Abstract:
An apparatus for the detection and enunciation of hazardous conditions within an environment comprises at least two detection circuits positioned to sense ambient conditions within a home or business environment. One of the detection circuits senses the presence of smoke, and the other detection circuit senses the presence of carbon monoxide. The apparatus also comprises an alarm circuit which is responsive to each of the detection circuits for generating at least one alarm pattern, and preferably a separate alarm pattern for each different sensed condition. A voice synthesizer circuit is also included, and is responsive to each of the detection circuits for generating at least one voice message. As with the alarm patterns, the voice synthesizer preferably generates separate voice messages for each separate detected condition. The apparatus advantageously also contains an interleaving control circuit. This interleaving control circuit interleaves the alarm patterns and voice messages in a predetermined sequence to reduce confusion in an emergency situation. A method for the detection and enunciation of multiple hazardous condition within an environment is also presented, and comprises the steps of: (a) sensing ambient conditions within the environment to detect at least two hazardous condition; (b) generating an alarm pattern and a voice message in response to sensing the hazardous conditions; (c) interleaving the alarm pattern and the voice message; and (e) enunciating these interleaved alarm patterns and voice.

Description:
This application is a continuation of application Ser. No. 09/271,574, filed Mar. 18, 1999, now U.S. Pat. No. 6,522,248, which application(s) are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The instant invention relates to the detection and enunciation of hazardous conditions, and more particularly to the detection and enunciation of smoke, carbon monoxide, and fire in residential and commercial settings. 
     BACKGROUND OF THE INVENTION 
     The improvement in reliability, decrease in cost and realization of the lifesaving benefits of commercial and consumer smoke and carbon monoxide detectors have resulted in an increased installation of these devices in homes and businesses. Many homes now include at least one and typically multiple smoke detectors located throughout the residence. Indeed, many state laws require that apartment dwellings include at least one smoke detector within an apartment for single floor plan apartments, and at least one per floor for multi level apartments. Further, many state laws also require that smoke detectors be installed in homes prior to their sale. 
     Additionally, many homes and apartments are also being equipped with separate carbon monoxide detectors. The increase in installation of these detectors is due in large part to the improved reliability of these detectors which have, for the most part, overcome the false triggering of early devices. This increased use is also due in part to the recognition of people in colder climates that central heating systems, wood burning stoves, and fireplaces are all potential sources of deadly carbon monoxide which, without a carbon monoxide sensor, would go undetected until it was too late. A majority of these carbon monoxide detectors are being installed in dwellings which also include a separate smoke detector. 
     In recognition of the fact that many residences install both carbon monoxide and smoke detectors within the dwelling, Underwriters Laboratory (UL) has issued an industry standard to distinguish these two alarms. This UL standard requires that a fire/smoke alarm shall sound three (3) beeps at a rate of 0.5 second on, 0.5 second off with a gap between these three beep patterns of 1.5 seconds. The UL standard for CO alarms is similar, to wit four beeps at a rate of 0.1 second on, 0.1 second off with a gap between these four beep patterns of five (5) seconds. Since UL has issued these patterns as an industry standard, detector manufacturers must utilize them for each type of detector they make in order to gain UL approval. 
     The importance of being able to distinguish these two alarm patterns becomes apparent when the preferred actions for each alarm are compared. Specifically, a resident whose smoke detector has triggered is encouraged to close doors and windows, call the fire department to indicate that a fire has been detected, and immediately leave the dwelling. However, a resident whose carbon monoxide detector has triggered is encouraged to open doors and windows to allow fresh air to enter the dwelling to displace the carbon monoxide gas, and leave the dwelling for a period of time to allow the carbon monoxide gas to escape the dwelling. Some carbon monoxide detector manufacturers also recommend contacting a heating and cooling expert to check and clean the furnace, or alternatively their local fire department to indicate that high levels of carbon monoxide have been detected within their dwelling. Clearly, the preferred actions to be taken upon the detection of these two conditions vastly differ, and may result in a life threatening condition should one be mistaken for the other. 
