Abstract:
A solid-state accelerometer module adapted to control the operation of the taillights in a motor vehicle for warning the driver of the trailing motor vehicle of a deceleration of the lead vehicle. A retrofit tail lamp contains the solid-state accelerometer module within its housing and by means of at least two separate lamp filaments, the tail lamp can replace the original tail lamp. A motor vehicle may have a receiving antenna and a transmitting antenna electrically connected to a receiver and a transmitter respectively located in the module. The transmitting-receiving system may be located on two different vehicles so that the following vehicle is quickly notified of the deceleration of the lead vehicle.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application is related to co-pending patent application claiming the benefit of Ser. No. 60/362,043 entitled “Solid-state Accelerometer Warning System” having attorney docket 02-02 filed on Mar. 6, 2002 by Chadwick Ray Traylor. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to accelerometers in general and more particularly to an accelerometer module as may be used in the brake light system of a motor vehicle or a braking/deceleration/acceleration warning system for any moving body.  
         BACKGROUND OF THE INVENTION  
         [0003]    At the present time, several accidents, more particularly rear end accidents with motor vehicles are caused because the striking or following vehicle following the struck or lead vehicle did not have sufficient warning that the lead vehicle was decelerating or slowing down. If the driver of the striking vehicle had sufficient warning, the driver might have taken successful evasive maneuvers to avoid the accident.  
           [0004]    Many times the driver of the following vehicle may not appreciate the rate of deceleration of the lead vehicle. Action to be taken by the driver of the following vehicle depends in a large measure in response to the deceleration of the lead vehicle. If the lead vehicle is slowing down at a very slow deceleration rate and the driver of the following vehicle “slams” on his brakes, the end result may be that the vehicle following him strikes his vehicle.  
         SUMMARY OF THE INVENTION  
         [0005]    The purpose of the preferred embodiment and all other embodiments to be described herein is to provide a brake light warning system to a following or trailing vehicle or moving body, when the lead vehicle, or moving body, is being decelerated. The intensity and the operational characteristic, speed of flashing, of the lead vehicle&#39;s brake lights will indicate to the trailing vehicle&#39;s driver the relative speed of deceleration from slow to very rapid. A very rapid deceleration might occur when the lead vehicle is being hard braked in an attempt to avoid an accident. A slow deceleration might occur when the lead vehicle is approaching a traffic light during normal driving conditions. The system is so designed to control its response to decelerations above a predetermined level thereby not responding to each and every deceleration of the lead vehicle, but only the decelerations that could lead to a “panic” or more rapid than normal type stop.  
           [0006]    As will be shown, the accelerometers in the system are responsive to single axis forces and will be capable of outputting a signal indicating a deceleration above a predetermined level. Such signals may well occur during side acceleration or deceleration as may happen when a motor vehicle is struck on its side such a “T-bone” crashes or when a vehicle is responding to road conditions that are less than ideal such as sliding on ice.  
           [0007]    The above advantages and objectives are found in the solid-state accelerometer module for use in a motor vehicle having a power supply with an light illumination voltage level, the module has at least one accelerometer aligned along one axis of the motor vehicle and responding to the variable speed of the motor vehicle to generate a first variable frequency accelerometer voltage signal representing the deceleration rate along said one axis.  
           [0008]    A microprocessor is located in the module having a memory for storing an algorithm, a calculation means and an electrical signal voltage threshold means having a designed voltage value representing a predetermined deceleration rate. The algorithm stored in the memory and controls the operation of the microprocessor in response to the first accelerometer signal and the voltage threshold means.  
           [0009]    A calculation means is located in the microprocessor and responds to the algorithm for generating a first variable frequency illumination voltage level control signal representing the deceleration rate of the motor vehicle.  
           [0010]    The solid-state accelerometer module may be designed to respond to the acceleration rate of the motor vehicle and the voltage threshold means to generate a predetermined acceleration level for the motor vehicle.  
