Patent Publication Number: US-10307660-B2

Title: Rider detection systems

Description:
CROSS-REFERENCES 
     This application is a continuation of U.S. patent application Ser. No. 15/864,939, filed Jan. 8, 2018, which is a continuation of U.S. patent application Ser. No. 15/432,807, filed Feb. 14, 2017, which is a continuation of U.S. patent application Ser. No. 15/275,067, filed Sep. 23, 2016, which is a continuation of U.S. patent application Ser. No. 14/934,024, filed Nov. 5, 2015, which claims priority from U.S. Provisional patent application Ser. No. 62/075,658, filed Nov. 5, 2014, which is hereby incorporated by reference for all purposes. The following related applications and materials are also incorporated herein, in their entireties, for all purposes: U.S. Pat. No. 9,101,817. 
    
    
     FIELD 
     The present disclosure is generally directed to self-stabilizing electric vehicles. More specifically, the disclosure is directed to rider detection systems and methods for such vehicles. 
     SUMMARY 
     The present disclosure provides systems and methods for determining and/or assessing rider presence on an electric vehicle, such as a self-balancing skateboard. 
     In some embodiments, an electric vehicle may include a board including first and second deck portions each configured to receive a left or right foot of a rider oriented generally perpendicular to a longitudinal axis of the board; a wheel assembly including a ground-contacting element disposed between and extending above the first and second deck portions; a motor assembly mounted to the board and configured to rotate the ground-contacting element around an axle to propel the electric vehicle; at least one orientation sensor configured to measure orientation information of the board; a first sensing region disposed in the first deck portion, the first sensing region including a first pressure-sensing transducer; and a motor controller configured to receive board orientation information measured by the orientation sensor and rider presence information based on an output of the first pressure-sensing transducer, and to cause the motor assembly to propel the electric vehicle based on the board orientation information and the rider presence information. 
     In some embodiments, an electric skateboard may include a foot deck having first and second deck portions each configured to support a rider&#39;s foot oriented generally perpendicular to a longitudinal axis of the foot deck; exactly one ground-contacting wheel disposed between and extending above the first and second deck portions and configured to rotate about an axle to propel the skateboard; at least one orientation sensor configured to measure an orientation of the foot deck; a pressure-sensing transducer disposed on the first deck portion; and an electric motor configured to cause rotation of the wheel based on the orientation of the foot deck and an output of the pressure-sensing transducer. 
     In some embodiments, a self-balancing electric vehicle may include a frame defining a plane and having a longitudinal axis; a first deck portion mounted to the frame and configured to support a first foot of a rider oriented generally perpendicular to the longitudinal axis of the frame; a second deck portion mounted to the frame and configured to support a second foot of a rider oriented generally perpendicular to the longitudinal axis of the frame; a wheel mounted to the frame between the deck portions, extending above and below the plane and configured to rotate about an axis lying in the plane; at least one orientation sensor mounted to the frame and configured to sense orientation information of the frame; a pressure-sensing transducer disposed on the first deck portion and configured to sense rider presence information based on a force applied to the first deck portion; a motor controller configured to receive the orientation information and the rider presence information and to generate a motor control signal in response; and a motor configured to receive the motor control signal from the motor controller and to rotate the wheel in response, thereby propelling the skateboard. 
     Features, functions, and advantages may be achieved independently in various embodiments of the present disclosure, or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a rider on an electric vehicle including a wheel assembly and pitch, roll, and yaw axes. 
         FIG. 2  is an exploded perspective view of the wheel assembly including a hub motor. 
         FIG. 3  is a semi-schematic cross-sectional view of the hub motor taken along the pitch axis. 
         FIG. 4  is a perspective view of a bottom side of the electric vehicle. 
         FIG. 5  is a schematic diagram of various electrical components of the electric vehicle. 
         FIG. 6  is a flowchart depicting exemplary initialization, standby, and operation procedures of the electrical components. 
         FIG. 7  is a side elevation view of the electric vehicle in a first orientation. 
         FIG. 8  is a side elevation view of the electric vehicle moved to a second orientation to activate a control loop for the hub motor. 
         FIG. 9  is a side elevation view of the electric vehicle moved to a third orientation to drive the hub motor in a clockwise direction. 
         FIG. 10  is a side elevation view of the electric vehicle moved to a fourth orientation to drive the hub motor in a counter-clockwise direction. 
         FIG. 11  is a semi-schematic front elevation view of the electric vehicle moved to a fifth orientation to modulate a rotational rate of the hub motor. 