     While the benefits of having both smoke detectors and carbon monoxide detectors installed within a dwelling far outweigh any problems associated therewith, problems which may become significant do exist. In addition to the above-described problem associated with the different courses of action to be pursued upon the detection of one of the two conditions, a similar situation may occur if both detectors trigger simultaneously. This situation may very well occur during an actual fire situation where the levels of smoke and carbon monoxide are typically high. In this situation, the sounding of both the carbon monoxide and the smoke detector alarms at the same time are most likely to cause confusion in the resident as to the cause and criticality of the situation. Precious seconds and minutes may be lost while the resident attempts to determine first what this new sound (the combination of the smoke and carbon monoxide detector alarms ringing simultaneously) is, and second, what action to take in response thereto. Therefore, this lack of coordination between the two alarm systems within the residence may lead to unnecessary confusion during a time of critical importance to the safety of the residents within the dwelling. 
     SUMMARY OF THE INVENTION 
     In view of the above-described problems existing within the art, and others not specifically elaborated herein, it is a primary object of the instant invention to overcome these problems. Specifically, it is an object of the instant invention to provide a coordinated alarm system which will allow the detection of potentially threatening conditions. It is a further object of the instant invention to provide a detection and alarm system which does not require that the user be able to distinguish separate alarm patterns in order to be informed as to the cause of the alarm. It is further an object of the instant invention to provide a detection and alarm system which will properly signal a resident in a straightforward manner to allow proper action to be taken to avoid injury from the type of situation detected. It is a further object of the instant invention to provide the detection and enunciation of multiple conditions which may occur individually or in combination without the associated problem of having multiple alarms being triggered simultaneously. 
     In view of these objects, it is a feature of the instant invention that both carbon monoxide and smoke may be detected individually or in combination. It is a further feature of the instant invention that the alarms generated by the detection of these conditions be audibly distinguishable one from another. It is a further feature of the instant invention that, in association with the distinctive alarm patterns, a synthesized human voice will provide warning and/or direction information for the residents of the dwelling. It is an additional feature of the instant invention that the distinctive alarm patterns and synthesized human voice will be interleaved in a fashion to alleviate confusion and foster proper response. It is a further feature of the instant invention that detection of both carbon monoxide and smoke will generate only a single alarm which is interleaved with a synthesized voice message providing an explanation of the probable cause of the alarm and/or direction as to the proper action to be taken. 
     In view of the above objects and features, it is an aspect of the instant invention that the carbon monoxide and smoke detectors, the multi-tone or multi-pattern alarm, and the voice synthesizer be housed in a compact integrated unit for installation in the home or business. It is a further aspect of the instant invention that the integrated unit include control processing technology which allows for a coordination of the sensing, detection, alarm sounding, voice message generation, and interleaving thereof. It is a further aspect of the instant invention to allow for the voice synthesized message to be generated in multiple languages selectable by the user to further enhance its effectiveness. 
     A preferred embodiment of the apparatus for the detection and enunciation of hazardous conditions within an environment of the instant invention comprises at least a first and a second detection circuits positioned to sense ambient conditions within the environment. An alarm circuit is responsive to both of the detection circuits, and generates at least a first alarm pattern, and preferably a distinct alarm pattern for each detected condition. The apparatus also comprises a voice synthesizer circuit which generates at least a first voice message, and preferably a distinct alarm pattern for each detected condition. An interleaving control circuit is preferably coupled to the alarm circuit and to the voice synthesizer circuit, and causes an enunciation circuit to selectively broadcast at least the first alarm pattern and the first voice message. 
     In a preferred embodiment, the apparatus includes both smoke and carbon monoxide detectors, each triggering a distinct alarm pattern and warning voice message. Preferably, the alarm circuit also generates a third alarm pattern which is characteristic of the presence of both smoke and carbon monoxide. A preferred embodiment of the voice synthesizer circuit generates voice messages in multiple selectable languages. 
     A preferred method of the instant invention for the detection and enunciation of multiple hazardous condition within an environment is also presented, and comprises the steps of: (a) sensing ambient conditions within the environment to detect at least two hazardous condition; (b) generating an alarm pattern and a voice message in response to sensing the hazardous conditions; (c) interleaving the alarm pattern and the voice message; and (e) enunciating these interleaved alarm patterns and voice. The interleaving of the alarm pattern and voice messages is preferably performed by the steps of: (f) enabling enunciation of the alarm pattern for a first period of time; (g) disabling enunciation of the alarm pattern at the expiration of the first period of time; (h) enabling enunciation of the voice message at the expiration of the first period of time for a second period of time; and (i) disabling enunciation of the voice message at the expiration of the second period of time. These steps are repeated until a reset is received. 
