Abstract:
One aspect is a device for displaying an indication of a system parameter. The device includes an input circuit, an optical sense circuit, a control circuit, and an output circuit. The input circuit is configured to receive input signals that are indicative of a measured system parameter. The optical sense circuit is configured to receive sense signals indicative of a sensed level of light and to receive programming signals related to a system parameter. The control circuit is configured to correlate the input and programming signals and to produce control signals dependant thereon. The output circuit is configured to display an indication of a system parameter that is based upon the control signals.

Description:
BACKGROUND 
       [0001]    The present invention relates to the use of an optical input, such as an optical input used for the calibration of an indicator, such as a fuel gauge on a motorized vehicle. In some applications, certain indicators or gauges will give an indication of a system parameter, such as a level of fuel in a motorized vehicle. On occasion, adjustments or recalibration of the system, or of the gauges monitoring and displaying parameters of the system, may be desired. Adding input devices for the calibration, such as switches and the like, is not always practical. 
         [0002]    For these and other reasons, there is a need for the present invention. 
       SUMMARY 
       [0003]    One embodiment includes a device for displaying an indication of a system parameter. The device includes an input circuit, an optical sense circuit, a control circuit, and an output circuit. The input circuit is configured to receive input signals that are indicative of a measured system parameter. The optical sense circuit is configured to receive sense signals indicative of a sensed level of light and to receive programming signals related to a system parameter. The control circuit is configured to correlate the input and programming signals and to produce control signals dependant thereon. The output circuit is configured to display an indication of a system parameter that is based upon the control signals. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The accompanying drawings are included to provide a further understanding of embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and together with the description serve to explain principles of embodiments. Other embodiments and many of the intended advantages of embodiments will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. 
           [0005]      FIG. 1  illustrates a fuel tank with instruments and gauges. 
           [0006]      FIG. 2  illustrates a fuel and battery gauge in accordance with one embodiment. 
           [0007]      FIG. 3  illustrates a control circuit for a gauge in accordance with one embodiment. 
           [0008]      FIG. 4  illustrates further detail of a control circuit in accordance with one embodiment. 
           [0009]      FIGS. 5A-5B  illustrates a sequence for adjusting a control circuit in accordance with one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. 
         [0011]    It is to be understood that the features of the various exemplary embodiments described herein may be combined with each other, unless specifically noted otherwise. 
         [0012]      FIG. 1  illustrates a motorized vehicle fuel tank  10  in accordance with one embodiment. In one embodiment, fuel tank  10  is configured on a motorcycle. In other embodiments, fuel tank  10  can be configured for other motorized vehicles. In one embodiment, fuel tank  10  includes fuel and battery level indicator  12 , instrumentation  14  and fill cap  16 . 
         [0013]    In operation, fill cap  16  is removed and fuel is pumped into fuel tank  10 . Fuel and battery level indicator  12  then provides an indication of the level of fuel within tank  10 . Indicator  12  can also provide an indication of the battery level of a battery on the vehicle on which fuel tank  10  is mounted. Instrumentation  14  can provide other indicators of the motor vehicle parameters, such as vehicle speed and engine RPM. 
         [0014]    In some instances, the actual level or value of system parameter and the measured level or value of that parameter are not well coordinated. In a system where an indicator displays an indication of the measured value, the displayed value and the actual value will not be correlated. For example, in some cases the actual level of fuel in fuel tank  10  can differ from the measured level, and thus different from the level displayed on indicator  12 . In one example, variations in different float mechanisms or sensor mechanisms that may be used to sense the level of fuel in tank  10 , and/or variations in the different transmission units that may be used to transmit the sensed level to indicator  12 , can cause different or varying relative levels to be displayed on indicator  12 . As such, indicator  12  may indicate a “full” tank when in fact tank  10  is only three-quarters full. 
         [0015]      FIG. 2  illustrates fuel and battery level indicator  12  in accordance with one embodiment. Indicator  12  includes fuel display  20 , battery display  22 , optical sensor  26  and control circuit  30  (not visible in  FIG. 2 ). In one embodiment, indicator  12  is a unitary piece that is insertable into tank  10  for mounting therein. Indicator  12  can include a tube or rod that extends down into tank  10  with a level sensor that measures the actual level of fuel in tank  10 . Further, indicator  12  can be configured with an input for receiving an indication of the level of a battery associated with the vehicle to which tank  10  is attached. In one example, indicator  12  can replace an existing indicator. 
         [0016]    In one embodiment, both fuel display  20  and battery display  22  each include a series of LEDs that are controllably enabled by control circuit  30 . As such, a number of LEDs will be turned on in accordance with a level detected and transmitted to indicator  12 . For example, if indicator  12  has an indication that tank  10  is full of fuel, all of the LEDs in fuel display  20  can be lit. 
