Abstract:
A user interface for a vehicle, including a steering wheel for the vehicle, including a grip, a sensor operable to detect objects at a plurality of locations along the grip, and an illuminator operable to illuminate different portions of the grip, a processor in communication with the sensor, with the illuminator and with a controller of vehicle functions, and a non-transitory computer readable medium storing instructions which cause the processor: to identify, via the sensor, a location of a first object along the grip, to illuminate, via the illuminator, a portion of the grip, adjacent to the identified location, to further identify, via the sensor, a second object being at the illuminated portion of the grip, and to activate, via the controller, a vehicle function in response to the second object identified as being at the illuminated portion of the grip.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 14/551,096, entitled LIGHT-BASED CONTROLS IN A TOROIDAL STEERING WHEEL and filed on Nov. 24, 2014, by inventors Gunnar Martin Fröjdh, Simon Fellin, Thomas Eriksson, John Karlsson, Maria Hedin and Richard Berglind, the contents of which are hereby incorporated herein in their entirety. 
         [0002]    This application is also a continuation-in-part of U.S. application Ser. No. 14/555,731, entitled DOOR HANDLE WITH OPTICAL PROXIMITY SENSORS and filed on Nov. 28, 2014, by inventors Sairam Iyer, Stefan Holmgren and Per Rosengren, the contents of which are hereby incorporated herein in their entirety. 
         [0003]    U.S. application Ser. No. 14/551,096 is a continuation of U.S. application Ser. No. 14/312,711, now U.S. Pat. No. 8,918,252, entitled LIGHT-BASED TOUCH CONTOLS ON A STEERING WHEEL and filed on Jun. 24, 2014 by inventors Gunnar Martin Fröjdh, Simon Fellin, Thomas Eriksson, John Karlsson, Maria Hedin and Richard Berglind, the contents of which are hereby incorporated herein in their entirety. 
         [0004]    U.S. application Ser. No. 14/312,711 is a continuation of U.S. application Ser. No. 14/088,458, now U.S. Pat. No. 8,775,023, entitled LIGHT-BASED TOUCH CONTOLS ON A STEERING WHEEL AND DASHBOARD and filed on Nov. 25, 2013 by inventors Gunnar Martin Fröjdh, Simon Fellin, Thomas Eriksson, John Karlsson, Maria Hedin and Richard Berglind, the contents of which are hereby incorporated herein in their entirety. 
         [0005]    U.S. application Ser. No. 14/088,458 is a non-provisional of U.S. Provisional Application No. 61/730,139 entitled LIGHT-BASED TOUCH CONTOLS ON A STEERING WHEEL AND DASHBOARD and filed on Nov. 27, 2012 by inventors Gunnar Martin Fröjdh, Thomas Eriksson, John Karlsson, Maria Hedin and Richard Berglind, the contents of which are hereby incorporated herein in their entirety. 
         [0006]    U.S. application Ser. No. 14/555,731 is a continuation-in-part of U.S. application Ser. No. 14/312,787 entitled OPTICAL PROXIMITY SENSORS and filed on Jun. 24, 2014 by inventors Stefan Holmgren, Sairam Iyer, Richard Berglind, Karl Erik Patrik Nordström, Lars Sparf, Per Rosengren, Erik Rosengren, John Karlsson, Thomas Eriksson, Alexander Jubner, Remo Behdasht, Simon Fellin, Robin Åman and Joseph Shain, the contents of which are hereby incorporated herein in their entirety. 
         [0007]    U.S. application Ser. No. 14/555,731 is a continuation-in-part of U.S. application Ser. No. 14/311,366 entitled OPTICAL TOUCH SCREENS and filed on Jun. 23, 2014 by inventors Robert Pettersson, Per Rosengren, Erik Rosengren, Stefan Holmgren, Lars Sparf, Richard Berglind, Thomas Eriksson, Karl Erik Patrik Nordström, Gunnar Martin Fröjdh, Xiatao Wang and Remo Behdasht, the contents of which are hereby incorporated herein in their entirety. 
         [0008]    U.S. application Ser. No. 14/555,731 is a continuation-in-part of U.S. application Ser. No. 14/140,635 entitled LIGHT-BASED PROXIMITY DETECTION SYSTEM AND USER INTERFACE and filed on Dec. 26, 2013 by inventors Thomas Eriksson and Stefan Holmgren, the contents of which are hereby incorporated herein in their entirety. 
         [0009]    U.S. application Ser. No. 14/312,787 is a continuation of International Application No. PCT/US14/40112 entitled OPTICAL PROXIMITY SENSORS and filed on May 30, 2014 by inventors Stefan Holmgren, Sairam Iyer, Richard Berglind, Karl Erik Patrik Nordström, Lars Sparf, Per Rosengren, Erik Rosengren, John Karlsson, Thomas Eriksson, Alexander Jubner, Remo Behdasht, Simon Fellin, Robin Åman and Joseph Shain, the contents of which are hereby incorporated herein in their entirety. 
         [0010]    International Application No. PCT/US14/40112 is claims priority benefit of U.S. Provisional Application No. 61/828,713 entitled OPTICAL TOUCH SCREEN SYSTEMS USING REFLECTED LIGHT and filed on May 30, 2013 by inventors Per Rosengren, Lars Sparf, Erik Rosengren and Thomas Eriksson; of U.S. Provisional Application No. 61/838,296 entitled OPTICAL GAME ACCESSORIES USING REFLECTED LIGHT and filed on Jun. 23, 2013 by inventors Per Rosengren, Lars Sparf, Erik Rosengren, Thomas Eriksson, Joseph Shain, Stefan Holmgren, John Karlsson and Remo Behdasht; of U.S. Provisional Application No. 61/846,089 entitled PROXIMITY SENSOR FOR LAPTOP COMPUTER AND ASSOCIATED USER INTERFACE and filed on Jul. 15, 2013 by inventors Richard Berglind, Thomas Eriksson, Simon Fellin, Per Rosengren, Lars Sparf, Erik Rosengren, Joseph Shain, Stefan Holmgren, John Karlsson and Remo Behdasht; of U.S. Provisional Application No. 61/929,992 entitled CLOUD GAMING USER INTERFACE filed on Jan. 22, 2014 by inventors Thomas Eriksson, Stefan Holmgren, John Karlsson, Remo Behdasht, Erik Rosengren, Lars Sparf and Alexander Jubner; of U.S. Provisional Application No. 61/972,435 entitled OPTICAL TOUCH SCREEN SYSTEMS and filed on Mar. 31, 2014 by inventors Sairam Iyer, Karl Erik Patrik Nordström, Lars Sparf, Per Rosengren, Erik Rosengren, Thomas Eriksson, Alexander Jubner and Joseph Shain; and of U.S. Provisional Application No. 61/986,341 entitled OPTICAL TOUCH SCREEN SYSTEMS and filed on Apr. 30, 2014 by inventors Sairam Iyer, Karl Erik Patrik Nordström, Lars Sparf, Per Rosengren, Erik Rosengren, Thomas Eriksson, Alexander Jubner and Joseph Shain, the contents of which are hereby incorporated herein in their entirety. 
         [0011]    U.S. application Ser. No. 14/311,366 is a continuation of International Application No. PCT/US14/40579 entitled OPTICAL TOUCH SCREENS and filed on Jun. 3, 2014 by inventors Robert Pettersson, Per Rosengren, Erik Rosengren, Stefan Holmgren, Lars Sparf, Richard Berglind, Thomas Eriksson, Karl Erik Patrik Nordström, Gunnar Martin Fröjdh, Xiatao Wang and Remo Behdasht, the contents of which are hereby incorporated herein in their entirety. 
         [0012]    International Application No. PCT/US14/40579 claims priority benefit of U.S. Provisional Application No. 61/830,671 entitled MULTI-TOUCH OPTICAL TOUCH SCREENS WITHOUT GHOST POINTS and filed on Jun. 4, 2013 by inventors Erik Rosengren, Robert Pettersson, Lars Sparf and Thomas Eriksson; of U.S. Provisional Application No. 61/833,161 entitled CIRCULAR MULTI-TOUCH OPTICAL TOUCH SCREENS and filed on Jun. 10, 2013 by inventors Richard Berglind, Erik Rosengren, Robert Pettersson, Lars Sparf, Thomas Eriksson, Gunnar Martin Fröjdh and Xiatao Wang; of U.S. Provisional Application No. 61/911,915 entitled CIRCULAR MULTI-TOUCH OPTICAL TOUCH SCREENS and filed on Dec. 4, 2013 by inventors Richard Berglind, Erik Rosengren, Robert Pettersson, Lars Sparf, Thomas Eriksson, Gunnar Martin Fröjdh and Xiatao Wang; of U.S. Provisional Application No. 61/919,759 entitled OPTICAL TOUCH SCREENS WITH TOUCH-SENSITIVE BORDERS and filed on Dec. 22, 2013 by inventors Remo Behdasht, Erik Rosengren, Robert Pettersson, Lars Sparf and Thomas Eriksson; of U.S. Provisional Application No. 61/923,775 entitled MULTI-TOUCH OPTICAL TOUCH SCREENS WITHOUT GHOST POINTS and filed on Jan. 6, 2014 by inventors Per Rosengren, Stefan Holmgren, Erik Rosengren, Robert Pettersson, Lars Sparf and Thomas Eriksson; and of U.S. Provisional Application No. 61/950,868 entitled OPTICAL TOUCH SCREENS and filed on Mar. 11, 2014 by inventors Karl Erik Patrik Nordström, Per Rosengren, Stefan Holmgren, Erik Rosengren, Robert Pettersson, Lars Sparf and Thomas Eriksson, the contents of which are hereby incorporated herein in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0013]    The field of the present invention is steering wheel user interfaces for vehicles. 
       BACKGROUND OF THE INVENTION 
