IES940235A2 - "Security Systems" - Google Patents

Abstract

In a security system consisting of a detection unit or transmitter (151) and an alert unit or receiver (152), the detection unit (151) is provided with microprocessor control responsive in an active mode of the unit (151) to an alarm condition in the vicinity of the unit (151) to communicate an alarm signal to the alert unit (152). Input means such as a panic button (176) on unit (151), an integral infrared detector (175), or an external connection, serve to communicate the alarm condition to the microprocessor of unit (151). A radio transmitter within unit (151) transmits the alarm signal to the alert unit (152). Within the unit (152), a radio receiver detects the alarm signal from the transmitter (151). A microprocessor controller of the alert unit (152) is responsive in an active mode of unit (152) to the alarm signal to report the alarm condition in the vicinity of the detection unit (151). Receiver (152) has a buzzer and indicator lights or other display arrangements to provide an aural and visual indication of the report of the alarm condition. j The alert unit (152) has a self-contained power supply in the form of a battery. The detection unit (151) is powered from a mains supply with battery back-up. In this manner, the detection unit (151) and the alert unit (152) together define an associated and portable security system, each of units (151) and (152) being independently portable. In use of the system, detection unit (151) is located within a region to be monitored and the wireless-linked alert unit (152) is held by a neighbour. The portability of the system enables interchange of roles between the premises monitored and the person carrying out the monitoring. The system is particularly directed to protecting domestic homes and to caring alarm situations in a neighbourhood context.

Description

Description Security Systems Technical Field The present invention relates to security and caring systems. In particular, the invention relates to an electronic security system for supporting and extending the concept of local neighbourhood protection as exemplified by schemes such as Neighbourhood Watch. The invention is particularly directed to security systems integrating intruder and personal alarm technology with radio technology in a portable and flexible configuration to provide improved and superior levels of security and protection. By a caring system is meant a system in which provision is made for an elderly or infirm person to raise a personal alarm in the event of need or danger, preferably also distinguishing between a call for attention for some personal necessity and an emergency situation, such as, for example, illness or attack.

LSH hU * Background Art The need for security or protection systems and warning systems within today's society is constantly increasing, for a variety of reasons, including, inter alia, the constant increase in crime rates, which makes security, alarm and protection systems an important consideration for many householders. Quite apart from crime, wealthier societies wish to protect their homes against fire loss, while increasing expectations regarding levels of care for the ill, elderly and infirm lead to personal alarm systems becoming an effective tool for calling help in the event of an emergency, i.e. to the application of alarm systems to caring scenarios, thereby providing caring systems as a sub-category of security systems as such.

Key aspects of an effective warning or alarm system are that it should function as reliably as possible, both in respect of its hardware or equipment and components and also in regard to its human interface. An effective system should also function as rapidly as possible in order to minimise danger, loss and destruction.

Many existing approaches to protection and protection systems suffer from various limitations and constraints which minimise the degree of security or protection afforded. In addition, present-day security systems are in general both costly to install and relatively expensive to maintain. Particular limitations of existing approaches to security and protection techniques are now identified.

Deficiencies in intruder alarm systems include the frequency of false alarms, which make neighbours tolerant or disregarding of alarm signals. In other words, neighbours and passers-by regard false alarms as the norm and do not pay any heed when alarm systems are activated.

In addition, if one of a number of alarms in a neighbourhood is triggered, neighbours can be unaware as to which home is affected.

Aural or visual signals emanating from or apparent on the exterior of a premises frequently lead to no specific or particular neighbour feeling S940239M - 3 involved or responsible for taking action, such as informing the police, so that very often no action whatever is taken. While alarms may be connected to a security control centre via a telephone line, valuable time can still be lost in the control centre's informing the police or other emergency service. Similarly, even once informed, the police can, in turn, take a considerable time to reach the particular dwelling from which the alarm has been raised, depending on current dispositions of vehicles and manpower, volume of work or traffic, and other similar factors. In addition, if a central monitoring facility requires to contact other key holders or nominated responsible persons other than the police, such as by ringing other family members, friends, neighbours etc. in a cascading order or priority, first, second, third and so on, there is no guarantee that any of these nominees will be available.

Even if one of the designated persons can be contacted, unless the individual in question is located close to the site of the alarm or other emergency, time will inevitably be lost before reaching the affected premises. Furthermore, telephone lines to the control centre may be engaged at the particular time when an emergency arises.

Finally, in this regard, the connection of alarm systems to a security control centre can add substantially to the expense of the system.

Known limitations applicable to fire alarm systems include the stand-alone nature of smoke alarms, which generally only offer a warning when the householder is present in his dwelling, smoke alarms being rarely connected to security control centres, at least in the domestic context.

Current personal alarm systems also suffer from a variety of limitations or deficiencies. These systems include so-called panic buttons attached to existing alarm systems, locket type alarms which trigger a telephone system to warn a control centre, or similar devices signalling a warning to the telephone system itself. Limitations of these systems include the possible inability of an ill or infirm person to reach a panic button or a telephone hand set in an emergency, for example, due either to weakness or to their passage being blocked by an intruder or ι S$402J9i by fire, or other similar factors. Locket type systems are also quite expensive to install and operate. Finally, in the case where locket type systems trigger a coded message to a security control centre, there can be delay in eliciting an appropriate response, for example, from the police, fire service, or ambulance, since the system depends both on the telephone system and also on messages being passed between the various emergency services.

Finally, so-called Neighbourhood Watch schemes have been introduced in many locations throughout the developed world in recent years. However, in most instances they tend to be paper tigers, depending on casual or accidental observation of suspicious or extraordinary circumstances, and lack positive structure. Typical limitations of such schemes include ineffective and inefficient detection of emergencies, too many variables in raising an alarm, and the likelihood of only very obvious emergency events being detected, although a strength of neighbourhood watch schemes is that they endeavour to make neighbours aware of their being part of a community, and that they can act to their mutual advantage in terms of protecting and assisting one another, so that such schemes can generate a spirit of co-operation and act as a partial deterrent to criminal elements by making them aware that neighbours in a particular community are prepared to act in support of one another and have taken at least basic steps to protect their property.

However, neighbourhood watch schemes have so far by and large lacked technological tools which could capitalize on the co-operative philosophy on which they are based and render them more wide-ranging and effective systems, despite a number of proposals for alarm systems specifically adapted to such application.

WO9O/O717O-A describes a security and alarm network system for separate and spaced premises or locations in which each premises or location is linked to each other premises or location by hard-wiring or by radio.

Radio signal transmitting and receiving means, where used, may be controlled by a programmed computer adapted to be rendered active by S94023S inputting a predetermined code. Sensors in each premises or location are operatively linked to the respective microcomputer and adapted to be activated by unauthorised intrusion, fire or other aggressive action.

The activated microcomputer is programmed to cause transmission of a radio alarm signal to the microcomputers in the other premises or locations, where an audible and/or visual alarm indication is given by the respective microcomputer.

EP 0,229,198-Al provides a computer-controlled radio-network-linked neighbourhood alarm system in which a number of premises are each provided with detecting means, such as burglar alarms or fire detectors, and also with a transmitter or a receiver under the control of a microprocessor. An alarm signal generated by a detector is transmitted by the transmitter located at the premises at which the detector is located to the other premises in the network. A preferred communication system consists of a packet switching network in which the network is a token passing ring. The token passing ring may be configured as a topological ring or arranged in a linear configuration.

In the alarm system of GB 2,009,478-A, a plurality of stations each includes alarm devices, alarm condition release means, and a current supply chargeable from the mains, along with a high frequency transmitter, which, in response to operation of the release means, transmits a signal over the mains. The alarm system also comprises a high frequency receiver tuned to the common carrier frequency of the transmitters. Thus when the release means of one station is operated, the alarms of all of the other stations are operated. Each transmitter transmits a respective coded signal so that an appropriate lamp in each station is lit up to identify the alarm-producing station. An acoustic alarm device at the alarm-producing station is however inhibited.

Disclosure of Invention It is an object of the present invention to provide a technological aid in the form of a security system directed to enhancing and fomenting the concept of Neighbourhood Watch. lS940235 λ - 6 It is a further object of the invention to provide an improved system making use of radio communication which is flexible and easy to use, and avoids the installation complexities required by at least some known systems proposed for application in the neighbourhood context.

According to the invention, there is provided a security system comprising a detection unit and an alert unit, the detection unit having: (a) control means responsive in an active mode of the detection unit to an alarm condition in the vicinity of the detection unit to communicate an alarm signal to the alert unit, (b) input means for communicating said alarm condition to said detection unit control means, and (c) radio transmitter means for transmitting said alarm signal to said alert unit; and the alert unit having: (a) radio receiver means for detecting said alarm signal transmitted by said radio transmitter means of the detection unit, (b) control means responsive in an active mode of the alert unit to said alarm signal to report said alarm condition in the vicinity of the detection unit, and (c) output means for providing an aural and/or visual indication of said report of said alarm condition; wherein: (i) the alert unit comprises a self-contained power supply, (ii) the detection unit is provided with means for power supply from an independent power source, and (iii) the detection unit also comprises a self-contained back-up power supply; so that the detection unit and the alert unit together define a cooperating and portable pair of units of the security system, each of which is independently portable.

Suitably, each said self-contained power supply comprises a battery. At least the detection unit battery is preferably fully rechargeable, and is maintained at full charge while the detection unit is powered from said independent power source, this latter being suitably mains power S 94 023 5 - 7 from an electrical utility. Thus in the case of the receiver unit, the battery is the primary power source, while for the transmitter, the primary source of power is the mains supply, with back-up being provided by the battery against mains black-out and brown-out. Each unit is also provided with a respective on-off switch for powering it up and turning it off, along with arrangements for monitoring the power supply situation and battery condition or charge, as appropriate. These various foregoing features of the system of the invention give it full portability, both the detection unit or transmitter and the alert unit or receiver being thus capable of being located wherever required by the particular application or use with maximum flexibility.

According to preferred features of the invention, (i) said detection unit control means is adapted to establish a unique identification signal coded to indicate transmission from said detection unit, (ii) said alert unit control means is configured to be responsive only to said unique identification signal, and (iii) said detection unit control means is further adapted so that all radio transmissions from said detection unit incorporate said unique identification signal.

