GB2205671A - Multiple environment monitoring system - Google Patents

Abstract

The system enables a single operator to supervise a number of different mutually isolated environmental regions and comprises a plurality of input transducers 11, one for each environmental region to be monitored, and each having its output supplied to a respective adjustable threshold detector 19, a common alarm indicator 29 connected to the outputs of all the adjustable threshold detectors, a common signal-responsive indicator device 27 operable at a level below that of the threshold detectors and a plurality of individual signal attenuators 18 separately operable to allow a selected signal or selected signals from the transducers to be supplied to the indicator device. As particularly described, the transducers are microphones and the common indicator device is a loudspeaker. Thus, whenever an alarm is provided, the operator can adjust the attenuator associated with the transducer that set off the alarm to enable the sounds in the corresponding region to be heard. The transducers may, alternatively, be thermopiles, TV cameras, optical transducers etc. <IMAGE>

Description

A MULTIPLE ENVIRONMENT MONITORING CIRCUIT In man situations there is 2 need to be able to provide constant supervision or surveillance for various different purposes. For example, security organisations frequently reguire to monitor activity in premises where intruders may be expected, for example buildings where valuables are housed, factories, offices and other premises which may he subjected to supervising surveillance for security purpcses.

For different reasons supervision is required of human activity in establishments such as hospitals or hostels, where it is necessary to maintain surveillance over the state of the inmates o patients in order to ensure their well being.Particularly in hospitals naving geriatric patients a conventional "nurse-call" system involvin tne necessity for tne patient to call for assistance by depressing 2 bell push or pulling a bell cord have een fount to ce inadequate due to the possibility that elderly patients who are weak or disabled may De sufficiently iii not to be able to reac.

tne bell pusn, althoug the may De able to cry out for assistance. Recent attention has been directed to the provision of extensive hostels for the elderly rather than housing them in closed homes having common areas, largely because this arrangement is more satisfactory from the user's point of view. A single warden is responsible for a number of individual chalet-type homes which are otherwise autonomous. The problem of supervision in such circumstances is obviously exacerbated b tne distance which has to be covered.

A similar problem is encountered with young children when it is known to provide so-called baby alarms which are switched on when a child is put down to sleep, and which alerts parents in a different part of the house if the child should wake and cry. Without such an alarm the volume of tne sound generated by the infant may not be sufficiently loud to alert parents to its need for attention.Such baby alarms are, however, simple signal transmitters which are active at all times and do not len themselves to simple adaptation to a multipleenvironment situation since in many circumstances there is a considerable amount of "normal" or background noise which does nct constitute an alarm signal ano which would obscure the arrival of an alarm signal from an one or tne monitored environments.

The present invention seeks, therefore, to provide a monitoring system capa@le of enabling surveillance to take place over a large number of separate environmental regions whior1 may themselves generate a level of bachground "noise" and which makes it possible to discriminate between normal and abnormal activity resuirinc attention.The present invention also makes t possible for supervising personnel to identify individual environmental regions under surveillance for specific attention irrespective of the separate indication of an alarm situation. @@@ According to one aspect of the present invention, therefore, a monitoring circuit to enable a single operator to supervise a plurality of different mutually isolated environmental regions, comprises a plurality of input transducers, one for each environmental region to be monitored, a plurality of individual adjustable threshold detecters, a common alarm indicator connected to the outputs of all the ad@ustable threshold detectors, a com@on signal-responsive indicator device operable at a level below that of tne threshold detectors and a plurality cf individual signal attenuators separately operable to allow a selected signal or selected signals to be supplied to the indicator device.

As used in this specification the term "noise" will be understood to refer to extraneous or background signals, wnether they are audible, visual or of other nature, which are present in an environment together with the required signal and against which the presence of the reguired signal must be discriminated. For example, "noise" may be defined as normal visual signals on a television cirouit to be discriminated from abnormal activity which constitutes the signal which is required.

Likewise, if the transducers were sensitive, for example, to heat in order to detect intruders, then the "noise" may be generated by small animals, changes in am@ient temperature due to solar radiation, and other sources of neat different from the intruders beat from which is intended to De detected.

The monitoring circuit of the present invention may have transducers of any type capable of producing an electrical signal in response to a physical event or change in physical parameters to which it is sensitive, and without loss of generality, specific transducers which may be of value in a system formed in accordance with the principles of the present invention may include microphones, thermopiles, television cameras, optical transducers, photocells @r the like. In a preferred em@odiment of the invention the input transducers are m@cropnones enabling a supervisor to monitor the level of audio activity in the monitored environment.In particular, then, the threshold detectors may be set, in use, to a level which would not normally be exceeded curing the expected activity over the monitored period, and the exceeding of which would indicate an abnormal, potentially serious event requiring investigation by the supervising personnel.Upon triggering of a threshold detector, it CS then possible to adjust the selected attenuator identified by an indicator linked to the t@reshold detector, in order to allow signals from the appropriate input transducer to be supplied to the indicator device. In the case o microphones as tne input transducers a loudspeaker would De provided as the indicator, correspondingly the attenuators may conveniently be formed as respective variable resistors in the electrical circuit.

