Abstract:
A tilt sensing apparatus, a system and a method detect the tilt of a vehicle using tilt sensing devices mounted to the vehicle. An accelerometer and a gyroscope provide orientation data to a processor. The processor calculates the tilt of the vehicle and provides an audible indication and/or a visual indication to an operator of the vehicle via a communications module. The communications module has a display panel accessible to the operator for receiving the tilt information. The system provides tilt information for different amounts of tilt of the vehicle. The method of detecting the tilt of the vehicle accumulates position data from the accelerometer and the gyroscope to provide tilt indications to the operator. The apparatus, system and method compare a tilt angle to preset values and generate corresponding output signals to the operator if the preset values are exceeded. The system disables a power take-off connected to the vehicle in the event of a tilt condition in which the vehicle may roll over.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention generally relates to a tilt sensor. More specifically, the present invention relates to a tilt sensing apparatus, a system and a method for using same to provide an indication of tilt for a variety of vehicles. 
         [0002]    Millions of vehicles are on the road today. Certain types of vehicles may also travel off the road. For example, SUVs, 4×4s, Jeeps® (a registered trademark of Chrysler Group LLC) and the like may travel on the road and off the road. Other types of vehicles, for example, sand rails, dune buggies and the like may be purpose-built to be used off the road for pleasure and/or entertainment. Moreover, military vehicles, industrial vehicles, farm vehicles and the like may be used primarily off the road on battlefields, in quarries, in mines, on farms, in fields, and in other locations that are not graded or paved for normal vehicle usage. 
         [0003]    Further, many vehicles have powered implements for performing a variety of different tasks. Such vehicles have a power take-off (“PTO”). The PTO is any of several methods for taking power from a power source, such as a running engine, and transmitting the power to an application such as an attached implement or separate machine, for example. Typically, the PTO is a system using a splined output shaft on a tractor or truck, designed so that a PTO shaft, a kind of drive shaft, may be connected and disconnected, and a corresponding input shaft on the application end. The PTO allows implements to draw energy from the engine. 
         [0004]    Vehicles with powered implements driven by a PTO may be, for example, lawnmowers, tractors, lawn tractors, soil tillers, snow throwers and the like. Many vehicles with powered implements are self-propelled, and an operator may ride on the vehicle. Vehicles with powered implements may tilt as they travel over sloped surfaces, such as hills and/or uneven terrain, for example. Such sloped surfaces are often encountered due to the nature of the work being performed and/or the area in which the work is performed. As a result, the vehicle with a powered implement may be required to travel over such sloped surfaces. 
         [0005]    However, if a vehicle with a powered implement tilts too much, the vehicle may potentially tip over and/or slide down an incline. Vehicles with powered implements have been equipped with various tilt sensors to provide the driver with an indication that the vehicle is approaching a tilt limit and to disable the powered implement. Axial inclinometers and tip switches are examples of commonly used devices. 
         [0006]    Tilt sensors may be used to provide input control signals for controlling, for example, machinery, devices and/or the like. Further, tilt sensors may be used in many different applications. For example, tilt sensors may be used on material handling vehicles, industrial machinery, flight simulators and the like. 
         [0007]    A typical tilt sensor produces an output signal corresponding to the angular displacement of the vehicle about orthogonal “X”, “Y” and “Z” axes. The output signal from a tilt sensor may typically be an input to a host device, such as a computer, a microcontroller and/or the like which processes the signal. The X-axis, Y-axis and Z-axis input signals may be used to control the vehicle, the powered implement and/or both. The tilt sensor may also provide an input command to a computer software program. In addition to providing X-axis, Y-axis and Z-axis input signals to a computer or other device, some tilt sensors provide indicators to the operator of the vehicle of the amount of tilt in a certain axis. 
         [0008]    Certain environmental conditions may affect the performance and/or operation of the tilt sensor. For example, extreme vibrations of the vehicle and/or the powered implement may interfere with the operation of the tilt sensor. For example, lawnmowers undergo such vibrations during mowing operations. The vibration of the engine coupled with the typically uneven terrain may cause such vibrations. The operation of the vehicle and/or the powered implement and/or user satisfaction and/or user safety may also be negatively impacted when the tilt sensor malfunctions and/or is inaccurate. Thus, many of the existing tilt sensors may be inadequate for controlling the operation of the vehicle and/or the powered implement and/or may cause numerous performance and/or safety problems when operating the vehicle and/or the powered implement. 
         [0009]    Therefore, a need exists for a tilt sensing apparatus, a system and a method for using same to provide an indication of tilt for a vehicle. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention relates generally to a tilt sensor. More specifically, the present invention relates to a tilt sensing apparatus, a system and a method for using same to provide an indication of tilt for a variety of vehicles. In particular, the vehicle may be a lawnmower. 