A particular arrangement for establishing said unique identification signal comprises the following steps: (a) associating said alert unit with said detection unit for transfer of identification data, (b) activating said detection unit control means to generate a random identification code during said association of of said alert unit with said detection unit, (c) transferring said identification code to said alert unit for storage in said alert unit control means, (d) storing said identification code in said detection unit control means, and (e) terminating said association of said alert unit with said detection unit; - 8 said randomly-generated identification code then defining said unique identification signal for incorporation in all radio transmissions. Provision may also be made for acknowledging or indicating that the identification or matching code transfer and storage of step (c) above has been successfully accomplished.

The security system according to the invention suitably also provides for said detection unit to be armed and disarmed by input to said detection control means of a unique user-selected arming code.

Said unique user-selected arming code is preferably inputted by the steps of: (a) associating said alert unit with said detection unit for transfer of identification data, (b) inputting an arming code to said detection unit code during said association of said alert unit with said detection unit, (c) storing said arming code in said detection unit control means, and (d) terminating said association of said alert unit with said detection unit.

A multiplicity of advantages are derived from the matching or identification procedures and facilities described above, as subsequently discussed in more detail. These aspects of the invention render the security system substantially proof against interference or failure in use, while further enabling the portability and flexibility which are particular characteristics of systems in accordance with the invention.

In an especially advantageous construction of the security system according to the invention: (i) said detection unit is profiled to accommodate said alert unit in a connected-together configuration of the units defining said association of the units, and ”S94 «?35 - 9 (ii) said detection unit and said alert unit are provided with respective cooperating connector means for data transfer in said connected-together configuration.

This association of the units may be effected in a particularly suitable manner by the detection unit or transmitter incorporating a so-called cradle or portion matching in concave profile the external profile or shape of the alert unit or receiver. Matching of the units for the establishment and storage in each unit of the unique and randomly-generated identification code and the arming code takes place by the receiver being put in position in the cradle of the transmitter with the receiver connector engaged with the cooperating connector of the transmitters. In a favoured embodiment, the cradle may be defined by a recessed region of the upper part of the transmitter casing, into which the receiver may be placed in convenient manner for the above-mentioned matching operations.

In an especially preferred embodiment of security system according to the invention: (i) said detection unit control means comprises a microprocessor, (ii) said alert unit control means comprises a microprocessor, and (iii) each said microprocessor comprises data storage means.

The realisation of the respective control means in the form of microprocessors particularly facilitates the achievement of the various control features of the invention by appropriate programming of the processors.

Suitably, the following further features are also provided: (i) the detection unit control means is adapted to initiate immediate transmission of said alarm signal when an alarm condition in the vicinity of the detection unit is communicated to said detection unit control means by said detection unit input means, and (ii) the alert unit control means is adapted to delay activation of the alert unit output means for a predetermined period during which the alarm condition may be terminated by a legitimate cancelling input to said detection unit input means.

S940235’ - 10 By virtue of this aspect of the invention, the possibility of the system failing to raise an alert due to an intruder damaging or disconnecting the transmitter within a short time after making an unauthorised entry into the premises in which the transmitter is located is substantially obviated, since by the time the intruder can interfere with the transmitter, the alert signal has already been transmitted. The alert unit can only be instructed to disregard this alert signal by the transmission, from the detection unit, of a recognised legitimate cancelling signal, incorporating the appropriate codes, within a predetermined period, this indicating that the nominal alarm condition has been addressed and rectified by an authorised user. Such a cancellation signal cannot be originated by an intruder, who will not know the arming/disarming code.

According to another advantageous aspect of the invention, the alert unit control means may be adapted to provide for a user test routine to be carried out in cooperation with the detection unit on receipt of the alert unit by the user. This feature is especially important in establishing user credibility. Disregard of existing systems is greatly encouraged by their unreliability. The system of the invention advances user acceptance of and trust in the system by giving the user the opportunity to check that it is working, by direct interaction with the receiver or alert unit in cooperation with the transmitter unit.

Yet another advantage of the invention resides in that: (i) the alert unit control means may be adapted to detect radio transmission interference, and (ii) the alert unit control means be be further adapted to activate said alert unit output means to provide an aural and/or visual indication of said interference.

Thus the system of the invention is enabled to detect and report on the presence of an interfering radio signal, whether accidental in origin such as arising out of a machine operating in the vicinity, or caused by deliberate jamming originating with a would-be intruder. $9402351 - 11 In a favoured embodiment, said detection unit input means may comprise: (i) a user-operable input switch provided on said detection unit, (ii) an input sensor provided on said detection unit, and (iii) connector means for linking said detection unit with an independent alarm system.

A particular arrangement provides a PA or emergency/caring alarm button, suitably of large dimensions, on the detection unit, as well as an integral PIR (infra-red) detector. These features allow direct activation of alarm information generated within the detection unit itself to the unit's processor, for onward reporting by radio to the alert unit or receiver. The detection unit is suitably also provided with connection points for interface with, for example, house alarm systems of conventional kinds already in situ in the premises to be monitored.

The detection unit may also comprise output means for providing an aural and/or visual indication at said detection unit of said alarm condition, for example, by way of display lights and/or aural means, such as a buzzer. The visual and aural alarm condition reporting arrangements provided on the alert unit may comprise similar features.

In yet another aspect of a favoured construction of system according to the invention, the detection unit preferably comprises a casing provided with a handle for manually transporting the unit between locations of use. The handle may be displaceable between retracted and extended conditions, so that when the transmitter is in use for monitoring purposes, the handle may be stowed in a tidy manner.

The casing may be further provided with adjustable legs for selectively disposing the detection unit in an optimum operational orientation.

Again the legs are suitably retractable from an extended disposition into a stowage configuration, in which they are flush with the casing.

A particular arrangement provides for the legs to have two alternative extended dispositions of use, thereby allowing the unit to be positioned - 12 in one or other of two orientations, one corresponding to full extension of the legs and other to partial extension.

The alert unit may comprise a casing provided with attachment means for linking the alert unit to a user's garment. The alert unit is suitably of compact dimensions, and by providing it with a clip or like feature by which it may be belt-mounted or otherwise retained on a user's clothing, portability of the device is further facilitated.

Accordingly, there is provided by the present invention an entirely new type of protectΐοη/alarm system aimed particularly but not exclusively at domestic dwellings and using radio technology to provide levels of protection hitherto unavailable. The system is devised so as to be capable of being used by neighbours, not necessarily living next door to one another, to provide one or more of the following types of protection, as required: (a) personal alarm, (b) intruder, and (optionally) (c) fire.

The system and apparatus of the invention overcome particular limitations of existing protection systems in a flexible and portable way and integrate intruder and personal protection within the general philosophy of the existing Neighbourhood Watch concept. The system of the invention provides an arrangement for supporting and extending Neighbourhood Watch in a real and tangible form using electronic means as opposed to casual and accidental observation. The system of the invention thus provides a facility which may be denominated as Neighbourlink, together with a Homeguard aspect. In other words, the system links neighbours in a mutually beneficial and supportive manner to protect or guard their persons, homes and properties, with a fully flexible arrangement in which the same transmitter and receiver may be used on one occasion to monitor a first user's premises with the transmitter or detection unit located in that premises and the receiver $940235 - 13 in a neighbour's house, and on a subsequent occasion with the transmitter in the neighbour's house and the receiver in the first user's home, so that the first user on this occasion monitors the neighbour's premises, but using the same equipment with interchange of the portable transmitter and receiver between the respective dwellings.

The system of the invention has also commercial application and scope for associated products and services. The system of the invention may operate in association with traditional type alarm systems, where these are installed, or as a stand-alone arrangement. Where co-operating with an existing system, the apparatus of the invention may be triggered by connection to a suitable detection device, e.g. by way of a basic three-wire switch from the house alarm when it is triggered, i.e. a hard-wired connection. The system of the invention may also cooperate with such further external devices as wireless or hard-wired smoke and/or fire detection devices and/or hard-wired or wireless passive infrared intrusion detection devices.

The basic system essentially consists of two hardware devices, as follows: 1. detection/transmitter device, i.e. the transmitter unit, and 2. alert/receiver device, the receiving unit.

The transmitter unit transmits a coded radio signal to the receiver unit, microprocessor and software techniques being used to decode the transmitted signal and provide an appropriate alarm indication.

External fire/smoke detection devices, external personal alarms such as locket-type devices, and passive infrared intrusion detection devices may be used to extend the system's capabilities and functions. These various external devices may have hard-wired interconnection facilities or employ radio transmission capability to interface with the transmitter unit of the system. Existing alarm systems may thus be equipped with a transmitting interface or hard-wire connection suitable for enabling the existing system to trigger the novel system of the invention. s 9 4 0 235 - 14 The heart of the novel system is that a willing neighbour agrees to provide caring monitoring for a neighbour and/or monitor significant protection parameters or aspects of a neighbour's house electronically, to provide an electronic extension of Neighbourhood Watch. To achieve this objective, the transmitter unit is armed and placed strategically in the dwelling to be protected, while the receiver unit is placed in the watching neighbour's dwelling. Activation of the transmitter unit sends a coded message to the receiver unit, to initiate both an audible alarm signal and to activate indicating lights denoting the type of alarm situation prevailing at the transmission location. The system may also be used in other secondary protection situations, for example within a single dwelling, to protect a garage, or to protect a parked vehicle.

The security system of the invention incorporates a variety of novel and unique features. In particular, activation of the PIR (intruder) alarm with the transmitter unit switched on and in the armed mode immediately dispatches an alarm signal to the receiver unit. The receiver unit waits for a prescribed period of time for possible receipt of a legitimate cancel signal. This feature ensures that the system is tamper proof in instances of physical damage to the transmitter unit by an intruder.

The system also has a variety of features to deal with power failure, low power, or supply interference. In particular, the transmission unit has battery back-up to avoid being immobilised as a result of power failure or power cut-off by an intruder. The transmission unit also flags the receiver unit to signify when, on extended power failure or otherwise, the transmitter battery back-up power runs dangerously low. The receiver unit also has a battery test indicator, calibrated to show the point at which battery power is suspect for safe operation of this unit.