         FIG. 12  is semi-schematic top view of the electric vehicle being moved to a sixth orientation to modulate the rotational rate of the hub motor. 
         FIG. 13  is a schematic diagram of a system including the electric vehicle in communication with a wireless electronic device. 
         FIG. 14  is a schematic diagram of a software application for the wireless electronic device. 
         FIG. 15  is an exemplary screenshot of the software application. 
         FIG. 16  is another exemplary screenshot of the software application, showing a navigation feature. 
         FIG. 17  is another exemplary screenshot of the software application, showing another navigation feature. 
         FIG. 18  is a semi-schematic screenshot of the software application, showing a rotating image. 
         FIG. 19  is an illustration of operations performed by one embodiment of the software application. 
         FIGS. 20A and 20B  when viewed together are another illustration of operations performed by one embodiment of the software application. 
         FIG. 21  is a schematic diagram of a system including the wireless electronic device in communication with multiple electric vehicles. 
         FIG. 22  is a schematic diagram of a system including the electric vehicle in communication with multiple wireless electronic devices. 
         FIG. 23  is a schematic diagram of an illustrative data processing system. 
         FIG. 24  is an isometric exploded view of an illustrative rider detection device including a deck and pressure-sensing transducer suitable for use in an electric vehicle in accordance with aspects of the present disclosure. 
         FIG. 25  is an isometric assembled view of the device of  FIG. 24 . 
         FIG. 26  is a schematic top view of another illustrative rider detection device including first and second sensing elements. 
         FIG. 27  is a schematic overhead view depicting the device of  FIG. 26  integrated into a deck of an electric vehicle in accordance with aspects of the present disclosure. 
         FIG. 28  is a schematic sectional view of the deck and rider detection device of  FIG. 27 , taken along line  28 - 28 . 
         FIG. 29  is a flow chart depicting steps in an illustrative method of operation for an electrical vehicle having a rider detection system in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     An electric vehicle having a rider detection system is described below and illustrated in the associated drawings. Unless otherwise specified, the electric vehicle and/or its various components may, but are not required to, contain at least one of the structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein. Furthermore, the structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein in connection with a system or method may, but are not required to, be included in other similar systems or methods. The following description of various embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application or uses. 
     Overview 
     An electric vehicle, generally indicated at  100 , and components and functionalities in conjunction thereof are shown in  FIGS. 1-29 . Vehicle  100  may be a self-stabilizing and/or self-balancing vehicle, such as an electrically-powered single-wheel self-balancing skateboard. Vehicle  100  may have a rider stance and/or motion similar to a surfboard or snowboard, which may make vehicle  100  intuitive to ride and provide for increased safety. 
     As shown in  FIG. 1 , vehicle  100  may include a board (or foot deck, or frame, or platform)  104  having an opening  108  for receiving a wheel assembly  112  between first and second deck portions (or footpads)  116 ,  120 . First and second deck portions  116 ,  120  may be of the same physical piece, or may be separate pieces. First and second deck portions  116 ,  120  may be included in board  104 . First and second deck portions  116 ,  120  may each be configured to support a rider&#39;s foot. First and second deck portions  116 ,  120  may each be configured to receive a left or a right foot of the rider. 
     Frame  104  may define a plane. First deck portion  116  may be mounted to frame  104  and configured to support a first foot of the rider. Second deck portion  120  may be mounted to frame  104  and configured to support a second foot of the rider. 
     Wheel assembly  112  may be disposed between first and second deck portions  116 ,  120 . First and second deck portions  116 ,  120  may be located on opposite sides of wheel assembly  112  with board  104  being dimensioned to approximate a skateboard. In other embodiments, the board may approximate a longboard skateboard, snowboard, surfboard, or may be otherwise desirably dimensioned. Deck portions  116 ,  120  of board  104  may be covered with non-slip material portions  124 ,  128  (e.g., “grip tape”) to aid in rider control. 
     Wheel assembly  112  may include a ground-contacting element (e.g., a tire, wheel, or continuous track)  132 . As shown, vehicle  100  includes exactly one ground-contacting element  132 , and the exactly one ground-contacting element is disposed between first and second deck portions  116 ,  120 . Ground-contacting element  132  may be mounted to a motor assembly  136 . Motor assembly  136  may be mounted to board  104 . Motor assembly  136  may include an axle  140  (see  FIG. 2 ), which may be coupled to board  104  by one or more axle mounts and one or more fasteners, such as a plurality of bolts (see  FIGS. 2 and 4 ). Motor assembly  136  may be configured to rotate ground-contacting element  132  around (or about) axle  140  to propel vehicle  100 . For example, motor assembly  136  may include a motor, such as a hub motor  144 , configured to rotate ground-contacting element  132  about axle  140  to propel vehicle  100  along the ground. The motor may be an electric motor. 
