Abstract:
A vehicle license plate holder having a frame including a receptacle for a license plate, first and second LED light sources disposed on each side of the frame, and one or more power generators attached to the frame. The frame also mounts an electronic circuit module including a battery and configured to detect deceleration of a vehicle and to illuminate the first and second LED light sources in response to detection of the deceleration.

Description:
BACKGROUND  
       [0001]    1. Field of the Disclosure 
         [0002]    The subject disclosure relates to vehicle safety devices and more particularly to a warning light for warning of sudden deceleration of a vehicle. 
         [0003]    2. Related Art 
         [0004]    Vehicle brake warning lights activated by brake depression are known in the art. However, they are ineffective in warning of quick deceleration which may occur without brake depression, such as may be experienced, for example, with motorcycles. 
       SUMMARY  
       [0005]    An illustrative embodiment of vehicle license plate holder according to the subject disclosure comprises a frame having a receptacle for a license plate, first and second LED light sources disposed on each side of the frame and one or more power generators attached to the frame. An electronic circuit module is located on the back of the frame and is configured to detect deceleration of a vehicle to which the license plate holder is attached and to illuminate the first and second LED light sources in response to detection of the deceleration. In one embodiment, the one or more power generators comprise first and second wind powered turbine generators positioned on respective sides of the license plate holder. In other embodiments, the one or more power generators comprise a solar power generator or a combination of solar power and wind turbine power generators. 
         [0006]    In one illustrative embodiment, the electronic circuit module comprises an accelerometer chip coupled through an A/D converter to a controller circuit, a battery charging circuit, and switching circuitry configured to switch power to the first and second LED light sources. In such an embodiment, the controller circuit is configured to control the battery charging circuit and the switching circuitry. In one embodiment, the controller circuit may comprise a microprocessor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a front perspective view of an illustrative embodiment; 
           [0008]      FIG. 2  is a back perspective view of the embodiment of  FIG. 1 ; 
           [0009]      FIG. 3  is an enlarged fragmentary view of a portion of  FIG. 1 ; and 
           [0010]      FIG. 4  is a schematic circuit diagram of electronic circuitry of an illustrative embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    An illustrative embodiment of a vehicle warning light  11  is shown in  FIGS. 1 and 2 . The illustrative embodiment includes a license plate frame  13  for use on motor vehicles, which includes a receptacle  12  for receiving a license plate, as well as mounting holes  14 . On the respective sides  15 ,  17  of the frame  13  are formed two air powered generators  19 ,  21  that generate DC current. A solar cell  22  may also be installed in the frame  13 , or alternatively, in place of the generators  19 ,  21 . Rear facing LED warning lights  23 , which may comprise one or more LEDs, are centrally positioned on the turbine pods. In one embodiment, the device  11  is completely self-contained and has no external switches. 
         [0012]    As seen in  FIG. 2 , the wind turbines  15 ,  19  include respective turbine blades  24  mounted on respective shafts  26  which are rotatably mounted in the central housing  28  of each turbine pod. Each central housing  28  is positioned and supported in the center of each pod by respective struts  30 . 
         [0013]    When the motor vehicle is moving, air flows through the turbine blades  24  which then spin to generate DC power. When the motor vehicle starts decelerating by either closing the throttle or applying the brakes an accelerometer S 5  ( FIG. 4 ) recognizes the deceleration and switches on the LED lights  23 . As soon as DC power is applied, the system electronics ( FIG. 4 ) autonomously begins monitoring the acceleration and deceleration of the motor vehicle. As soon as a forward deceleration situation is sensed the electronics will turn on the LED warning lights  23  until one of these situations occurs: 
         [0014]    1. there is no more DC power available for powering the LEDs  23  and/or the electronics. 
         [0015]    2. the forward deceleration is no longer occurring. 
         [0016]    In one embodiment, as shown in  FIG. 2 , the electronics for controlling the LEDs  23  and power generators, e.g.,  19 ,  22 , is contained in a module  41 , which may be molded as part of the license plate holder  13  or separately attached thereto. In one embodiment, the module  41  includes a removable water tight cover  43 , which provides access to the electronics within the module. Suitable electrical leads or cables  45 ,  47  provide power to the LEDs  23  and transmit voltage from the power generators, e.g.,  19 ,  21  to a rechargeable battery  51  located in the module  41 . A lead  46  may transmit power from the solar cell  22  to the rechargeable battery  51 . In one embodiment, the electrical leads or cables  45 ,  46 ,  47  may reside in channels or raceways which are pre-formed in the license plate structure and which may be covered and held in place by suitable covers or by epoxy or other methods. In an alternate embodiment, the electrical leads or cables may be installed during the molding process of a molded embodiment of the license plate holder and hence encapsulated in, for example, plastic or other molded material. 
         [0017]    The electrical componentry within the module  41  is illustrated in  FIG. 4 . As shown, the componentry includes a battery  51 , suitable switches  52  to control application of power to light the LEDs  23  and a battery charging circuit  53 , which receives power from the power generators, e.g.,  15 ,  19 . In one embodiment, the battery  51  may be a lithium ion battery. 
         [0018]    In an illustrative embodiment, the electrical componentry further includes an accelerometer chip  55  and a controller circuit, such as for example, a microprocessor or microcontroller  57 , together with suitable memory  58 . In one embodiment, the accelerometer chip  53  may be part no. ADXL330 as manufactured by Analog Devices, Inc., One Technology Way, Norwood, Mass. 
         [0019]    The ADXL330 is a 3-axis accelerometer measurement system on a single monolithic IC, which has a measurement range of ±3 g minimum. It contains a polysilicon surface micromachined sensor and signal conditioning circuitry to implement an open-loop accelerometer measurement architecture. The output signals are analog voltages that are proportional to acceleration. The accelerometer can measure the static acceleration of gravity in tilt sensing applications as well as dynamic acceleration resulting from motion, shock, or vibration. 
         [0020]    The sensor is a polysilicon surface micromachined structure built on top of a silicon wafer. Polysilicon springs suspend the structure over the surface of the wafer and provide a resistance against acceleration forces. Deflection of the structure is measured using a differential capacitor that consists of independent fixed plates and plates attached to the moving mass. The fixed plates are driven by 180° out-of-phase square waves. Acceleration deflects the moving mass and unbalances the differential capacitor resulting in a sensor output whose amplitude is proportional to acceleration. Phase-sensitive demodulation techniques are then used to determine the magnitude and direction of the acceleration. 
         [0021]    In one embodiment, the demodulator output may be amplified and brought off-chip through a resistor. The user may then set the signal band-width of the device by adding a capacitor. This filtering improves measurement resolution and helps prevent aliasing. 
         [0022]    In one embodiment, the outputs of the accelerometer  53  are A to D converted by converter  59  and supplied as inputs to the microprocessor  57 . If the microprocessor  57  detects a sudden deceleration based on the accelerometer inputs, it causes power to be immediately supplied to the LEDs  23  via switches  52  to generate a warning light signal. Additionally, the microprocessor  57  monitors the charge state of the battery  51  and controls charging of the battery  51  by the auxiliary power supply sources. The battery  51  in turn supplies operating voltage on respective lines, e.g.  61 ,  63  to the microprocessor  55  and accelerometer  53 . In some embodiments, suitable circuitry may be implemented to provide different operating voltages to different components. 
         [0023]    Thus, those skilled in the art will appreciate that various adaptations and modifications of the just described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.