       [0014]    Reference is made to  FIG. 1 , which is a simplified illustration of a prior art steering wheel. A steering wheel  400 , shown in  FIG. 1 , includes a circular gripping member  401 , one or more connecting members  402 - 404  that connect the gripping member  401  to steering column  407 , and buttons  405  and  406  on connecting members  402  and  403  for controlling various devices in the vehicle. Connecting members  402 - 404 , which connect gripping member  401  to steering column  407 , are also referred to as spokes. In  FIG. 1 , button  405  is used to answer an incoming phone call on the vehicle&#39;s BLUETOOTH speaker phone and button  406  hangs up the call. BLUETOOTH is a trademark owned by the Bluetooth SIG of Kirkland, Wash., USA. Controls mounted in a steering wheel can be operated comfortably and safely since the driver is able to control and operate these controls without taking hands off the wheel or eyes off the road. 
         [0015]    Historically, the first button added to a steering wheel was a switch to activate the car&#39;s electric horn. When cruise control systems were introduced, some automakers located the operating switches for this feature on the steering wheel as well. Today additional button controls for an audio system, a telephone and voice control system, a navigation system, a stereo system, and on board computer functions are commonly placed on the steering wheel. 
         [0016]    U.S. Patent Publication No. 2012/0232751 A1 for PRESSURE SENSITIVE STEERING WHEEL CONTROLS describes adding pressure-sensitive controls to the circular gripping member of the steering wheel. Pressure sensors are located at various locations along the perimeter of the gripping member, and different locations correspond to different controls. A control is actuated in response to application of pressure at a sensor location, e.g., by the user tightening his grip. 
         [0017]    Prior art user interfaces associated with steering wheels, such as the buttons and grips discussed hereinabove, associate a function with an absolute position on the steering wheel. This is conceptually analogous to a touch-sensitive screen displaying icons where the user touches the location on the screen at which the icon is located to activate the icon. The concept of absolute positioning for user input goes back even further: each key on a keyboard is positioned at an absolute position within the keyboard. Similarly, early graphical user interfaces using light pens required the user to place the light pen onto a graphic displayed on the screen in order to activate a corresponding function. 
         [0018]    In contrast to these user interfaces based on absolute positioning, the computer mouse introduced a user interface for controlling a cursor based on relative positioning. Namely, the mouse cursor moves on the screen in a direction that the mouse moves from point A to point B, but this movement is not at all contingent on the actual coordinates—the absolute positions—of points A and B. This shift from absolute positioning to relative positioning frees the user from having to look at, or be aware of, the location of the mouse on the table. The user only has to control the direction in which the mouse moves on the table, which he can do without looking at the mouse. One of the objectives of the present invention is to provide a user interface for a driver based on the relative positioning user interface model. 
       SUMMARY 
       [0019]    The present disclosure relates to user interfaces for on board vehicle systems, and teaches a user interface that does not require the user to be aware of the location at which he is touching the steering wheel in order to activate a function. The present disclosure teaches a robust vocabulary of user gestures that can be mapped to a wide variety of applications. The user gestures of the present disclosure are performed with absolute confidence by a user, without the user looking at the surface on which the gestures are performed. In certain embodiments of the invention the gestures are performed on the rim of a steering wheel. The nature of these gestures and the underlying hardware provided for detecting these gestures enables each user interface gesture to be performed by the user without any need for looking at the steering wheel. Furthermore these gestures are entirely independent of how the steering wheel is rotated at the time the gestures are performed. 
         [0020]    There is thus provided in accordance with an embodiment of the present invention a steering wheel that identifies gestures performed on its surface, including a circular gripping element including a thumb-receiving notch disposed along its circumference, an array of light-based proximity sensors, mounted in the gripping element, that projects light beams through the notch radially outward from the gripping element, and detects light beams reflected back into the gripping element by a moving object at or near the notch, and a processor, coupled with the proximity sensor array, for determining polar angles along the circumference of the gripping element occupied by the object, responsive to light beams projected by the proximity sensor array and reflected back by the object being detected by the proximity sensor array. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The present invention will be more fully understood and appreciated from the following detailed description, taken in conjunction with the drawings in which: 
           [0022]      FIG. 1  is a simplified illustration of prior art steering wheel; 
           [0023]      FIG. 2  is an exploded view of a steering wheel, in accordance with a first embodiment of the present invention; 
           [0024]      FIG. 3  is a cutaway view of a segment of the steering wheel of  FIG. 2 , in accordance with an embodiment of the present invention; 
           [0025]      FIGS. 4 and 5  are exploded views of the steering wheel segment illustrated in  FIG. 3 , in accordance with an embodiment of the present invention; 
           [0026]      FIG. 6  is a simplified illustration of electronic components in the steering wheel segment of  FIG. 2  connected to a processor, in accordance with an embodiment of the present invention; 
           [0027]      FIG. 7  is a simplified illustration of a structure of light baffles placed upon the electronic components in  FIG. 6 , in accordance with an embodiment of the present invention; 
           [0028]      FIGS. 8 and 9  are simplified illustrations of light beams detecting an object, in accordance with an embodiment of the present invention; 
           [0029]      FIG. 10  is simplified side view illustration of light beams projected radially outward from a steering wheel, in accordance with an embodiment of the present invention; 
           [0030]      FIG. 11  is a simplified illustration of communication between touch detection firmware and multiple clients over a network, in accordance with an embodiment of the present invention; 
           [0031]      FIG. 12  is a simplified illustration of five basic gesture components used in a steering wheel user interface, in accordance with an embodiment of the present invention; 
           [0032]      FIG. 13  is a flowchart of an exemplary vehicle user interface, in accordance with an embodiment of the present invention; 
           [0033]      FIG. 14  is a simplified illustration of user interface gestures performed on a steering wheel for an exemplary adaptive cruise control function, in accordance with an embodiment of the present invention; 
           [0034]      FIG. 15  is a simplified illustration of a multi-touch double-tap gesture and an exemplary user interface to activate an autonomous drive mode, in accordance with an embodiment of the present invention; 
           [0035]      FIG. 16  is a simplified illustration of a gesture and an exemplary user interface for exiting the autonomous drive mode, in accordance with an embodiment of the present invention; 
           [0036]      FIG. 17  is a simplified illustration showing how an incoming call is received, in accordance with an embodiment of the present invention; 
           [0037]      FIG. 18  is a simplified illustration showing how to hang up a call, in accordance with an embodiment of the present invention; and 
           [0038]      FIG. 19  is a simplified illustration of a user interface for a park assist function, in accordance with an embodiment of the present invention. 
       