     These and other aims, objectives, and features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified block diagrammatic illustration of an embodiment of the instant invention; 
         FIG. 2  is a simplified block diagrammatic illustration of an alternate embodiment of the instant invention; 
         FIG. 3  is a simplified block diagrammatic illustration of a further alternate embodiment of the instant invention; 
         FIG. 4  is a functional flow diagram illustrating operational aspects of the instant invention; 
         FIG. 5  is a functional flow diagram illustrating in greater detail a particular operated aspect of an embodiment of the instant invention; 
     
    
    
     While the invention is susceptible of various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment of the instant invention is illustrated in block diagrammatic form in FIG.  1 . As may be seen from an examination of this figure, a detector of the instant invention  10  comprises both a carbon monoxide detector  12  and a smoke detector  14 . As will become apparent to those skilled in the art from the following description, other detectors may be integrated in the detector of the instant invention  10  without departing from the spirit and scope of the invention as will be defined by the claims appended hereto. These detectors  12 ,  14  may be of conventional design utilizing various topologies known in the art. 
     In a preferred embodiment of the instant invention, the output  16  from the carbon monoxide detector  12  is coupled to both an alarm circuit  18  and a voice synthesizer  20 . Likewise, the output  22  from the smoke detector  14  is also coupled to both the alarm circuit  18  and the voice synthesizer  20 . The output  24 ,  26  from each of these circuits  18 ,  20  are coupled to an interleaving control circuit  28 . In a preferred embodiment, this interleaving control circuit  28  also includes a synthesizer enable output  30  which is coupled back to the voice synthesizer  20 . The output  32  of the interleaving control circuit  28  is coupled through an amplifier  34  to at least one device speaker  36 . 
     The operation of the embodiment of the instant invention illustrated in  FIG. 1  will now be described under three separate conditions. First, assuming high levels of carbon monoxide in the environment within which the detector  10  is located, the carbon monoxide detector  12  will generate an output signal on line  16  to both the alarm circuit  18  and the voice synthesizer  20 . The receipt of the carbon monoxide detector input  16  by the alarm circuit  18  will result in a generation of an alarm pattern on line  24 . Additionally, the voice synthesizer circuit  20  will select the carbon monoxide appropriate message to pass to the interleaving control circuit  28  via line  26 . The interleaving control circuit  28  is responsible for interleaving the voice synthesized message with the alarm patterns in an appropriate manner. Preferably, the interleaving control circuit includes timing elements which first pass the alarm patterns on line  24  to the output  32  for a given period of time. After the expiration of the given period of time, the interleaving control circuit then preferably enables the voice synthesizer  20  via an enable signal on line  30  to allow the voice synthesizer to generate the voice synthesized appropriate message for the carbon monoxide detection condition. Through the use of the enable signal  30  the interleaving control circuit  28  may ensure that the signal passed from line  26  to output  32  always begins at the start of the message generated by the voice synthesizer  20 . After the voice synthesized message  26  has been played at least one time, the interleaving control circuit  28  then reverts back to the alarm patterns generated by the alarm circuit for a given period of time. The interleaving control circuit  28  continues to operate in similar fashion, alternatively passing the alarm patterns and voice synthesized message to amplifier  34  for broadcast by the speaker  36 . 
     While the above description includes an enable signal on line  30  to enable the voice synthesizer to begin transmitting its voice synthesized message on line  26 , one skilled in the art will recognize that the interleaving control circuit  28  may accomplish its function without the use of a voice synthesizer enable command through appropriate timing control. Without the use of an enable signal  30 , both the alarm circuit  18  and the voice synthesizer  20  would begin transmitting on outputs  24 ,  26 , and would continuously transfer their generated message or alarm pattern to the interleaving control circuit  28 . It would then be the responsibility of the interleaving control circuit  28  to interleave these two signals  24 ,  26  so that the output  32  to amplifier  34  would allow for proper broadcasting by speaker  36 . By proper broadcasting it is meant that the detector  10  broadcasts an audible alarm pattern which is interleaved at given intervals with a voice synthesized message providing indication of the alarm condition, and may include directions for the dwelling occupants. The interleaving would be preferably controlled such that the voice synthesized message is broadcasted from its beginning until its completion before interleaved again with the alarm patterns. In this way, confusion is minimized by the interleaved coordination of the alarm pattern and voice synthesized signal. 
