Abstract:
A video game controller for home video game systems is situated between a player&#39;s feet and is used to detect positions outside the footprint of the controller. The controller transmits the position data to the video game system and enables game play. In dance games, the controller detects dance steps when the player dances around the controller. A signal is transmitted from locations at the perimeter of the controller, reflected by the player&#39;s foot, and then received back at the controller. In a preferred embodiment the location is detected as a function of the time the signal is transmitted/received and by the matrix of signals received. Modulation of the transmission and reception minimizes detection of noise and distant reflections and therefore minimizes or eliminates false position detection.

Description:
FIELD OF THE INVENTION 
       [0001]    The present application is generally related to a video game controller, and specifically to one that detects the movement of a player&#39;s feet optically. 
       BACKGROUND OF THE INVENTION 
       [0002]    Video games are an enjoyable diversion and the video game industry enjoys ever increasing sales and penetration. Some time ago, video games that make a player physically dance were developed. In particular, an arcade game console called Dance Dance Revolution is extremely popular in Japanese arcades. Dancing games are now available for home video game systems and are gaining in popularity. 
         [0003]    Some prior controllers for use with dancing games generally involve a large mat that covers the full game play area. A player dances on top of the mat and the mat transmits the user&#39;s position to the game system. These dance mats tend to wear out quickly when used by zealous gamers that frequently and vigorously dance upon them. Furthermore, they are bulky and inconvenient to use and transport. Other prior controllers detect the movement of the player by sensing when an optical or other type of beam is interrupted on a path from a transmitter to a receiver. In these devices, when the beam is not received by the receiver, the player&#39;s position is determined to be in the path from transmitter to receiver. 
         [0004]    There exists a need for a reliable, accurate, and portable game controller for use with dancing and other games that does not deteriorate with regular gaming usage. 
       SUMMARY OF INVENTION 
       [0005]    The present invention comprises a corded or cordless game controller that detects a player&#39;s foot position. It can be used with any game that requires a user to move his feet around from position to position, but is especially useful in dancing related video games. It can be used with any home video gaming system. 
         [0006]    The controller is a small unit that fits in between a player&#39;s feet. The player then dances around it, rather than on it. Although the player may stand on the platform, and in some embodiments, game control buttons are activated from the top of the platform, the dance steps are performed and detected outside of the perimeter of the controller. Unlike in dance pads or mats where the user plays within the footprint of the mat and lands on it repeatedly, the present invention utilizes non-impact position detection, and is therefore more durable as it does not wear out due to repeated impact. Furthermore, it is significantly more compact than those designs. 
         [0007]    The controller of the present invention transmits a beam from a detection unit of the controller, which is reflected off the user or player&#39;s foot back towards the controller. It is then sensed by a receiver of the given detection unit. The use of this reflective technique allows the controller to have a small footprint. Two or more signals that overlap, each sent from different locations and received by the receiver, identify the location of an object (e.g. a foot). A single receiver, or receiving module is used in each detection unit of the preferred embodiment. This is achieved with time division modulation as several beams can be sent and received well within the time a foot is in a given location. The time sent and/or received indicates which beam was reflected and the position of the foot. However, some embodiments may utilize more than one receiver per detection unit. 
         [0008]    In a preferred embodiment a detection unit is located on each of the left, right, top and bottom sides of the controller, for a total of four detection units. Game control buttons that allow a user to navigate and select from menus of the game are located at one or more of the corners of the controller. In other embodiments they may be otherwise distributed. They can be activated from above or from the side, but are preferably activated from the side as it is more convenient for a user during play, and lessens inadvertent strikes that tend to occur with a top activated switch when a user&#39;s foot travels over the top of the controller in the heat of game play. 