     Vehicle  100  may have a pitch axis A 1 , a roll axis A 2 , and a yaw axis A 3 . Pitch axis A 1  may be an axis about which tire  132  is rotated by motor assembly  136 . For example, pitch axis A 1  may pass through axle  140  (e.g., pitch axis A 1  may be parallel to and aligned with an elongate direction of axle  140 ). Roll axis A 2  may be perpendicular to pitch axis A 1 , and may substantially extend in a direction in which vehicle  100  may be propelled by motor assembly  136 . For example, roll axis A 2  may extend in an elongate direction of board  104 . Yaw axis A 3  may be perpendicular to pitch axis A 1  and to roll axis A 2 . For example, yaw axis A 3  may be normal to a plane defined by deck portions  116 ,  120 . 
     Wheel  132  may be mounted to frame  104  between deck portions  116 ,  120 . Wheel  132  may extend above and below the plane defined by frame  104 . Wheel  132  may be configured to rotate about an axis (e.g., pitch axis A 1 ) lying in the plane. In addition, roll axis A 2  may lie in the plane defined by frame  104 . In some embodiments, the pitch and roll axes may define the plane. 
     Tire  132  may be wide enough in a heel-toe direction (e.g., in a direction parallel to pitch axis A 1 ), so that the rider can balance themselves in the heel-toe direction using their own balance. Tire  132  may be tubeless, or may be used with an inner tube. Tire  132  may be a non-pneumatic tire. For example, tire  132  may be “airless”, solid, and/or made of foam. Tire  132  may have a profile such that the rider can lean vehicle  100  over an edge of tire  132  (and/or pivot the board about roll axis A 2  and/or yaw axis A 3 —see  FIGS. 11 and 12 ) through heel and/or toe pressure to ‘corner’ vehicle  100 . 
     Hub motor  144  may be mounted within tire (or wheel)  132  and may be internally geared or may be direct-drive. The use of a hub motor may eliminate chains and belts, and may enable a form factor that considerably improves maneuverability, weight distribution, and aesthetics. Mounting tire  132  onto hub motor  144  may be accomplished by either a split-rim design that may use hub adapters, which may be bolted on to hub motor  144 , or by casting a housing of the hub motor such that it provides mounting flanges for a tire bead directly on the housing of the hub motor. 
       FIG. 2  shows an embodiment of wheel assembly  112  with bolt-on hub adapters  148 ,  152 . One or more fasteners, such as a plurality of bolts  156  may connect a first side of hub motor  144  to hub adapter  148 . Hub motor  144  and hub adapter  148  may be positioned in an opening  158  of tire  132  with an outer mounting flange  148   a  of adapter  148  positioned adjacent a tire bead on a first side (not shown) of opening  158 . One or more fasteners, such as a plurality of bolts  160  may connect hub adapter  152  to a second side of hub motor  144 , and position an outer mounting flange  152   a  of adapter  152  adjacent a tire bead  162  on a second side of opening  158 . Mounting flanges  148   a ,  152   a  may engage the respective tire beads to seal an interior of time  132  for subsequent inflation. Mounting flanges  148   a ,  152   a  may frictionally engage tire  132  to transmit rotation of hub motor  144  to tire  132 . 
     Axle  140  may be inserted through a central aperture of a first axle mount  164 . An enlarged head portion  140   a  of axle  140  may be retained by axle mount  164 . For example, the central aperture of mount  164  may have a narrowed portion with a diameter that is less than a diameter of portion  140   a . A threaded portion  140   b  of axle  140  may be serially extended through a sleeve  168 , a central aperture (not shown) of hub adapter  148 , a central aperture  172  of hub motor  144 , a central aperture of hub adapter  152 , a central aperture  176  of a torque bar  180 , and a central aperture of a second axle mount  184 . After threaded portion  140   b  has been extended through the central aperture of mount  184 , a nut  186  may be tightened onto threaded portion  140   b  to secure together wheel assembly  112 . For example, the central aperture of mount  184  may have a narrowed portion with a diameter that is less than a diameter of nut  186 . 