A particular feature of the system is that the transmitter and receiver units are uniquely matched using a seven digit randomly generated - 15 matching code. The use of a randomly generated matching code is far superior to the normal method of using DIP switches. In a particular adaptation or development, the system may also provide for unique matching of peripheral detection devices to an individual transmitter, thus obviating any possibility of spurious links setting off, for example, an alarm next door. This further matching of peripheral detection devices to the transmitter provides that, for example, a transmitter will then only respond to a particular remote and matched PIR input.

The user may also choose his/her own three digit arming code. Because it is chosen by the user, this arming code can be changed as frequently as desired. Also, it is not known to anyone other than the user and people authorised by him/her. Normal systems involve the alarm installer knowing the user's arming code at all times.

An especially advantageous feature of the invention is that the transmitter and receiver units are preferably fully portable and interchangeable between neighbours. Multiple receivers may also be used, although this does not necessarily represent a favoured application of the invention. However, multiple transmitters in individual close dwellings, e.g. apartment blocks, retirement/nursing homes etc., with central monitoring of their respective matched but individual receiver units by a supervisor such as a concierge, nurse or the like, is advantageous within the context of the invention.

The system provides for full activity test procedure in place to test all functions of the transmitter and receiver units, on power up. The system may include a facility to switch off transmission unit PIR to allow a full test procedure to take place, so that both units can be tested. Buzzer activation is available on both units to augment flashing lights. The option may also be provided on the transmitter unit to leave the buzzer silent, i.e. when it is desirable not to alert or frighten an intruder in the event of an alarm condition. The receiver unit is also provided with arrangements for reporting in detail on the nature of an alarm. $940235 - 16 Conventional features are also provided by the system, including, inter alia, a timed exit/entry routine. The transmitter PA facility (for either emergency or caring calls) may be operated directly on the transmitter unit or by remote cable (which can be as long as desired).

The system is designed for ease of use (user friendly). The transmitter unit may be provided with adjustable legs to:(a) ensure it is stable when in the normal upright position (b) allow the unit to be tilted upwards to give a better PIR operating radius/range when operating on low levels i.e. floor, hall table etc. - this being an adjunct to its portability.

In further development of this ease of use aspect of the invention, the function of displaying alarms or other messages using lights can be also performed by an LCD display. In addition, more complex and higher performance chips may also be applied as microprocessors within the invention in substitution for the specific such units identified in the embodiments described herein.

Thus the system has 2 basic functions:(a) it provides a security alarm, and (b) it provides a caring call system, while distinguishing between these.

The basic functions of the system in the transmitter power-up unarmed mode are : (a) PA - emergency, - caring help. (b) interference (signal jamming) alarm. The transmitter system also deals with unintentional interference. (c) transmitter power failure/interference. (d) transmitter low battery back-up power. (e) receiver low battery power indicator.

The basic functions of the system in the transmitter power-up armed mode are: $ΟΧΛ9Ϊ5’· - 17 (a) PA - emergency, - caring help. (b) PIR (intruder) alarm - integral in unit. (c) house alarm, e.g. where a fixed-wire system is already installed. (d) transmitter power failure/interference. (e) duress disarm. (f) interference (signal jamming) alarm. (g) receiver low battery power indicator. (h) transmitter/receiver transmission test (walk test). (i) mains power restored to transmitter after a generally-recognised power failure, in other words, mains failure. (j) brownout power condition recognised, but not flagged as a power failure alarm until brownout proceeds to blackout, i.e. over 3 minutes of power failure. (k) restart facility to allow neighbour who is watching the user's house to enter (ignore the intruder alarm on the receiver unit) and restart the transmitter unit to its normal armed condition without knowing the user's arming code. Normal exit delay procedures are observed to allow the neighbour to safely exit the user's house. (l) a stand down or home safe signal transmitted to receiver unit after user on his/her return legitimately disarms the transmitter unit.

Uses of the invention include : (a) domestic dwellings. (b) commercial/industrial premises. (c) hotel usage. - transmitter in car in car park, - transmitter in hotel room if resident not in room. (d) car parked (transmitter unit in car) and user near and within range, e.g. in pub, visiting relatives, outside house etc. (e) caravan. (f) boating. - offshore and within range, - marina.

S 94 0 2 35 - 18 (g) vacant dwellings (public housing, estate agents etc.). (h) building sites. (i) rooms with valuable equipment on a temporary or full time basis, e.g. laboratories. (j) supplement to existing fixed-wire systems where a rapid reliable response is desired as against the poor response from existing fixed-wire/central control systems.

The system may include the following range of features: (a) fire. (b) smoke. (c) gas. (d) any number of peripheral and remote intruder PIRs (in addition to PIR on transmitter unit). (e) vibration sensor. (f) water. (g) intruder beams. (h) switches of any form.

Brief description of the drawings Embodiments of the invention and its application in a variety of configurations will now be described in more detail, having regard to the accompanying drawings, in which Figure 1 shows in diagrammatic form detection and alert units of a first embodiment of a system according to the invention, Figure 2 is a schematic block diagram showing the principal component parts of a detection unit and an alert unit for an embodiment of a system according to the invention, Figures 3 to 8 show a variety of application configurations of systems according to the invention in diagrammatic manner, S94n?J5^ - 19 Figure 9 shows in diagrammatic block form, a further embodiment of a security system in accordance with the present invention, incorporating a number of enhancements or additional features and capabilities as compared with the embodiments of Figures 1 and 2, Figure 10 is a diagrammatic representation of the transmitter unit of the system of Figure 9, Figure 11 is a diagrammatic representation of the receiver unit of the system of Figure 9, Figure 12 is a pictorial representation of a preferred embodiment of transmitter and receiver in accordance with the invention.

Figure 13 is an enlarged pictorial representation of the receiver, Figure 14 shows the receiver positioned to be received in the cradle region of the transmitter, for unit matching, Figure 15 shows the receiver within the transmitter cradle, during unit matching, Figure 16 is a schematic diagram of an embodiment of transmitter unit according to the invention, and Figure 17 is a schematic diagram of an embodiment of receiver unit in accordance with the invention.

Detailed description of the drawings Figures 1 and 2 are diagrammatic representations of the invention in a first embodiment showing the invention in conceptual terms. Figures 3 s 94 0 235' - 20 to 8 show applications of the invention. Figures 9 to 11 then show, again in block diagrammatic form, a more detailed embodiment of the invention. Figures 12 to 15 are pictorial views of practical constructions of units according to the invention in preferred embodiments, while Figures 16 and 17 are electrical schematics of particular manners of realisation of the internal features of the transmitter and receiver respectively.

Embodiment of Figures 1 and 2 External features of a first embodiment of a system according to the invention are shown in Figure 1. A detection or transmitter unit 1 and a neighbour alert unit or receiver 2 are provided. The detection unit 1 comprises a portable radio transmitter, capable of being triggered by a number of inputs. The unit has an on/off switch 3, for activating and deactivating it, and a lamp 4, which is illuminated when the device 1 is switched on, i.e. in an active condition. An alarm switch 5 provides for direct triggering of the unit 1, by the user. A number of input connections such as are designated by references 6, 7 and 8 may be provided for interfacing with one or more existing alarm systems, such as remote PA (personal alarm), fire alarms, etc., or the like. An optional microphone 9 may facilitate triggering of the device 1 by a direct audio signal, although this variant does not necessarily represent a preferred feature of the invention.

In a further development, the system may also provide for radio connection of peripherals. Thus the range of input possibilities includes the following (non-exhaustive) list: 1. direct personal alarm input at transmitter. 2. connection from existing system. 3. PIR (passive infra-red) incorporated in transmitter. 4. audio input. . radio links from peripheral devices.

When the detection unit 1 is triggered, it produces coded signals, the S94 0235 - 21 code identifying, inter alia, the transmitter from which they are emanating. The neighbour alert unit 2 consists of a small portable radio receiver capable of receiving coded signals from the detection unit 1. Each detection unit 1 and alert unit 2 are paired, so that the alert unit 2 is only activated by alarm signals transmitted by the particular detection unit 1 with which it is associated. The alert unit 2 has, like the detection unit 1, an on/off switch 13 and a lamp 14 to indicate whether or not the unit 2 is in an active condition, as well as a bleep device 15 which generates an alerting signal, when the alert unit 2 is activated by a coded signal transmitted from the detection unit 1.

The input connections or sockets 6, 7 and 8 of the detection unit 1 may be arranged to interface with a variety of systems and thereby serve a number of different purposes. The interface arrangements may include coupling with a simple detection device, such as an infrared or photocell detector for establishing the presence of an intruder, the unit 1 preferably however also incorporating such an integral detector. The output signal from such a device or detector provides an input to the detection unit 1 of the invention. Alternatively, the output signal from an existing burglar alarm system may be inputted to the detection unit 1 of the invention. The audio or microphone input 9, where provided, may serve for triggering of the detection unit of the system of the invention by an audible smoke detector, a locket alarm, or the like, but preferably, radio links from peripherals are suitably provided.

In summary therefore, in the arrangements shown, the detection unit has a three-fold switch closure input, connectible to an existing intruder alarm system, or to another similar such installation. The optional audio input 9, where provided, is arranged to have a frequency band width suitable to cater for either a smoke alarm or other specialised noise source indicative of an emergency circumstance. The detection unit 1 preferably incorporates an infrared detector and may also provide for an interface with such a detector, while the on/off switch 3 may 594 02 3^ - 22 consist of a key input for enable/disable changeover of the unit 1. Preferably however, enable/disable is effected by use of an arming code entered by means of a keypad. On recognition of an alarm condition, the detection unit 1 of the system transmits an alarm code to the receiver or alert unit 2. The receiver unit 2 is activated by this signal and triggers the audio alarm 15 and preferably also a visual alarm.

Particular features of the invention are lights 4, 14 on both the transmitter or detection unit 1 and the receiver or alert unit 2 indicating that the respective unit is powered-up. The transmitter armed condition is indicated by illumination of further lights designating house alarm, intruder alarm etc. Both the transmitter 1 and receiver 2 are provided with batteries and may therefore operate in a self-contained manner. However, basic or normal operation of the transmitter unit is effected by mains power, and the battery is for back-up purposes only in the event of failure of normal power input, while the receiver unit is self-contained with primary power being provided by the battery. The alert or receiver unit 2 provides an audio output advising that an intruder or other alarm condition has been detected and alerting neighbour action. In addition to providing an audio alert output for the neighbour, a visual alert is suitably also effected.