    
    
       [0039]    In the disclosure and figures, the following numbering scheme is used. Light transmitters are numbered in the  100 &#39;s, light detectors are numbered in the  200 &#39;s, light guides and lenses are numbered in the  300 &#39;s, miscellaneous items are numbered in the  400 &#39;s, light beams are numbered in the  600 &#39;s, and flow chart elements are numbered  1000 - 1100 . Like numbered elements are similar but not necessarily identical. 
         [0040]    The following tables catalog the numbered elements and list the figures in which each numbered element appears. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Light Transmitters 
               
             
          
           
               
                   
                 Element 
                 FIGS. 
               
               
                   
                   
               
               
                   
                 100 
                 4, 5 
               
               
                   
                 101 
                 6 
               
               
                   
                 102 
                 6 
               
               
                   
                 105 
                 8-10 
               
               
                   
                 106 
                 6, 7 
               
               
                   
                 107 
                 6, 7 
               
               
                   
                 108 
                 6, 7 
               
               
                   
                 109 
                 6, 7 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Light Detectors 
               
             
          
           
               
                   
                 Element 
                 FIGS. 
               
               
                   
                   
               
               
                   
                 200 
                 4 
               
               
                   
                 201 
                 6, 8, 9 
               
               
                   
                 202 
                 6, 8, 9 
               
               
                   
                 203 
                 8, 9 
               
               
                   
                 205 
                 8, 9 
               
               
                   
                 206 
                 8 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Light Guides and Lenses 
               
             
          
           
               
                   
                 Element 
                 FIGS. 
               
               
                   
                   
               
               
                   
                 300 
                 2-7  
               
               
                   
                 301 
                 8, 9 
               
               
                   
                 302 
                 8, 9 
               
               
                   
                 303 
                 8, 9 
               
               
                   
                 304 
                 8, 9 
               
               
                   
                 305 
                 8-10 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Miscellaneous Items 
               
             
          
           
               
                 Element 
                 FIGS. 
                 Description 
               
               
                   
               
               
                 400 
                 1 
                 steering wheel 
               
               
                 401 
                 1 
                 grip 
               
               
                 402 
                 1 
                 right spoke 
               
               
                 403 
                 1 
                 left spoke 
               
               
                 404 
                 1 
                 bottom spoke 
               
               
                 405 
                 1 
                 answer button 
               
               
                 406 
                 1 
                 reject button 
               
               
                 410 
                 12, 14-19 
                 steering wheel 
               
               
                 411 
                 2-5 
                 steering wheel frame 
               
               
                 412 
                 2-5 
                 top cover 
               
               
                 413 
                 2-5 
                 thumb notch 
               
               
                 414 
                 2-7 
                 PCB 
               
               
                 415 
                 2-5, 7 
                 light baffle 
               
               
                 416 
                  3, 5 
                 transparent cover section 
               
               
                 417 
                  3, 5 
                 transparent cover section 
               
               
                 418 
                 12, 14, 15, 17, 18 
                 finger 
               
               
                 419 
                 12, 14, 16-19 
                 hand 
               
               
                 420 
                 12, 15 
                 steering wheel surface 
               
               
                 421-424, 428, 
                 12, 15 
                 hand/finger movement directions 
               