     A non-circular member  190  may be fixedly attached to a stator (see  FIG. 3 ) of hub motor  144 . When wheel assembly  112  is secured together, member  190  may be seated in a slot  180   a  of torque bar  180 , and torque bar  180  may be seated in a slot  184   a  of mount  184 . Slot  184   a  may be similarly shaped and/or dimensioned as a slot  164   a  of mount  164 . Member  190  may frictionally engage mount  184  to prevent rotation of the stator during operation of hub motor  144 . 
     Sleeve  168  may be dimensioned to provide desirable spacing of wheel assembly components between mounts  164 ,  184 . For example, a first end of sleeve  168  may be seated in or adjacent the central aperture of mount  164 , a second end of sleeve  168  may be seated adjacent a side (not shown) of aperture  172  proximal hub adapter  148 , and sleeve  168  may have a length between its first and second ends that provides the desired spacing. 
     Preferably, hub motor  144  is a direct-drive transverse flux brushless motor. The use of a transverse flux motor may enable high (substantially) instantaneous and continuous torques to improve performance of the electric vehicle. 
       FIG. 3  depicts a schematic example of a direct-drive transverse flux brushless embodiment of hub motor  144  sectioned at the pitch axis. As shown, hub motor  144  may include magnets  192  mounted on (or fixedly secured to) an inside surface of an outer wall of a rotor  194 . Rotor  194  may be fixedly attached to hub adapters  148 ,  152  (see  FIG. 2 ). A stator  196  may be fixedly attached to a sleeve  198  through which central aperture  172  (see  FIG. 2 ) extends. Sleeve  198  may extend through rotor  194 . Sleeve  198  may be fixedly attached to member  190  (see  FIG. 2 ). Sleeve  198  may ride on bearings  200  attached to rotor  194 . In some embodiments, bearings  200  may be attached to sleeve  198  and may ride on rotor  194 . Phase wires  202  may extend through aperture  172  (or other suitable opening) and may electrically connect one or more electric coils  203  of stator  196  with one or more other electrical components (see  FIGS. 4 and 5 ) of vehicle  100 , such as a power stage. The one or more electrical components may drive hub motor  144  based on rider inputs to propel and actively balance vehicle  100  (see  FIGS. 7-12 ). For example, the one or more electrical components may be configured to sense movement of board  104  about the pitch axis, and drive hub motor  144  to rotate tire  132  in a similar direction about the pitch axis. Additionally, the one or more electrical components may be configured to sense movement of board  104  about the roll axis and/or the yaw axis, and modulate a rate at which the motor is driven based on this sensed movement, which may increase a performance of vehicle  100 , particularly when cornering. 
     For example, the one or more electrical components may be configured to selectively energize the electric coils, based on rider inputs (e.g., movement of board  104 ), to produce an electromagnetic field for exerting forces on magnets  192  to cause the desired rotation of rotor  194  relative to stator  196 . 
     In some embodiments, hub motor  144  may be a brushed hub motor. Alternatively, the electric vehicle may include any apparatus and/or motor suitable for driving the hub of a wheel, such as a chain drive, a belt drive, a gear drive and/or a brushed or brushless motor disposed outside of the wheel hub. 
     Preferably, hub motor  144 , tire  132 , and axle mounts  164 ,  184  may be connected together as a subassembly (e.g., wheel assembly  112 ) and then integrated into the overall vehicle (e.g., operatively installed in board  104 ) to facilitate tire changes and maintenance. The subassembly may be operatively installed in board  104  by connecting mounts  164 ,  184  to board  104  with one or more respective fasteners, such as respective bolts  204 ,  206  (see  FIG. 2 ).  FIG. 4  shows bolts  204  connecting mount  184  to a portion of board  104 . Bolts  206  may similarly connect mount  164  to an opposite portion of board  104 . Axle mounts  164 ,  184  may be configured to be unbolted from board  104 , and the motor may be configured to be ‘unplugged’ from the one or more electrical components disposed in board  104  to enable the rider to remove the subassembly from board  104 , for example, to change the tire or perform other maintenance on wheel assembly  112  and/or on board  104 . 
     Referring to  FIGS. 1 and 4 , a first skid pad  208  may be integrated into (or connected to) a first end of board  104  proximal first deck portion  116 , and a second skid pad  212  may be integrated into (or connected to) a second end of board  104  proximal second deck portion  120 . Skid pads  208 ,  212  may be replaceable and/or selectively removable. For example, the skid pads may include replaceable polymer parts or components. In some embodiments, the skid pads may be configured to allow the rider to bring vehicle  100  to a stop in an angled orientation (e.g., by setting one end of the board against the ground after the rider removes their foot from a rider detection device or switch, which is described below in further detail). The respective skid pad may be worn by abrasion with the surface of the ground as that end of the board is set against (or brought into contact with) the ground. 