Figure 2 is a schematic block diagram showing, on the left hand side, the principal component sub-units of the transmitter or detection unit 1 of the system and, on the right hand side, similarly depicted, the principal sub-components of the receiving unit or alarm or alert device 2 of the invention.

As shown on the left hand side of Figure 2, the heart of the transmitting or detecting unit 1 is a microprocessor 21, to which a number of inputs are applied. Keypad input 3 of an arming code enables activation or deactivation of the device 1. A separate power switch allows it to be turned on or off. A number of further switch closures, S 94 02 35 - 23 designated generally by a single such input 22, provide for interfacing with existing alarm systems, such as by sockets 6, 7 and 8. An infrared input 23 allows for direct on-transmitter detection of intruder presence using an infrared detection system. Finally, on the input side, an optional microphone 9 may be arranged to detect noises of a predetermined unusual nature, to provide an input to the microprocessor 21 through an audio circuit 24. The detector system unit 1 is powered from the 220/240 volt mains through a power supply unit 25 with battery back-up 26. Other supply voltages may also be accepted. Indicator lamp 4 provides confirmation that the system has been turned on and is connected to a power supply. The power supply 25 is switched on and off by a suitable switch means 27 co-operating with the keypad arming code switch input 3.

Outputs from the microprocessor 21 are primarily the transmission of coded signals by radio for reception by the alert unit 2. This is designated in general schematic terms by the radio transmitter block 28 and associated aerial or antenna 36 of the diagram of Figure 2. A variety of alternative local outputs may also be provided, as designated generally by reference 29. Finally, if desired, the microprocessor 21 may drive a speech-processing chip 31, the output of which drives a speaker 32 through an audio-amplifier 33. In this manner, triggering of the detection unit 1 may generate an audio-speech output locally at the detection unit 1, so as to possibly alarm and deter an intruder.

Turning now to the receiver or neighbour alert unit 2 of the system of the invention, this includes a radio receiver 41 and a receiving aerial or antenna 46, adapted for specific reception of coded signals from an individual associated transmitter or detection unit 1 of the system of the invention. A power board 42 fed by battery 43 supplies the alert unit 2 of the system of the invention, with on/off switch arrangement 13 and lamp indicator 14 to show that the unit 2 is switched on. Outputs from the radio receiver 41 include an audio alert or bleep device 15, driven by the radio receiver through an audio amplifier 44, and visual indication of an alarm condition by illumination of a warning light.

S 9 4 0 235 - 24 Use of the system of the invention will now be described. The detection unit 1 of the system is armed by input of a keypad arming code at 3.

The alert unit 2 of the system must be switched on. The system is now ready to operate and to detect signals input to it by any of the various alternative triggering features. Validity of signals may optionally be ensured by the detection system requiring a particular triggering signal to be present for a set time before it transmits an alarm message to the receiver or alert unit 2, thereby bringing the alarm condition to the attention of the monitoring neighbour. The radio transmission preferably takes place using the VHF mode. Essentially, the transmitter unit 1 is placed at the location to be protected and wired into or set up for triggering by one or more of a variety of input signals, which may include, inter alia, a detector device, an existing alarm system, a smoke detector, or a locket type alarm device. A neighbour, or perhaps a group of neighbours if more than one receiver 2 is in question (this not however being a preferred manner of use of the invention), are then asked to monitor the receiver or receivers 2 and to take appropriate action if the alarm is triggered by the transmitter 1. The action in question may consist of calling the police or other neighbours, telephoning to the dwelling in which the transmitter 1 is located, or other agreed procedures. Accordingly, the neighbour or neighbours become actively involved in the monitoring process, and neighbours can reciprocate so far as monitoring one another's property is concerned by interchange of transmitter and receiver. A particular group of neighbours could, for example, share a certain configuration of the system of the invention.

The system of the invention facilitates monitoring of households or other locations to be protected in accordance with approved Neighbourhood Watch procedures, to achieve the objective of reliable and speedy identification of the existence of an emergency or alarm situation, without risk to the monitoring party. A particular configuration of units 1 and 2 in a system according to the invention may be purchased by a group of residents or a community association. Similarly, a group of residents or friends or dwellers in a single S 9 40 2 35' - 25 apartment block may combine to share ownership of a system according to the invention, thereby rendering the unit costs of the system very attractive as compared to less effective protection and warning systems.

Applications of Figures 3 to 8 Figures 3 to 8 illustrate use of the invention in a variety of configurations, modes and applications, in diagrammatic or representational form only.

Zn Figure 3, two co-operating neighbours are involved, with the transmitting unit 51a located in dwelling A and the receiving unit 52a located in dwelling C, which does not necessarily require to be immediately adjacent to dwelling A. As shown in Figure 3, dwelling C is spaced from dwelling A by dwelling B.

In Figure 4, the system of the invention is shown in use by a group of neighbours. A single transmitting unit 51b is located in dwelling C, with receivers in dwellings A and D, dwelling A being separated from dwelling C by dwelling B. Triggering of the transmitting unit 51b of the system activates both of the receiving units 52b, so that two neighbours may be advised of the emergency condition in dwelling C.

While representing an advantageous manner of applying the invention in certain specific and limited circumstances, the multi-receiver application of the invention does not represent a preferred manner of use. The invention is best suited to an arrangement in which just one transmitter and one receiver are used, working in matched cooperation and interchanged between neighbours in reciprocation as required.

Figure 5 shows use of the system of the invention to provide an emergency alarm and support system for an infirm or ill person 55. The transmitting unit 51c is located in dwelling A, where the infirm person lives. The receiver unit 52c is located in dwelling C. The infirm person wears a locket alarm, which, when activated, generates a radio δ 9 4 0 2 3 5 ' - 25 signal providing an input to the transmitter unit 51c of the system of the invention. Alternatively, the infirm person may press a PA button on the transmitter or a PA button on an extension cable from the transmitter. In this way the neighbour in dwelling C is rapidly apprised of the existence of an emergency condition in dwelling A.

This aspect of the invention is especially suited to caring alarm systems as distinct from security systems as such.

Figure 6 shows use of the system of the invention as a smoke and/or intruder alarm. In this instance, the transmitter 51d is located in a downstairs room 56 of a dwelling 57, while the receiver 52d is placed beside a bed 58 in an upstairs room 59 of the dwelling 57. The optional audio input of the transmitter may be arranged to pick up the audio alarm produced by a smoke detector 61, should the premises go on fire, or an alternative fire alarm interface is provided, while either the infrared input to the transmitter or triggering by a conventional burglar alarm system 62 provides an intruder detection facility. Thus, in the event of fire or the presence of an intruder, the householder 63 asleep in the upstairs bedroom is immediately alerted of the existence of an emergency condition.

Figure 7 shows a generally similar arrangement so far as dwelling 57 is concerned, but with a second receiver 52e located in a neighbouring dwelling B, where the householder 63 in dwelling A, i.e. house 57, is an infirm or ill person. Thus, in the event of an emergency, whether by fire or burglary, both the infirm or ill person 63 in dwelling A is alerted and also the supporting neighbour in dwelling B. Again, this application of the invention is adapted to a caring scenario.

Finally, Figure 8 shows use of the system of the invention for multiple protection in an apartment block 64. Each of three apartments 64a, 64b, 64c indicated in general schematic terms has an individual transmitter unit 51f, each transmitting uniquely coded signals for reception by a matched and associated receiver unit 52f. All of the receiver units 52f are located in the porter's quarters 65, so that the porter may be S 94 0235 - 27 immediately alerted of the existence of an emergency condition in any of the apartments and also exactly which of the apartments 64a, 64b, 64c is in question. The receiver units 52f may be mounted in a suitably constructed frame or mounting means, to give easy recognition of the particular apartment in question. The devices may be arranged in the manner of bell signals in traditional call systems. Again, the arrangement is pertinent to caring needs.

Embodiment of Figures 9 to 11 A more extensive security system according to the invention is shown in Figures 9, 10 and 11 and will now be described. The general construction of the system is broadly similar to that of the arrangement previously described and is shown in diagrammatic overview in Figure 9. A security or alarm system in accordance with the invention consists, as previously described, of two units, a transmitter unit and a receiver unit. A transmitter unit 71 is located within a territory 73 associated with a first neighbour. The receiver unit 72 of the system is located in premises 74 belonging to a second neighbour. The transmission unit incorporates a multiplicity of features to be described, including the features of the systems of Figures 1 and 2 and various further enhancements. The transmission unit 71 is itself also responsive to radio signals received from external units 75, 76 and 77. In a typical installation, unit 75 may represent one or more external passive infrared units, adapted to transmit radio signals to transmitter 71, or unit 75 may be an interface or adapter device directed to transmitting signals from an existing alarm system to transmitter unit 71. A direct interface may be provided as a connection for an external house alarm. Unit 76 typically represents an external personal alarm device, again adapted to transmit alarm signals to transmitter 71 for processing and onward alerting of receiver 72 in the neighbour's house. Unit 77 may represent an external fire or smoke alarm, again communicating with transmitter 71 by means of a radio link. In the context of the present system, the word external refers to a unit which is not incorporated in the transmitter module 71 itself.

S 94 0 235 - 28 The transmitter unit is depicted in schematic form in Figure 10.

Reference 80 designates a microprocessor of the unit, in which the operating characteristics of the system of the invention are embodied.

A keypad-activated feature 81 may inter alia allow the transmitter to be moved into a test mode of configuration by suitable code input at the keypad. The unit may also incorporate a reset facility. An on/off indicator light 82, in the form of an LED, may be provided to show the condition of the unit 71, while a test indicative light emitting diode 83 may be provided to advise whether the apparatus is under test or active.

Control features of the system designated by references 84, 85 and 86 enable, respectively, arming of the personal alarm (PA) portion of the system, the passive infrared (PIR) aspect, and, thirdly, the external inputs, for example from a fire or smoke alarm. Corresponding indicator lights, again in the form of LEDs, respectively 87, 88 and 89, may indicate whether or not PA, PIR and external are armed. Yet another indicator light 91 may inform the user whether the system as a whole is armed or not, or the armed condition may be reported by display of individual sub-system lights, e.g. house alarm, intruder PIR, etc., while a further indicator light 92, referred to as the active LED, may be provided to indicate a failure condition within the transmitter itself. Keypad 93 enables the input of key code information, by activation of individual keys 94 and the subsequent depressing of an arm key 95 or a disarm key, and is used, inter alia, for arming the system as a whole and thereby triggering illumination of LED 91.