         [0017]    Optical sensor  26  is configured to sense the amount of light present at indicator  12 . If the amount of light sensed by sensor  26  is relatively great, this typically indicates a daylight mode. In such a mode, control circuit  30  will adjust the brightness of the LEDs in both fuel display  20  and battery display  22  so that they are at their brightest in order to ensure their visibility. When the amount of light sensed by sensor  26  is relatively slight, this typically indicates a night mode. In such a mode, control circuit  30  will adjust the brightness of the LEDs in both fuel display  20  and battery display  22  so that they are less bright, as that is all that will be needed to ensure visibility. 
         [0018]      FIG. 3  illustrates basic control circuit  30  in accordance with one embodiment. Control circuitry  30  includes control logic  32 , input circuit  34 , optical sense circuit  36 , and output circuit  38 . In one embodiment, control circuit  30  is fully integrated into indicator  12 . 
         [0019]    In operation, input circuit  34  is configured to generate and/or receive input signals, such as the level of fuel in tank  10 , or the level of a battery. Input circuit  34  is configured to transmit these input signals to control logic  32 . Optical sense circuit  36  is configured to generate and/or receive sense signals that are indicative of a light level at a particular location, such as at the face of indicator  12  where optical sensor  26  is located. Optical sense circuit  36  is configured to transmit these sense signals to control logic  32 . Output circuit  38  is configured to control fuel display  20  and battery display  22 , enabling, disabling and adjusting the intensity of associated LEDs in accordance with control signals from control logic  32 , which is coupled thereto. The control signals from control logic  32  for controlling the LEDs are based in the input signals from input circuit  34  and the sense signals from optical sense circuit  36 . 
         [0020]    In one example, input signals from input circuit  34  include an indication of a measured level of fuel in tank  10 . These input signals are transmitted to control logic  32 . Control logic  32  then generates control signal based on the input signals and transmits these control signals to output circuit  38 . These control signals then control how many LEDs are lighted in fuel display  20 , which will be in proportion to the measured level of fuel in tank  10 . Control signals can also include an indication of the level of light proximate to fuel display  20  from the sense signals that are transmitted from optical sense circuit  36 . As such, the level of intensity of the LEDs of fuel display can be adjusted based upon this measured level of light. 
         [0021]    Furthermore, sense signals from optical sense circuit  36  can further include programming signals. For example, when variations in sensing and transmission mechanisms of indicator  12  cause inaccuracy in the relative levels between the actual level and those that are measured and displayed, an operator may wish to recalibrate indicator  12 . Recalibration can ensure, for example, that when fuel tank  10  is in fact empty, the fuel display  20  also displays empty, and when fuel tank  10  is in fact full, the fuel display  20  also displays full. This recalibration can be accomplished by generating programming signals in optical sense circuit  36 , which are then used to generate control signals in control logic  32 . 
         [0022]    In one example, optical sensor  26  can be manipulated in order to generate these programming signals in optical sense circuit  36 . In one embodiment, a user can signal that fuel tank  10  is in fact empty, or “an empty condition”, by blocking and unblocking optical sensor  26  in a certain specified sequence for a certain specified period of time. This programming signal indicative of an actual empty condition is sent to control logic  32 . Control logic  32  also receives input signals from input circuit  34  that are indicative of the measured level of fuel in fuel tank  10 . Control logic  32  can then assign this measured level as the empty condition and recalibrate accordingly. 
         [0023]    Additional programming signals can generate be similarly generated in order to indicate other conditions, such as “full condition” when tank  10  is full, a “half condition” when tank  10  is half full, and so on. Only one indication of the actual condition input through optical sensor  26  as a programming signal is needed for recalibration with the measured signals, and then the remaining correlation between actual and measured conditions can be extrapolated, or a plurality of such condition indications can also be used. 
         [0024]      FIG. 4  illustrates additional detail of control circuit  40  in accordance with one embodiment. Control circuit  40  includes microcontroller  42 , optical sensor circuit  46 , fuel sensor  50 , fuel level sensor circuit  52 , battery level sensor circuit  54 , fuel LEDs  60 , fuel LED control circuit  62 , battery LEDs  64 , battery LED control circuit  68 , and power supply regulator  70 . In one embodiment, power supply regulator  70  is provided to provide regulated power to the various components of control circuit  40 . 