         [0009]    In a preferred embodiment, the detection modules will sense an object at the left, right, top and bottom of the controller, but not at the corners. This eliminates inadvertent detection of a move (at or near a corner) when a player&#39;s foot sweeps from one side to another, for instance from a position near the top of the controller to position at the right of the controller. 
         [0010]    In a preferred embodiment, not all pairs of overlapping signals indicate a game location, and therefore, those that do not are ignored. This improves accuracy of the controller by minimizing the detection of unwanted reflections from an object other than a player&#39;s foot or from the player&#39;s foot when it is in a location outside of the area meant to define a position of the controller and the game being played. For example, inadvertent reflections from nearby walls or other objects are not interpreted as steps of the player&#39;s feet. In some embodiments, the optical emitters are directed substantially parallel to the ground while in others they are angled toward the ground such that they hit the ground near the controller. In such an embodiment, a foot can be detected before the beam hits the ground, or by the weakened signal after it has been reflected by the ground, so long as it is reflected back to the controller a short enough distance thereafter that it will have sufficient energy at the detector. Otherwise, in the case of a ground reflected signal reflected far from the controller, it will not have the proper trajectory back to the receiver, or will otherwise have insufficient energy to be deemed a foot position or dance step. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1A  is top view of game controller  100 , an embodiment of the present invention. 
           [0012]      FIG. 1B  is a profile elevation of game controller  100 . 
           [0013]      FIG. 1C  is a diagram illustrating the game play zones  112  surrounding game controller  100 . 
           [0014]      FIG. 1D  is a diagram illustrating activation of foot activated game control switches/buttons  104  in directions  105 . 
           [0015]      FIG. 1E  is an exploded view of game controller  100 . 
           [0016]      FIG. 2A  is an illustration of a position detection unit  120  of game controller  100 , and the footprint of a detection area or game play zone  112 . 
           [0017]      FIG. 2B  is an illustration of the areas defined by the overlap of beams created by position detection unit  120 . 
           [0018]      FIG. 2C  is reproduction of Table 1, a table of the areas defined by the overlap of the beams shown in  FIG. 2B . 
           [0019]      FIG. 3  is an illustration of reflection from an object inside a predefined detection area. 
           [0020]      FIG. 4  is an illustration of reflection from objects outside the predefined detection areas. 
           [0021]      FIG. 5  is an illustration of a reflection from a nearby object  150  outside of the game play zones  112  shown in  FIG. 1C . 
           [0022]      FIG. 6  is a side view elevation of position detection unit  120  illustrating the path of signals emitted and received by the unit, relative to the ground and bottom of game controller  100 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]      FIG. 1A  is a top view of game controller  100 , an embodiment of the present invention. A game player can stand on controller  100  and steps around the platform of controller  100  to play the game. For example, if the game instructs the player to step to the player&#39;s right the player will then step on the ground to the right side of controller  100 . Likewise, the position of the player&#39;s feet will be detected relative to controller  100  for actions required in front, back or to the left of the player&#39;s relative position. Arrows  110  A, B, C, and D serve to indicate to a user that the controller is sensitive to positions at the front side, right side, back side, and left side respectively. In some embodiments the arrows may be of translucent material and will illuminate in sync with the user&#39;s detected movements. 
         [0024]    Game control buttons or switches  104  A, B, C, and D are located at the corners of the controller  100 . The preferred embodiment of controller  100  is substantially rectangular as shown, with the corner clipped or rounded. Other embodiments may have other shapes. The game control buttons may in certain embodiments be activated from the top of the controller platform, or, as illustrated, may be activated with a motion and in a direction parallel to the ground. This way, a user can touch the switch with either his toe or heel from around the perimeter of the controller. For example, a user may choose to back her heel into button  104 A, while it may be more convenient for a user to kick or touch button  104 B with the front of her foot. 