         [0011]    To this end, in an embodiment, an apparatus for sensing tilt of a vehicle is provided. The apparatus may have an accelerometer mounted to the vehicle wherein the vehicle has a first axis and a second axis oriented at an angle with respect to the first axis. The accelerometer senses a first tilt angle defined between the first axis and a horizontal reference plane and generates first data associated with the first tilt angle. Further, the accelerometer senses a second tilt angle defined between the second axis and the horizontal reference plane and generates second data associated with the second tilt angle. A gyroscope is mounted to the vehicle. The gyroscope senses the first tilt angle and generates third data associated with the first tilt angle. Further, the gyroscope senses the second tilt angle and generates fourth data associated with the second tilt angle. A processor may be connected to the accelerometer and the gyroscope. The processor determines a tilt angle of the vehicle based on the first data and the second data from the accelerometer and the third data and the fourth data from the gyroscope. 
         [0012]    In an embodiment, the processor compares the tilt angle to a first preset angle and provides a first indicator if the tilt angle exceeds the first preset angle. 
         [0013]    In an embodiment, the processor compares the tilt angle to a second preset angle and provides a second indicator if the tilt angle exceeds the second preset angle. 
         [0014]    In an embodiment, the accelerometer and the gyroscope generate information associated with the tilt angle relative to the first axis, the second axis, and a third axis. 
         [0015]    In an embodiment, the accelerometer provides initial startup data and the gyroscope provides tilt data during operation of the vehicle. 
         [0016]    In an embodiment, the first axis and the second axis are arranged perpendicular to each other. 
         [0017]    In another embodiment of the invention, a method of determining a tilt condition of a vehicle is provided. The method has the steps of sensing an orientation of the vehicle using an accelerometer to provide first coordinates; sensing a three-dimensional orientation of the vehicle using a gyroscope to provide second coordinates; calculating the orientation of the vehicle based upon the first coordinates and the second coordinates; and comparing the orientation of the vehicle to a preset tilt limit to determine whether the vehicle is in the tilt condition. 
         [0018]    In an embodiment, the method has the step of accumulating the first coordinates and the second coordinates prior to calculating the orientation of the vehicle. 
         [0019]    In an embodiment, the orientation is sensed in three dimensions. 
         [0020]    In an embodiment, the method has the step of generating a signal of the tilt condition of the vehicle. 
         [0021]    In an embodiment, the method has the step of comparing the tilt angle to a preset value and generating a signal if the a tilt angle exceeds the preset value. 
         [0022]    In an embodiment, the method has the step of providing a panel for communicating information associated with the tilt of the vehicle to the operator of the vehicle. 
         [0023]    In an embodiment, the method has the step of providing a communications module having at least one of an audible indication or a visual indication to an operator of the vehicle. 
         [0024]    In an embodiment, the method has the step of disabling a power take-off connected to the vehicle in response to a tilt condition which exceeds the preset tilt limit. 
         [0025]    In an embodiment, the method has the step of storing information associated with the tilt condition of the vehicle. 
         [0026]    In another embodiment, a system for sensing tilt of a vehicle is provided. The system may have an accelerometer configured to sense a first tilt angle and a second tilt angle relative to a horizontal reference plane and to generate a first tilt output and a second tilt output. A gyroscope may be configured to sense the first tilt angle and the second tilt angle and to generate a third tilt output and a fourth tilt output. A controller may be configured to receive the first tilt output and the second tilt output from the accelerometer and the third tilt output and the fourth tilt output from the gyroscope wherein the controller determines a tilt angle of the vehicle based on the first tilt output, the second tilt output, the third tilt output and the fourth tilt output. 
         [0027]    In an embodiment, a communications module may be configured to provide an indication associated with the tilt angle of the vehicle to an operator of the vehicle. 
         [0028]    In an embodiment, the system may have a multimedia panel for presenting information associated with the tilt of the vehicle to the operator of the vehicle. 
         [0029]    In an embodiment, the system may have a wiring harness having an electrical interface connecting the controller, the accelerometer and the gyroscope. 
         [0030]    In an embodiment, the system may have a relay connected to the controller wherein the relay disables a power take-off connected to the vehicle in response to a tilt angle which exceeds a preset tilt limit. 
         [0031]    It is, therefore, an advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide an indication of tilt for a variety of vehicles. 
         [0032]    Another advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide a warning to an operator of a vehicle in the event of an imminent tilt condition. 
         [0033]    A further advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide a visual indicator for an operator. 
         [0034]    Yet another advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide an audible indicator for an operator. 
         [0035]    An advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may disconnect a PTO from the vehicle and an implement in a tilt condition of the vehicle. 
