Abstract:
The present invention is directed at a volume control for an automobile turn signal indicator. The volume control allows the driver to raise or lower the volume of the clicking sound that is produced when a turn signal indicator is activated. As such, the driver is able to increase the volume of the audible clicking sound when operating in a environment having a high background noise (i.e. a radio or traffic) or when the driver is hearing impaired.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/190,008, filed on Mar. 17, 2000, which is incorporated herein by reference in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention is generally related to automobile control systems, and applications of the same. More specifically, the invention is related to a volume control for an automobile turn signal indicator.  
           [0004]    2. Background Art  
           [0005]    Automobile turn signal indicators utilize flashing lamps on the outside of the automobile to warn surrounding traffic of a prospective change in direction. To indicate a turn, the driver moves a lever that is mounted on the steering wheel, which activates the respective turn signal indicator and causes the corresponding exterior lamps to blink on-and-off. Conventional turn signal indicators also include lamps on the dash board that blink on-and-off in synchronization with the blinking of the exterior lamps. Additionally, an audible “clicking” sound is often produced that is also synchronized with the blinking of the exterior lamps. The dash board lamps and audible clicking sound are meant to inform the driver that a particular turn signal indicator is activated. When the driver makes a sufficiently wide turn, a mechanical control device automatically deactivates the turn signal indicator, and stops the blinking lamps and the audible clicking sound.  
           [0006]    A problem with conventional turn signal indicators is that occasionally the driver will activate the turn signal, and then not complete the turn for some reason. Alternatively, the driver may execute a turn that is not wide enough to automatically deactivate the indicator, as often occurs when changing lanes during highway driving. When this occurs, the driver must manually deactivate the turn signal indicator in order to stop it. If the turn signal indicator is not manually deactivated, then the driver travels down the road with a blinking turn signal, when no turning maneuver is immediately planned.  
           [0007]    As mentioned above, the dash board lamps and the audible clicking sound are supposed to notify the driver when a turn signal indicator is activated. The dash board lamps can be ineffective because the driver&#39;s visual attention is often focused on the road ahead, especially during highway driving. The audible clicking sound is difficult to hear for those drivers that are hearing impaired. Additionally, the audible clicking sound can be drowned-out by traffic noise or the radio, even for those drivers with good hearing.  
           [0008]    Therefore, what is needed is away to improve the effectiveness of the turn signal indicator so that drivers, including hearing impaired drivers, will realize when a turn signal indicator is activated.  
         BRIEF SUMMARY OF THE INVENTION  
         [0009]    The present invention is directed at a volume control for an automobile turn signal indicator. The volume control allows the driver to raise or lower the volume of the clicking sound that is produced when a turn signal indicator is activated. As such, the driver is able to increase the volume of the audible clicking sound when operating in a environment having high background noise (i.e. a radio or traffic), or when the driver is hearing impaired.  
           [0010]    In embodiments, a thermally sensitive switch connects/disconnects a power supply voltage to the indicator lamps when the driver activates a turn signal lever. The thermally sensitive switch generates an audible clicking sound that is the result the switch action. A microphone receives the clicking sound and generates a corresponding electrical signal. A variable gain amplifier amplifies or attenuates the amplitude of the electrical signal according to the desired volume that is determined by the user/driver. Finally, a speaker converts the electrical signal back into an audible clicking sound that is re-broadcast into the driver compartment.  
           [0011]    An advantage of the invention is that the driver is able to raise or lower the volume of the clicking sound, by increasing or decreasing the gain of the variable gain amplifier. Therefore, hearing impaired drivers can increase the volume of the clicking sound as necessary, and decrease the likelihood that they will drive around with an unintended blinking turn signal.  
           [0012]    In an alternate embodiments, two or more thermally sensitive switches are configured so that the switches produce clicking sounds of varying sound volume. The driver then selects a switch based the desired volume. For example, low, medium, or high selections could be provided. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES  
       [0013]    The present invention will be described with reference to the accompanying drawings, which are briefly described as follows.  
         [0014]    [0014]FIG. 1 illustrates a turn signal indicator  100  with volume control according to embodiments of the present invention.  
         [0015]    FIGS.  2 - 3  illustrate variable gain amplifiers according to embodiments of the present invention.  
         [0016]    [0016]FIG. 4 illustrates a turn signal indicator  400  with volume control according to embodiments of the present invention.  
         [0017]    [0017]FIG. 5 illustrates a turn signal indicator  500  with volume control according to embodiments of the present invention.  
         [0018]    [0018]FIG. 6 further illustrates the audio generator  404  in the turn signal indicator  400  according to embodiments of the present invention.  