Transmitter unit 71 also incorporates a built-in personal alarm switch in the form of a push-button, indicated by reference 96, activatable on the spot by the householder, as well as built-in passive infrared detection, reference 97, i.e. an intruder sensor. Built-in receiving circuitry 98 is adapted to activate transmitter 71 in response to radio signals received from external devices, whether PA, PIR, or fire or the like. A direct connection or input for an external or house alarm may also be provided, as distinct from a radio link. The unit also S 94 0 235 - 29 incorporates an output relay switch 99 enabling optional additional systems to be driven directly by the transmitter unit 71 by virtue of a suitable interface. A connection for a remote help or personal alarm facility may thus be provided. Further features of the transmitter include mains power supply 101 along with battery back-up 102. A power failure light emitting diode 103 provides a visual indication to the householder in the event of the mains power supply failing and the unit changing over to operation from the battery. Finally, the transmitter 71 incorporates transmission circuitry 104 by which messages are transmitted as radio signals to the receiver unit 72 in the neighbour's house. The radio transmissions emanate from an antenna 105, while the unit suitably also includes a buzzer 106 to provide a local alarm in addition to the remote activation of the receiver 72. The local alarm feature may also include flashing of warning lights at the same frequency as buzzer sounding.

On the transmitter unit 71, the buzzer 106 may alternatively be selected so as to be silent during all alarm conditions. The position of the buzzer switch is noted only at certain times. Thus switching the buzzer 106 on or off may not have an immediate effect.

Referring now to Figure 11, the receiver unit 72 is depicted, again in schematic representation. It comprises processor circuitry 110 and an on/off switch 111 and suitably also a test button to check warning lights and buzzer action. The power on or off condition of the receiver 72 is indicated by a flashing red LED 112. Further indicator lights in the form of LEDs 113, 114, 115, 116, 125, 126 and 117 indicate those features of the system which have been armed at the transmission end, respectively PA, PIR, and external or house, for LEDs 113 to 115, while LED 116 indicates an additional variant, to be described subsequently in more detail, designated intruder, forced entry or duress. LED 125 indicates radio interference in communications between the transmitter 71 and the receiver 72, while LED 126 is indicative of power failure at the transmitter 71. LEDs 113, 114, 115, 116, 125 and 126 are red, while LED 117, which also relates to the reporting of alarm s 9 4 0235 4 - 30 conditions, is suitably green, although both the number and colouration of the LEDs may be varied within the scope of the invention. A preferred arrangement provides 8 red LEDs and 1 green, and may include, in addition to the conditions noted above, indications for home safe/stand down at the transmitter, this indicating or signifying that the user has returned safely to his/her dwelling, and power restore, in the event of temporary failure of the power supply at the transmitter.

Alarm conditions are indicated by flashing of one or more of the above listed red LEDs at the receiver unit at a rate of 0.5 seconds on and 0.5 seconds off, apart from an emergency condition of the PA emergency alarm 113, which may be two or four times faster. Finally, in addition to on/off switch 111, a test button 127 is also provided.

Receiver buzzer 118 provides an audible indication at the same rate of activation as the LEDs of an alarm condition at the transmission point. Receiver power supply unit 119 is fed by battery 121. Means may be provided for indicating transmitter mains power failure as required, e.g. by way of a power-off red LED. Radio signals emanating from transmitter 71 are received and processed by circuitry 123 through an antenna 124. Illumination of LED 126 indicates the presence of radio interference between the transmitter and receiver which would degrade the performance of the system. The various functions are effected under the control of a receiver microprocessor comprised in circuitry 110.

A description of the operation of the security system of the invention as embodied in Figures 9 to 11 now follows. The various functions are effected by software embodied in the microprocessors of the system working in cooperation with the various features and components of the system.

In order to be sure that a receiver unit 72 can only display alarms received from its own transmitter unit 71, a recognition code is sent by the transmitter unit 71 along with each alarm signal. The receiver S94 0235 - 31 unit 72 compares this code with a code previously stored in its memory. Accordingly, the code in question must be put into the receiver unit 72 before the system is first used, as otherwise the receiver will ignore any alarms sent to it. This process of storing the correct code is carried out by matching the units 71 and 72 in the following manner.

With both units powered off, receiver unit 72 is placed in a so-called cradle portion or region of transmitter unit 71. The cradle is defined by a section of the transmitter casing or housing which is shaped or profiled to accommodate the receiver and is provided with a connector to cooperate with a corresponding connector on the receiver for data or information exchange. Suitably the connectors comprise an 8-pin plug and socket arrangement. The units are thus connected together by way of suitable eight-way connectors on the sides of their respective casings. The transmitter unit 71 is turned on and transmits its recognition code to the receiver unit 72, with the receiver powered off. Successful receipt of the code is indicated by flashing of the LEDs of the receiver unit and sounding of its buzzer. The procedure typically takes about 15 seconds, and its completion indicates that the receiver has successfully received the transmit code from the transmitter unit. The units may then be separated, but the transmitter unit will continue to transmit the code for a further twenty seconds, thus allowing time for a further receiver unit to be matched if desired. Completion of code transmission is indicated by illumination of the PA LED 87 on the transmitter unit 71, or by flashing more than one LED. The recognition code is stored in storage systems of the respective microprocessors of the transmitter and receiver.

A particular feature of the invention is that the transmission unit and the receiver unit are uniquely matched using a 7-digit matching code, which is randomly generated by the transmitter during a matching process. The initial establishment of the matching code takes place when the transmitter unit and the receiver unit or units with which it is to cooperate are placed together in the transmitter cradle. Since S94 0 2 35 - 32 the matching code is randomly generated, it is not known even to the user of the system. The use of randomly generated matching codes is far superior to the normal method of establishing codes by the use of DIP switches. Any communication between the transmitting unit and the receiver unit must incorporate the matching or transmission code. The establishment of this unique matching of receiver and transmitter also prevents an intruder from attempting to disarm the system by bringing along a receiver unit of his own. This is because the actual user-selected arming code can only be inserted following this initial matching of the units, with the receiver again in place in the cradle of the transmitter. The setting of the arming code, which requires association of the transmitter and receiver, is to be distinguished from the actual arming of the system in use, which is effected by entering the code on the transmitter keypad and is carried out with the units separated. Unique matching of peripherals to individual transmitters and receivers may also be achieved, thereby avoiding any spurious links which might set off alarms in an inappropriate location.

Thus, the inputting of an arm/disarm code must also be carried out in the set-up mode before the system is used. This code is selected by the owner and should be kept secret as it enables the owner to arm and disarm the system. The code selection operation is again carried out with the transmitter unit 71 and receiver 72 located in the cradle. A suitable digital code selected by the user is entered on the transmitter using key pad 93. Following loading of the arming code, the receiver may again be removed from the cradle.

In order to arm the system, the transmitter is powered up by operation of the on/off switch 81. The microprocessor 80 checks system functioning and indicates that all is in order by flashing the PA LED 87. The transmitter microprocessor then establishes which of the various devices of the system are armed, to determine whether or not the system is in one or other of the following two modes, although a single mode system is also possible. Mode 1 is an alarm system mode in which both PA, PIR and/or external devices are armed. Mode 2 is a caring S 94 0235 - 33 alarm mode in which only the PA function is operational. This mode is favoured when, for example, the householder is alone in the premises, but does not require automated fire or intruder protection, triggered by sensors, although such circumstances could clearly give rise to the householder initiating a PA signal. The PA function may be triggered by a locket carried by the householder, which does not depend on access to the transmitter for activation, or it may be directly activated by depressing the PA button on the transmitter itself or a remote-cabled PA button.

The control features 84, 85 and 86 enable arming of particular inputs. The system as a whole is however armed by the householder's correctly entering the arming code on the key pad 93 and then pressing the ARM key. In Mode 1, where inputs apart from or in addition to personal alarm are in question, a sixty second exit delay is also activated by the microprocessor to enable the householder leave the premises, if required, before the relevant alarm features become activated. Thus during this period, the intruder alarm is not activated, but the help or PA alarm is available for activation immediately. Intermittent flashing of the LEDs and intermittent sounding of the buzzer confirm that the system has been satisfactorily armed during this period. In the personal alarm only mode, Mode 2, there is no time delay, the PA alarm being active at all times. Irrespective of mode, following arming of the system using the key pad, the transmitter 71 is fully armed and monitors all relevant alarm inputs. The system may be disarmed by entering the arming code and pressing a DISARM key.

Following the sixty second exit delay, there is a further thirty second period at the end of which the transmitter unit starts a test transmission if the alarm has not been activated. This enables reception at the receiver unit to be tested. The transmitter unit transmits thirty-three test signals over a five minute period, with a five second interval between each signal. This transmission test may however be interrupted at any time by a legitimate alarm. Further features of the test procedure are addressed in discussion of the receiver unit below. - 34 In its alarm detection disposition, transmitter 71 monitors all alarm inputs, including PA, PIR, external inputs received through circuitry 98, and the built-in alarm features 96 and 97. Triggering of any of these alarm inputs initiates the alarm procedure.

When the alarm procedure is initiated, irrespective of the mode, an alarm code and an alarm identification code are transmitted by circuitry 104 to the receiver 72. Typically, the transmission takes the form of coded microprocessor based signals, readable by the receiver unit. However, in mode 1, the unit also moves into a monitoring or entry delay condition, in the case of the PIR/intruder alarm, for a sixty second period in case a legal cancelling signal is input to it. This need may rise, for example, when a door or window is inadvertently opened or opened on return to the house, thereby triggering the alarm system, even though no emergency situation exists. During this sixty second delay period, the house or external inputs LED 89 is illuminated and buzzer 106 operates, while relay switch 99 for the external outputs is also closed. Thus a PIR-activated house alarm signal is immediately transmitted, without delay, but may be cancelled at the receiver by transmission of a disarm code from the transmitter.