         [0036]    Still another advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may disconnect a PTO from the vehicle and the implement upon disconnection of a wiring harness. 
         [0037]    A further advantage is to provide a tilt sensing apparatus, a system and/or a method that may be capable of distinguishing between tilt of the vehicle and vibrations and/or other minor disturbances. 
         [0038]    Another advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide a three-axis accelerometer to detect tilt of a vehicle. 
         [0039]    A further advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide a three-axis gyroscope to detect tilt of a vehicle. 
         [0040]    Yet another advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide a communications module for communicating information to an operator. 
         [0041]    A further advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide an instrument panel, GPS, data recorders, data retention and/or storage and/or the like. 
         [0042]    A further advantage is to provide a tilt sensing apparatus, a system and/or a method that may be capable of distinguishing between tilt of a lawnmower and an approximately zero radius turn of the lawnmower. 
         [0043]    Yet another advantage of the present invention is to provide a tilt sensing apparatus, a system and/or a method that may provide an accelerometer to provide initial startup data and a gyroscope to provide primary tilt data during operation. 
         [0044]    Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the presently preferred embodiments and from the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0045]      FIG. 1A  is a side elevation view of a diagram of a vehicle with a tilt sensing system in an embodiment of the present invention. 
           [0046]      FIG. 1B  is a view taken along lines  1 B- 1 B in  FIG. 1A . 
           [0047]      FIG. 1C  is a view taken along lines  1 C- 1 C in  FIG. 1A . 
           [0048]      FIG. 2  is a perspective view of a lawnmower with the tilt sensing system in an embodiment of the present invention. 
           [0049]      FIG. 3  is a schematic diagram of the tilt sensing system illustrating electrical connections in an embodiment of the present invention. 
           [0050]      FIG. 4  is a schematic diagram of the tilt sensing system illustrating wiring harness connections in an embodiment of the present invention. 
           [0051]      FIG. 5  is a flowchart illustrating accumulator operations in a system and a method for detecting tilt in an embodiment of the present invention. 
           [0052]      FIG. 6  is a flowchart illustrating a main processing loop of a method for detecting tilt in an embodiment of the present invention. 
           [0053]      FIG. 7  is a flowchart illustrating wiring harness operations in a system and a method for detecting tilt in an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0054]    The present invention generally relates to a tilt sensor. More specifically, the present invention relates to a tilt sensing apparatus, a system and a method for using same to provide an indication of tilt for a variety of vehicles. In particular, the vehicle may be a lawnmower. 
         [0055]    To this end, in an embodiment, an apparatus for sensing tilt of a vehicle is provided. The apparatus may have an accelerometer mounted to the vehicle wherein the vehicle has a first axis and a second axis oriented at an angle with respect to the first axis. The accelerometer senses a first tilt angle defined between the first axis and a horizontal reference plane and generates first data associated with the first tilt angle. Further, the accelerometer senses a second tilt angle defined between the second axis and the horizontal reference plane and generates second data associated with the second tilt angle. A gyroscope is mounted to the vehicle. The gyroscope senses the first tilt angle and generates third data associated with the first tilt angle. Further, the gyroscope senses the second tilt angle and generates fourth data associated with the second tilt angle. A processor may be connected to the accelerometer and the gyroscope. The processor determines a tilt angle of the vehicle based on the first data and the second data from the accelerometer and the third data and the fourth data from the gyroscope. 
         [0056]    In another embodiment of the invention, a method of determining a tilt condition of a vehicle is provided. The method has the steps of sensing an orientation of the vehicle using an accelerometer to provide first coordinates; sensing a three-dimensional orientation of the vehicle using a gyroscope to provide second coordinates; calculating the orientation of the vehicle based upon the first coordinates and the second coordinates; and comparing the orientation of the vehicle to a preset tilt limit to determine whether the vehicle is in the tilt condition. 
         [0057]    Referring now to the drawings wherein like numerals refer to like parts,  FIGS. 1A-1C  illustrate a schematic diagram of a vehicle  10 . The vehicle  10  may have a tilt sensing apparatus  12 . The tilt sensing apparatus  12  may have a tilt sensing device  14 . The tilt sensing device  14  is configured to sense a tilt in a first sensing axis  16  and a tilt in a second sensing axis  18 . As described in more detail below, by sensing the tilt angles of the two sensing axes  16 ,  18 , the tilt sensing device  14  may determine a maximum tilt angle of the vehicle  10 . 
         [0058]    The vehicle  10  illustrated in  FIGS. 1A-1C  is generic since the tilt sensing apparatus  12  may be implemented on a wide variety of different types of vehicles. The vehicle illustrated by  FIGS. 1A-1C  includes wheels  20  and a frame or body  22 . As shown, the vehicle  10  may have imaginary axes of tilt or rotation. For example, a side-to-side vehicle axis  30  and a front-to-back vehicle axis  32  are shown in  FIGS. 1A-1C . 