         [0019]    [0019]FIG. 7 illustrates a flowchart  700  that further describes the operation of a volume control for a turn signal indicator. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    [0020]FIG. 1 illustrates a turn signal indicator  100  according to a first embodiment of the invention. Turn signal indicator  100  includes: a 12 volt battery  101 , a heater circuit  102 , a thermally sensitive switch  104 , a turn signal switch  106 , a turn signal lever  116 , left indicator lamps  109 , right indicator lamps  113 , and a volume control circuit  118 . The left indicator lamps  109  include a left exterior lamp  108  and a left dash board lamp  110 . The right indicator lamps  113  include a right dash board lamp  112  and a right exterior lamp  114 . The volume control circuit  118  includes a microphone  122 , a variable gain amplifier  125 , and a speaker  128 . The turn signal indicator  100  operates as follows.  
         [0021]    The turn signal switch  106  is a 3-pole switch that is controlled by the turn signal lever  116  that is located on the steering column. When the driver moves the turn signal lever  116  to the down position in preparation for a left hand turn, the selector switch  106  connects the 12 volt battery  101  to the left indicator lamps  109 . When the driver moves the turn signal lever  116  to the up position in preparation for a right hand turn, the selector switch  106  connects the 12 volt battery to the right indicator lamp  113 .  
         [0022]    The heater circuit  102  and the thermally sensitive switch  104  are connected in series between the indicator lamps  109 ,  113  and the battery  101 . The heater circuit  102  includes a low resistive winding that heats up when current flows through it. The thermally sensitive switch  104  is normally closed, but opens when the temperature is raised.  
         [0023]    In embodiments, the thermally sensitive switch  104  is a bi-metallic thermal switch that has one or more bi-metallic strips that flex open and closed based on the temperature.  
         [0024]    Once either of the indicator lamps  109  or  113  are coupled to the battery  101 , electrical current begins to the flow to the indicator lamps through the heater circuit  102  and the thermal switch  104 , causing the lamps to light. After one or two seconds, the heater circuit  102  raises the temperature by a sufficient amount to cause the thermally sensitive switch  104  to flex open and stop the current flow. After being open for 1 or 2 seconds, the thermally sensitive switch  104  cools sufficiently, and flexes closed. As such, the thermally sensitive switch  104  repeatedly opens and closes, and causes the selected indicator lamps to blink on-and-off until the selector switch  106  is returned to the neutral position. Additionally, a “clicking” sound  121  is produced by the thermally sensitive switch each time the bi-metallic strips flex open and closed. Volume control circuit  118  picks up the clicking sound and controls the volume as described below.  
         [0025]    Referring now to volume control circuit  118 , the microphone  122  picks up the clicking sound  121 , and converts the clicking sound into an electrical signal  124 . The amplifier  125  amplifies the electrical signal  124  according to the volume control input  120 , resulting in an electrical signal  126 . The volume control input  120  controls the gain of the amplifier  125 , and therefore the amplitude of the electrical signal  126 . The speaker  128  converts the electrical signal  126  back into an audible clicking sound  129  that is re-broadcast back into the driver compartment of the automobile. The speaker  129  can be the same speaker that is used for the car radio.  
         [0026]    An advantage of the invention is that the driver is able to raise or lower the volume of the clicking sound  129 , by increasing or decreasing the gain of the amplifier  125 . Therefore, hearing impaired drivers can increase the volume ofthe clicking sound as necessary, and decrease the likelihood that they will drive around with an unintended blinking turn signal.  
         [0027]    [0027]FIG. 2 illustrates a variable gain amplifier  201  that is one embodiment for the variable gain amplifier  125 . Variable gain amplifier  201  includes an operational amplifier (op amp)  202 , a variable resistor  204 , and a resistor  206 . Op amp  202  can be any type of op amp suitable for audio amplification.  
         [0028]    Variable gain amplifier  201  has a gain that is determined by the equation:  
         Vo/Vin=(1+ R   2   /R   1 );  
         [0029]    where R 2 is the variable resistor  204 , and R 1  is the resistor  206 . The variable resistor  204  (also called a potentiometer) is controlled by the volume control  120  that is set by the driver. As such, the gain of the amplifier  201  (and ultimately the volume of the clicking sound  129 ) are controlled by the control input  120 , using the variable resistor  204 .  
         [0030]    Operational amplifiers can be configured as attenuators using the appropriate resistor combination as will be understood by those skilled in the arts. Therefore, the variable gain amplifier  125  can provide attenuation if a driver wants a lower volume than that provided by the unprocessed clicking sound  121 .  
         [0031]    [0031]FIG. 3 illustrates variable gain amplifier  301  that is an alternate embodiment for the variable gain amplifier  125 . Variable gain amplifier  301  is similar to variable gain amplifier  201 , except that R 1  and R 2  for the op amp are fixed. The variable resistor  204  is used to control the power supply voltage or current for the op amp  202 , and thereby controls the amplifier gain.  