               
                 431-434 
               
               
                 425 
                 12  
                 clock icon 
               
               
                 426 
                 12  
                 finger 
               
               
                 430 
                 14  
                 double-tap gesture 
               
               
                 436 
                 14-16 
                 Illumination 
               
               
                 437 
                 14  
                 movement of illumination 
               
               
                 438 
                 14, 17 
                 tap gesture 
               
               
                 440 
                  6, 11 
                 Processor 
               
               
                 441-443 
                 11  
                 network client 
               
               
                 444 
                 11  
                 message bus 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 Light Beams 
               
             
          
           
               
                   
                 Element 
                 FIGS. 
                 Description 
               
               
                   
                   
               
               
                   
                 601 
                 10 
                 light beam 
               
               
                   
                 602 
                 3, 8-10 
                 light beam 
               
               
                   
                 603 
                 8, 9 
                 light beam 
               
               
                   
                 604 
                 8, 9 
                 light beam 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 Flow Chart Stages 
               
             
          
           
               
                   
                 Element 
                 FIGS. 
                 Description 
               
               
                   
                   
               
               
                   
                 1001-1005 
                 13 
                 vehicle application state 
               
               
                   
                 1010-1019 
                 13 
                 vehicle application action 
               
               
                   
                   
               
             
          
         
       
     
       DETAILED DESCRIPTION 
       [0041]    Aspects of the present disclosure relate to light-based touch controls that allow a driver to keep his hands on a steering element while operating peripheral electronic devices and automated features in a vehicle. 
         [0042]    According to a first embodiment of the invention, a steering wheel is provided with a touch sensitive strip disposed along the entire circumference of the steering wheel. In order to facilitate locating the strip, it is disposed in a thumb receiving notch or groove that is etched or otherwise formed along the circumference of the steering wheel. In addition to a touch sensor, there is also a visible-light illuminator behind or around the touch sensitive strip that is used to indicate the state of the user interface to the user, and also indicate where certain tap gestures should be performed. 
         [0043]    A user interface for this steering wheel is designed to be independent of the rotation of the steering wheel. Sweep gestures are clockwise and counter-clockwise so that they are independent of rotation of the wheel. A function is activated in response to a gesture, such as a double-tap, performed anywhere along the circumference of the wheel. The activation of some functions places the user interface into a state in which one or more additional functions can be selectively activated. In order to activate these additional functions, the touch location at which the initial gesture was performed is illuminated and subsequent gestures are performed in relation to the illuminated portion of the wheel. When a portion of the wheel is thus illuminated, and the driver slides his hand along the steering wheel grip, the illuminated portion of the steering wheel follows the hand so that the hand is always next to the location for performing subsequent gestures. Similarly, when the user switches hands gripping the steering wheel, the illumination jumps to the newly gripped part of the wheel. 
         [0044]    Reference is made to  FIG. 2 , which is an exploded view of a steering wheel, in accordance with a first embodiment of the present invention. Elements of this steering wheel include steering wheel frame  411 , PCB  414 , an array of lenses  300 , a light baffle structure  415 , and a steering wheel top cover  412 . A thumb-receiving notch  413  is disposed within steering wheel cover  412 . 
         [0045]    Reference is made to  FIG. 3 , which is a cutaway view of a segment of the steering wheel of  FIG. 2 , in accordance with an embodiment of the present invention. Thumb-receiving notch  413  is illustrated in  FIG. 3 . Two light transmissive portions of cover  412  are also shown in  FIG. 3 . A first light transmissive portion  417  forms the side wall of thumb-receiving notch  413 . Light beams traveling into and out of this portion provide touch detection and proximity detection, as explained below. Three touch detection light beams  602  are shown directed radially outward from the steering wheel gripping element. The second light transmissive portion  416  forms a floor of thumb-receiving notch  413 , and is used for visible illumination indicating a state of the user interface to the driver, and at which location the driver should perform additional user interface gestures. 
         [0046]    Reference is made to  FIGS. 4 and 5 , which are exploded views of the steering wheel segment illustrated in  FIG. 3 , in accordance with an embodiment of the present invention. As shown in  FIG. 4 , two concentric rows of elements are mounted on PCB  414 . Namely, an inner row of light detectors  200  and an outer row of light emitters  100 . Light from the emitters enters lenses  300  through which it is re-directed out of the steering wheel through light transmissive portion  417  as light beams  602 , illustrated in  FIGS. 3 and 8-10 . An object such as a thumb placed in notch  413  reflects the light back through portion  417  and lenses  300  onto one or more of the light detectors  200 , thereby providing touch detection, as illustrated in  FIGS. 8 and 9 . Similarly, an object such as a user&#39;s hand placed along the outer rim of the steering wheel outside notch  413  and opposite light transmissive portion  417  also reflects the light back through portion  417  and lenses  300  onto one or more of the light detectors  200 , thereby providing proximity detection. 
         [0047]      FIG. 5  shows an exploded view from below of the steering wheel segment illustrated in  FIG. 3 , in accordance with an embodiment of the present invention. 
         [0048]    Reference is made to  FIG. 6 , which is a simplified illustration of electronic components in the steering wheel segment of  FIG. 2  connected to a processor, in accordance with an embodiment of the present invention.  FIG. 6  shows processor  440  connected to PCB  414  on which three concentric arrangements of light elements are mounted, namely, an inner circular arrangement of inward facing light detectors, including detectors  201  and  202 ; a middle circular arrangement of inward facing light emitters, including emitters  101  and  102 ; and an outer circular arrangement of outward facing light emitters  105 - 108 . The inward facing light emitters are used for touch and proximity detection and typically emit light in the near infrared range. Processor  440  controls activation of the emitters and detectors, and detects gestures performed on the steering wheel based on these activations and based on the outputs of the detectors. 
         [0049]    The outward facing light emitters are used to provide visual indications to the user by illuminating light transmissive portion  416  of the steering wheel cover, and emit light in the visible range. Lenses  300  are described in assignee&#39;s co-pending application U.S. Ser. No. 14/555,731, entitled DOOR HANDLE WITH OPTICAL PROXIMITY SENSORS, the contents of which are incorporated herein in their entirety by reference. 
         [0050]    Reference is made to  FIG. 7 , which is a simplified illustration of a structure of light baffles placed upon the electronic components in  FIG. 6 , in accordance with an embodiment of the present invention.  FIG. 7  shows PCB  414  and lenses  300  of  FIG. 6 , but with baffle structure  415  placed above the mounted light elements. 
         [0051]    Reference is made to  FIGS. 8 and 9 , which are simplified illustrations of light beams detecting an object, in accordance with an embodiment of the present invention.  FIGS. 8 and 9  show a light path used to detect an object. Shown in  FIGS. 8 and 9  are individual lens structures  301 - 305 . Each lens structure serves a respective opposite emitter and two detectors, one to the left of the emitter and one to the right of the emitter. Thus, for example, lens structure  305  serves emitter  105  and detectors  205  and  206 . In addition each detector is served by two lens structures; e.g., detector  205  receives reflected light from lens structures  304  and  305 . In the example shown in  FIGS. 8 and 9 , light from emitter  105  is reflected by an object (not shown) into lens structure  303  and onto detector  203 . Three segments of the detected light are indicated in  FIGS. 8 and 9 ; namely, light beam  602  projected outward from lens structure  305  and radially outward of the steering wheel, light beam  603  reflected by the object into lens structure  303 , and light beam  604  directed by lens structure  303  onto detector  203 . 
         [0052]    Reference is made to  FIG. 10 , which is simplified side view illustration of light beams projected radially outward from a steering wheel, in accordance with an embodiment of the present invention.  FIG. 10  shows a cutaway side view of the light path illustrated in  FIGS. 8 and 9 .  FIG. 10  shows light beam  601  from emitter  105  entering lens structure  305 , where it is redirected outward as light beam  602 . 
         [0053]    Methods for determining two-dimensional coordinates of an object detected by the disclosed proximity sensor array are described in assignee&#39;s co-pending application Ser. No. 14/312,787, entitled OPTICAL PROXIMITY SENSORS, and U.S. Ser. No. 14/555,731, entitled DOOR HANDLE WITH OPTICAL PROXIMITY SENSORS, both incorporated herein in their entireties by reference. Because the present application is for a steering wheel and the proximity sensor array is arranged along an arc-shaped grip of the steering wheel, the determined coordinates are polar coordinates, including a polar angle and a radial coordinate. The polar angle corresponds to a coordinate along the proximity sensor array, which in application Ser. Nos. 14/312,787 and 14/555,731 is described as an x-axis coordinate. The radial coordinate corresponds to a distance from the proximity sensor array, which in application Ser. Nos. 14/312,787 and 14/555,731 is described as a y-axis coordinate. 
         [0054]    Discussion now turns to the firmware and software used to detect and interpret user gestures. There are five basic gesture components that are detected by the hardware and low level drivers: (i) Thumb-Tap, (ii) Thumb-Glide, (iii) Thumb-Long-Press, (iv) Grab and (v) Rim-Tap. These components are emitted on the network as they are detected, and are used by higher level software to assemble more complex gestures such as double-taps. Application software interprets these gestures as input commands. In some embodiments of the invention multiple client applications are connected via a network to the detector firmware. The firmware sends information for each detected gesture component over the network, and a client application translates that information into commands and/or constructs compound gestures from multiple gesture components. 
         [0055]    Reference is made to  FIG. 11 , which is a simplified illustration of communication between touch detection firmware and multiple clients over a network, in accordance with an embodiment of the present invention.  FIG. 11  shows an exemplary network architecture in which processor  440  sends detected gesture components over message bus  444 , e.g., using the Message Queue Telemetry Transport (MQTT) messaging protocol on top of the TCP/IP protocol, to connected clients  441 - 443 . 
         [0056]    The five basic gesture components are categorized according to whether they are performed by a large object (hand) or small object (thumb), and whether the nature of the gesture component is discrete or continuous, as presented in the table below. 
         [0000]                                        Component   Description   Object   Type                   Thumb-Tap   Tap thumb on steering   Small   Discrete           wheel rim       Thumb-Glide   Glide thumb along   Small   Continuous           steering wheel rim       Thumb-Long-   Hold thumb on steering   Small   Continuous       Press   wheel rim       Grab   Grab hold of steering   Large   Continuous           wheel rim       Rim-Tap   Tap hand on steering   Large   Discrete           wheel rim                    
These gesture components are alternatively referred to as follows.
 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                 Component 
                 Alternative Name 
               