         [0025]      FIG. 1B  is a profile elevation of game controller  100  seen in  FIG. 1B . Controller  106  comprises a housing with a top plate  106  and a base plate  108 . The electronic components (not shown) are generally between top plate  106  and base plate  108 . Controller  100  preferably communicates wirelessly to a video game system, although corded communication is provided in certain embodiments. Logic of the controller is accomplished either with a microprocessor or other logic circuitry. Wireless communication is preferably according to the well known Bluetooth radio specification 2.0, although any RF transmission spectrum and protocol can be utilized. The controller also preferably interfaces as a human interface device regardless of the transmission frequency and protocol. Base plate  108  rests upon the floor during game play or otherwise. 
         [0026]      FIG. 1C  is a diagram illustrating the game play zones  112  surrounding game controller  100 . In the preferred embodiments, game play is detected at the front, right, back and left sides of the controller  100 , as represented by zones  112 A,  112 B,  112 C, and  112 D respectively. As seen by the axes, the front of the controller may also be thought of as the north side, or the zero degree point of the axes. For simplicity the zones are depicted in  FIG. 1C  as rectangular, although in reality the geometry of the zones is more complex, as will be described later. Many different positions can be determined within each of the zones. In the preferred embodiment, a user&#39;s position will not be detected in areas  114 , adjacent to the corners of the controller. In games that do not require position detection location in those areas, this reduces false detection as the user&#39;s feet pass though the areas  114 . In other embodiments, position may be detected all around the controller, including locations at or near the corners. 
         [0027]      FIG. 1D  is a diagram illustrating activation of foot activated game control switches or buttons  104  in directions  105 . Button  104 A may be activated by a stroke in direction  105 A. Direction  105 A a can be anywhere from 0 to 90 degrees but is preferably between 30 and 60 degrees. Likewise, button  104 B may be activated by a stroke in direction  105 B, which can be anywhere from 90 to 180 degrees, but is preferably between 120 and 150 degrees, button  104 C may be activated by a stroke in direction  105 C, which can be anywhere from 180 to 270 degrees, but is preferably between 210 and 240 degrees, and button  104 D may be activated by a stroke in direction  105 D, which can be anywhere from 270 to 360 degrees but is preferably between 300 and 330 degrees. 
         [0028]      FIG. 1E  is an exploded view of game controller  100 . In addition to the components previously described, position detection units  120 A,  120 B,  120 C, and  120 D can be seen. These serve to detect the position of the user&#39;s feet around the game controller. Of course, greater or fewer position detection units may be utilized depending on the embodiment and geometry of controller  100 . 
         [0029]      FIG. 2A  is an illustration of a position detection unit  120  ( 120 A, B, C, or D) of game controller  100 , and the footprint of game play zone  112 , where the position of a user&#39;s foot will be detected. Each position detection unit  120  comprises two optical illumination modules  122  and  126 . Each optical illumination module comprises a group of 2 or more of illumination chambers. Module  122  comprises illumination chambers  124 A,  124 B, and  124 C. Module  126  comprises chambers  124 D,  124 E, and  124 F. Each illumination chamber  124  comprises a source or emitter, which is preferably an IR emitting LED, and other optical components such as lenses and optical guides to shape and direct the IR light emitted by the LED. Position detection unit  120  also comprises optical receiver  128 . 
         [0030]      FIG. 2B  is an illustration of the areas defined by the overlap of beams created by position detection unit  120 . Each of the illumination chambers  124  produces a beam. The beams are positioned such that pairs of beams overlap in a given area. These are shown as position detection areas  131 - 136 . Each pair is comprised of a beam from a chamber of module  122  and a beam from a chamber of module  126 . When a signal transmitted from each chamber of the pair is sensed as having been reflected by an object, the position of the object is within the corresponding position detection area. The pairs used for each detection area are as shown in Table 1 below, which is also reproduced as  FIG. 2C . 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Module 
                 Module 
                 Position 
               