           [0011]    These and other objects and advantages will be found in the following drawings and detailed description. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    In the drawings:  
         [0013]    [0013]FIG. 1 is a block diagrammatic schematic of a solid-state accelerator module;  
         [0014]    [0014]FIG. 2 is a system schematic of the module of FIG. 1 in a motor vehicle embodiment;  
         [0015]    [0015]FIG. 3 is a top diagrammatic view of a motor vehicle illustrating the x-y acceleration coordinates;  
         [0016]    [0016]FIG. 4 is a rear view of the motor vehicle of FIG. 4 showing the location of various brake lights;  
         [0017]    [0017]FIG. 5 is a brake-light assembly incorporating the module;  
         [0018]    [0018]FIG. 6 is another embodiment of the brake-light assembly of FIG. 3;  
         [0019]    [0019]FIG. 7 is an end view of FIG. 6;  
         [0020]    [0020]FIG. 8 is the end view of another embodiment of FIG. 6;  
         [0021]    [0021]FIG. 9 is a top diagrammatic view of another embodiment of a motor vehicle;  
         [0022]    [0022]FIG. 10 is a rear view of the motor vehicle of FIG. 9;  
         [0023]    [0023]FIG. 11 is a front view of the motor vehicle of FIG. 9; and  
         [0024]    [0024]FIG. 12 is a system schematic of the system incorporating the module as found in the motor vehicle of FIG. 9. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    Referring to the Figs by the characters of reference, FIG. 1 is a block diagrammatic schematic of a solid-state accelerometer warning system module  20 , SSAWC, in the form of a chip that is the main component of the brake system. It is to be understood, that while the preferred embodiments are dealing with the rate of deceleration; the rate of acceleration is equally applicable.  
         [0026]    The preferred embodiment of the solid-state accelerometer module  20  illustrated in FIG. 1, is for use in a motor vehicle having a power supply  22  with one or more outputs  24 ,  26  including a light illumination voltage level  28 . The module  20  may well be constructed as an integrated circuit chip. While there are illustrated three accelerometers  30 ,  32 ,  34 , the module requires at least one accelerometer  30  aligned along one axis of the motor vehicle  36 . The accelerometer  30  responds to the variable speed of the motor vehicle  36  to generate a first variable frequency accelerometer voltage signal  38  representing the deceleration rate along the one axis. The output of the accelerometer is an accelerometer signal which may be a voltage signal, a current signal, or any form of an acceleration signal. Likewise, in the descriptions that follow, while couched in terms of a voltage, the characteristic of the signal may be a current signal, a digital signal or any other characteristic that is available.  
         [0027]    Each of the other accelerometers  32 ,  34  responds respectively to the deceleration rate of the motor vehicle  36  along one of the other axes.  
         [0028]    A microprocessor  40  with an I/O circuitry,  39  has a memory  42  storing an algorithm  41 , a calculation means  44  and a signal or voltage threshold means  46  having a designed voltage value representing a predetermined deceleration rate. Such a value is set in the calculation means  44  for each axis by the vehicle designer and corresponds to the characteristics of the particular motor vehicle  36 . The algorithm  41  controls the operation of the microprocessor  40  in response to the first accelerometer signal  38  and the voltage threshold means  46 . If there are other accelerometers  32 ,  34  in the module  20 , the algorithm  41  responds to the presence of each accelerometer signal  48 ,  50  and each voltage threshold means  46  to operate on a brake illumination control system in the vehicle&#39;s braking system. The calculation means  44  including the voltage threshold means  46  has a designed value representing a predetermined deceleration rate. This rate is the minimum rate that the overall system responds to. The algorithm  41  determines the level of deceleration and compares that level against a predetermined level set into the system  20  by the system designer. In one embodiment the microprocessor  40  is a Parallax BS1 micro-controller from Parallax; the accelerometers  30 ,  32 ,  34  are AD XL202AE from Analog Devices; a voltage regulator in the power supply is an National LM78LXX, 5 volt 100 ma; and in the signal alteration circuitry  54  there are the output transistor is a IRF 510 1A NMOS, and an OpAmp is an NTE 928M single supply op amp both from National Semiconductors.  
         [0029]    The present embodiment is operatively connected in parallel which the vehicle&#39;s normal brake control system so as to not modify or interrupt the integrity of the normal brake control system. One of the outputs  48  of the module  20  of FIG. 1 is an electrical signal that operates on the brake lights  60 ,  62  through the signal alteration circuitry  54 . The output signals  56 ,  58  from the signal alteration circuitry  54  operate on the brake lights  60 ,  62 . This is illustrated in FIG. 2. This electrical signal travels through a straight low resistance passive path to the brake lamp filament and/or other type light source in order that normal brake light or brake illumination operation remains in tact even if SSAWC system fails.  