               
                   
                   
               
             
             
               
                   
                 Thumb-Tap 
                 small-object tap 
               
               
                   
                 Thumb-Glide 
                 small-object glide 
               
               
                   
                 Thumb-Long-Press 
                 small-object touch-and-hold 
               
               
                   
                 Grab 
                 large-object grab 
               
               
                   
                 Rim-Tap 
                 large-object tap 
               
               
                   
                   
               
             
          
         
       
     
         [0057]    The parameters are the same for all gesture components; namely, time stamp, start angle (min_angle), end angle (max_angle), center angle (angle) and state. 
         [0058]    The angle parameters refer to a polar angle along the steering wheel at which the object is detected. Because of the object&#39;s size, there is a first polar angle at which the object begins (start angle) and a last polar angle at which the object ends (end angle). The midpoint between the start and end angles (center angle) is used as the object&#39;s polar angle. The start and end angles are useful for determining the size of a detected object. 
         [0059]    The state parameter takes on three values: RECOGNIZED, UPDATED and ENDED. The ENDED state is applied to all discrete gesture components, and also when a continuous gesture component ends. The RECOGNIZED and UPDATED states are only applied to continuous gesture components. The RECOGNIZED state is applied when a continuous gesture component is first detected. The UPDATED state is applied during the course of a continuous gesture component. 
         [0060]    The discrete gesture components, Thumb-Tap and Rim-Tap, are emitted to the clients after they happen, and then only one message is sent for the gesture component. They are only sent with the state ENDED. 
         [0061]    The continuous gesture components, Thumb-Glide, Thumb-Long-Press and Grab, are emitted to the clients intermittently from the instant that they are recognized until they end when the hand or finger leaves the rim. When they are first recognized, they are sent to the network with the state RECOGNIZED. With a configurable interval, the gesture component is reported to the network with new parameters and the state UPDATED. When the gesture component ends, the gesture component is sent with the state ENDED. 
         [0062]    Reference is made to  FIG. 12 , which is a simplified illustration of five basic gesture components used in a steering wheel user interface, in accordance with an embodiment of the present invention.  FIG. 12  shows the five gesture components performed by thumb  418  and hand  419  on steering wheel  410 . Some gesture components are illustrated both from above and from the side. When illustrated from the side, thumb  418  is shown interacting with steering wheel surface  420 . 
         [0063]    A Thumb-Tap gesture component is generated when a small object touches the rim (or gets very close) and then is lifted from the rim within a short period. This period is configurable, but typically it is 100-200 ms.  FIG. 12  shows the Thumb-Tap gesture component from above and from the side, and illustrates the movement of thumb  418  by arrows  421 . 
         [0064]    A Rim-Tap gesture component is the same as a Thumb-Tap, but for a large object such as a hand.  FIG. 12  shows the Rim-Tap gesture component from the side and illustrates the movement of hand  419  by arrows  424 . 
         [0065]    A Thumb-Glide gesture component is generated when a small object touches the rim and moves at least a certain threshold distance along the rim. That distance is configurable. When it continues to move, UPDATE messages are sent when the object has moved a certain distance, also configurable.  FIG. 12  shows the Thumb-Glide gesture component from above and from the side, and illustrates the movement of thumb  418  by arrows  422  and  423 . 
         [0066]    A Grab gesture component is the same as a Thumb-Glide gesture component, but for a large object touching the rim, and with the difference that the Grab gesture component does not have to move to be reported on the network. When the hand has been on the rim for a certain time threshold, the Grab gesture component is recognized and messages are intermittently sent to the network.  FIG. 12  shows the Grab gesture component from above by showing hand  419  gripping steering wheel  410 . 
         [0067]    A Thumb-Long-Press gesture component is generated when a small object is present, and not moving, on the rim. When the small object has been present for a certain time, messages are sent intermittently to the network about the gesture component. If the object starts moving, the Thumb-Long-Press gesture component is ended and a Thumb-Glide gesture component is started instead.  FIG. 12  shows the Thumb-Long-Press gesture component from above and from the side. Clock icon  425  indicates the time threshold required to distinguish this gesture component from a Thumb-Tap. 
         [0068]    As mentioned above, gesture components are combined into compound user interface gestures. In some cases, environment conditions at the gesture location are combined with the gesture component to define a gesture. For example, a Thumb-Tap gesture performed at one end of an illuminated portion of the rim is translated into a first command, and a Thumb-Tap gesture performed at the other end of the illuminated portion of the rim is translated into a second command. The following table lists the different gestures and compound gestures in the steering wheel user interface, the gesture components that make up each gesture, additional gesture parameters, and example context and commands for each gesture. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                   
               