               
                 122 
                 126 
                 detection area 
               
               
                   
               
             
             
               
                 124A 
                 124F 
                 131 
               
               
                 124C 
                 124D 
                 132 
               
               
                 124C 
                 124F 
                 133 
               
               
                 124B 
                 124F 
                 134 
               
               
                 124C 
                 124E 
                 135 
               
               
                 124B 
                 124E 
                 136 
               
               
                   
               
             
          
         
       
     
         [0031]    The detection signals from the different chambers are distributed in time. Only one chamber emits the detection signal during a given period or moment of time. Each position detection signal comprises a plurality of bursts, preferably 4 or 5, and each burst in turn comprises a plurality of pulses, preferably between 15-25 pulses. The emitted signal preferably comprises IR light of approximately 880 nm wavelength, and the frequency of the pulses is approximately 455 kHz. The period between bursts is approximately 150 us. 
         [0032]    If receiver  128  receives a signal with an energy level above a minimum threshold, it provides an output signal to the processing circuitry of the controller. In one preferred embodiment, the output signal comprises pulses of output voltage. In such a case, the receiver provides one pulse per burst of received light. This modulation filters out ambient noise such as sun light, light from nearby lamps, and from IR remote controls, that may otherwise contain sufficient energy to be interpreted as position data. 
         [0033]    In the games with the fastest action or changing of foot positions, the minimum time a foot may be in a given position is about 120 milliseconds, although in the vast majority of situations a foot will be present in a given position for much longer. With the preferred embodiment, a foot can be detected within about 16 milliseconds. That is to say that position detection unit  120  can sequence though one cycle where all the illumination chambers of a given detection unit emit a signal in about 16 milliseconds. In certain embodiments the cycle can be repeated to increase accuracy. For example, if four cycles are performed, this will require about 60-65 milliseconds. This means that about 7 or 8 cycles could be performed within the minimum detection window. All position detection units  120  may cycle simultaneously, or may alternatively be sequenced to cycle at different times. 
         [0034]      FIG. 3  is an illustration of reflection from an object inside a predefined detection area. Object  140  can be seen within area  131 . As seen in Table 1, this means that a signal emitted from chambers  124 A and  124 F has been reflected to and received by receiver  128 . Signal  144  is emitted by chamber  124 A, and the directly emitted portion is shown as  144 D, while the portion reflected from object  140  is shown as  144 R. Likewise, signal  142  is emitted by chamber  124 F, and the directly emitted portion is shown as  142 D, while the portion reflected from object  144  is shown as  142 R. Receiver  128  has a field of view sufficient to receive signals from any of the predefined position detection areas. 
         [0035]      FIG. 4  is an illustration of reflection from objects outside the predefined detection areas. In this figure, two different objects  146  and  148  are located outside of the predefined areas. Object  146  reflects a signal  145  from chamber  124 F, but not from any other chamber. It is therefore not indicative of a user position. Object  148  reflects signals  147  and  149  from chambers  124 B and  124 D. However, since this pair of signals does not correlate with a desired detection area, it does not indicate a user position. Again, as mentioned previously, this selectivity and rejection aids in eliminating erroneous position detection. 
         [0036]      FIG. 5  is an illustration of a reflection from a nearby object  150  outside of the game play zones  112  shown in  FIG. 1C . The field of view of the various chambers and the resulting detection areas is potentially vulnerable to unwanted detection of “ghost” objects that are not actually within one of the detection areas, as touched upon earlier. In some cases, the surrounding obstacles could simulate or “ghost” an object in a position detection area due to reflections from paired chambers. In  FIG. 5 , the wall or other distant object  150  would indicate a ghost object  149  in area  132 . In the aforementioned embodiments, the emitted beams are transmitted in a direction substantially parallel to the ground. 
         [0037]    One solution employed in other embodiments in order to minimize unwanted reflections involves angling the beams from illumination chambers  124  towards the ground, as seen in  FIG. 6 .  FIG. 6  is a side view elevation of position detection unit  120  illustrating the path of signals emitted and received by the unit, relative to the ground and bottom of game controller  100 . The furthest distance for game play is significantly less than the nearest recommended distance from potential obstacles. For example, a player&#39;s feet may be detected within about 3 feet, and the player will be instructed to keep objects approximately 4-6 feet away from controller  100 . Theses distances can of course vary, as can the strength of the LED&#39;s and the minimum energy levels at the receiver used to indicate a detected position, all of which factor into the size and geometry of the game play zones and detection areas, and the minimum distance in relation to obstacles. 
         [0038]    In  FIG. 6 , beam  152 , created by one of chambers  124 , is shown as having a direct component  152 D and a component reflected from the floor,  152 F. Angling the beam  152  reduces the chance that it will be reflected from a nearby obstacle. A reflection of either the direct component  152 D or the reflected component  152 F may be sensed by receiver  128  when it is within the field of view  160  of receiver  128 , if it has sufficient energy and the proper trajectory. The component reflected from the floor will in most circumstances be of a diffused nature and will have significantly less energy than the direct component. Thus, any subsequent reflection from a foot or any other object will have much less energy than a reflection of direct component  152 D and it is preferable that reflections from reflected component  152 F not be used for position data. This is accomplished by selecting the strength and trajectory of the LED&#39;s and the minimum energy levels at the receiver such that the reflections of component  152 F will not indicate position data. Such an embodiment is effective at limiting unwanted detection of obstacles and ghosting. 
         [0039]    While the preferred embodiments have been described with regard to dancing games, many different types of games can be played with a controller according to the present invention. Although the various aspects of the present invention have been described with respect to exemplary embodiments thereof, it will be understood that the present invention is entitled to protection within the full scope of the appended claims.