     Further, the level of CO detected may be used to select different appropriate voice synthesized messages. UL publishes various levels of CO and their associated exposure time hazard. For example, a low level of detected CO becomes hazardous as the length of exposure is increased, while high levels of CO can be lethal for very short duration exposure. Recognizing this fact, an embodiment of the detector of the instant invention may incorporate different messages based on the detected level of CO. A low level of detected CO may result in a cautionary warning while a high level of detected CO may result in an emergency evacuation warning. The overall pattern of the warnings may be different or the same. If different, the low level cautionary warning may be enunciated at a much slower rate, i.e. more time passing between repetition of the pattern of voice and alarm tones, than that required for a high level. A similar level detection may be included for the smoke detection if desired. 
     Operation during a smoke condition is similar to that described above, with the exception that the initial detector signal is generated by the smoke detector  14  on line  22 . Once the signal  22  is generated and passed to the alarm circuit  18  and the voice synthesizer circuit  20  the appropriate outputs are generated on lines  24  and  26 . The appropriate output from the alarm circuit  18  on line  24  may be the same alarm pattern signal as was generated in response to the receipt of input  16 , or, more preferably, is a separate distinct alarm pattern which allows differentiation between the detected conditions. Likewise, the voice synthesizer  20  may generate a generic occupant warning message on line  26  regardless of the receipt of the signal on line  16  or the signal on line  22 , or may, more preferably, generate a separate distinct voice synthesized message characteristic of the type of input received. In a preferred embodiment of the instant invention, therefore, the signal  24  generated by alarm circuit  18  in response to a signal on line  22  representative of a detected smoke condition is a distinct alarm pattern signal from that generated upon receipt of signal  16  representative of a carbon monoxide condition. Likewise, the output from voice synthesizer  20  provides a smoke appropriate message on line  26  in response to the receipt of the signal on line  22 . As described above, this voice synthesized message may provide the occupant with an indication of the sensed condition as well as instructions as may be appropriate. The interleaving control circuit  28  operates in similar fashion as that described above, and for the sake of brevity, will not be described again. 
     A third situation is possible, particularly during a fire situation within the dwelling. This condition results in both the generation of smoke which will be detected by smoke detector  14  as well as the generation of carbon monoxide which will be detected by a carbon monoxide detector  12 . As a result of the dual generation of both carbon monoxide and smoke, the outputs on lines  16  and  22  will both be present at the alarm circuit  18  and the voice synthesizer circuit  20 . During this condition, the alarm circuit  18  may generate the same alarm pattern generated above on line  24 , or more preferably a third distinct alarm pattern indicative of the fire condition. Likewise, the voice synthesizer  20  may also generate the generic message on line  26  indicating a dangerous condition within the dwelling, or may, more preferably, generate a unique message which is appropriate to the sensed condition. As described above, the interleaving control circuit  28  operates to interleave these alarm patterns  24 , and voice synthesized message  26  in the manner described above. 
     In an alternate embodiment of the instant invention, as illustrated in simplified block diagrammatic form in  FIG. 2 , the output  16  from the carbon monoxide detector  12  and the output  22  from smoke detector  14  are both coupled to controller  17 . The controller  17  analyzes the inputs  16 ,  22  and generates an appropriate alarm signal  19  to alarm circuit  21  which, in response, drives speaker  36 B. In this embodiment of the instant invention the controller  17  analyzes the inputs  16 ,  22  to determine the appropriate signal to generate on line  19  to drive alarm circuit  21  in the appropriate manner in accordance with the UL specification as described above. In addition to the appropriate alarm signal generated by controller  17  on line  19 , this controller  17  also generates an output voice enable signal  23  to enable the generation of the voice synthesized message. In this embodiment, the controller  17  also transmits via address lines  25 ,  27  a coded signal to decoder  31  to select the appropriate message based on the sensed conditions from inputs  16 ,  22 . The decoded signals are transmitted to the voice synthesizer sound chip  33  which then transmits the appropriate voice synthesized message to amplifier circuit  35  to drive output speaker  36 A. As illustrated in this embodiment, two separate speakers  36 A,  36 B are utilized to provide maximum effectiveness and pattern quality for the two types of signals generated by the detector of the instant invention  10 . However, one skilled in the art will recognize that appropriate selection of the proper speaker may allow for the use of a single output speaker  36  illustrated above in FIG.  1 . 
