Abstract:
An emergency warning system including a sensor for detecting an environmental condition. A first transmitter is connected to the sensor for broadcasting a communication signal carrying information describing the environmental condition. A first receiver receives the communication signal from the first transmitter. A second transmitter is connected to the first receiver for broadcasting an alert signal carrying information describing the environmental condition. A second receiver receives the alert signal from the second transmitter and has an indicator for exhibiting the information indicative of the environmental condition.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to electrical communications systems and, more particularly, to condition responsive indicating systems with particular safety functions. 
     BACKGROUND OF THE INVENTION 
     As society has moved into the 21 st  Century, some of its disaffected members have resorted to acts of extreme violence and terror as a way of being heard. Some of these acts have taken the lives of thousands of people and have injured thousands more. Unfortunately, no one foresees an end to acts such as these. At this point in time, one can only hope to be forewarned a reasonable period of time in advance of such an act so that precautions can be taken to altogether avoid or minimize the expected harm. 
     To a certain extent, mass media—radio and, television in particular—is effective in rapidly alerting the public of impending, ongoing and completed acts of terrorism. The principal drawback of relying principally upon radio and television to provide alerts of terrorist activities is that the alerts cannot be transmitted to receivers that are turned off. Of course, most users do not keep their radios and televisions turned on at all times, and broadcasters lack the ability to energize conventional radios and televisions. Thus, it can be expected that many would miss critical broadcast alerts about impending and ongoing terrorist activities and would be harmed as a result. 
     SUMMARY OF THE INVENTION 
     In light of the drawbacks associated with using broadcast media to rapidly and accurately disseminate information important to public health and welfare, it is a principal object of the invention to provide an emergency warning system that could be used only by authorized personnel to notify specified people of impending dangers. These dangers might include: fires, explosions, chemical spills, hostage takings, radiation leaks, and the spread of biological agents or gasses to name a few. Apart from news regarding dangers, time-critical information related to weather and earth movements can be delivered to interested parties by modified forms of the system. 
     It is a further object of the invention to provide an emergency warning system of the type described that can be employed to provide time-critical information wherever they may be located, whether at home, at work, in a vehicle, or otherwise. 
     It is another object of the invention to provide an emergency warning system of the type described that alerts users of its activation with audible and visual alarms. Once the alarms have sounded, detailed information may be obtained in a visual and audible manner. Message transmission can be selectively terminated by a user. 
     It is an object of the invention to provide improved elements and arrangements thereof in an emergency warning system for the purposes described that is rugged in construction, inexpensive to manufacture, and dependable in use. 
     Briefly, the emergency warning system in accordance with this invention achieves the intended objects by featuring a transmitter for broadcasting a radio frequency (RF) communication signal carrying information produced by a sensor to a receiver. The receiver is connected to another transmitter so as to permit the broadcast an RF alert signal carrying public warnings as required by the content of the communication signal to a desktop receiver or a pocket pager. Upon detecting the alert signal, the desktop receiver and the pager issue audible and visual alarms. 
    
    
     The foregoing and other objects, features and advantages of the present invention will become readily apparent upon further review of the following detailed description of the preferred embodiment as illustrated in the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWING 
     The present invention may be more readily described with reference to the accompanying drawing which is a schematic diagram of an emergency warning system in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the accompanying drawing, an emergency warning system in accordance with the present invention is shown at  10 . System  10  includes a transmitter  12  for broadcasting a radio frequency (RF) communication signal  14  carrying information produced by a sensor  16  to a receiver  18 . Receiver  18  is connected to another transmitter  20  in such a manner as to permit the broadcast an RF alert signal  22  carrying public warnings as required by the content of communication signal  14  to a desktop receiver  24  or a pocket pager  26 . Upon detecting alert signal  22 , receiver  24  and pager  26  issue audible and visual alarms. A mobile transceiver  28  serves as a backup to transmitter  20 . 
     Sensor  16  is mounted on a tower  30  in a predetermined geographical area. Sensor  16  detects airborne particulate matter immediately harmful to humans and produces a unique electrical detection signal in response. Preferably, sensor  16  is capable of identifying a select disease-causing microbe, poisonous gas or radioactive compound. Sensor  16 , however, may be a seismograph or weather-monitoring instrument. Sensors of the sort described are commercially available from a variety of sources. 