Normally, then, tne attenuators are set such that the signals from the individual input transducers are attenuated to 2 lee; sufficiently far below the threshold value as to create no perceptible signal at the indicator.Upon triggering by the threshold detector the adiustment of the attenuator would then allow supervising personnel to "listen in" to the sounds coming from the particular monitored environment in order to establish whether the event exceeding the thresnold detector warranted the physical presence of tne monitoring personnel. Tn present invention also incorporates the possi@ility of two-way communication between the central monitoring station and the individual monitored environmental regions so that closer checks can be made into circumstances from time to time.Likewise, random or arbitory monitoring may be effected b adjusting the attenuators without necess arily waiting for any event to trigger the threshold aetector.

In a preferred embodiment of the present invention the common alarm indicator and the common signal-responsive indicator device are housed in a common casing to which are attachable modular channel casing parts housing the individual threshold detectors and signal attenuators.

The modular channel casing parts may be provided with bus connectors and the common casing may have respective bus conductors for transferring all the signals generated by tne individual input transducers to the common alarm indicator device and the common signalresponsive indicator device.Such a modular construction maKes it possible to produce monitors individually adapted to monitor any given number of environmental regions, and it is also envisaged, within the scope of tne present invention, tat G casin structure designed to allow the simple plug-in connection of additional modular channel casing parts to be effected.

The individual input transducers may have an associated transducer corruption monitor operable to generate an alarm signal if an input transducer is disconnected from the line linking it to the monitoring circuits or otherwise disabled from operatina normally. Such a corruption monitor me act, for examp e, by app yin a signal to the line joining the transducer to the channel casing housing the signal processing units.Likewise, there is preferably provided a common tamper alarm connected b individual lines to the input lines from the input transducers and operable to generate an alarm indication in the event of tamper with the associated input transducer, the common tamper alarm being housed in the common part of the casing and connected to the individual input lines fro the input transducers b a common transer bus. The common tamper alarm may be connected by the tamper alarm bus to a point between the signal processing circuit and the signal attenuator of each channel.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is simplified perspective view of the outer casino housing G receiver it comprising common casin- with a plurality of modular channel casing parts; an Figure 2 is a schematic circuit diagram illus rating the manner in which a circuit incorporating the invention may be set up.

Ref erring now to the drawings the unit of the present invention is adapted to enable one person to monitor several different remote environments, such as the rooms of geriatric hostel or the wards of a hospital simultaneously for sounds of distress. Each monitored environment is provided with transducer, in this case a microphone 11 connected by a line 12 to an individual channel of a receiver unit generally indicated 13. As can be seen in Figure 1, the receiver unit 13 comprises a main casinc 14 housing the common components, and a plurality of individual channel casings identified 151, 152, 153 ect. Any number of channels may be provided to accommodate different reguirements: ten channels have been illustrated in Figure 1 with only the cnanne 1510 being illustrated in detail.As can be seen in Figure 1 the channel 1510, which is exactly identical to channels 151-15@ is a rectangular casing component housing, as can be seen In Figure 2, signal processing circuits 16 comprising hig an low level filters for eliminating extraneous sounos, an amplifier 17 and the three main input channel circuit components comprising an attenuator 18 (in this embodiment in the form of a variable resistor) a threshold detector 19 and a tamper signal detector 20. These tnree components, together with the signal processin@ circuits 16 and amplifier 17 are identical in each channel. Extending throughout the casing @ 3 are three bus conductors, namely an audio bus 21, an alarm bus 22 ane a tamper bus 23. The audio us 21 is connected, via an amplifier 24 and a variable resistor 25 to a furt@er amplifier 26 feeding an audic monitor loudspeaker 27 positioned at the front of tne common part 14 of the casing as illustrated in Figure 1.

The alarm bus 22 is connected via a control@ circuit 28 to an audible indicator 29, again in the form of a loudspeaker or buzzer, and this is also connected to a switching circuit 30 for transfer to a remote alarm location if a back up monitoring facility is reguired.

Tne tamper bus 23 is connected via a circuit 3i to a further, different alarm indicator 32 and again connected via the switching circuit 30 to the remote alarm if provided.