In Mode 2, a PA alarm is always flagged immediately at the receiver unit and there is no delay period providing for transmission of a cancelling signal. A PA alarm can only be rectified by verbal conttact, such as by telephone or by the carer paying a visit. In the event of transmitter power failure taking place while the unit is operating, switch over to the back-up battery 102 takes place automatically.

While the mains supply is inoperative but the unit is is a switched-on condition, the on/off LED 82 flashes. A power failure may also trigger a power failure indication 103 on the transmitter, while in addition transmitting a power failure signal to receiver 72, to illuminate the power failure LED 126 on the receiver device. Power failure at the transmitter also activates the buzzer 118 of the receiver 72. The power failure features are identical irrespective of operating mode.

S940235* - 35 Use of the receiver unit of Figure 11 will now be described. The unit is switched on by on/off switch 111 and the on/off indicator LED 112 is illuminated in a flashing mode. The unit remains in an idling or quiescent status while waiting for an alarm signal. Depression of the test button 127 initiates a check in which all of the LEDs will flash and the buzzer will sound twice.

During a test transmission as already adverted to in connection with the transmitter, the LEDs on the receiver unit flash in sequence and the buzzer sounds. As each of the test signals arrive, one LED flashes and the buzzer sounds five times. The number of flashes distinguishes test transmissions from an alarm condition. The transmission test may be cancelled at any time by pressing the test (test alarms) button 127 on the receiver unit. The receiver then ignores the rest of the test transmission. The microprocessor of the receiver is switched on during the test, but automatically switches off either on termination of the test transmission or after a predetermined time period from receipt of the last test transmission, if the test is terminated prematurely.

Thus the microprocessor does not remain permanently switched on, even if a test signal is missed.

On receipt of a valid alarm signal, the alarm identification code is stored by receiver processor 110. The receiver unit 72 then waits fifty-nine seconds before taking further action. It next monitors the input for a further six seconds in case a cancel signal is received.

If a cancel signal is received, the unit returns to its idling condition, but if no cancel signal arrives, the buzzer 118 is activated. In addition, an appropriate one or more of indicator lights or LEDs 113, 114, 115, 116, 117, 125 and 126 is illuminated to provide an indication of the alarm conditions at the transmitter end and to advise the receiving householder of the nature of the emergency or alarm which prevails at the transmitter.

A particular feature provided by the receiver is a forced entry or duress dearming indication 116. If the householder at the transmitting S 9 4 0 2 3 5 - 36 end is forced by an intruder to enter a code into his alarm system to nominally disarm it, the code should be entered in reverse. The system is programmed to respond to entry of the owner's code in reverse sequence, i.e. backwards. This activates the transmission system to illuminate the forced entry or duress disarm light 116 at the receiver and sounds the buzzer 118 to alert the neighbour. In order to reassure intruders in these circumstances, the transmitter unit may also incorporate a light signal indicating completion of a normal disarming operation. Power failure at the transmitter end is indicated by illumination of the receiver unit power failure light or LED 126.

At the receiver unit, the mode of operation at the transmitter may optionally be indicated in greater detail, by various means. For example, a flashing personal alarm light on the receiver may indicate a PA mode emergency. The PA mode is intended to encompass also the caring aspect of the system of the invention by providing a facility for distinguishing between a call for assistance at the carer's convenience and an urgent call for immediate help in an emergency situation. Similarly a different buzzer tone may be used if a PA alarm is in question. Additional levels of information may be conveyed by combinations of lights being illuminated in different groups, with further augmentation of information possible by having one or more of the lights flashing. However, these additional features may result in additional complexity for the user in interpreting the signals transmitted. A text display feature may however be added to both the transmitter and receiver of the system of the invention, the advantage being that information is in this manner capable of being communicated more clearly than by combinations of lights, especially when certain combinations involve flashing, the text display either complementing or replacing the information light arrangements described.

A thus enhanced system of the invention may also incorporate facilities for test procedures. Various test functions may be required, as follows: (a) a test for the radio link between the transmitter unit and the receiver unit, S 94 0 235^ - 37 (b) a test to ensure that any external devices associated with the system are linked to the transmitter unit, and (c) a test to ensure that devices located on the transmitter work correctly.

The first test function may take place automatically when the system is armed, in the manner described previously.

Each test function may be implemented by entering a test code on the key pad. Each external device may be tested in turn, and correct operation of each device may be reported by flashing of the lights on the transmitter relating to that particular feature.

Particular features of embodiment of Figures 9 to 11 More details may now be given of particular features of a specific embodiment of the system of the invention. In this configuration, the PA alarm is immediately operational on power up and remains operational at all times while power at the transmitter is on. A PA alarm condition is activated by depressing the PA button, or by remote input as previously described.

PA (HELP) ALARM The PA or help alarm becomes automatically and immediately operational on power up and remains operational or effective at all times in the presence of transmitted power. Two levels of PA alarm may be provided, defined as PA help and PA emergency. PA help may be activated by a single depression of the PA button, while a PA emergency signal may be triggered by more than once rapid depression of the PA button within a predetermined interval.

In either circumstance, a PA alarm condition is indicated at the transmitter unit by flashing of the PA LED and sounding of the buzzer.

If a PA emergency alarm is in question, the flashing and the buzzing S 94 0 23 51 - 38 becomes more urgent. The transmitter unit sends the alarm signal six times with nine second delays between each transmission, the entire transmission period thus approximating to a minute. At the transmitter unit, the LED continues to flash and the buzzer sounds until the disarm code is entered, or the unit is switched off.

At the receiver unit, the PA LED flashes and the buzzer sounds until the unit is switched off. Again a more urgent flashing and buzzing applies if a PA emergency alarm is received. Activation of a PA alarm condition immediately initiates a PA help alarm signal, and if further depressions of the PA button takes place within the specified period, this alarm signal is upgraded to PA emergency. Thus the LEDs and buzzer on the receiver unit always register a PA or help alarm condition in first instance, with precedence over any other alarm message.

POWER FAILURE The system may also allow for a transmitter power failure alarm. This feature also suitably becomes operational on power up of the transmitter. A power failure alarm occurs on failure of mains supply or disconnection of the transmitter unit from the mains power. A power failure alarm is transmitted immediately on power failure and a three minute time-out period then applies during which further alarm signals may be detected at the receiver, but the transmitter unit may not be disarmed, by virtue of the keypad not being scanned. The green power LED on the transmitter flashes at this time to indicate that the transmitter is on battery power.

A power alarm may conclude by cancellation, if mains power returns before the three minute time-out period expires. A power alarm cancel signal is transmitted to the receiver, and transmitter keyboard scanning is restored. The green power LED of the transmitter reverts to a steady mode from the flashing condition. At the receiver unit, reception of a cancel signal means that no power alarm is reported.

S94 0 2 35 ' - 39 If however the power alarm is not cancelled as set forth above, the buzzer at the transmission unit indicates detection of an alarm condition. Key pad scanning is resumed at the transmitter. Entry of a disarm code at this time stops the buzzer and returns the transmitter to its normal unarmed state. However, on the receiver, a power-off LED continues to flash and the buzzer to sound until the receiver unit is switched off.

Power failure alarm may also be overridden by another alarm during the three minute time-out period. During this first three-minute period, therefore, all other armed inputs may be triggered. Triggering of a further alarm results in the appropriate overriding alarm signal being displayed on the transmitter and at the receiver. The power-off alarm also comes on at the receiver in the absence of a cancel signal, i.e. transmission of a power restore signal, as subsequently further detailed.

PIR (INTRUDER) ALARM The PIR alarm becomes active only when the system is armed. Detectors for PIR are activated by heat from moving bodies. When PIR detection occurs, the transmitter unit PIR LED flashes and the buzzer sounds urgently. A PIR alarm signal is transmitted to the receiver immediately. However a sixty second entry/exit delay applies before the alarm is reported by the receiver unit, since it is not possible to disarm the transmitter unit without activating a PIR alarm.

Thus with the transmission unit in the on condition, PIR or intruder activation, which is possible only in the armed mode, immediately despatches an alarm signal to the receiver unit. The receiver unit waits for a period of time to receive a legitimate cancel signal. This feature ensures that the system is substantially tamper-proof in instances of physical damage of the transmission unit by the intruder, since the alarm message has already been transmitted before the intruder has an opportunity to damage the transmitter. In other words, the »>3402353 - 40 delay in confirming the alarm condition takes place at the receiver unit rather than at the transmitter, thereby providing for added security against physical attack.

There are three possible outcomes to PIR alarm. If the alarm is not cancelled after the sixty second time-out or entry delay, the PIR LED and buzzer continue to operate at the transmitter unit, and a PIR alarm signal is transmitted on five occasions over a further period of one minute. Buzzer sounding is effected in a less urgent manner. At the receiver unit, the PIR alarm signal is received, but sixty-two seconds elapse before activation of the PIR LED at the receiver takes place and sounding of the receiver buzzer at the receiver is initiated. Thus the receiver waits for a cancel signal. If no cancel signal is received during this period, a PIR alarm is raised at the receiver.

A second possible outcome is that during the sixty second period following a PIR alarm activation, the alarm is cancelled at the transmitter unit by entering the appropriate code. The transmitter intruder (PIR) LED and buzzer are then turned off, and a cancel signal is transmitted to the receiver. The transmitter is then disarmed, all red LEDs except the PA LED being turned off. At the receiver unit, reception of the cancel signal results in illumination of the green LED in the alarm display (home safe/stand down) and operation of the buzzer for five minutes. The receiver unit then reverts to standby mode waiting another signal.

The alarm may also be nominally disarmed under duress at the transmitter unit by entering the reverse of the code digits, this representing the third outcome. The duress disarm signal is transmitted immediately and the transmitter unit is then nominally disarmed, all LEDs being switched off except PA and the buzzer also being switched off. Thus the appearance of normality is restored. However, at the receiver unit, the duress disarm LED flashes and the buzzer buzzes. After the usual sixty-two second delay, the PIR LED also flashes. Cancellation of these alarms is possible only by switching off the unit. s 9 4 0 2 J 5 - 41 HOUSE ALARM The house alarm is active only when the system is armed and when the house alarm has been connected correctly to the transmitter unit before power on. If the house alarm is activated, the transmitter house LED flashes and the buzzer sounds urgently. The house alarm signal is transmitted immediately, but there is a sixty second delay before the alarm is reported by the receiver unit, during which period the alarm can be cancelled.

