Alarm apparatus & method

Abstract

Alarm system 10 comprising one or more control units 20 and one or more LiFi sensors. One or more of the LiFi sensors is a LiFi sensor module 14 adapted to connect to one or more existing light units 16. Also provided is a LiFi sensor module suitable for use with an alarm system, comprising a body, a light fitting attachment portion, a light bulb attachment portion, a sensor and a transmitter. Lastly, a method of detecting a presence within a space 26 using light and LiFi transmission comprising the steps of fitting one or more control units 20, attaching one or more LiFi sensors and wherein one or more of the LiFi sensors are LiFi sensor modules 14 to one or more existing light sources 16 within the space 26. The sensor may monitor a light signature of the space 26 and send a control signal from the sensor to one or more control units 20 depending on any changes of the light signature. The system 10 may be used as a burglar alarm by monitoring movement of persons 18 or objects within the space 26, or a fire alarm by monitoring build-up of smoke within the space 26.

Description

Field of the Invention The present invention relates to alarms and alarm systems and methods for carrying out same. The alarm systems may be used to monitor intruders, smoke, fires, etc. Background to the Invention LiFi transmits data using optical frequencies, generally in the ultraviolet, visible light and infrared spectra. LiFi may be used for home intruder alarm systems to transmit information between a central control unit and individual sensors. LiFi sensors may be setup to monitor access and egress points and persons or objects crossing the light pathways may be detected. The disadvantage of prior art systems is that avoiding the set light paths may avoid detection by the system. Moreover, setting up such LiFi sensors includes additional cost in providing such sensors which may be better served by existing light emitting sources. Summary of the Invention According to a first aspect of the present invention there is provided an alarm system comprising one or more control units and one or more LiFi sensors, wherein one or more of the LiFi sensors is a LiFi sensor module adapted to connect to one or more existing light units. The alarm system may be adapted to monitor movement of persons or objects within a space, smoke or other pollutants, etc. The alarm system may therefore be used as a burglar alarm by monitoring movement of unauthorized persons within a space, as a fire alarm by monitoring build-up of smoke within a space. The LiFi sensor module may comprise a body, a light fitting attachment portion, a light bulb attachment portion, a sensor and a transmitter. The sensor may be adapted to monitor a prevailing light signature of the space. The sensor may be adapted to send a control signal via the transmitter to the control unit depending on any changes of the prevailing light signature. The change of prevailing light signature may be subject to a threshold assessment. The LiFi sensor module may then be attached between an existing LED or similar light bulb and the existing light fitting. The existing light fitting may be a central downlighter, a wall mounted uplighter, a standing lamp, a table lamp, etc. The sensor and transmitter may be mounted on a printed circuit board (PCB). According to a second aspect of the present invention there is provided a LiFi sensor module suitable for use with an alarm system, comprising a body, a light fitting attachment portion, a light bulb attachment portion, a sensor and a transmitter. The LiFi sensor module may be provided with an integrated light source attached to the light bulb attachment portion. According to a third aspect of the present invention there is a method of detecting a presence within a space using light and LiFi transmission comprising the steps of: fitting one or more control units; attaching one or more LiFi sensors; wherein one or more of the LiFi sensors are LiFi sensor modules according to the second aspect of the present invention to one or more existing light sources within the space. The space may have existing lights / light emitters or the LiFi sensor modules may provide a visible light source. The method may further comprise creating a light signature of the space. This light signature will be dependent on known physical attributes and objects within the space. The light signature may be monitored for potential changes within the space, which may be indicative of a foreign body, person or substance being present within the space. Brief Description of the Drawings Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings, in which: Fig. 1 is a schematic view of a first embodiment system according to the present invention; Fig. 2 is a schematic view of a second embodiment system according to the present invention; Fig. 3 is a schematic view of a third embodiment system according to the present invention; Fig. 4 is a side elevation of a LiFi sensor module according to the present invention; Fig. 5 is a further schematic representation of the system of Fig. 2; Fig. 6 is a circuit diagram of the present invention; and Fig. 7 is a flowchart of the system in operation. Referring to the drawings and initially to Fig. 1, an alarm system 10 for monitoring a space 26. The space 26 may be a room within a home, shop premises, a warehouse, etc. An existing light unit 16 is provided to illuminate the space 26. The existing light unit 16 comprises a light fitting and a light bulb. The light bulb is in the present embodiment an LED bulb. The LED bulb will have a defined light output in the visible spectrum to provide adequate lighting to the space 26. The alarm system 10 comprises a LiFi sensor module 14 and a control unit 20. A line of sight 22 is provided within the space 26 between the LiFi sensor module 14 and the control unit 20. The control unit 20 is of an existing prior art type found within current LiFi alarm systems. The LiFi sensor module 14 is adapted to connect to the existing light unit 16. The LiFi sensor module 14 has a line-of-sight path 22 to the control unit 20. A person 18 is located within the space 26. The person 18 may be for example a burglar who has broken into the space 26 to remove something of value (not shown). The LiFi sensor module 14 produces a signal that allows a room signature to be created based on the captured reflections from the environment