Both tne threshold detector 19 and the tamper detector circuit 20 are also provided with respective visible indicators 33, 34 respectively. In this way when a transaucer produces an output signal which is in excess of the threshold set by any threshold detector, the threshold detector 19 passes an alarm signal to the alarm bus 22 to energise the loudspeaker 29 to alert the supervising personnel that an alarm condition exists, ano te visible indicator 33 Identifies which channel the alarm indication is arriving on.By changing the setting of the variable resistor iS, by means of a rotary knob 35 at the front of the casing, the signal arriving on the line 12 can be passed to the audio monitor loudspeaker 27 so that the precise nature of the alarm signal can b assessed b the supervisor.If this appears simply to De a loud but otherwise normal sound, example in the monitoring of geriatric hostels, the alarm. trigger may be initiated if an elderly person were to drop an item of crockery, it would be possible nevertheless to detect that this event did nct recuire attendance at the location of tne event by the supervising personnel.If, on the other hand, the activating event were loud cries for assistance, these would normally be attenuated by the attenuators 18 until tne threshold detector were triggered to produce an output signal on the threshold alarm indicator 29, and tnen adjustment of the attenuator 18 would allow the signals to pass to the loudspeaker 27 so that the supervisor could immediately identify the nature of the crIes for help and, via tne visible indicator 33, the channel on which the signals were arriving and therefore the location of tne need for assistance.

In order to ensure that the system is operating at 211 times a tamper alert input circuit 36 (Figure 2} is provided, this applying a signal on the line 12 of channel 1510, and on the corresponding lines of all other active channels, the presence of which is detected by the tamper detector 20 in each individual channel.

Snould a microp-hone be switched off or unplugged, or the wire cut, this signal will disappear creating a tamper alarm condition indicated by Illumination of the lamp 34 ano the generation of a signal at the output or the tamper detection circuit 20 wnic is applied to the tamper bus 23 resulting in energisation of the tamper alarm 32.Again, the visible indicator 34 will provide te supervising personnel with an identification of the channel being tamper witn and their attention is drawn to the tapering event bv tne audible warning produced t the tamper alarm 32.

In this way, in normal use, the monitoring system provides no audible output when tnere is no requirement for attendance by the supervisor although tne supervisor can "listen in" to any location simply by turning the knob 35 controlling the attenuator 18 td establish that the noise generated at that location is normal. If, for example, there were complete silence when the random monitoring check were made it may indicate that a requirement for attendance exists because of the possibility that a monitored patient may be unconscious.

Any signs c distress resulting in an increased noise level will automatically trigger the circuit and result in an audible warning from a common indicator and an identification of the location from a visible indicator associated only wit the channel in question.

Claims (8)

1. A monitoring circuit to enable a single operator to supervise a plurality of different mutually isolated environmental regions, comprises a plurality of input transducers, one for each environmental region to be monitored, a plurality of individual adjustable threshold detectors, a common alarm indicator connected to the outputs of all the adjustable threshold detectors, a common signal-responsive indicator device operable at a level below that of the threshold detectors and a plurality of individual signal attenuators separately operable to allow a selected signal or selected signals to be supplied to the indicator device.

2. A monitoring circuit according to claim 1, wherein the transducers include microphones, thermopiles, television cameras, optical transducers, photocells or the like.

3. A monitoring circuit according to claim 1 or claim 2, wherein microphones enabling a supervisor to monitor the level of audio activity in the monitored environment and a loudspeaker is provided as the indicator and wherein the attenuators are variable resistors in the electrical circuit.

4. A monitoring circuit according to any of the preceding claims, wherein the common alarm indicator and the common signal responsive indicator device are housed in a common casing to which are attachable modular channel casing parts housing the individual threshold detectors and signal attenuators.

5. A monitoring circuit according to claim 4, wherein the modular channel casing parts are provided with bus connectors and the common casing has respective bus conductors for transferring all the signals generated by the individual input transducers to the common alarm indicator device and the common signal-responsive indicator device.

6. A monitoring circuit according to any of the preceding claims, wherein the individual input transducers have an.

associated transducer corruption monitor operable to generate an alarm signal if an input transducer is disconnected from the line linking it to the monitoring circuits or otherwise disabled from operating normally.

7. A monitoring circuit according to any of the preceding claims, wherein a common tamper alarm is connected by individual lines to the input lines from the input transducers and operable to generate an alarm indication in the event of tampering with the associated input transducer, the common tamper alarm being housed in the common part of the casing and connected to the individual input lines from the input transducers by a common transfer bus.

8. A monitoring circuit according to claim 7, wherein the common tamper alarm is connected by the tamper alarm bus to a point between the signal processing circuit and the signal attenuator of each channel.