         [0059]    As shown in  FIG. 2 , the vehicle  10  may be a lawnmower  50 . The position of the vehicle  10  or the lawnmower  50  on a slope  40  may define a tilt angle θ of the vehicle  10  or the lawnmower  50  with respect to a horizontal reference plane  42 . The tilt angle θ is approximately zero degrees with the vehicle  10  or lawnmower  50  on a flat, level, horizontal surface. The tilt angle θ may increase with the vehicle  10  or the lawnmower  50  operating on an incline or traversing uneven terrain. The tilt angle θ may be calculated by sensing the tilt relative to the horizontal reference plane  42  or a vertical reference line  44 . 
         [0060]    The tilt sensing apparatus  12  may be particularly useful on vehicles  10  that have powered implements for performing a variety of different operations. Such vehicles  10  may have a PTO  11 . The PTO  11  may be used to provide power to an implement or separate machine. The PTO  11  may allow implements to use power from the vehicle  10 . Vehicles  10  with powered implements may benefit from the tilt sensing apparatus  12  to prevent accidental separation of the PTO  11  on the vehicle  10  from the implement. For example, excessive tilt on the vehicle  10  may cause the PTO  11  to disconnect from the implement. The tilt sensing apparatus  12  may be used on any vehicle  10  that is self-propelled and that an operator may ride upon. The tilt sensing apparatus  12  may be beneficial for such vehicles  10  that do not include an enclosed cabin for the operator to protect the operator from harm and/or injury in the event of a rollover of the vehicle  10 . 
         [0061]    In an exemplary vehicle illustrated in  FIG. 2 , the vehicle may be the lawnmower  50  with a tilt sensing apparatus  12 . The lawnmower  50  may also have a PTO  11 . The lawnmower  50  may be of a type referred to as a “zero radius” lawnmower. For example, such lawnmowers may have front caster wheels  55  attached at the front of the lawnmower  50 . The front caster wheels  55  may swivel to enable zero radius turning of the lawnmower  50 . 
         [0062]    Typically, the lawnmower  50  may have a frame  60 . The front caster wheels  55  may be connected at the front of the frame  60 . Rear wheels  65  may be connected at the rear of the frame  60 . Typically, the rear wheels  65  may be the drive wheels which propel the lawnmower  50  in a forward direction and/or in a reverse direction. The drive wheels  65  may be independently controlled and/or operated. Further, the rear wheels  65  may be driven by an engine  70 . A mower deck  75  may be suspended from the frame  60 . A cutting blade  80  may be connected and/or arranged under the mower deck  75  and may be driven by the engine  70 . A seat  85  for the operator may be supported by the frame  55 . 
         [0063]    In an embodiment, a display panel  100  may be provided. The display panel  100  may be located for use by the operator. For example, the display panel  100  may be located in front of the seat  85  as shown in  FIG. 2 . However, the display panel  100  may be located in other locations on the lawnmower  50 , such as, for example, on either side of the seat  85 . The display panel  100  may provide information to the operator related to the position and/or tilt of the lawnmower  50 . The display panel  100  may also have an instrument panel, GPS, data recorders, data retention and/or storage and/or the like. In an embodiment, the display panel  100  may be mounted to a gimbal on the floor of the vehicle  10  and/or on the dashboard of the vehicle. 
         [0064]    In an embodiment, the tilt sensing device  14  may have an accelerometer  110  and/or a gyroscope  111 . As shown in  FIG. 2 , the accelerometer  110  and/or the gyroscope  111  may be located on an engine cover  115 . However, the accelerometer  110  and/or the gyroscope  111  may be located in other positions on the lawnmower  50 . The accelerometer  110  may provide initial startup data and the gyroscope  111  may provide primary tilt data during operation of a system  200  and/or a method of the present invention. For example, the accelerometer  110  may be used in the initial calibration of the system  200 . 
         [0065]      FIG. 3  is a schematic diagram of the tilt sensing apparatus  12  of the system  200 . In particular,  FIG. 3  illustrates electrical connections and data flows in an embodiment of the present invention. The tilt sensing apparatus  12  may have a first microcontroller  210 . The first microcontroller  210  may be mounted to a printed circuit board (not shown) and may receive power from a power supply  215 . The power supply  215  may be connected to a voltage source  220 . The voltage source  220  may be a twelve volt source, for example. A protection circuit  225  may be provided between the voltage source  220  and the power supply  215 . The protection circuit  225  may have voltage regulation and or voltage conditioning to prevent damage to the power supply  215  and/or the first microcontroller  210 . 