within the space 26. The signature can be monitored and when a change between two subsequently observed signatures changes more than a pre-set threshold, the system would report an event. This may be for example person 18 walking within the space 26 and altering the light signature of the space 26. Further to the above, the system could also be used in conjunction with specialized software that could be programmed to recognize certain room signatures (and / or sequences of signatures) and associate them with events / activities etc. thereby giving the system the ability to provide even more information. A second embodiment alarm system 100 is depicted in Fig. 2. It will be understood that like numbered integers to the first embodiment share a similar purpose or function except prefixed with the number “1” such as the control unit being numbered 120. The second embodiment system 100 is likewise located within a space 126. The second embodiment alarm system 100 comprises an integrated sensor / bulb unit 115, comprising a light emitting portion 114 and a sensor portion 116. This may be attached directly to any available light fittings within the space 126. A LiFi control unit 120 is provided which the integrated sensor / bulb unit 115 has a line-of-sight 122 to. A second control unit 128 is provided in addition to the existing LiFi control unit 120. This second control unit 128 may provide an ethernet wi-fi / hardwired connection 124 and / or may also provide an addition LiFi line of sight transmission 124 vector for the system 100. Fig. 4 depicts a schematic representation of the integrated sensor / bulb unit 115. Fig. 5 is a further schematic representation of the integrated sensor / bulb unit 115 providing light to the space 126 with the reflected light signature being monitored by the integrated sensor / bulb unit 115 and the control unit 120. A third embodiment alarm system 200 is depicted in Fig. 3. It will be understood that like numbered integers to the first and / or second embodiment share a similar purpose or function except prefixed with the number “2” such as the control unit being numbered 220. The second embodiment system 200 is likewise located within a space 226. The space 226 for the second embodiment alarm system 1200 comprises four integrated sensor / bulb units 215, 217, 219, 221 each comprising a light emitting portion and a sensor portion as per the second embodiment. These are attached directly to four available light fittings within the space 226. A LiFi control unit 220 is provided which the integrated sensor / bulb units 215, 217, 219, 221 have a line-of-sight to. Moreover, each of the integrated sensor / bulb units 215, 217, 219, 221 have a line-of-sight to at least two other units within the system 200, and may have line-of-sight LiFi communication to all other units within the system 200. A second control unit 228 is provided in addition to the existing LiFi control unit 220. This control unit 220 may likewise provide an ethernet wi-fi / hardwired connection 224 and / or may also provide an addition LiFi line of sight transmission 224 vector for the system 200. A further control unit 230 is provided for the system 200. In this embodiment, the further control unit 230 is a laptop computer 230 which is connected to the integrated sensor / bulb units 215, 217, 219, 221 via a wireless ethernet (wi-fi) attachment 225. Fig. 6 is a circuit diagram of the second embodiment. A PIR (passive infrared) sensor 150 detects changes in the ambient light environment, such as intruders / smoke / etc. The circuit loop 152 shown in Fig. 6 for the alarm signal stays closed during normal background ambient light conditions. The circuit loop 152 is opened once a change in ambient light conditions is detected. This System On Module (SoM) 154 therefore detects the presence of an intruder using the sensor 116 and transmits the relevant data through LiFi to the next SoM 156 which is interfaced to the alarm panel 120. The second SoM upon receiving the signal triggers the alarm panel 120, which activates appropriate alarm signals, such as a sonic alarm. If the PIR sensor 150 is tampered with, the sensor 116 sets the circuit loop to open from closed. As with an alarm signal, the data is sent over the LiFi channel to SoM 156 which is interfaced to the alarm panel 120. The alarm panel 120 sets off an alarm signal (such as a buzzer) for a tamper signal. If there is an attempt to block the the LiFi signal, the SoM 156 connected to the alarm panel 120 sends the tamper signal. This way the system has been made tamper resistant. The SoMs 154, 156 are used to interface the LiFi system with the alarm system. Relay 158 and relay 160 are used to mimic the functions of the PIR sensors 150 so that the SoM can be interfaced with the alarm panel 120. It will be understood that even though described in relation to the second embodiment system, this arrangement is similar for the arrangements on the other embodiments. Fig. 7 depicts the flowchart of the system software 300. It will be understood that this will be indicative of software function for all described embodiments. At the top, the system is armed at step 310 by pressing the necessary button or command input into the control panel. The system initially checks if the alarm circuit is open at step 320. If so, the control panel activates 340 the alarm signal at step 400. If the alarm circuit is closed, the control panel checks whether it has LiFi connectivity to the various LiFi units at step 330. If it does not, the alarm signal is triggered at 350 to sound alarm at 400. Assuming the alarm circuit is closed and there is LiFi connectivity, the system software 300 takes a reading of the ambient light conditions creating a signature at step 360 and also determines whether the tamper circuit is open at step 370. If the tamper circuit is open (indicating that the system has been tampered with) the system moves to step 350 where the alarm signal is triggered to sound alarm at 400. The system 300 continues to monitor the ambient light conditions at step 360 until such times as it detects a change in these ambient light conditions. When such a change is detected, this causes the control panel to activate 340 the alarm signal at step 400. The system 300 may employ different alarm signals for the separate conditions of (a) lack of LiFi connectivity (b) ambient light change and (c) tamper circuit activation.