     Tower  30  carries a transmitter  12  connected to sensor  16 . Transmitter  12  receives a detection signal from sensor  16  after such has identified harmful matter and, in response, broadcasts a unique, RF communication signal  14  to receiver  18  in a secure location under the control of community leaders. Communication signal  14  carries information regarding the location of transmitter  12  and the type and, perhaps, concentration of the harmful matter detected by sensor  16 . Of course, if sensor  16  is a seismograph or weather gauge, the pertinent information regarding: earth tremors, temperature, rainfall, etc., would be encoded by transmitter  12  and carried by communication signal  14  to receiver  18 . 
     Transmitter  12  and receiver  18  are connected together through conventional telephone communications lines (not shown). Should transmitter  12  be unable to establish a RF communications link with receiver  18 , the telephone lines permit transmission of the communication signal to receiver  18 . Thus, system  10  is provided with a backup connection between transmitter  12  and receiver  18  making the connection failsafe. 
     Receiver  18  can detect and process communications signals from secondary sources. Such secondary sources might include the National Oceanic and Atmospheric Administration (NOAA) having ground-based and earth-orbiting weather sensors: Additionally, the new Office of Homeland Security has an intelligence-gathering network yielding terror forecasts that could be broadcast to receiver  18 . These forecasts may be accompanied by a color-coded warning to indicate the immediate likelihood of an act of terror. 
     Upon receipt of a communications signal by receiver.  18 , it acts to energize both a visible indicator light  32  and an audible alarm  34 . Further, receiver  18  causes a message to be produced on an LCD display  36  that summarizes the data received from sensor  16 . That data might include an indication that deadly  C. botulinum  microbes or abnormally high radiation levels were detected. A reset button  38  on receiver  18  permits an operator to deenergize light  32  and alarm  34  and clear LCD display  36 . 
     Receiver  18  is connected to a computer processor  40  within which is stored a map of the geographical area where tower  30  are positioned. Processor  40  is connected to a monitor  42  that displays the stored map along with the position of tower  30  and the substance of any communications signals  14  from sensor  16 . For manipulating the images exhibited by monitor  42 , processor  40  is connected to a keyboard  44  into which image-manipulating commands may be types. A printout of an image exhibited by monitor  42  may be obtained from a printer  45  also connected to processor  40 . 
     Receiver  18  is connected to stationary transmitter  20  for alerting the public of any dangerous conditions detected by sensor  16 . Transmitter  20  is in the possession of an authority responsible for emergency preparedness for the geographical area having tower  30 . Transmitter  20  is connected to a computer processor  48  for the development of written messages for broadcast to desktop receivers  24  and pagers  26  via transmitter  20 . Processor  48  is connected to a keyboard  50  and an associated monitor  52  for viewing the written messages during their entry into processor  48 . A printer  54 , connected to processor  48 , permits a permanent record of all written messages to be made. Additionally, a microphone  56  is connected to transmitter  20  for entering verbal messages into transmitter  20 . To ensure that authorized personnel only enter of written and verbal messages into transmitter  20 , transmitter  20  is provided with a lockout circuit (not shown), capable of being closed only with a key or combination, which normally disconnects keyboard  50  and microphone  56  from transmitter  20 . 
     To use transmitter  20 , an operator closes the lockout circuit so as to connect keyboard  50  and microphone  56  to transmitter  20  by turning a key in a lock  58  provided for this purpose or by typing the correct combination into a keypad  60 . Next, the operator selects the geographic area that he wishes to receive his broadcast by pressing keys on keypad  62  so as to select the frequency of the RF signal generated by transmitter  20 . Then, the operator enters into keyboard  50  an appropriate written message and a code corresponding with the level of alert. If desired, the operator can speak into microphone  56  to enter a verbal message into receiver  20 . Transmitter  20  transduces the verbal message into an encrypted RF alert signal stream including any written messages and alert codes that are, finally, broadcast by transmitter  20  at a desired frequency. 
     The code corresponding with the level of alert will vary from time to time as conditions dictate. For example, the Office of Homeland Security has developed a scheme tied to five colors: green, blue, yellow, orange, and red that are supposed to convey an impression of the immediate likelihood of an act of terror. It is anticipated that each of these colors would be represented by a unique sequence of numbers or code that, when input into transmitter  20  through keyboard  50  and broadcast by transmitter  20 , would cause correspondingly colored LEDs as at  64  and  66  on transmitter  20  and desktop receiver  24  to be illuminated. All other broadcasts would include a code that would cause white LEDs  68  and  70  on transmitter  20  and desktop receiver  24  to glow. 