         [0066]    In an embodiment, the first microcontroller  210  may be connected to the accelerometer  110  via a small peripheral interface (“SPI”)  230 . The SPI  230  may be a serial connection. The SPI  230  may be bi-directional as shown in  FIG. 3 . The first microcontroller  210  may also be connected to the gyroscope  111  via a small peripheral interface (“SPI”)  230 . An interrupt  235  may be provided between the accelerometer  110  and the first microcontroller  210 . Another interrupt  240  may be provided between the gyroscope  111  and the first microcontroller  210 . The interrupts  235 ,  240  may have a smart sensor that may allow an operator to set degree settings for tilt of the tilt sensing apparatus  12 . Operations of the SPI  230  and/or the interrupts  235 ,  240  may be further described hereafter with reference to the method of the present invention. 
         [0067]    As shown in  FIG. 3 , the accelerometer  110  may be a three-axis accelerometer. Also, the gyroscope  111  may be a three-axis gyroscope. The three-axis accelerometer  110  may correspond to orthogonal axes X, Y, and Z. The three-axis gyroscope  111  may correspond to orthogonal axes X, Y, and Z. 
         [0068]    The accelerometer  110  and/or the gyroscope  111  may be used as tilt sensors of the tilt sensing device  14 . The X-axis may correspond to the first sensing axis  16  and sense a first tilt angle. Similarly, the Y-axis may correspond to the second sensing axis  18  and sense a second tilt angle. The Z-axis may correspond to a third sensing axis, positioned orthogonally to both the X-axis and Y-axis, generally pointing up with the vehicle  10  positioned on the horizontal reference plane  32  and sensing the tilt angle relative to the vertical reference line  44 . The tilt sensing device  14  may generate a first tilt signal corresponding to the first tilt angle (X-axis), a second tilt signal corresponding to the second tilt angle (Y-axis), and a third tilt signal corresponding to the tilt relative to the vertical reference line  44  (Z-axis). 
         [0069]    The tilt sensing apparatus  12  of the system  200  may have a communications module  250  connected to the first microcontroller  210 . The communications module  250  may have multiple features, functions and/or capabilities. For example, the communications module  250  may be connected to the display panel  100 . The communications module  250  may have an instrument panel, GPS, data retention and/or storage, data recorders and/or the like. The communications module  250  may also have visual and/or audible indicators, for example. The visual and/or audible indicators may be provided on the display panel  100 . 
         [0070]    Further, the tilt sensing apparatus  12  of the system  200  may have a single wire serial interface. The tilt sensing apparatus  12  may also have data recording. A count accumulator may record each time a set angle may be obtained and/or surpassed, such as, a tilt condition of fifteen degrees or greater may be obtained or surpassed, for example. A thirty second data recorder may record up to a set angle. Angle magnitudes and turn degrees may be recorded. For example, in a tilt condition in which a forty-five degree tilt may be obtained and/or surpassed, all angles within the thirty second time period leading up to the forty-five degree angle condition may be recorded, along with rotations performed perpendicular to the ground, for example, the Z axis. 
         [0071]      FIG. 4  is a schematic diagram of the system  200  for sensing tilt illustrating wiring harness connections in an embodiment of the present invention. A second microcontroller  260  may be mounted to the printed circuit board (not shown) and may receive power from the power supply  215 . The power supply  215  may be connected to the voltage source  220 . The voltage source  220  may be a twelve volt source, for example. The protection circuit  225  may be provided between the voltage source  220  and the power supply  215 . The protection circuit  225  may have voltage regulation and or voltage conditioning to prevent damage to the power supply  215  and/or the second microcontroller  260 . 
         [0072]    The second microcontroller  260  may be connected to the communications module  250  via a bi-directional connection  262 . In an embodiment, the bi-directional connection  262  may be a four-wire serial connection, for example. Pin  1  may have one wire serial data. Pin  2  may have +12V. Pin  3  may have the control signal. Pin  4  may be a ground. The wiring harness  266  may have an input. The input may be a control signal from tilt sensing apparatus  12 . 
         [0073]    The second microcontroller  260  may be connected to accessories, such as, a buzzer  265 , a light  270  and/or a relay  275 , for example. The buzzer  265  may provide an audible indication to the operator in response to certain tilt conditions of the lawnmower  50 . The light  270  may provide a visual warning to the operator in response to certain tilt conditions of the lawnmower  50 . The light  265  may be an LED or other light indicator. In an embodiment, the buzzer  265  and the light  270  may operate together to provide audible and visual indications and/or warnings to the operator of the lawnmower  50  and/or the vehicle  10 . For example, at a tilt condition of approximately fifteen degrees, the buzzer  265  may produce an audible sound at a first frequency and the light  270  may produce a light that may flash in unison with the audible sound at the same frequency. At a tilt condition of approximately forty-five degrees, the buzzer  265  may produce an audible sound at a second frequency and the light  270  may produce a light that may flash in unison with the audible sound at the second frequency. The second frequency may be greater than the first frequency. The greater frequency may indicate a greater tilt of the lawnmower  50 . Thus, the operator may recognize and/or may distinguish the tilt condition of approximately fifteen degrees from the tilt condition of approximately forty-five degrees by the difference in frequency of the sound of the buzzer  265  and the rate of flashing of the light  270 . 