Claims

1. An alarm system comprising one or more control units and one or more LiFi sensors, wherein one or more of the LiFi sensors is a LiFi5 sensor module adapted to connect to one or more existing light units, the LiFi sensor module is attached between an existing LED or similar light bulb and an existing light fitting, and wherein there is further provided a passive infrared sensor to detect changes in the ambient light environment and to communicate such changes to a control unit via the io LiFi sensor module, wherein the control unit compares the detected changes with a baseline light signature to determine whether to trigger an alarm.

2. A LiFi sensor module suitable for use with an alarm system, is comprising a body, a light fitting attachment portion, a light bulb attachment portion, a sensor and a transmitter, wherein the sensor is adapted to monitor a prevailing light signature of a space, the sensor is adapted to send a control signal via the transmitter to the one or more control units depending on any changes of the prevailing light signature-20 the LiFi sensor module is attached between an existing LED or similar light bulb and an existing light fitting, and wherein there is further provided a passive infrared sensor to detect changes in the ambient light environment and to communicate such changes to a control unit via the LiFi sensor module, wherein the control unit compares the detected25 changes with a baseline light signature to determine whether to trigger an alarm.

3. The LiFi sensor module of claim 2 wherein an integrated light23 09 24source attached to the light bulb attachment portion.

4. A method of detecting a presence within a space using light and LiFi transmission comprising the steps of:5 fitting one or more control units;attaching one or more LiFi sensors;wherein one or more of the LiFi sensors are LiFi sensor modules according to claims 2 or 3 to one or more existing light sources within the space.io5. The method of claim 4 further comprising creating a light signature of the space.

6. The method of claims 4 or 5 wherein light signature is monitored for is potential changes within the space, which may be indicative of a foreign body, person or substance being present within the space.

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