     Mobile transceiver  28  is employed in the event that transmitter  20  becomes inoperative through act of terror or when it is desired to extend the range of system  10 . As shown schematically, transceiver  28  is carried by a land vehicle  72  for movement near tower  30 . Transceiver  28  is connected to a keyboard  74  and computer processor  76  for entering written messages for broadcast to desktop receivers  24  and pagers  26 . A monitor  78  is associated with processor  76  for viewing the writings during entry. Additionally, a microphone  80  is connected to transceiver  28 . To ensure that the entry of written and verbal messages into transceiver  28  is authorized, transceiver  28  has a lockout circuit like that in transmitter  20 . 
     Transceiver  28  is capable of receiving communication signals  14  from transmitters  12  and other sources. Incoming signals may be diverted to processor  76  for processing and subsequent displaying on monitor  78 . A sound transducer  80  may be provided for generating audible messages. 
     Use of transceiver  28  is substantially identical to that of transmitter  20 . First, an operator closes the lockout circuit to connect processor  76 , keyboard  74  and microphone  82  to transceiver  28 . Next, the operator selects the frequency of the RF alert signal produced by transceiver  20  by manipulating keypad  84 . Then, the operator enters into keyboard  74  any writing and codes corresponding to the level of alert. If desired, the operator speaks into microphone  82  to broadcast a verbal message. Transceiver  28  transduces the verbal message into an encrypted RF alert signal  86  including any written messages and alert codes for broadcast at the selected frequency. 
     If desktop receiver  24  is tuned to the right frequency and is provided with correct decryption codes, then it will receive alert signal  22  or  86  from either transmitter  20  or transceiver  28 . In response, receiver  24  decrypts alert signal  22  or  86  and energizes both an audible alarm  88  and one of colored LEDs  66  and  70  connected thereto. The decrypted alert signal  22  or  86  may also yield a verbal message that is transduced to audible sound by speaker  90 . An LCD display  92 , connected to receiver  24 , displays any written message associated with alert signal  22  or  86 . A reset button  94  on receiver  24  permits a user to deenergize illuminated LED  66  or  70 , clear LCD display  92 , and place receiver  24  in a “stand-by” mode waiting for the next alert signal  22  or  86 . 
     LCD display  92  will exhibit written messages that generally correspond to the different levels of threats issued by the Office of Homeland Security. Display  92  may exhibit the word “low” for a green alert, “guarded” for blue, “elevated” for yellow, “high” for orange, and “severe” for red to correspond with each level of threat. Of course, the exact content of the written message will be determined by inputs made with keyboard  50  or  74 . 
     Receiver  24  may be adjusted using conventional switches or other means (not shown). For example, receiver  24  can, and will, be made to receive only RF alert signals at a frequency specified for a given geographic area. Also, the decryption codes required to energize LEDs  66  and  70  and to obtain the contents of a written or verbal massage can be varied from time to time and place to place to guarantee security of the alert signals. These adjustments are preferably made at the time that receiver  24  is manufactured or distributed, but could be accomplished by a user. Of course, receiver  24  may be made to receive RF weather bulletins directly from NOAA or to receive signals from an alternative source. 
     A portable pocket pager  26  operates much like receiver  24  to receive an RF alert signal  22  or  86  from either transmitter  20  or transceiver  28  and notify a user. Provided that pager  26  is correctly tuned and provided with correct decryption codes, then it will receive alert signal  22  or  86 . On receipt, pager  26  decrypts alert signal  22  and  86  and energizes an audible alarm  96  and an LED  98  connected thereto. The decrypted alert signal may also yield an audible message transduced by a speaker  100 . An LCD display  102 , also connected to pager  26 , displays any written message associated with alert signal  22  or  86 . A reset button  104  on pager  26  permits LED  98  and LCD display  102  to be deenergized to wait for the next alert signal  22  or  86 . Like receiver, pager  26  may be adjusted to receive only alert signals  22  and  86  at a frequency specified for a set geographic area and to decrypt only specified alert signals. 
     From the foregoing, it should be appreciated that use of system  10  is straightforward. Only authorized personnel can provide alert signals  22  and  86  to receivers  24  and pagers  26  in affected areas. Since pagers  26  can be carried virtually anywhere, it is possible for a user to never miss a broadcast warning important to his health or welfare. 
     While the invention has been described with a high degree of particularity, it will be appreciated by those skilled in the art that modifications may be made thereto. For example, the number and location of transmitters  12  and  20 , transceivers  28 , sensors  16 , receivers  18  and  24 , and pagers can all be varied to suit local conditions of operation of system  10 . Therefore, it is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.