               
                   
                 Gesture 
                 Additional 
                 Example 
                 Example 
               
               
                 Gesture 
                 Components 
                 Parameters 
                 Context 
                 Command 
               
               
                   
               
             
             
               
                 Tap inside 
                 Thumb-Tap 
                 Thumb-tap 
                 Cruise 
                 Increase or 
               
               
                 notch 
                   
                 performed at top or 
                 control is 
                 decrease cruise 
               
               
                   
                   
                 bottom of illuminated 
                 active 
                 control speed in 
               
               
                   
                   
                 portion of illuminated 
                   
                 5 mph 
               
               
                   
                   
                 segment of steering 
                   
                 increments 
               
               
                   
                   
                 wheel 
               
               
                 Tap on 
                 Rim-Tap 
                   
                 During 
                 Reactivate phone 
               
               
                 steering 
                   
                   
                 phone call 
                 interaction, e.g., 
               
               
                 wheel outer 
                   
                   
                   
                 when phone call 
               
               
                 rim 
                   
                   
                   
                 is active for set 
               
               
                   
                   
                   
                   
                 period of time. 
               
               
                   
                   
                   
                   
                 Enables hanging 
               
               
                   
                   
                   
                   
                 up the phone call 
               
               
                   
                   
                   
                   
                 with a clockwise 
               
               
                   
                   
                   
                   
                 swipe gesture 
               
               
                 Single 
                 Two Thumb- 
                 Thumb-taps have 
                 Vehicle is in 
                 Activate cruise 
               
               
                 object 
                 Taps 
                 different time stamps, 
                 motion 
                 control and 
               
               
                 double-tap 
                   
                 similar center 
                   
                 illuminate 
               
               
                 inside notch 
                   
                 angles 
                   
                 location of 
               
               
                   
                   
                   
                   
                 double-tap 
               
               
                 Single 
                 Two Rim-Taps 
                 Side of steering 
                 Car is not 
                 Activate Park 
               
               
                 object 
                   
                 wheel rim (left or 
                 moving, and 
                 Assist to park on 
               
               
                 double-tap 
                   
                 right) at which 
                 Park Assist 
                 left or right side 
               
               
                 on steering 
                   
                 double-tap is 
                 icon is 
                 of car, based on 
               
               
                 wheel outer 
                   
                 performed 
                 displayed on 
                 tapped side of 
               
               
                 rim 
                   
                   
                 HUD 
                 rim 
               
               
                 Multi-touch 
                 Two Thumb- 
                 Thumb-taps have 
                 Autonomous 
                 Activate 
               
               
                 double-tap 
                 Taps 
                 similar time stamps, 
                 drive is not 
                 autonomous 
               
               
                 inside notch 
                   
                 different center 
                 active 
                 drive 
               
               
                   
                   
                 angles 
               
               
                 Extended 
                 Thumb-Long- 
                 Thumb-long-press 
                 Cruise 
                 Increase or 
               
               
                 touch inside 
                 Press 
                 performed at top or 
                 control is 
                 decrease cruise 
               
               
                 notch 
                   
                 bottom of illuminated 
                 active 
                 control speed in 
               
               
                   
                   
                 portion of illuminated 
                   
                 1 mph 
               
               
                   
                   
                 segment of steering 
                   
                 increments 
               
               
                   
                   
                 wheel 
               
               
                 Grab 
                 Grab 
                   
                 Autonomous 
                 Deactivate 
               
               
                   
                   
                   
                 drive is 
                 autonomous 
               
               
                   
                   
                   
                 active 
                 drive, and enter 
               
               
                   
                   
                   
                   
                 cruise control 
               
               
                   
                   
                   
                   
                 mode 
               
               
                 Swipe 
                 Thumb-Glide 
                 clockwise/counter- 
                 Cruise 
                 Increase or 
               
               
                   
                   
                 clockwise 
                 control is 
                 decrease distance 
               
               
                   
                   
                   
                 active 
                 from forward car 
               
               
                   
                   
                   
                   
                 in cruise control 
               
               
                   
                   
                   
                   
                 mode 
               
               
                 Radial swipe 
                 Thumb-Glide 
                 Thumb-glide data 
                 Cruise 
                 Open cruise 
               
               
                   
                   
                 structures have 
                 control is 
                 control menu on 
               
               
                   
                   
                 similar center angles 
                 active 
                 HUD 
               
               
                   
                   
                 and different radial 
               
               
                   
                   
                 coordinates 
               
               
                 Slide 
                 Grab 
                 Grab data structures 
                 Portion of 
                 Move illumination 
               
               
                   
                   
                 have different time 
                 steering 
                 to new hand 
               
               
                   