         [0074]    Further, at a tilt condition of approximately forty-five degrees, the relay  275  may shut off the PTO  11 . The tilt sensing apparatus  12  of the system  200  may provide a wiring harness control signal to trigger attached accessories, such as, the buzzer  265 , the light  270  and/or the relay  275 . 
         [0075]    For example, the first microcontroller  210  may produce a tone that may be provided to the communications module  250  via a control cable  264  of a wiring harness  266 . The first microcontroller  210  may produce a tone having a frequency of approximately 1,000 Hertz, for example. The 1,000 Hertz tone may be provided to the communications module  250  to indicate a satisfactory condition for the system  200 . For example, the lawnmower  50  may be relatively level and not in a tilt condition. The first microcontroller  210  may also produce a tone having a frequency of approximately 500 Hertz, for example. The 500 Hertz tone may indicate that the lawnmower  50  may be in a tilt condition of greater than approximately 15 degrees, for example. The amount of tilt angle may be set to other angles of tilt, as desired. Further, the first microcontroller  210  may produce a tone having a frequency of zero Hertz. The zero Hertz tone may indicate that the lawnmower  50  may be in a tilt condition of greater than approximately 45 degrees, for example. The amount of tilt angle may be set to other angles of tilt, as desired. Further, the communications module  250  may receive no tone from the first microcontroller  210  which may indicate that the wiring harness  266  has been disconnected and/or severed, for example. The PTO  11  may be disabled in a zero Hertz condition indicating a tilt condition of greater than approximately 45 degrees or in a no tone condition indicating a disconnection of the wiring harness  266 . Thus, the first microcontroller  210  may provide a safety feature for the system  200  on the lawnmower  50  by disabling the PTO  11  in such conditions. 
         [0076]      FIG. 5  is a flowchart illustrating accumulator operations  300  in the system  200  and/or the method for detecting tilt in an embodiment of the present invention. For example, upon start up of the system  200 , both the accelerometer  110  having an internal microprocessor (not shown) and the gyroscope  111  having an internal microprocessor (not shown) may begin to respectively trigger and/or send interrupts to the first microprocessor  210  via the interrupt  325  and the interrupt  240  as shown in step  310  of the accumulator operations of the method illustrated in  FIG. 5 . The interrupts may indicate that the accelerometer  110  and/or the gyroscope  111  may have data to send to the first microprocessor  210 . Each of the internal microprocessors in the accelerometer  110  and the gyroscope  111  may send interrupts at a different rate. For example, the accelerometer  110  may send interrupts at a rate of 800 Hertz. The gyroscope  111  may send interrupts at a rate of 760 Hertz. To synchronize the reading of the data from the accelerometer  110  and the gyroscope  111  and to allow collection of the data to proceed at a constant rate during further processing, two accumulator objects, for example, Accumulator A and Accumulator B, may be provided. 
         [0077]    The data may be read from the accelerometer  110  and from the gyroscope  111  into The Accumulator A as shown in step  315 . The Accumulator A may collect data until the Accumulator A may be full as shown in decision step  320  of  FIG. 5 . The Accumulator A may then be marked as full as shown in step  325 . If the Accumulator A may not be full, as shown in the decision step  325 , further data may be read from the accelerometer  110  and from the gyroscope  111  into the Accumulator A. 
         [0078]    The data may be read from the accelerometer  110  and from the gyroscope  111  into the Accumulator B as shown in step  330 . The Accumulator B may collect data until the Accumulator B may be full as shown in decision step  335  of  FIG. 5 . The Accumulator B may be marked as full as shown in step  340 . If the Accumulator B may not be full, as shown in the decision step  335 , further data may be read from the accelerometer  110  and from the gyroscope  111  into the Accumulator B. 
         [0079]    The Accumulator A may collect data for a time period of 100 milliseconds from each of the accelerometer  110  and from the gyroscope  111 , for example. Different collection times may be used. The interrupts  235 ,  240  from the accelerometer  110  and the gyroscope  111 , respectively, may add data to the Accumulator A. The data collection time may pass, and the Accumulator A may have been filled with data from both the accelerometer  110  and the gyroscope  111 . Thus, the Accumulator A may be marked as full and/or ready to use as shown in step  325 . The Accumulator A may be ready for use by a main processing loop shown in  FIG. 6 . 