Again, a house alarm has three possible outcomes, depending on whether a no-cancel condition applies, the alarm is cancelled, or the alarm situation progresses to duress disarm. The detailed progress of each outcome essentially parallels those already described for an intruder alarm condition.

OTHER FEATURES A restart facility may also be provided to allow the person with the receiver unit to enter the house under protection while the alarm is armed without needing to know the arming code. On entry with the receiver unit turned off, the transmitter unit will send any necessary alarm messages, but these may be ignored or the receiver unit may be switched off. On exit, the restart button of the transmitter is pressed and the transmitter unit begins the sixty second exit delay. After sixty seconds, the system is then rearmed exactly as before the person entered. Under these conditions, the system does not enter its self-test routine. The restart button functions only however when the system is already armed, after an alarm has been triggered, and all cancelled lookout delays are over.

A facility for transmission of a power restore signal may also be provided, for dissemination when the transmitter unit is switched on or when the unit recovers power after a total power loss, such as no mains power, i.e. a blackout lasting more than three minutes, and a flat $94 0 2 - 42 battery. Appropriate indications may be provided at the receiver unit to indicate this condition.

Another scenario applies for power up when the unit is already armed.

In this condition, the transmitter unit is already armed when it is switched on. None of the LEDs are initially lit, until expiry of a period of sixty seconds. At this time, the LEDs indicating the armed alarms come on. During this initial sixty seconds, the PA (help) alarm is however armed, but this is not indicated by its LED.

An important feature of the system according to the invention is the presence of an interference alarm. This is triggered on the receiver unit if an unrecognised radio signal is present for more than one minute, or if more than forty incorrect transmissions are detected without a break in transmission. Under these conditions the interference LED flashes and the buzzer sounds. If a valid alarm is detected after the interference alarm is triggered, it also will be displayed.

For physical connection of a house alarm to the transmitter unit of the invention, a three-pin socket is preferably provided on the transmitter, into which a plug connector from the house alarm is inserted as required. This provides for easy connection and disconnection of the house alarm. The connection arrangements suitably also provide for recognition by the transmitter unit of connection of an external house alarm, such as by bridging or interconnecting two pins of the connector unit. Triggering of the house alarm bridges a further pair of pins of the connector, by closure of a normally open switch. A similar three-pin socket may be provided for a remote personal attack alarm, with again activation of the alarm being effected by depression or closing of a normally open switch configuration to bridge two pins of the socket connector.

Finally, a system according to the invention provides a comprehensive alarm testing mode, in which all aspects of the system and all its $9402351 - 43 various alarm features may be verified by appropriate sequences of key activations. In particular, an alarm test mode may be initiated by turning on the transmitter unit and arming it as previously described. After commencement of exit delay, a test code is entered and the arm button is pressed. In this manner, the unit is brought into test mode and no real alarms will be recognised. The receiver unit is then switched on. The various inputs, namely the help alarm, the house alarm, PIR alarm, and the power failure alarm conditions, may then be tested in turn. If all is in order, the appropriate LEDs flash on both the transmitter and receiver units and the relevant buzzer sounds are effected. The disarm and duress codes may then be similarly checked, followed by a final disarm to remove the system from the test mode and place it again in a condition ready for activation and arming.

The control and sequence features of the invention are preferably provided in software, of which that at the transmitter may provide the following sequence of steps, on detection of an alarm signal: 1. The radio carrier is turned on. 2. A one and a half second time lapse applies. 3. A 24 bit transmission code is sent, i.e. the originally randomly-generated code established on initial unit matching. 4. A further delay period applies.

. An 8 bit alarm code is transmitted. 6. A further time delay is introduced. 7. Steps 3 to 6 are repeated. 8. Steps 3 to 6 are repeated. 9. Steps 3 to 6 are repeated.

. The radio is turned off again - carrier off.

This complete sequence occupies a little over 4.5 seconds in transmission. In the case of an alarm without a delay, the entire sequence 1 to 10 is repeated again immediately. In the case of an alarm with a delay, for example house, power or PIR, the sequence 1 to - 44 $9402354 is repeated once again after the delay period has expired, unless the alarm has been cancelled. If the alarm has not been cancelled, the sequence is repeated four times, each after a nine second delay.

The total time taken to fully transmit an alarm is therefore approximately 63.6 seconds, plus any alarm delay time.

The operation of the receiver is also embodied in software. This includes a main programme and two interrupt routines, one of which handles an internal timer while the other handles audio output from the radio. When no alarm is active or pending, the microprocessor is normally turned off. When any particular interrupt is being serviced, all other interrupts are disabled.

The timer interrupt is used in reading the radio signal by reading the number of external interrupts since the last time interrupt and incrementing counters which are then used by the main programme to flash appropriate LEDs, sound the buzzer and initiate any time delays.

Time interrupt steps are appropriately defined. External interrupt is used to count pulses received from the audio output of the radio.

The main loop of the programme takes care of all LED flashing and buzzer sounding as well as alarm time-outs and other features of the system. Suitable known techniques are applied to effect the necessary operations.

Embodiment of Figures 12 to 15 Figure 12 shows in pictorial representation a transmission unit and receiver unit according to the invention. Figure 13 is an enlarged pictorial representation of the receiver unit on its own. Figure 14 shows the receiver in position immediately preparatory to reception in or insertion into the cradle region of the transmitter, for unit matching. Figure 15 corresponds to Figure 14, but with the receiver now accommodated within the transmitter cradle and the receiver and transmitter 8-pin connections made, for transfer of information between S 94 0 2 35 ’ - 45 the respective units during unit matching. The particular constructions of transmitter and receiver unit shown in these drawings represent preferred configurations, specifically adapted for convenience of use and ready portability from site to site. Other features of this preferred construction of the unit correspond with the features previously described, as now briefly indicated.

A preferred embodiment of security or caring system according to the invention is shown in Figures 12 to 15 inclusive. As shown in Figure 12, the system comprises a transmitter 151 and a receiver 152.

Electrical schematic diagrams for the internal arrangements of the units 151 and 152 are shown in subsequent Figures 16 and 17. The operations of the system comprising the units of Figures 12 to 15 are essentially the same as already described for the embodiment of Figures 9 to 11, with certain minor detail differences, and are again described briefly subsequently.

External features of the transmitter are as follows. The transmitter has an attractively styled external casing, which has switch and display features commencing, from the base of the unit, with a power on/off switch 161 and a corresponding LED 162. Immediately above power switch 161 is a buzzer on/off switch 163 and associated display LED 164. A battery test switch 165 is located above the buzzer switch 163, together with an associated battery charge indicator 166. Finally, in the array of switches, is a restart switch 167 for use by the watching neighbour, following entry to the protected premises for checking or inspection purposes.

Approximately midway along one of the narrower faces of the generally rectangular upright unit, the vertical dimension of which is longer than either of its other two dimensions, there is located a keypad, consisting of twelve keys, numerical keys numbered 0 through 9 and referenced generally as 168, the remaining two keys being arm key 169 and disarm key 171. Above the keypad, three LEDs are provided for §-84 0 235 ' - 46 indicating alarm conditions, namely help 172, house alarm 173 and intruder alarm 174. Each LED and key is located within a depression or recess in the casing wall, for ease of visibility and protection. Immediately above these LEDs is an integral PIR or infrared intruder detector 175. On the top end casing portion of the transmitter 151, there is finally provided a large PA button 176, preferably coloured red, for ease of identification and use in any emergency circumstance.

On the vertical rear face of the transmitter unit 151, there are provided the following further features, from bottom to top again, firstly a socket 177 for receiving a help extension line for remote PA activation, a power socket 178, and a house alarm socket 179. A rocker switch 181 is also provided for switching internal PIR on and off for test purposes.

Portability of the device is particularly provided for by an extensible handle 154, which may be displaced between a retracted disposition which it occupies when the system is in security use and an extended disposition, shown in ghost outline 154a, which it takes up for transport purposes. At the lower end of the unit, there are provided legs 155, which may be moved outwardly and downwardly to allow the PIR face of transmitter 151 to be disposed at an angle to the vertical, for optimal PIR effectiveness. Preferably legs 155 have two extended dispositions, corresponding to partial and full displacement from their dispositions of rest or stowage, shown in the drawings.

Referring now to the receiver unit 152, Figure 13, this is also housed in a shaped generally rectangular casing, of considerably smaller dimensions than the transmitter. External features include two buttons, at the top end of the receiver, a power on/off button 201 with an associated indicator LED 202, and a test switch 203. The remaining features on the front face of the receiver unit consist of a series of LEDs, of which LED 204 is illuminated when transmitter power is restored. A row of LEDs indicates the particular alarm condition at the receiver unit, namely help 205, duress 206, intruder 207, house - 47 S94 023V alarm 208, transmitter power off 209, and interference 211. A green LED 212 indicates the home safe/stand-down condition, when the householder at the transmitter end has returned home and legitimately terminated the watching procedure. On the rear face of the unit, there is provided the further feature of a battery test switch 221 and indicator 222 (Figure 14).

For matching of the units, Figure 14, the transmitter 151 has on its upper surface, to the rear of the PA button 176, a cradle region 191, comprising a concave or recessed portion defined between two lateral ribs 192. At the front end of this region, immediately to the rear of the PA button 176, the cradle region 191 terminates in a wall portion 193, in which a transmitter connector 194 is located. This may be an 8-pin socket, for cooperation with a matching 8-pin plug of the receiver. The cross-sectional profile of the receiver 152 is matched to that of the cradle region in such a manner that the receiver may be accommodated between the lateral ribs 192 with its lower end 157 directed towards the inner end wall portion 193 of the cradle. This lower end or base 157 of receiver 152 is provided with a receiver connector 196 for engagement with the transmitter connector 194 when the transmitter and receiver units are brought together or associated, with the receiver accommodated in the cradle for unit matching and loading of arming codes. The styling of both components of the system is such that the receiver unit sits in a neat and convenient manner within the cradle 191, Figure 15, which is also convenient for portability of the system, the two units being transportable together in the associated or cradle condition.