         [0032]    [0032]FIG. 4 illustrates a turn signal indicator  400  according to embodiments of the invention. Turn signal indicator  400  includes: a turn signal lever  402 , a turn signal audio generator  404 , a controller  406 , the variable gain amplifier  125 , the left indicator lamps  109 , and the right indicator lamps  113 . The turn signal generator  400  operates as follows.  
         [0033]    The controller  406  receives the driver volume control input  120  and appropriately sets the gain of the variable gain amplifier  125 . The controller  406  detects when the driver has moved the lever  402  to indicate a left turn or a right turn. Once the lever  402  has been activated, the controller  406  activates the turn signal audio generator  404 . Audio generator  404  generates an audio signal  405  that simulates the clicking sound  121  that is produced by the thermally sensitive switch  104  in FIG. 1. The variable gain amplifier  125  amplifies the audio signal  405  according to the control signal  120 , resulting in audio signal  406 . Speaker  128  receives the audio signal  406  and broadcasts it into the driver compartment.  
         [0034]    As with turn signal indicator  100 , indicator  400  permits the driver to raise or lower the volume of the clicking sound by using the control input  120 .  
         [0035]    In FIG. 6, the turn signal audio generator  404  includes an address generator  602 , a read only memory (ROM)  604 , and a digital-to-analog converter (DAC)  606 . The ROM  604  stores a digital representation of the clicking sound  121  that is produced by the thermally sensitive switch  104 . The address generator  602  generates addresses  603  of the ROM  604 , so as to read-out a digital signal  605  that carries the digital representation ofthe clicking sound  121 , when the turn signal lever  402  is engaged. The DAC  606  converts the digital signal  605  to analog to generate the audio signal  405 , which is variably amplified by the amplifier  125  based on the volume control signal  120 .  
         [0036]    As stated, the ROM  604  stores a digital representation of the clicking sound  121  that is produced by the thermally sensitive switch  104 . The digital representation can be an approximation of the clicking sound  121 . Alternatively, the ROM  604  can store a digital representation of another type of sound to indicate that the turn signal indicator is activated including: alarms, beeps, buzzes, and taped messages in any one of numerous languages.  
         [0037]    [0037]FIG. 5 illustrates a turn signal indicator  500  according to embodiments of the present invention. Turn signal indicator  500  is similar to turn signal indicator  100  except that the volume control circuit  118  is replaced with a selection switch  502  and two thermally sensitive switches  104   a  and  104   b . Thermally sensitive switches  104   a  and  104   b  operate similar to that described above, except that one switch  104   a  is configured to admit a louder clicking sound when being switched than the switch  104   b . As such, switch  104   a  can be described as a high volume switch, and switch  104   b  can be described as a low volume switch. The volume control signal  120  controls the selection switch  502 , and therefore enables the driver to select either the high volume clicking sound from the switch  104   a  or the low volume clicking sound from the switch  104   b . The invention is not limited to two switch selections, as any number of thermally sensitive switches corresponding to different volumes could be provided. For example, low, medium, and high selections could be provided using three switches  104 .  
         [0038]    [0038]FIG. 7 illustrates a flowchart  700  that further describes the operation of a volume control for a turn signal indicator.  
         [0039]    In step  702 , a user engages (or activates) the turn signal lever to indicate a pending change in direction.  
         [0040]    In step  704 , an electrical signal is generated that is representative of a sound that is associated with a turn signal indicator. For example, in FIG. 1, the microphone  122  generates an electrical signal  124  from a clicking sound  121  that is generated by the thermally sensitive switch  104 . Alternatively, the turn signal generator  404  generates an audio signal  405 . More specifically, the ROM  604  reads-out a digital signal  605  that carries a digital representation of the clicking sound  121 , which is then converted to analog by the DAC  606  to produce the audio signal  405 .  
         [0041]    In step  706 , the electrical signal is variably amplified according to a control signal  120 . For example, the variable amplifier  125  amplifies the electrical signal  124  (or the audio signal  405 ) according to the volume control signal  120 . In other words, the volume control signal  120  determines the gain of the amplifier  125  and therefore the amplitude of the amplified electrical signal.  
         [0042]    In step  708 , the amplified electrical signal is converted to audible sound. For example, the speaker  128  converts the amplified electrical signal into audible sound  129 .  
         [0043]    In step  710 , the volume of the audible sound  129  is increased or decreased by adjusting the volume control signal  120 . The volume control signal  120  adjusts the gain of the amplifier  125 .  
         [0044]    Conclusion  
         [0045]    Example embodiments of the methods, systems, and components of the present invention have been described herein. As noted elsewhere, these example embodiments have been described for illustrative purposes only, and are not limiting. Other embodiments are possible and are covered by the invention. Such other embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.