         [0080]    At this point of the method, the Accumulator B may begin to fill with data as shown in step  330 . Upon completion of the time span of data collection and the Accumulator B may have been filled with data from both the accelerometer  110  and the gyroscope  111 , the Accumulator B may be marked as full and/or ready to use as shown in step  340 . The Accumulator B may also be ready for use by the main processing loop shown in  FIG. 6 . 
         [0081]      FIG. 6  is a flowchart illustrating a main processing loop  400  of the method for detecting tilt in an embodiment of the present invention. Upon start up of the system  200 , the main processing loop  400  may calculate a constant alpha as shown in step  410 . The constant alpha may be used in a complementary filter equation in step  450  of  FIG. 6 . The complementary filter equation may weigh the inputs from both the gyroscope  111  and the accelerometer  110  to filter any jumps in data less than the seconds indicated in a variable entitled FilterLength as shown in step  410 . Next, the system  200  may wait for the first accumulator, the Accumulator A, to trigger as full as shown in step  415  to build initial calibrations and position calculations for the system  200 . In step  420 , a reading of the gyroscope  111  may be used to build a set of constants to indicate an average level of background noise. The average level of background noise may be filtered from all further calculations in the main processing loop  400 . The readings from the accelerometer  110  may then be used to produce the starting pitch and roll of the system  200 . 
         [0082]    The system  200  may perform environmental calibration prior to operation. After the environmental calibration and the initial position may be set, the main processing loop  400  may start to scan whether either the Accumulator A may be full as shown in step  425  or the Accumulator B may be full as shown in step  435 . When the system  200  may detect that the Accumulator A may be full, the system  200  may use the data from the Accumulator A to calculate a new position for the system  200  board as shown in step  430 . When the system  200  may detect that the Accumulator B may be full, the system  200  may begin to use the data from the Accumulator B to calculate a new position for the system  200  as shown in step  440 . 
         [0083]    Readings from the accelerometer  110  may give the average position angle theta θ of the system  200  board in radians across two axes X and Y for the collection time as shown in step  445 . The readings from the gyroscope  111  may give the average change of degrees around three axes, X, Y and Z for the collection time. The readings from the accelerometer  110  may be converted from radians to degrees. The matching X and Y axes data for the gyroscope  111  and the accelerometer  110  may be run through the complementary filter equation as shown in step  450 . 
         [0084]    The complementary filter equation shown in step  450  may operate as a low-pass filter by weighing changes in position in both the accelerometer  110  and gyroscope  111 . The complementary filter equation may rely more upon the gyroscope  111  since the gyroscope  111  may be less affected by noise and/or may have a quicker reaction time than the accelerometer  110 . Also, short bumps in the accelerometer  110  may be filtered. However, depending solely on the gyroscope  111  may produce some drift in the calculations over time. Therefore, the relative long term stability of the accelerometer  110  may be used to control and/or assure the accuracy of the position over the long term. After the complementary filter equation shown in step  450  may be used to produce the new position of both the X and Y axes of the system  200 , the magnitude of both positions may be taken to be used as a current output angle theta θ as shown in step  460  of the system  200 . In an embodiment, the system  200  may have a current angle refresh rate for the current output angle theta θ of approximately 100 milliseconds. The system  200  may have an angle resolution of approximately 0.1 degrees and an angle accuracy of ±0.05 degrees. 
         [0085]    The current output angle theta θ may be tested against a set limit as shown in step  465 . For example, the set limit may be a certain angle which may be preset in the system  200 . The set limit may correspond to a desired tilt sensing trigger for the system  200 . For example, an angle of approximately forty-five degrees may indicate an unsafe tilt condition for the system  200  and/or the lawnmower  50 . However, the set limit may be any angle greater than zero degrees up to an angle of approximately ninety degrees. At least one set limit may be preset at the manufacturer of the system  200 . 
         [0086]    In an embodiment, the set limit may have a first set limit. For example, the first set limit may be approximately fifteen degrees. The first set limit may be labeled Limit 1  in step  465 . The first set limit Limit 1  may correspond to a tilt condition of the system  200  and/or the lawnmower  50  in which the lawnmower  50  may be in a tilt condition of approximately fifteen degrees. 
         [0087]    The set limit may also have a second set limit labeled Limit 2  in step  490 . The second set limit Limit 2  may be an angle of approximately forty-five degrees, for example. The second set limit Limit 2  may correspond to a tilt condition of the system  200  and/or the lawnmower  50  in which the lawnmower  50  may be in a tilt condition of approximately forty-five degrees. 