         [0025]    In operation, fuel sensor  50  is configured to measure the actual level of fuel in a tank, such as tank  10 . Sensor  50  can be any of a variety of mechanisms configured to measure the actual level of fuel in a tank, such as a float sensor. The measured level of fuel is then sent to fuel level sensor circuit  52  as an input signal. Similar input signals, but reflective of a measured battery level rather than measured fuel level, can be sent to battery level sensor circuit  54 . Input signals from fuel level sensor circuit  52  and battery level sensor circuit  54  are then transmitted to microcontroller  42 . 
         [0026]    Optical sensor circuit  46  is configured to measure and/or receive sense signals that are indicative of a light level at a particular location, such as at the face of indicator  12 . In one case, a sensor, such as optical sensor  26 , is used to measure a light level and transmit the measured level as a sense signal to optical sensor circuit  46 . Optical sense circuit  46  is configured to transmit these sense signals to microcontroller  42 . 
         [0027]    Optical sensor circuit  46  is further configured to receive programming signals that are indicative of an actual system parameter. For example, when variations in sensing and transmission mechanisms of a system cause inaccuracy in the relative levels between the actual level and those that are measured and displayed, programming signals can be used to recalibrate these levels to establish a better correlation between actual and measured levels. These programming signals are then transmitted to microcontroller  42 . 
         [0028]    In one embodiment, microcontroller  42  receives input signals from fuel level sensor circuit  52  and battery level sensor circuit  54 , receives sense and programming signals from optical sensor circuit  46 , and uses these signals to generate control signals that are asserted on fuel LEDs  60 , fuel LED control circuit  62 , battery LEDs  64 , and battery LED control circuit  68 . As such, microcontroller  42  controls how many LEDs are on and off, as well as the overall intensity of the LEDs that are on. 
         [0029]    In one example, fuel and battery LEDs  62  and  64  each include 10 LEDs that can be turned on and off. As such, when input signals indicate that fuel level is in a full condition, all 10 LEDs will be turned on, when input signals indicate that fuel level is in a half condition, 5 of the 10 LEDs will be turned on, and the other 5 will remain off, and so on. 
         [0030]    In one example, control circuit  40  is provided in an indicator, such as indicator  12  above. As such, optical sensor  26  can be used to generate programming signals so that microcontroller  42  can generate a good correlation between actual and measured levels, upon prompting by a user. 
         [0031]    In one example, programming signals are generated in optical sensor circuit  46  by having a user block and unblock optical sensor  26  in a specified sequence for a certain specified period of time. In one example, a user can program an indication that fuel tank  10  is empty. As such, microcontroller  42  can correlate the measured fuel level from fuel sensor  50  with an empty condition when it receives this programmed indication from a user. 
         [0032]    A user initiates the programming process by covering optical sensor  26  for three seconds, and then releasing it. This process of covering for three seconds can be referred to as the “programming initiating step.” In response to this programming initiating step, microcontroller  42  then lights only a single LED near the center of the 10 LEDs in fuel LEDs  62 . In response to the single LED coming on, the user then again covers optical sensor  26 . Next, in response to optical sensor  26  being covered again, microcontroller  42  turns off the single LED so that all 10 LEDs in fuel LEDs  62  are off. When the user sees that all of the LEDs are off, the user again covers optical sensor  26 . In response to this blocking, microcontroller  42  then again lights only a single LED near the center of the 10 LEDs in fuel LEDs  62 . 
         [0033]    This responsive process of covering and releasing optical sensor  26  in response to microcontroller  42  turning on and off a LED, or the “programming responsive steps,” can be repeated several times in order to ensure that it is a true programming sequence and not a random occurrence. 
         [0034]    For example, where control circuit  40  is provided in indicator  12 , which is mounted in the fuel tank of a motorcycle, it is possible that the motorcycle could randomly pass through tunnel or other obstacle to light that suddenly darkens optical sensor  26  for three seconds, much like would occur when a user covers sensor  26 , thereby initiating the programming sequence. 
         [0035]    If the random occurrence is perceived as the programming initiating step, microcontroller  42  will light a single LED near the center fuel LEDs  62  in response to this blocking. If the user does not follow this with the programming responsive steps, however, then microcontroller  42  will not continue with the programming sequence and will not correlate the measured fuel level from fuel sensor  50  with an empty condition. As such, only a true programming sequence, with a programming initiating step followed by programming responsive steps, will correlate measured input signal with actual, and random occurrence will not do so. 
         [0036]      FIGS. 5A-5B  are block diagrams illustrating one exemplary process that can be used to program a control circuit such as control circuit  30  of  FIG. 3  or control circuit  40  of  FIG. 4 . Other variations on the process will also achieve programming a control circuit to recalibrate system parameters to correlate a measured parameter with an actual parameter. 