         [0030]    The solid-state accelerometer module  20  is electrically connected in circuit with a vehicle brake actuation initiation device  64 . The initiation device  64  is responsive to a vehicle operator desiring to reduce the speed of his/her motor vehicle. The initiation device  64  is normally a brake pedal actuating a switch  66  to initiate an electrical signal  68 .  
         [0031]    The vehicle normally has a power supply  22  for generating a plurality of voltage levels including a ground level and an illumination level  28  for operating the various lights in the vehicle including the brake lights  60 ,  62 . The brake lights are in a brake illumination control system  70  that in the preferred embodiment responds to the first variable frequency illumination voltage level control signal  38 . A subsystem of the brake illumination control system is a brake illumination system having at least one brake light  60 ,  62  that are responsive to the control signal  38  to illuminate the brake lights. The original brake light signal degradation does not occur.  
         [0032]    The switch  66  is actuated in response to the movement of the brake pedal  64 . When the driver of the vehicle operates the brake pedal or any other brake initiation device such as a hand brake, the switch  66  is actuated to send an electric signal  68  to the solid-state acceleration module  20 . This signal is processed according to the algorithm  41  and a power signal  28  is supplied to the brake lights  60 ,  62  causing a pulsing of the brake light. As illustrated in FIG. 1, the algorithm  41  responds to the several inputs from the accelerometers  30 ,  32 ,  34  and the engine control signals  72  such as engine speed, fuel control signal, transmission control, etc. to determine the harshness of the braking action. The brake lights will pulse more rapidly on a “panic” stop than it will on a normal slowing down.  
         [0033]    Referring to FIG. 3 there is illustrated the orientation of the motor vehicle  36  as respects the solid-state accelerometer module  20 . The x-axis is along the normal longitudinal axis of the vehicle and the y-axis is orthogonal thereto. In this way the calculated acceleration vector will take into account and movement of the vehicle  36  including straight and swerving for any reason such as driver controlled or as a result of a side impact or “T-bone” impact.  
         [0034]    [0034]FIG. 4 is a rear view of a “normal” motor vehicle  36  illustrating the several locations for brake light assemblies. One location is with each taillight  60 ,  62 . Another brake light  74  location is mounted high up on the vehicle such as inside the rear window, i.e., a typical third brake light.  
         [0035]    Referring to FIG. 5 that is a plan view of a brake light bulb  76  as may be use as a retrofit as well as may be used as an original part of the motor vehicle  36 . This FIG. 5 illustrates a first hollow cylindrical body member  78  enclosed at one end  80 . The enclosed end  80  of the first body member  78  is adapted to be inserted into a bulb socket in the brake system of a motor vehicle  36 . The first body member  78  has a terminal  82  adapted to receive a voltage control signal that is generated by a vehicle brake actuation initiation device. The voltage control signal has a magnitude equal the illumination voltage level  28  of the vehicle power supply  22 .  
         [0036]    A second hollow cylindrical body member  84  is connected to the first cylindrical body  78 . This second cylindrical body member  84  has a diameter different than the diameter of the first cylindrical body  78  for enclosing the module  20 . Typically the diameter of the second body member  84  is greater than the diameter of the first body member  78 .  
         [0037]    A third hollow cylindrical body  86  enclosed at one end  88  is connected to the second cylindrical body  84 . Typically the third cylindrical body  86  is transparent and usually fabricated from glass or a similar material. The glass end  88  is open at the end adjacent to the second body and closed at the opposite end  90 .  
         [0038]    The first and second hollow cylindrical body members  78 ,  84  may be extruded or drawn to be an unitary structure wherein the outside surfaces are blended together. Regardless of how the first, second and third hollow cylindrical bodies are individually manufactured, the end result as illustrated in FIG. 5 is a unitary structure.  
         [0039]    Located in the third body  86  are at least two lamp filaments  92 ,  94  or light sources that are mounted coaxially. At least one of the filaments, typically  94 , is electrically connected for varying the intensity of the filament  94  according to the first variable frequency illumination voltage level control signal. The other of the filaments  92  is electrically connected to receive the control signal having a magnitude equal to the illumination voltage level  28  of the power supply  22 . This control signal bypasses the module  20  to supply the normal illumination found in brake light circuits. Either or both filaments may be multiple filaments.  
         [0040]    Depending upon the algorithm  41  and the system designer, the variable frequency illumination voltage level can also control the flashing of the filament to which it is electrically connected in circuit.  
