Patent Publication Number: US-6714142-B2

Title: Proximity signaling system and method

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to proximity signaling systems and more particularly to proximity signaling systems for alerting a user of an approaching vehicle. 
     School buses and similar mass transit systems often require school children or passengers to wait at appointed stops for a particular bus to arrive. For several reasons, it is typically desirable to reduce the amount of time that a passenger must spend at an appointed stop waiting for transportation. For example, for the safety and comfort of school children, it is desirable to reduce the amount of time they must spend waiting for a school bus alone, with other children, or in inclement or adverse weather conditions. This holds true regardless of whether the child is waiting to be picked up by the school bus or waiting to be picked up by a parent or other responsible adult after being dropped off by a school bus. As another example, it is simply desirable to make more efficient use of ones time by reducing the amount of time wasted waiting on a bus or other transportation. 
     There have been a number of attempts at providing early warning systems to alert users of approaching buses, and a number of different approaches have been taken. A few examples include the systems disclosed in U.S. Pat. No. 4,350,969, issued to Greer in 1982, U.S. Pat. No. 5,021,780, issued to Fabiano et al. in 1991, U.S. Pat. No. 5,144,301, issued to Jackson et al. in 1992, and U.S. Pat. No. 6,006,159, issued to Schmier et al in 1999. The disclosures of these references are incorporated herein by reference. Prior attempts have offered some advantages but still suffer from a number of disadvantages. For example, the receivers used in these systems typically lack flexibility regarding how they receive and process signals and in how they provide information to users. Also, the systems that are disclosed in these references are typically not well suited for school bus transportation systems. For example, some receivers may not be used to signal the approach of multiple buses. Some systems require significant setup, such as requiring that the location of all stops be predetermined. Other systems require a driver to take action at each stop to update the transmitted signal. These systems typically offer too little flexibility, require too much set-up, and introduce too many chances for error. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a flexible proximity signaling system and method particularly suited for use in providing early warning of the approach of a bus or other vehicle. 
     It is a further object of the present invention to provide a system and method of the above type that allows a single receiver to be used to identify and alert users of the approach of two different buses or vehicles. 
     It is a still further object of the present invention to provide a system and method of the above type that is very user friendly and requires very little set-up. 
     It is a still further object of the present invention to provide a system and method of the above type that eliminates the need for detailed mapping of a bus route. 
     It is a still further object of the present invention to provide a system and method of the above type that eliminates the need for a transmitted signal to be updated or changed as a bus travels its route. 
     It is a still further object of the present invention to provide a system and method of the above type that eliminates the need for a driver to take affirmative actions to update or change the transmitted signal as the bus travels over its route. 
     It is a still further object of the present invention to provide a system and method of the above type that allows a bus to vary from its usual route without introducing error into the system. 
     It is a still further object of the present invention to provide a system and method of the above type that uses signal strength to progressively trigger a variety of alerts. 
     It is a still further object of the present invention to provide a system and method of the above type that provides a gradual proximity display for incrementally displaying the approach of a bus. 
     It is a still further object of the present invention to provide a system and method of the above type that uses a voice chip to provide a message that helps a user to determine which bus is approaching. 
     It is a still further object of the present invention to provide a system and method of the above type that uses a voice chip and that allows a user to customize one or more messages to be used to alert a user when one or more buses are approaching. 
     It is a still further object of the present invention to provide a system and method of the above type that uses receiver addresses to distinguish signals sent by different buses. 