         [0037]    At step  100 , the process is started. At step  102 , the fuel level is checked. In one example, fuel level sensor circuit  52  checks fuel sensor  50  to determine the measured level of fuel. At step  104 , battery level is checked. In one example, battery level sensor circuit  54  checks a battery to determine the measured level of battery voltage. At step,  106  a light sensor is checked to determine the present level of ambient light. For example, optical sensor  26  could be monitored to determine the level of ambient light at the sensor. 
         [0038]    Next, at step  108 , a determination is made as to whether the level of light at the light sensor has changed from the last time that the sensor was checked. If the light level has not changed, then at step  110  fuel and battery levels are displayed on the LEDs in accordance with the levels measured at steps  102  and  104 . At step  112 , the intensity level of the LEDs is adjusted in accordance with the light level measured at the sensor at step  106 . The program sequence then cycles back to the start step  100 . 
         [0039]    If a determination is made at step  108  that the level of light at the light sensor has changed from the last time that the sensor was checked, then at step  120  a programming sequence is initiated. Once the programming sequence is initiated, a determination is made as to whether the light level at the sensor was low for three seconds at step  122  (in  FIG. 5B ). If the light level was not low for at least three seconds, then the display is updated in accordance with the currently sensed light level at step  130 , and the process returns to step  110  on  FIG. 5A . 
         [0040]    If a determination is made at step  122  that the light level was low for at least three seconds, then the programming sequence on the fuel LED, or “programming initiating step,” is initiated at step  124 . Next, at step  126  a determination is made as to whether the light sensor followed the programming sequence, or “programming responsive steps.” If the light sensor did not follow the programming responsive steps, then the determination is made at step  126  that this was a random occurrence and not a programming sequence and the display is updated at step  130 . 
         [0041]    If the light sensor did follow the programming responsive steps, however, then the determination is made at step  126  that this was a programming sequence. As such, a new low fuel level is set at step  128 . In one example, this is accomplished by correlating the current measured level of fuel with the empty condition for the fuel tank. 
         [0042]    One skilled in the art understands that variations to the process illustrated in  FIGS. 5A-5B  are possible in accordance with alternative embodiments. For example, although the determination is made as to whether the light level at the sensor was low for three seconds at step  122 , other timing parameters can also be used the programming initiating step. A shorter or a longer time for covering the optical sensor can be used. 
         [0043]    Similarly, variations in the conditions that verify programming responsive steps can also be used. For example, rather than turning a single LED on and off and having a user responsively cover the optical sensor over a series of three cycles, more or less cycles can be used. Furthermore, additional LEDs could be used in the process. For example, when a single LED is lighted, the user may need to cover the optical sensor for one second, when two LEDs are lighted, the user needs to cover the optical sensor for two seconds, when three LEDs are lighted, the user needs to cover the optical sensor for three seconds, and so on. 
         [0044]    Any similar non-random sequences can be used to verify programming responsive steps that are differentiated from a random occurrence, which can be caused when the optical sensor is simply randomly blocked from a light source for short periods of time. For example, when the light source is integrated in a motorized vehicle such as a motorcycle, the light source may effectively blocked for a short period time by a random occurrence like passing through a tunnel. This can trigger the programming initiating step. Such a random occurrence is not likely, however, to follow the specific pattern of turning on and off the LEDs that follows, and thus, will not verify the programming responsive steps. 
         [0045]    Although one embodiment illustrates optical sensor used as a programming switch for correlating or recalibrating fuel level in a tank, one skilled in the art will understand that this input can also be used to trigger other programmable events. For example, microcontroller  42  of control circuit  40  is configured to receive inputs from fuel level sensor circuit  52  and battery level sensor circuit  54 . Although the recalibration or correlation described above is used with respect to the fuel level input from fuel level sensor circuit  52 , similar use could be made of a battery level input from battery level sensor circuit  54 . 
         [0046]    Furthermore, other input signals from other system parameters could be routed to microcontroller  42 , and an optical sensor coupled to optical sensor circuit  46  can be used to trigger programming use of these input signals. Microcontroller  42  can differentiate which input signal is to be used, as well as what use is to made of the input signal, by the different programming signals that are sent from optical sensor  46 . 
         [0047]    For example, blocking optical sensor for three seconds may initiate the fuel calibration process described above, while blocking optical sensor for six seconds may initiate a different process relating to a system parameter, such as calibrating the battery, calibrating a speedometer, calibrating a tachometer, turning off a gauge, turning on a gauge, and so on. In each case, after the programming initiating step is verified, it is followed by a programming responsive step, similar to that described above, to verify that this was a programming sequence rather than a random occurrence. 
         [0048]    Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.