         [0088]    The current output angle theta θ may be monitored to eliminate false positives. For example, the current output angle theta θ may be compared to the first set limit Limit 1  as shown in step  465 . The current output angle theta θ may less than the first set limit Limit 1 . In this condition, a debounce counter may be set equal to zero as shown in step  470 . 
         [0089]    Alternatively, the current output angle theta θ may exceed the first set limit Limit 1 . For such a value of the current output angle theta θ, the debounce counter may be incremented as shown in step  475 . The debounce counter may be incremented for each pass of the main processing loop  400 . A debounce limit may be set to eliminate false positives. The debounce limit may be set to three, for example. Thus, the current value of the debounce counter may be compared to the debounce limit as shown in step  480 . In the event the debounce counter may exceed the debounce limit, a first event flag SetEvent 1  may be set as shown in step  485 . 
         [0090]    The current output angle theta θ may also be compared to the first set limit Limit 1  as shown in step  490 . The current output angle theta θ may exceed the second set limit Limit 2 . In the event the current output angle theta θ may exceed the second set limit Limit 2 , a second event flag SetEvent 2  may be set as shown in step  495 . 
         [0091]    Thus, the debounce counter may reach the first set limit Limit 1 . As a result, the first event flag SetEvent 1  may be set as shown in step  485 . Further, the current output angle theta θ may exceed the second set limit Limit 2 , and a second event flag SetEvent 2  may be set as shown in step  495 . Up to and at this point in the main processing loop  400 , in the event that the current output angle theta θ may ever fall below the first event limit Limit 1  and/or the second event limit Limit 2 , the debounce counter may be set back to zero and the respective event flag may be cleared. After the first event flag SetEvent 1  may be set, the current output angle theta θ may then be tested against the higher limit of the second set limit Limit 2 . In the event that the second set limit Limit 2  may be exceeded, the second event flag SetEvent 2  may be set as shown in step  495  and may remain so until reboot of the system  200 . 
         [0092]    Another safeguard against false positives at this stage in the main processing loop  400  of the method of the invention may use the Z axis of the gyroscope  111  to test if the system  200  may be in a turn as shown in step  455 . Heavy rotation around the Z axis may cause a centripetal force reading on the gyroscope  111  that may lead to a false positive on the current output angle theta θ. When the safeguard may be triggered, the last current output angle theta θ may be locked until such time as the Z axis change may be reduced down to normal levels. Doing so may filter a zero radius turn, for example. 
         [0093]    After performance of all of the foregoing steps, the main processing loop  400  may return to a waiting state for the next accumulator to trigger full and begin the main processing loop  400  again. 
         [0094]      FIG. 7  is a flowchart illustrating wiring harness operations  500  in the system  200  and the method for detecting tilt in an embodiment of the present invention. In step  510 , the wiring harness  266  may be powered. In step  515 , the system  200  may wait for the tone from the first microcontroller  210  to be sent to the communications module  250 . The tone may be decoded to determine the frequency of the tone as shown in step  520 . 
         [0095]    Also, the system  200  may determine whether Limit 2  may be clear or not in step  520 . Limit 2  may indicate a tilt condition of forty-five degrees. If Limit 2  is not clear, the relay  275  may be turned off and the Limit 2  alarm may be activated as shown in step  545 . If Limit 2  is clear, the output of the relay  275  may be turned on as shown in step  525 . 
         [0096]    Further, the system  200  may determine whether Limit 1  may be clear or not in step  520 . Limit 1  may indicate a tilt condition of fifteen degrees. If Limit 1  is not clear, the Limit 1  alarm may be activated as shown in step  535 . If Limit 1  is clear, the Limit 1  alarm may be cleared as shown in step  540 . 
         [0097]    Other variations and/or geometric configurations which are known to one having ordinary skill in the art are possible and are deemed to be within the scope of this disclosure. The materials used for the components of the tilt sensing apparatus  12  and/or the system  200  may be selected from any suitable material to perform the desired function for operation of the tilt sensing apparatus  12  and/or the system  200 . The materials must also be capable of withstanding environmental conditions that may be encountered. Considerations of performance and/or reliability are also important in the selection of the material. Other materials which are known to one having ordinary skill in the art may be selected and are deemed to be within the scope of this disclosure. The tilt sensing apparatus  12  and/or the system  200  may have additional components which may provide enhanced functionality of the tilt sensing apparatus  12  and/or system  200 . 
         [0098]    Moreover, the present invention is not limited to the specific arrangement of the components of the tilt sensing apparatus  12  and/or the system  200  illustrated in the drawings. It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those having ordinary skill in the art. Such changes and modifications may be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is, therefore, intended that such changes and modifications be covered by the appended claims.