                   
                 stamps and different 
                 wheel is 
                 location (follow 
               
               
                   
                   
                 center angles 
                 selectively 
                 slide movement) 
               
               
                   
                   
                   
                 illuminated 
               
               
                 Switch 
                 Grab 
                 Grab data structures 
                 Portion of 
                 Move illumination 
               
               
                 hands 
                   
                 have different time 
                 steering 
                 to new hand 
               
               
                   
                   
                 stamps and different 
                 wheel is 
                 location (jump to 
               
               
                   
                   
                 center angles 
                 selectively 
                 other side of 
               
               
                   
                   
                   
                 illuminated 
                 wheel) 
               
               
                   
               
             
          
         
       
     
         [0069]    Reference is made to  FIG. 13 , which is a flowchart of an exemplary vehicle user interface, in accordance with an embodiment of the present invention. The flowchart illustrates the different application states, different commands within each state, and the gestures used to issue those commands. The details of the gestures are illustrated in  FIGS. 14-19 . In some embodiments a heads-up display (HUD) is provided. 
         [0070]    The flowchart of  FIG. 13  illustrates a highway scenario that includes three driving modes: Normal Drive  1001 , Adaptive Cruise Control  1002  and Autonomous Drive  1003 . In Normal Drive mode, the driver steers the vehicle and controls its speed. In Adaptive Cruise Control mode the driver steers the vehicle but the vehicle&#39;s speed, its distance from the next vehicle on the road, and other parameters are controlled by the vehicle. In Autonomous Drive mode the vehicle is driven and steered automatically without driver input. 
         [0071]    The user enters Adaptive Cruise Control mode from Normal Drive mode by performing a double-tap gesture. The user enters Autonomous Drive mode from Normal Drive mode and from Adaptive Cruise Control mode by performing a multi-touch double-tap gesture. These gestures are described below. In order to alert the driver that Autonomous Drive mode will begin shortly, the steering wheel is illuminated with an illumination pattern that indicates a countdown until Autonomous Drive is activated. 
         [0072]    The user exits Adaptive Cruise Control mode by performing a double-tap gesture that opens a menu on the HUD for changing the mode  1015  of cruise control. The user performs clockwise or counter-clockwise swipe gestures to scroll through the different modes on the HUD, and performs a single-tap gesture to select the displayed mode. One of the modes is Exit ACC  1018 , and selecting this mode exits Adaptive cruise Control. Another mode configures the cruise control application to follow the road signage  1019 . 
         [0073]    The user exits Autonomous Drive mode  1013  by grabbing the rim of the steering wheel. In order to alert the driver that Autonomous Drive mode is about to exit, the steering wheel is illuminated with an illumination pattern that indicates a countdown until Autonomous Drive is deactivated. Upon exiting Autonomous Drive mode, the vehicle enters Adaptive Cruise Control mode. 
         [0074]    In Adaptive Cruise Control mode  1002  the user adjusts a distance  1016  between the vehicle and the vehicle directly in front of it, by performing a clockwise or counter-clockwise swipe gesture. The user adjusts the speed of the vehicle by performing either a tap gesture or an extended touch gesture. When the vehicle enters Adaptive Cruise Control mode  1002  a segment of the steering wheel is illuminated. A tap gesture or extended touch gesture at one end of the illuminated segment increases the vehicle speed, and a tap gesture or extended touch gesture at the other end of illuminated segment decreases the vehicle speed. 
         [0075]    A voice control state  1004  can be entered from Normal Drive mode and Adaptive Cruise Control mode. In this state, the user can initiate a phone call by saying “call” and the name of a contact from his phone&#39;s contact list. Once the call has been connected, the user can hang up  1010  by performing a clockwise swipe gesture. The user can also adjust the volume  1011  by saying the word “volume” and then performing a counter-clockwise swipe gesture to raise the volume, or a clockwise swipe gesture to lower the volume. 
         [0076]    When an incoming phone call  1005  is received, the user can answer the call  1012  by performing a counter-clockwise swipe gesture, or decline the call  1012  by performing a clockwise swipe gesture. 
         [0077]    Reference is made to  FIG. 14 , which is a simplified illustration of user interface gestures performed on a steering wheel for an exemplary adaptive cruise control function, in accordance with an embodiment of the present invention. In order to enter Adaptive Cruise Control mode from Normal Drive mode the user performs a single object double-tap gesture. Namely, the user taps twice with his thumb on the thumb notch in the steering wheel. This gesture is illustrated in drawing (a) in  FIG. 14 , showing steering wheel  410 , hand  419  gripping steering wheel  410 , and double-tap gesture  430 . The present invention enables the user to perform the double-tap gesture  430  at any location along the perimeter of steering wheel  410 . 
         [0078]    When Adaptive Cruise Control is active the user has four options; namely, adjust cruise control speed, adjust the distance between the vehicle and the vehicle ahead, open an adaptive cruise control menu, and activate Autonomous Drive mode. As mentioned above Adaptive Cruise Control is activated when the user taps twice with his thumb in the steering wheel thumb notch. The location of these taps is subsequently illuminated to indicate to the user where to perform future gestures. This is illustrated in drawing (b) in  FIG. 14 , showing illuminated segment  436  of the steering wheel  410  at the location at which double-tap  430  was performed. Thus, to increase the cruise control speed the user performs a gesture, e.g. a single-tap, above the illuminated portion. This is illustrated in drawing (d) in  FIG. 14  showing tap gesture  438  at the counter-clockwise edge of illuminated portion  436 . The “+” indicates that this gesture increases the speed of the vehicle. Drawing (e) in  FIG. 14  shows gesture  438  performed at the clockwise end of illuminated portion  436 , and the “−” indicates that the gesture decreases the speed of the vehicle. 
         [0079]    If the user slides his hand  419  along steering wheel  410 , the illuminated portion  436  moves with the hand so that the user&#39;s thumb is always next to the illuminated portion of the steering wheel. This is illustrated in drawing (c) in  FIG. 14 , in which hand  419  gripping steering wheel  410  slides clockwise as indicated by arrow  428 , and illuminated portion  436  also slides in the same direction as indicated by arrow  437 . 
         [0080]    In some embodiments the cruise control speed is also adjusted in response to extended touch gestures above and below the illuminated portion of the steering wheel. For example, the speed is adjusted by 5 km/h in response to a tap gesture, and is adjusted by 1 km/h in response to an extended touch gesture. 