     Yet another alternate preferred embodiment of the instant invention is illustrated in simplified block diagrammatic form in  FIG. 3 , to which specific reference is now made. As may be seen from this  FIG. 3 , the output  16 ,  22  from the carbon monoxide detector  12  and smoke detector  14  respectively are coupled to control logic circuitry  38 . The control logic  38  analyzes the inputs  16 ,  22  and generates an output select signal  40  and an output enable signal  42 . Each of these signals  40 ,  42  are received by an alarm circuit  44  and a voice synthesizer circuit  46 . The output on line  48  from the alarm circuit  44  is coupled to amplifier  52 , as is the output  50  from voice synthesizer  46 . The amplifier  52  drives an output speaker  36  in a conventional manner. Preferably, both an alarm reset signal  54  and an alarm test signal  56  are coupled to the control logic  38  to allow resetting, and testing of the appropriate circuits to ensure proper operation during the installed life of the device  10 . Additionally, a language select signal  55  may also be provided as an input to logic  38  (or alternatively to voice synthesizer  46  directly). 
     The operation of this embodiment of the instant invention will also be described in relation to three separate operating conditions: carbon monoxide only; smoke only; and both carbon monoxide and smoke in combination. First, during the presence of high levels of carbon monoxide, detector  12  generates a signal on line  16  which is transmitted to the control logic  38 . The control logic  38  processes the input  16  and generates an output select signal on line  40  indicative of a detected carbon monoxide gas condition. Both the alarm circuit  44  and the voice synthesizer circuit  46  then select the appropriate pattern and message respectively for eventual transmittal via lines  48  and  50  to an amplifier  52 . The control logic  38  alternately enables the alarm circuit  44  and the voice synthesizer  46  via line  42  to allow each circuit in turn to generate its output to amplifier  52 . Specifically, the control circuit  38  first enables one of the circuits, e.g. alarm circuit  44 , for a predetermined period of time, followed by the enabling of the other circuit, e.g., voice synthesizer  46 . Preferably, only one of the circuits  44 ,  46  are enabled at any one time to allow for clear broadcasting of either the alarm pattern or the appropriate voice synthesized message. As described above, and as will be recognized by one skilled in the art, both the alarm circuit and the voice synthesizer circuit may generate single or multiple patterns and messages as desired. Preferably, both the alarm circuit  44  and the voice synthesizer circuit  46  will generate unique patterns and messages indicative of the sensed condition by detectors  12  and  14 . 
     Once the control logic has begun to trigger the alarm circuit  44  and the voice synthesizer circuit  46 , it will preferably continue to do so until reset manually by a user on line  54 . This reset input  54  may be via a push button switch or other appropriate circuitry as appropriate and desired. In addition to the reset line  54 , provision is also made to allow a user to test the alarm functionality of the unit  10  via a test input  56 . As with the reset, this test signal  56  may be generated by a push button switch or other appropriate circuitry as desired. Additionally, one skilled in the art will recognize that the function provided by inputs  54 ,  56  may be accomplished through a single input. In this way, if the control logic is generating the select and enable signals  40 ,  42 , the receipt of the single combined input will be processed as a reset signal, whereas if the control logic  38  is not generating the select and enable signals  40 ,  42 , the receipt of the combined input will be processed as a test signal. 
     The use of control logic  38  also allows the unit  10  to detect and enunciate varying levels of the detected conditions. In this way, the unit  10  may alert occupants to the formation of a potentially dangerous situation at earlier, lower detection levels. The control logic  38  may also store historical information of detected conditions and levels, and utilize this information to enunciate the existence of a persistent low level problem. For example, a furnace which is beginning to burn inefficiently or require cleaning may generate low levels of carbon monoxide each time the furnace operates. While these low levels of carbon monoxide generation may be too low to warrant a warning of dangerous levels of carbon monoxide, an analysis of the historical detection of these low levels of carbon monoxide will allow the control logic  38  to inform the occupant of the possible beginnings of a problem. In this way, a potential problem may be detected and corrected much earlier, before the situation becomes critical. The control logic  38  may also use other combinational logic to control the output alarm pattern and synthesized message generation. For example, during the detection of a smoke condition, if the reset input  54  is also triggered while the existence of smoke is still being detected by detector  14 , the control logic  38  could disable the alarm and synthesized message generation until the presence of smoke has been eliminated and returns. Such a feature may be advantageous if the cause of the smoke is from cooking or other controlled situations where the occupant is aware of the problem but does not wish to be continuously alerted to the situation by the unit  10 . 