     Toward the fulfillment of these and other objects and advantages, a system is disclosed in which first and second transmitters are disposed on first and second mobile objects. The first and second transmitters generate first and second RF signals with first and second receiver addresses, respectively. A receiver is disposed remotely from the first and second transmitters. The receiver has first and second microcontroller decoders for recognizing the first and second RF signals, respectively. The receiver has a gradual proximity display, such as a bar graph display, for indicating signal strength. The receiver also has first and second proximity alerts, such as lights, beepers, or voice chips, for signaling proximity of the first and second objects, respectively. In use, the first microcontroller decoder filters signals received by the receiver and passes only signals having the first receiver address along to the display and alerts. Similarly, the second microcontroller decoder filters signals received by the receiver and passes only signals having the second receiver address along to the display and alerts. A microphone may be incorporated into the receiver so that a user may record different custom messages for announcing the proximity of different approaching objects. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above brief description, as well as further objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of the presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a schematic of a proximity signaling system of the present invention; 
     FIG. 2 is a block diagram of a transmitter for use in a system of the present invention; 
     FIG. 3 is a circuit schematic of a transmitter for use in a system of the present invention; 
     FIG. 4 is a block diagram of a receiver for use in a system of the present invention; 
     FIG. 5 is a circuit schematic of a receiver for use in a system of the present invention; 
     FIG. 6 is a circuit schematic of a voice chip for use in a system of the present invention; and 
     FIG. 7 is a circuit schematic of a bar graph display for use in a system of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, the reference numeral  20  refers in general to a proximity signaling system of the present invention. The system and method generally involve the use of one or more transmitters  22  and receivers  24 , as described in more detail below, to signal the approach of one or more mobile objects  26 , such as buses. The system  20  is particularly useful for alerting a user  28  waiting at a location  30  when a bus  26  approaches a boarding stop  32 . 
     As best seen in FIGS. 2 and 3, the transmitter  22  is used to generate RF signal data having a designated receiver address and to send the data through antenna  34 . An 8 bit or 12 bit adjustable data input device  36  provides a selected receiver address in binary code. The 8 bit DATA IN configuration will support up to 256 sets of unique addresses, whereas the 12 bit configuration will support up to 4096 unique addresses. For most applications, an 8 bit configuration will be able to provide more receiver addresses than needed. Still, if more addresses are needed, a 12 bit configuration is available. The data can be inputted through a series of on/off switches  36  for flexibility, or it can be hard-wired. The switches will allow a user  28  to set the receiver address in binary code. Hard-wiring would reduce the flexibility of the transmitter  22  but would simplify construction and eliminate the need for the switches  36 . The data from the data input device  36  is encoded by a microcontroller encoder  38 . The outputs  40  and  42  of the encoder  38  are then divided into packets of data providing electrical inputs to digital counters  44  and  46  and logic gate  48 . Digital counter  44  works in conjunction with digital counter  46  to provide an input to digital timer  50 . Although headers  52  and  54  (FIG. 3) may be used, in the preferred embodiment, headers  52  and  54  are unnecessary. Data packet output from the digital timer  50  joins the microcontroller encoder output  42  as the first and second inputs, respectively, to logic gate  48 . 
     The intermittent data output of the logic gate  48  provides both inputs to another logic gate  56 , whose output feeds directly into a transmitter chip/radio frequency (RF) module  58 , where it is modulated with a carrier frequency at the VHF/UHF range. The design will vary depending upon the carrier frequency selected for transmission. The modulation method used in this preferred embodiment is amplitude shift keying (ASK), and some transmitters  22  may employ frequency shift keying (FSK) modulation. The RF module  58  sends the modulated data output through microstrip  60 , into a power amplifier  62 . The power amplifier  62  amplifies the modulated data and radiates it through microstrip  64  into the transmission antenna  34  for transmission to receivers  24  located at homes, offices, or other convenient waiting places  30  of users  28 . Microstrips  60  and  64  are strips of copper designed for impedance matching to facilitate efficient transmission of the RF signal. Without the microstrips  60  and  64 , the RF signal loss would be significant. The antenna  34  is preferably a half-wave whip style antenna, and the RF signal data is transmitted in the form of electromagnetic waves. 
     Referring to FIG. 3, in one embodiment, the transmitter  22  is powered by the vehicle&#39;s battery  66 . The transmitter  22  will receive 12V of DC voltage from the vehicle battery  66 , and a regulator  68  will regulate the voltage to 5V or 3V depending on the chip requirements. The transmitter  22  may also have a rechargeable power source, such as using a rechargeable battery. Using transmitter  22  with an independent power supply could add to the flexibility and ease of use of the transmitter  22 , eliminating the need for wiring the transmitter  22  to a vehicle battery  66 . This would make it easier to move a transmitter  22  from one vehicle  26  to the next and would minimize concerns about vehicle notification when vehicle power fails. Of course, the transmitter  22  may be powered by the vehicle&#39;s battery  66  and still have separate battery backup power. 
     The receiver  24  of the present invention typically performs three basic functions: it receives and verifies the transmitted RF signals from transmitters  22  within range; it displays the gradual proximity of a transmitter  22  to the receiver  24 ; and it notifies the user  28  of a desired vehicle&#39;s  26  pending arrival when the signal reaches a predetermined strength. As best seen in FIGS. 4 and 5, an antenna  70  receives a modulated signal from one or more transmitters  22 . The modulated signal is fed from the antenna  70  through microstrips  72  to a RF chip/module  74 . The RF chip/module  74  demodulates the received signal and reconditions it to recover the encoded data. The RF chip/module  74  sends the reconditioned signal to a gradual proximity display  76  to provide a visual representation of the signal strength, thereby providing an approximation of the distance between the transmitter  22  and receiver  24 . Although the RF signal strength provides a fair approximation of the distance between the transmitter  22  and receiver  24 , RF reception and signal strength is dependent upon a number of factors, including terrain and weather conditions. The gradual proximity display may be calibrated, and a user  28  may adjust the sensitivity of the receiver  24  to accommodate for variances. 
     The RF chip/module  74  also sends the reconditioned signal to a microcontroller decoder  78  where it is decoded. The receiver address of the signal is compared to one or more selected receiver addresses for a match. A user  28  inputs the data concerning the desired receiver address using a series of on/off switches  80 . These switches  80  set the receiver address in binary code. The switches  80  will typically be set by turning a dial or setting switches to one or more desired numbers that corresponds with one or more numbers assigned to one or more desired buses  26  or route. When there is no match, the decoder  78  does not pass the signal along for further processing. When there is a matching address, the decoder  78  sends a signal to a digital timer  82  that can activate one or more proximity alerts  84 . The signal to the gradual proximity display  76  may also be routed through the decoder  78  so that gradual proximity display  76  will only be activated by buses  26  having one or more desired receiver addresses. 
     The embodiment depicted in FIG. 4 has a second microcontroller decoder  86  so that the receiver  24  may be used to signal the proximity of a second vehicle  26  having a transmitter  22  broadcasting a signal with a different receiver address. It may be possible to provide a decoder  78  or  86  that is capable of screening for two or more different receiver addresses. For the sake of cost and simplicity of design, it is preferred to use a separate decoder  78  or  86  to screen for each separate receiver address desired. Similarly, it may be possible to use common digital timers  82  or  88  and proximity alerts  84  or  90 , but for the sake of cost and simplicity of design, it is preferred to use separate digital timers  82  and  88  and proximity alerts  84  and  90  for each separate receiver address to be monitored. 
     Proximity alerts  84  and  90  may take any number of forms, and different combinations of proximity alerts may be used. A proximity alert  84  or  90  may use any number of different visual signals, including but not limited to one or more lights that emit continuous or flashing light, an LED display, a bar graph, and the like. Similarly, a proximity alert  84  or  90  may use any number of different audio signals, including but not limited to bells, buzzers, beepers, horns, recorded messages, and the like. The system of the present invention typically uses a combination of visual and audio alerts or signals. 
     The embodiment depicted in FIG. 5 uses a rechargeable battery pack  92  to power the receiver  24 . This adds to the mobility and flexibility of the receiver  24 . This also minimizes vulnerability to problems that might be caused by power outages. Of course, the receiver  24  may be powered by any conventional means, and may include a plug for plugging into a home&#39;s existing electrical system. Of course, the transmitter  22  may have multiple power sources, including battery backup power. 
     As best seen in FIGS. 5 and 6, input to the voice chip  94  is derived from the drive transistor  96 , which is driven from the digital timer  82 . A microphone  98  is preferably provided for recording customized messages. For example, in homes  30  with two or more children  28  riding two or more different school buses  26 , different messages could be recorded to call out the appropriate child&#39;s  28  name when that child&#39;s bus  26  is approaching. The voice chip  94  also has an LED display  100  to indicate when the message has been played. This feature is helpful in case a user  28  is hearing impaired or is simply out of hearing range when the message is initially played. When activated, the voice chip  94  transmits the appropriate message to a power amplifier  102  and to speaker  105 . The voice chip  94  is activated when a signal having the desired receiver address reaches a desired signal strength. Once activated, the voice chip  94  may be deactivated in any number of ways. For example, the voice chip  94  may play the message once or any preset number of times, the voice chip  94  may repeat the message until the signal strength falls below a desired value, the voice chip  94  may repeat the message for a preset time period, or the voice chip  94  may repeat the message until manually deactivated. 
     In use, each bus  26  or each route in a desired system is assigned a number that corresponds with a particular receiver address. A transmitter  22  is placed on a bus  26 , and a dial or series of switches  36  on the transmitter  22  are manually set to the number assigned to that bus  26  or that route. The switches  36  set the data input to generate a desired receiver address. A user  28  has a receiver  24  at a desired location  30  such as at home. The user  28  sets one or more dials or series of switches  80  and  104  on the receiver  24  to correspond with the numbers assigned to the desired buses  26  or routes. 
     When a driver begins his route, he checks to make sure that the transmitter  22  is set to the proper number assigned to his bus  26  or route, and he turns on the transmitter  22 . The transmitter  22  generates and transmits a signal having a particular receiver address. The transmitter  22  continues transmitting this signal as the bus  26  travels along its route. The signal being generated and transmitted is not dependent on where the bus  26  is located along the course of its route, on how many stops  32  the bus has passed, or on how far the bus  26  has traveled. Similarly, the driver is not required to input any additional information into or via the transmitter  22  as the bus  26  travels over its route. This reduces the risk of human error, such as the risk that an inexperienced driver might enter erroneous information or the risk that a distracted driver may simply forget to input required information at one of many stops  32 . Similarly, the transmitter  22  does not process information obtained mechanically, such as mileage information from a bus odometer. This also reduces the risk of mechanical and human error. If the transmitted signal depends upon data from an odometer, forgetting to reset an odometer or deviating slightly from a set route could lead to the transmission of erroneous data. 
     The signal that is generated and sent by the transmitter  22  preferably has a frequency of approximately 413 MHz to approximately 418 MHz. It is of course understood that any number of different frequencies may be used as desired or as may be required by the FCC. It may typically be picked up and recognized by a receiver  24  at distances of up to approximately 1 mile. The receiver  24  receives the signal and processes it to determine whether it has one or more desired receiver addresses. If the signal is from one of the selected buses  26  or routes, the receiver address will match the preset receiver addresses set at the receiver  24 , and the receiver  24  will further process the signal. The gradual proximity display  76  provides a visual display representing the approach of a bus  26 . The receiver  24  may be designed so that the gradual proximity display  76  may be actuated by any transmitter  22  or may be actuated only by transmitters  22  emitting signals having the desired receiver addresses. 
     When the receiver  24  receives a signal having a desired receiver address, the receiver  24  processes and monitors the signal. When the monitored signal reaches a desired signal strength, the gradual proximity display  76  is activated. As one example, the gradual proximity display  76  may be a series of lights that come on as the signal strength reaches predetermined levels, indicating that the bus  26  is approaching. The series of lights may be lit, for example, as follows: a first light may be lit when the signal strength reaches a level indicating that the bus  26  is approximately 1 mile from the receiver  24 , a second light may be lit when the signal strength reaches a level indicating that the bus  26  is approximately ½ mile from the receiver  24 , and a third light may be lit when the signal strength reaches a level indicating that the bus  26  is approximately ¼ mile from the receiver  24 . The gradual proximity display  76  may take any number of forms, such as a bar graph display in which the display adds or deletes bars as the signal strength increases. A preferred bar graph display is depicted in FIG.  7 . As seen in FIG. 7, signal strength data is received at input  106 . The signal strength data is processed by driver  108  which controls the lights  110  in bar graph  112 . The proximity alert  84  or  90  may be set so that it is activated at the same signal strength as the third light or at some other signal strength as desired. 
     In one preferred embodiment, the proximity alert  84  or  90  is a voice chip  94  with one or more pre-recorded custom messages. In this embodiment, when a signal with a desired receiver address reaches a desired signal strength, the voice chip  94  is activated to play the message, such as calling the name of the appropriate child  28  or calling the name of the bus  26 , or of the school or route associated with the approaching bus  26 . When the voice chip  94  is activated, an LED display  100  is also activated to give visual confirmation that the audio alert has been sounded. It is of course understood that any number of different combinations of proximity alerts  84  and  90  may be used, including but not limited to different combinations of light and sound alerts. 
     Although RF signal strength provides a fairly accurate approximation of distance, it is dependent upon a number of factors, including terrain and weather conditions. To offset possible variances, the user  28  may adjust the sensitivity of the receiver  24  to provide the various alerts at desired signal strengths. This allows a user  28  to in effect calibrate the receiver  24  for his or her particular location  30 . Similarly, different homes or waiting locations  30  will typically be located different distances from the various boarding stops  32  along a route. It will therefore typically take different users  28  different amounts of time to travel from theirs homes  30  to their boarding stops  32 . Allowing a user  28  to adjust the sensitivity of the receiver  24  provides added flexibility, allowing a user  28  to receive more or less advance warning as needed or desired. 
     The system and method of the present invention may be used in the morning, when one or more children  28  are waiting to be picked up by one or more buses  26 , and in the evening, when a parent  28  is waiting for one or more children to be dropped off by one or more buses  26 . 
     The system and method of the present invention offer a number of advantages. For example, a receiver  24  of the present invention may signal the approach of multiple buses  26 . The gradual proximity display  76  provides a continuous display of signal strength, which provides a good, real-time approximation of the distance between the bus  26  and the receiver  24 . The voice chip  94  provides added flexibility for audibly announcing the approach of one or more school buses  26 . The use of batteries to power the transmitters  22  and receivers  24  adds to the flexibility and ease of use of the system  20 . Further because the system  20  uses many digital components, rather than analog components, the system is less prone to make notification errors. 
     Although the above discussion relates primarily to using the system and method for notifying school children  28  of an approaching school bus  26 , it is understood that the system and method may have any number of different uses. For example, the present invention may be adapted for use with a wide variety of vehicles  26 , including but not limited to taxis, company transportation such as trams, day care vans, boats, trains, subway trains, rail cars, trolleys or similar vehicles. The system  20  could be adapted to allow for the notification of potential passengers  28  using a paging system. The system could also be adapted to provide early notification of the approach of other vehicles  26 , including but not limited to vehicles used by spouses, older children, delivery services, postal services, housekeeping services, lawn care services, or any of a wide variety of services. Further, the system could be integrated into a home or business and programmed to automatically perform various tasks that are part of a daily or periodic routine. For example, the system could be used to turn off alarm systems, turn on lights, unlock doors, open gates or garage doors, or start a car engine when a transmitter  22  with the appropriate receiver address approaches a receiver  24 . 
     Other modifications, changes, and substitutions are intended in the foregoing, and in some instances, some features of the invention will be employed without a corresponding use of other features. For example, any number of different proximity alerts  84  and  90  may be used in any number of different combinations. Similarly, any number of different decoders  78  and  86  may be used in the receiver  24 , and different decoders  78  and  86  may be used activate the same or any number of different combinations of proximity alerts  84  and  90 . Further, different proximity alerts  84  and  90  and different combinations of proximity alerts may be activated by different transmitter signals, and some may be activated regardless of the receiver address of the transmitter  22 . Further still, any number of different ways may be used to generate and transmit signals having desired receiver addresses and to check received signals to see if they match receiver addresses set at the receiver  24 . Further, the receiver address data may be input into the transmitter  22  and into the receiver  24  in any number of different ways. Also, the signal may be encoded, sent, and decoded in any number of different ways. It is understood that all quantitative information are given by way of example only and are not intended to limit the scope of the invention. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.