         [0081]    In order to increase or decrease the distance between the vehicle and the vehicle in front of it on the road, the user performs clockwise and counter-clockwise swipe gestures. These are illustrated in drawings (f) and (g) in  FIG. 14 . Drawing (f) illustrates a counter-clockwise gesture  431  to increase the distance between vehicles, and drawing (g) illustrates a clockwise gesture  432  to decrease the distance between vehicles. 
         [0082]    In order to change the mode of Adaptive Cruise Control the user performs a radial swipe gesture with his thumb across the width of the steering wheel thumb notch. This is illustrated in drawings (h) and (i) in  FIG. 14 . Drawing (h) illustrates swipe gesture  433  that moves outward across the width of illuminated portion  436 . Drawing (i) illustrates swipe gesture  434  that moves inward across the width of illuminated portion  436 . Either gesture causes the HUD to present a mode option for selection. The user performs a single-tap gesture with his thumb in the steering wheel notch to accept the displayed mode. The mode displayed in the HUD is changed in response to a swipe gesture. For example, a first mode is to follow road signage. If the user performs a single-tap when this mode is displayed on the HUD, a Follow Road Signage mode is activated. If the user swipes clockwise or counter-clockwise, a next or previous mode is displayed such as exit Adaptive Cruise Control. The user performs a single-tap to activate this mode. If no interaction from the user is received within a fixed amount of time, such as 5 seconds, then the change mode user interface is deactivated. 
         [0083]    Reference is made to  FIG. 15 , which is a simplified illustration of a multi-touch double-tap gesture and an exemplary user interface to activate an autonomous drive mode, in accordance with an embodiment of the present invention. Drawing (a) in  FIG. 15  illustrates two fingers,  418  and  426 , simultaneously tapping at two locations on steering wheel  410 . The upper part of this drawing is a view from above, and the lower part of this drawing is a view from the side of each of the fingers  418  and  426 . The tap gesture is a brief down and up gesture illustrated by arrows  421  and  428  touching surface  420  of the steering wheel. 
         [0084]    Once the user performs this multi-touch double-tap gesture, a series of locations on the steering wheel are sequentially illuminated over time to indicate a countdown until Autonomous Drive is activated, as illustrated in drawings (b) and (c). For example, viewing the upright steering wheel as a clock, drawing (b) illustrates a sequence of illuminations that begins with (i) the 2:30 and 9:30 clock positions indicated by a 1; followed by (ii) the 1:30 and 10:30 clock positions indicated by 2; followed by (iii) the 12:30 and 11:30 clock positions indicated by 3. Drawing (c) illustrates finally illuminating the 12 o&#39;clock position indicated by the word “Go” to inform the user that Autonomous Drive is activated and the user can safely take his hands off the wheel. 
         [0085]    In order to exit Autonomous Drive mode and enter Adaptive Cruise Control mode, the user grabs the steering wheel. Reference is made to  FIG. 16 , which is a simplified illustration of a gesture and an exemplary user interface for exiting autonomous drive mode, in accordance with an embodiment of the present invention.  FIG. 16  shows two hands  419  gripping steering wheel  410 , in accordance with an embodiment of the present invention. A series of locations on the steering wheel is then sequentially illuminated to indicate that Autonomous Drive mode is about to be the deactivated. For example, drawing (a) illustrates a sequence of illuminations that begins with (i) the 11:30 and 12:30 clock positions indicated by a 1; followed by (ii) the 10:30 and 1:30 clock positions indicated by 2; followed by (iii) the 9:30 and 2:30 clock positions indicated by 3. When Autonomous Drive mode is deactivated the vehicle enters Adaptive Cruise Control mode, and a portion  436  of steering wheel  410  next to one of the hands  419  gripping the steering wheel is illuminated, as illustrated in drawing (b) of  FIG. 16 , and as discussed above with reference to  FIG. 14 . 
         [0086]    In both Normal Drive mode and Adaptive Cruise Control mode the user can enable voice activated controls by tapping twice on the outer rim of the steering wheel. When voice-activated controls are enabled the user disables these controls by repeating the same double-tap gesture. 
         [0087]    Two voice-activated controls are illustrated in  FIG. 13 : placing a phone call and enabling volume adjustments. To place a phone call the user says “call” and the name of the person to call, e.g., “call Mom”. In order to hang up the call the user performs a swipe gesture along the thumb notch in the steering wheel. To adjust the volume of a call or the stereo system, the user says the word “volume” and then adjusts the volume up or down by swiping clockwise or counter-clockwise along the thumb notch in the steering wheel. 
         [0088]    Reference is made to  FIG. 17 , which is a simplified illustration showing how an incoming call is received, in accordance with an embodiment of the present invention.  FIG. 17  shows that when an incoming call is received, the user answers or declines the call by swiping finger  418  clockwise or counter-clockwise along the thumb notch of the steering wheel, e.g. swipe counter-clockwise to accept the call and swipe clockwise to reject the call. 
         [0089]    Reference is made to  FIG. 18 , which is a simplified illustration showing how to hang up a call, in accordance with an embodiment of the present invention. The gesture to hang up a call is a clockwise swipe gesture. However, when a call has been active for a certain amount of time, the system ignores clockwise swipe gestures so that the user does not inadvertently hang up the call. In order to hang up the call, the user first taps the outer rim of the steering wheel, as shown by hand  419 , to indicate that the system should respond to the next swipe gesture, followed by a clockwise swipe gesture by finger  418  to hang up the call. 
         [0090]    In a city scenario the user interface provides a park assist function that automatically parks the car without the user&#39;s intervention. Reference is made to  FIG. 19 , which is a simplified illustration of a user interface for a park assist function, in accordance with an embodiment of the present invention. When the vehicle is moving at less than 30 km/h, the Park Assist function begins automatically scanning for available parking spaces. In addition, a faded Park Assist icon appears on the HUD, as illustrated in drawing (a) of  FIG. 19 . As the car further slows down, this icon becomes bolder until the car has stopped moving, as illustrated in drawings (b) and (c) of  FIG. 19 . The HUD then presents information about available parking spots; e.g. whether the vehicle can fit into that spot. The user performs a double-tap on the outer rim of the steering wheel, as illustrated in drawing (d), by hand  419  to begin the automated parking. To indicate to the Park Assist function that the parking space is on the left side of the car, the user performs this double-tap on of the left half of steering wheel rim. To indicate to the Park Assist function that the parking space is on the right side of the car, the user performs this double-tap on of the right half of steering wheel rim. 
         [0091]    In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made to the specific exemplary embodiments without departing from the broader spirit and scope of the invention. In particular, sensors other than optical sensors may be used to implement the user interface, inter alia capacitive sensors disposed along the circumference of the steering wheel, and cameras that captured images of the steering wheel. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.