         [0041]    If the light bulb  76  of FIG. 5 is used in a modification or retrofit of a vehicle, the electrical system of the vehicle is not changed as the original brake light is removed from its socket and the new modified brake light  76  is inserted. The base of the bulb  82  is a standard configuration that will be capable of being inserted into the brake lamp socket. Power to the module  20  is via the power to the lamp, hence when the brake light is not powered up; there is no power to the module. If the accelerometer module  20  should fail, the normal brake lights will not be affected as the fail-safe mode for the SSAWC module  20  is off.  
         [0042]    Sometimes the driver of the vehicle by either downshifting or up-shifting at a very fast pace can cause an acceleration output signal  52  to be generated by the module  20 . In the case of a quick downshift from gear number five to gear number two, the magnitude of the deceleration is such that the trailing driver should be made aware. In this case, the driver of the lead vehicle may not actuate the brake pedal  64  causing power to be delivered to the brake lights  60 ,  62 . An auxiliary power supply is then needed to supply power to the brake lights. Such an auxiliary supply may be a controlled power signal from the main supply  22  that is only active when there is a sudden deceleration or in some case an acceleration that is determined by the accelerometers  30 ,  32 ,  34  and a signal indicating the brake pedal  64  has not been actuated. This auxiliary power supply signal is supplied to the module  20  in parallel with the main power supply. Logic in the microprocessor  40  actuated by the algorithm  41  controls the exclusion of the auxiliary power when the main power is present. Thus, the rapid deceleration caused by means other than the actuation of the brakes will activate the SSAWC  20  and flash the brake lights  60 ,  62 .  
         [0043]    FIGS.  6 - 8  are views of another embodiment of a taillight bulb. In FIG. 6, the third cylindrical body  86  encloses the normal brake lamp filament  92  while surrounding the third cylindrical body are a plurality of auxiliary lamps  96 . In particular these lamps may well be LEDs that are powered from the solid-state accelerometer chip or module  20 . FIG. 6 shows the LEDs surrounding the third cylindrical body  86  while in FIG. 8 the third cylindrical body  86  and its enclosed filaments  92 ,  94  are replaced by LEDs  96  having the required brightness and are powered by the normal brake-light circuit. One advantage of using LEDs is that individually they consume less power, a longer operational life and have a faster response than normal lamp filaments.  
         [0044]    A modification of the schematic of FIG. 1 would be to add both a transmitter  100  and a receiver  102 , as illustrated in FIG. 12. The transmitter  100  is mounted in the module of the lead vehicle for transmitting the signals from the microprocessor indicating the change in acceleration or deceleration. These signals would be transmitted through an antenna, or an optical source,  104  mounted on the rear or any positioning such as side view mirrors, that allows the trailing vehicle to see, electrically or optically or any by other communication means, the antenna of the lead vehicle as shown in FIG. 10. Typically this is a directional antenna  104  in that it is aligned to be directed rearward of the lead vehicle. Depending upon the power of the transmitted signal and direction of transmission, a design decision can be made to limit the signal to only the in-line trailing vehicle or also to include vehicles on either side of the in-line trailing vehicle.  
         [0045]    A receiving antenna  106 , or optical source, mounted in the front end of the trailing vehicle or vehicles, then receives the transmitted signals. The receiving antenna  106  may be mounted in the grill area or any frontal area of the trailing vehicle as shown in FIG. 11. The antenna  106  is electrically connected to a receiver  102  mounted in the module  20  and inputted into its microprocessor causing the warning system to operate based on the action of the lead vehicle, which is at least two cars away. Therefore in a multi-vehicle situation wherein the lead car suddenly decelerates and generates a warning signal, the trailing cars will each receive and transmit the warning signal to each of the vehicles trailing it.  
         [0046]    [0046]FIG. 12 is a block diagrammatic schematic illustrating the system discussed in reference to FIGS.  9 - 11 .  
         [0047]    While the present invention has been described in an illustrative manner, it should be understood that the terminology used is intended to be in a nature of words of description rather than of limitation. Accordingly, various changes and modifications may be made to the illustrative embodiment without departing from the spirit or scope of the invention. It is to be appreciated that those skilled in the art will readily apply these teachings to other possible variations of the inventions. However, it is intended that the scope of the invention not be limited in any way to the illustrative embodiments shown and described.