     The second condition of operation of the unit  10 , as has been briefly discussed above, is the detection of smoke by detector  14 . The smoke detector  14  transmits its output on line  22  to control logic  38  which then, in similar fashion to the above-described situation, transmits an output select signal to alarm circuit  44  and voice synthesizer circuit  46  to allow each of the circuits to select the proper pattern and voice synthesized message. The control logic  38  then alternatively enables the alarm circuit  44  and the voice synthesizer circuit  46  via output enable signal  42 . As described above, alarm circuit  44  may generate a unique pattern for the smoke condition, or may utilize a generic pattern warning of a dangerous condition. Likewise, voice synthesizer  46  may also generate a generic warning message to the occupants of a dangerous condition, or may generate a specific message directed to the sensed condition. 
     The voice synthesized message may be generated in a single language, in multiple languages, or in a language which is user selectable upon initial installation via line  55 . The selection of the appropriate language or language combination may be accomplished directly within the voice synthesizer  46 , or may preferably be accomplished within the control logic  38  and transmitted to the voice synthesizer  46  via the condition select lines  40 . This selection may be accomplished via a simple selector switch, a push button switch which allows cycling through the available languages, or other appropriate user interface. 
     The third sensed condition is that of both high levels of carbon monoxide and smoke which occur during many actual fire situations. During this condition, the control logic  38  receives input signals on both lines  16  and  22 . The control logic recognizes this condition and selects the appropriate alarm pattern and voice synthesized message via the output selector signal  40 . As described above, both the alarm circuit  44  and the voice synthesizer circuit  46  may generate a generic warning, or more preferably a distinctive alarm pattern and appropriate warning message for this particular sensed condition. Also, as described above, the control logic then interleaves the operation of the alarm circuit  44  and the voice synthesizer  46  via the enable line  42 . 
     The above-described operation is illustrated in flow diagrammatic form in  FIG. 4 , to which specific reference is now made. As may be seen from this figure, upon initiation  58  the control logic  38  (see  FIG. 3 ) receives  60  the detector signal from the associated detector circuits. The control logic  38  determines the type of detector signal received at decision block  62 . If the carbon monoxide signal is the only signal received by the control logic  38 , the carbon monoxide alarm pattern is selected  64 , as is the carbon monoxide voice warning  66 . The control logic interleaves the alarm and voice warnings  68  until the process is terminated  70 . If, however, decision block  62  determines that the smoke detector signal is the only signal received, the smoke alarm pattern is selected  72  as is the smoke voice warning message. As with the previous condition, the control logic interleaves the alarm and voice messages  68  until the process is terminated  70 . If both the smoke and carbon monoxide detector outputs are received  60  as determined by the decision block  62 , the fire alarm pattern is selected  76  as is the fire voice warning  78 . These signals are also interleaved  68  as described above until the process is terminated  70 . 
     While the interleaving of the alarm pattern and voice message may be accomplished in various manners, a preferred method of interleaving is illustrated in FIG.  5 . Once the interleaving process begins  72  the alarm circuitry is enabled  74 . An interleaving timer is started  76  once the alarm has been enabled  74  to allow the alarm to sound for a predetermined period of time. Once it has been determined that the time has expired  78  the timer is reset  80  and the voice synthesizer circuitry is enabled  82 . Once enabled, the interleaving timer is started  84  and allows the generation of the voice synthesized signal for a predetermined period of time. Once this time has expired  86 , the timer is reset  88  and the process is continued. While the flow diagram of  FIG. 5  illustrates that the alarm circuit is enabled first, one skilled in the art will recognize that either the alarm of the voice message may be enabled initially upon detection of the condition. The interleaving timer for the pattern and voice message may be the same, or may be different, but preferably allow the voice message to begin and run to its completion at least one time before re-enabling the alarm circuit for pattern generation and broadcast. 
     Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode for carrying out the invention. The details of the structure and architecture may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved.