel 51 will also be at the fifth voltage 48 (for example 0 V), there being a voltage drop across the pull up resistor 52. The pin 50 in the control panel 51 being at the fifth voltage 48 may indicate to the control panel 50 a no tamper condition.

In the event that the bell box 1 has been tampered with, the processor 31 may be operable to open the relay switch 47. With the relay switch 47 open, the fourth control pin 44 is no longer held at the fifth voltage 48. The pin 50 in the control panel 51 (to which the fourth control pin 44 is connected) will be held at the sixth voltage 53 (for example 5 V), there being no voltage drop across the pull up resistor 52. The pin 50 in the control panel 51 being at the sixth voltage 53 may indicate to the control panel 50 a tamper condition.

In this way, the processor 31 is operable to use the fourth control pin 44 to signal to the control panel that the bell box 1 has been tampered with. Again, with the arrangement shown in Figure 9, in the event that a wire or cable connecting the control panel to the fourth control pin 44 is severed, the pin 50 in the control panel 51 (to which the fourth control pin 44 is connected) will be held at the sixth voltage 53, which may indicate to the control panel 50 a tamper condition.

Generally, the processor 31 will only determine, via the third control pin 43, that an alarm has been triggered if the first voltage (for example 0 V) on the third control pin 43 is detected for a predetermined time period, for example for 200 ms. Similarly, generally the control panel will only determine, via the fourth control pin 44, that the bell box 1 has been tampered with if fourth control pin 44 is in a state that indicates a tamper condition for a predetermined time period, for example for 200 ms.

Therefore, the processor 31 and the control panel may exchange information without triggering alarm conditions by varying the voltages on the third and fourth control pins 43, 44 at a sufficiently high rate. In this way, the control panel can communicate, for example via the third control pin 43, to the processor 31 a desired brightness level of the light-emitting module 25.

Modulation of the voltage on the third and/or fourth control pins 43, 44, at a sufficiently high rate may be used to communicate the desired brightness using any suitable protocol. The voltage on the third and/or fourth control pins 43, 44 may, for example, be modulated at a rate of 1 kHz or higher, for example at a rate of the order of 10 kHz. The processor 31 is operable to monitor the third and/or fourth control pins 43, 44 for the presence of any such high speed serial data. Upon receipt of such a signal, the processor 31 is operable to generate and send a suitable control signal 28 to the processor 29 of the light-emitting module 25.

This third embodiment may allow for one of a vast number of different brightness levels to be selected remotely. For example, of the order of 2,000 different brightness levels may be available. It will be appreciated that the communication with the control panel via the third and fourth control pins 43, 44 may be achieved via the internet or a hardwired telecoms network.

An advantage of the third embodiment is that the brightness level can be adjusted remotely, for example from a control panel, which is usually more easily accessible than the bell box 1 itself. A further advantage of this embodiment is that control panels are commonly connected via IP or telecoms networks such that they can be remotely maintained by bona fide engineers. In this circumstance it would be possible for engineers to remotely adjust the brightness of the light-emitting module 25 of the bell box 1 remotely over the telecoms network without having physically access the control panel. A further advantage of this embodiment is that it can be accomplished without adding any additional components to the bell box 1 or control panel electronics, since the third and fourth control pins 43, 44 are already present.

It will be appreciated that the first, second and third specific embodiments as described above with reference to Figures 6, 7 and 8 respectively may be combined, as appropriate.

In some embodiments, the alarm bell box 1 described above may further comprise a photo sensor arranged to output a light level signal indicative of an ambient light level to the light-emitting module. For such embodiments, the light-emitting module 25 may be configured to emit light 26 only when the ambient light level is below a threshold.

As explained above, embodiments of the invention comprise a light-emitting module which may comprise one or more LEDs (for example it may comprise the lighting panel 15). For such embodiments the brightness of the light-emitting module 25 may be a time averaged or perceived brightness. Emission of light from the LEDs brightness may be controlled by any suitable means, for example the control may be achieved by electronics, which produces a pulse width modulated (PWM) control signal that is provided to the LEDs. For example, the LEDs may be pulsed using an appropriate control signal, at a sufficiently high frequency that the individual pulses cannot be distinguished by the human eye. The perceived brightness by, for example, the human eye is effectively a time averaged brightness which is dependent on the duty cycle of the control signal. The brightness can be controlled by controlling the duty cycle of the control signal. For example, the frequency of the pulsed control signal may remain fixed and the width of the pulses may be varied.

The alarm bell box 1 is advantageous because it allows a user (for example an installer of an alarm system) to control the brightness of the light emitting module 25. This allows the bell box to be installed in a plurality of different environments where, in general, different requirements may be imposed on the brightness of light 26 emitted by the bell box 1. For example, it may allow the bell box 1 to be used both in commercial and residential environments.

The bell box 1 may be particularly suitable for installation in an environment where it is desirable for the brightness of light 26 emitted by the bell box 1 be within a particular range. For example, if the bell box 1 is used as part of a residential installation (where, for example, the bell box 1 may be attached to an external wall of a house) it may be desirable for the brightness to be below a particular level so as to ensure that it does not cause annoyance to neighbours or contravene local light pollution or planning regulations or bylaws.

While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.

Claims

CLAIMS:

1. An alarm bell box comprising: a housing; a light-emitting module disposed in the housing and operable to emit light; and an adjustment module operable to provide a control signal to the light-emitting module; wherein the light-emitting module is configured such that upon receipt of a control signal from the adjustment module a brightness of the light emitted by the light-emitting module is adjusted.

2. The alarm bell box of claim 1 wherein the adjustment module is switchable between at least two operational modes: a first mode wherein the adjustment module is operable to produce and send the control signal to the light-emitting module and a second mode wherein the adjustment module is operable to produce and send a signal for another purpose.

3. The alarm bell box of claim 2 wherein the adjustment module is configured to switch between the first and second modes in response to a mode control signal.

4. The alarm bell box of claim 2 or claim 3 wherein the adjustment module comprises a switch and, upon power up of the alarm bell box the operational mode of the adjustment module is dependent on a state of the switch.

5. The alarm bell box of claim 4 wherein the adjustment module is configured to switch from the first mode to the second modes upon actuation of the switch from a first state to a second state.

6. The alarm bell box of any preceding clam wherein the adjustment module comprises an input device arranged to receive an input signal.

7. The alarm bell box of clam 6 wherein the input device comprises a switch disposed in the housing.

8. The alarm bell box of clam 6 wherein the input device comprises an input terminal or pin.

9. The alarm bell box of any one of claims 2 to 8 wherein the light-emitting module is configured to emit light while the adjustment module is operating in the second mode.

10. The alarm bell box of any preceding claim wherein the light-emitting module is configured to have a plurality of selectable modes, wherein the brightness of the light emitted by the light-emitting module being dependent on a current mode of the light-emitting module and wherein adjustment of the brightness of the light emitted by the light-emitting module is achieved by changing the current mode of the light-emitting module from one of the plurality of selectable modes to another of the plurality of selectable modes.

11. The alarm bell box of any preceding claim wherein the control signal comprises one or more pulses and wherein the brightness of the light emitted by the light-emitting module is dependent on the number of pulses.

12. The alarm bell box of claim 11 when dependent on claim 10, wherein the plurality of selectable modes of the light-emitting module are ordered and stored in a predetermined sequence and wherein each pulse of the control signal causes the mode of the light-emitting module to change from one of the plurality of selectable modes to the next one of the plurality of selectable modes in the predetermined sequence.

13. The alarm bell box of any one of claims 10 to 12 further comprising a memory configured to store the mode of the light-emitting module.

14. The alarm bell box of any preceding claim further comprising a photo sensor arranged to output a light level signal indicative of an ambient light level to the light-emitting module.