Further features of the rear of receiver 152 are a clip 223 for holding the unit on, for example, a belt or waistband, and a battery compartment cover 224.

Realisation of Figures 16 and 17 Figure 16 is a schematic diagram of one manner of implementation of the transmission unit, while Figure 17 is a schematic diagram of a Λ . I * fl w ·» - 48 particular manner of realisation of the receiver unit. The circuitry shown in these schematics and embodied in the units and its manner of working will be readily apparent to those skilled in the art. A preferred microprocessor is one belonging to the MCS-48 family of single chip microcomputers, in respect of which detailed data is known from the Intel User's Manual, September 1981.

All radio signal data transmission suitably takes place in the manner previously noted and again briefly summarised. One or zero bits are transmitted and interpreted in terms of numbers of pulses over a predetermined period. The format of radio transmissions includes the emanation initially of the transmission code, which is compared at the receiver unit with the code stored in the erasable programmable read only memory of the receiver from the original matching process. After a brief delay to enable this comparison, the alarm code is transmitted. Repetition of these steps may be effected a number of times, for example four in total, before transmission is terminated by turning off the carrier wave. After a lengthier time interval, further repeated transmissions may take place in cyclic manner up to, for example, a total of six, involving switching on the carrier wave again and repeating the entire sequence briefly noted above.

Matching or unique identification data is transferred when both units are located in the cradle. When the transmitter is turned on but not armed, then the transmitter sends its transmission code to the receiver unit. This is suitably a 3 byte code, the first byte of which starts with a 1. The cycle is repeated a large number of times. As soon as the receiver unit receives two codes one after the other which are the same, it updates its transmission or matching code as stored in memory using the received code and ignores any further transmission codes while the power remains on. Updating or changing of the arming code, i.e. the code selected by the user, also takes place while the transmission and receiving units are located in the cradle and transmitter power is off. For this purpose, a particular loading code is sent to the receiver unit, which responds by reporting its transmission code, thereby enabling the user to update the arming code. 0235’ - 49 The procedures taking place on activation of an alarm have been outlined previously. In order to achieve this, a program stored within the transmitter is adapted to effect the required steps. The software for this program consists of a main program and an interrupt routine, this latter servicing an internal timer interrupt. The timer interrupt is used to transmit and receive data, debounce mechanical inputs, flash the indicators or LEDs, sound the buzzer and provide a suitable clock for the main program. On each clock cycle, all necessary LEDs and the buzzer are updated. Similarly on each clock cycle, each mechanical input is read on the relevant port. These include buzzer active/silent switch, house alarm input, PA (help) button, restart switch and PIR (intruder) input. Each input is compared with its previous value. If the value is different then a debounce register for that input is reset. If they are the same, then the debounce register for that input is updated. Likewise the keypad is scanned and debounced, in similar manner to that applicable to the mechanical inputs as noted above. A check is carried out to establish whether data transmission is required. If radio transmission is required, then an appropriate flag is set. The timer interrupt also checks whether or not data requires to be read while the receiver is in the cradle. On termination of the cycle, the routines commence over again.

The main program passes information to and from the internal timer interrupt routine. Information read in is processed during a timer interrupt and the interrupt routine is informed if any output is required. On power up, initialisation and enabling takes place, and the program enters an initial status, namely power up. There are a further six valid states, as follows: monitoring inputs, loading new arming code, arming unit, system armed, alarm test mode and alarm state. After initialisation, the program must be in one of the above seven states or statuses. The various outputs and actions of the system in each of the various statuses or conditions have already been described at length in earlier text. In the alarm state, which is entered only when an alarm has been activated, each alarm is checked in turn to see which has been activated. Appropriate outputs are then 9 4 0 2 35 11 - 50 established. Immediate transmission of an alarm condition always takes place. After transmission, a check is carried out to establish whether or not a delay should apply to the alarm in question. Various recovery situations are monitored during the relevant delay period, such as applies to intruder or house alarm and also to power failure. In the case of brown-out, or partial power failure, a three minute time delay suitably applies. In the case of PA or help alarm, monitoring takes place to establish whether or not the signal in question is a normal call for help or an emergency circumstance.

At the receiver, the software consists of a main program and two interrupt routines, one handling an internal timer and the other handling audio output from the radio. When no alarm is active or pending, the microprocessor is normally turned off. When an interrupt is being serviced, all other interrupts are disabled.

The internal timer interrupt is used to read the radio signal by reading the number of external interrupts since the last internal timer interrupt and to implement counters used by the main program to indicate any emergency conditions, by flashing the LEDs, sounding the buzzer, and implementing any time delays required.

The external interrupt is used to count pulses received from the audio output of the radio. In the MCS-48 family of microprocessors, the external interrupt is level triggered, and must therefore be maintained for a full time period to prevent reentry into the same interrupt. The necessary flags are set on receipt of a transmission.

The main loop of the receiver program takes care of all LED flashing and buzzer sounding, as well as alarm time-outs and other relevant tasks.

The nature of the functions of the system will be apparent from the schematic diagram and the previous descriptive matter. On power turn-on, the program undertakes initialisation, and enters into one of eight valid states, as follows: S 94 0 2 354 - 51 Status 0 - power on - source of power unknown.

Status 1 - reading radio data (used in interrupt only).

Status 2 - transmission and alarm codes received (process alarm).

Status 3 - transmission test (transmission received).

Status 4 - alarm - delay time-out.

Status 5 - alarm - flash LEDs and sound buzzer.

Status 6 - cradle power.

Status 7 - waiting next transmission test - scan test cancel button and check for end of test transmission.

The main loop examines a status byte and sets the appropriate status, with cross-checks to ensure that an inappropriate status is not entered in the event of the receiver unit having already received a valid alarm and reporting or waiting to report it. Appropriate distinctions apply between genuine alarm conditions and test transmissions, to ensure that a false or deceptive output is not generated.

All of the foregoing functions and features of the system may be embodied in software in a manner which will be apparent to those skilled in the security systems art from the foregoing description and the related schematics. In association with the development of such procedures, detailed test procedures or steps may also be established and suitable user documentation also be developed.

The system of the invention has many advantages over more traditional protection and warning systems. These include responsibi1ity for taking definite action being pinpointed once an alarm is triggered. The system capitalises on the existing Neighbourhood Watch concept, to give it added reality, immediate practical and tangible benefits, and to increase its effectiveness. The system of the invention integrates different types of protection, including, inter alia, fire, intruder, personal protection, cars, or other property. The portable units provide flexibility and the opportunity for many different applications and uses. The system enables much more responsive reaction to the raising of an alarm. Neighbours situated locally can phone the police $94 02354 - 52 or other emergency service directly, or can summon other neighbours, or even call or telephone to the dwelling affected. Use of the system of the invention serves as a deterrent to criminal elements, since it shortens the time between the raising of an alarm and the arrival of support or assistance. This rapid response inherent in the system of the invention is of particular advantage in support of the ill and infirm. The technology employed in the system of the invention is relatively inexpensive, thereby providing especially economic security, emergency, and caring protection. Wide use of the system of the invention reduces crime rates and also enhances social and health care of the infirm and elderly. The test facilities of the system restore credibility to alarm systems, while the system also enables false alarms to be minimised. The system of the invention establishes a Neighbourlink concept in security for the purpose of effecting an improved Homeguard situation. Finally, the superior protection of the system of the invention adds to the peace of mind of its users, whether they are in their dwelling or temporarily absent from it.

The system of the invention is also applicable to commercial and business use, in that it uses proven technology, is portable, and is economically competitive with existing systems. The link with the proven neighbourhood watch concept is a further attraction. The system of the invention is in addition suitable for use by specialist security organisations, and also to use within the retail and distribution sectors.

Claims (5)

1. A security system comprising a detection unit and an alert unit, the detection unit having: (a) control means responsive in an active mode of the detection unit to an alarm condition in the vicinity of the detection unit to communicate an alarm signal to the alert unit, (b) input means for communicating said alarm condition to said detection unit control means, and (c) radio transmitter means for transmitting said alarm signal to said alert unit; and the alert unit having: (a) radio receiver means for detecting said alarm signal transmitted by said radio transmitter means of the detection unit, (b) control means responsive in an active mode of the alert unit to said alarm signal to report said alarm condition in the vicinity of the detection unit, and (c) output means for providing an aural and/or visual indication of said report of said alarm condition; wherein: (i) the alert unit comprises a self-contained power supply, (ii) the detection unit is provided with means for power supply from an independent power source, and (iii) the detection unit also comprises a self-contained back-up power supply; so that the detection unit and the alert unit together define a cooperating and portable pair of units of the security system, each of which is independently portable.

2. A security system according to Claim 1, wherein: (i) said detection unit control means is adapted to establish a unique identification signal coded to indicate transmission from said detection unit, (ii) said alert unit control means is configured to be responsive only to said unique identification signal, and S 94 0 235 ' - 54 (iii) said detection unit control means is further adapted so that all radio transmissions from said detection unit incorporate said unique identification signal, and said unique identification signal is established by the steps of: (a) associating said alert unit with said detection unit for transfer of identification data, (b) activating said detection unit control means to generate a random identification code during said association of of said alert unit with said detection unit, (c) transferring said identification code to said alert unit for storage in said alert unit control means, (d) storing said identification code in said detection unit control means, and (e) terminating said association of said alert unit with said detection unit; said randomly-generated identification code then defining said unique identification signal for incorporation in all radio transmissions.

3. A security system according to Claim 1 or Claim 2, wherein said detection unit is armed by input to said detection unit control means of a unique user-selected arming code, and said unique user-selected arming code is inputted by the steps of: (a) associating said alert unit with said detection unit for transfer of identification data, (b) inputting an arming code to said detection unit code during said association of said alert unit with said detection unit, (c) storing said arming code in said detection unit control means, and (d) terminating said association of said alert unit with said detection unit.

4. A security system according to Claim 2 or Claim 3, wherein: (i) said detection unit is profiled to accommodate said alert unit in a connected-together configuration of the units defining said association of the units, and '5840235 - 55 (ii) said detection unit and said alert unit are provided with respective cooperating connector means for data transfer in said connected-together conf igurat i on.

5. 5. A security system as described herein with reference to and as shown in any one or more of the accompanying drawings.