     Vehicle  100  may include one or more side-skid pads configured to protect the paint or other finish on board  104 , and/or otherwise protect vehicle  100  if, for example, vehicle  100  is flipped on its side and/or slides along the ground on its side. For example, the one or more side-skid pads may be removably connected to one or more opposing longitudinal sides of the board (e.g., extending substantially parallel to the roll axis).  FIG. 1  shows a first side-skid pad  216  connected to a first longitudinal side  104   a  of board  104 . In  FIG. 4 , side-skid pad  216  has been removed from first longitudinal side  104   a . A second side-skid pad (not shown) may be similarly removably connected to a second longitudinal side  104   b  (see  FIG. 4 ) of board  104  opposite first longitudinal side  104   a . The side-skid pads may be incorporated into the electric vehicle as one or more removable parts or components, and/or may be or include replaceable polymer parts or components. 
     A removable connection of the skid pads and/or the side-skid pads to the board may enable the rider (or other user) to selectively remove one or more of these pads that become worn with abrasion, and/or replace the worn pad(s) with one or more replacement pads. 
     As shown in  FIG. 4 , vehicle  100  may include a handle  220 . Handle  220  may be disposed on an underside  104   c  of board  104 . Handle  220  may be integrated into a housing or enclosure of one or more of the electrical components. 
     In some embodiments, handle  220  may be operable between IN and OUT positions. For example, handle  220  may be pivotally connected to board  104 , with the IN position corresponding to handle  220  substantially flush with underside  104   c  of board  104 , and the OUT position corresponding to handle  220  pivoted (or folded) away from underside  104  such that handle  220  projects away from deck portion  120 . 
     Vehicle  100  may include any suitable mechanism, device, or structure for releasing handle  220  from the IN position. For example, vehicle  100  may include a locking mechanism  224  that is configured to operate handle  220  between a LOCKED state corresponding to handle  220  being prevented from moving from the IN position to the OUT position, and an UNLOCKED state corresponding to handle  220  being allowed to move from the IN position to the OUT position. In some embodiments, the rider may press locking mechanism  224  to operate the handle from the LOCK state to the UNLOCKED state. The rider may manually move handle  220  from the IN position to the OUT position. The rider may grasp handle  220 , lift vehicle  100  off of the ground, and carry vehicle  100  from one location to another. 
     In some embodiments, handle  220  may include a biasing mechanism, such as a spring, that automatically forces handle  220  to the OUT position when operated to the UNLOCKED state. In some embodiments, locking mechanism  224  may be configured to selectively lock handle  220  in the OUT position. 
     Vehicle  100  may include any suitable apparatus, device, mechanism, and/or structure for preventing water, dirt, or other road debris from being transferred by the ground-contacting element to the rider. For example, as shown in  FIG. 1 , vehicle  100  may include first and second partial fender portions  228 ,  232 . Portion  228  is shown coupled to first deck portion  116 , and portion  232  is shown coupled to second deck portion  120 . Portion  228  may prevent debris from being transferred from tire  132  to a portion of the rider positioned on or adjacent deck portion  116 , such as when tire  132  is rotated about pitch axis A 1  in a counter-clockwise direction. Portion  232  may prevent debris from being transferred from tire  132  to a portion of the rider positioned on or adjacent deck portion  120 , such as when tire  132  is rotated about pitch axis A 1  in a clockwise direction. 
     Additionally and/or alternatively, vehicle  100  may include a full fender  240 , as shown in  FIGS. 7-10 . Fender  240  may be configured to prevent a transfer of debris from the ground-contacting element to the rider. For example, a first portion  240   a  of fender  240  may be coupled to first deck portion  116 , a second portion  240   b  of fender  240  may be coupled to second deck portion  120 , and a central portion  240   c  of fender  240  may connect the first and second portions  240   a ,  240   b  of fender  240  above a portion of tire  132  that projects above an upper-side of board  104 , as shown in  FIG. 7 . 
     Fender  240  and/or fender portions  228 ,  232  may be attached to at least one of deck portions  116 ,  120  and configured to prevent water traversed by wheel  132  from splashing onto the rider. Fender  240  may be attached to both of deck portions  116 ,  120 , and may substantially entirely separate wheel  132  from the rider, as is shown in  FIGS. 7-10 . 
     Fender  240  may be a resilient fender. For example, fender  240  may include (or be) a sheet of substantially flexible or resilient material, such as plastic. A first side of the resilient material may be coupled to deck portion  116  (or board  104  proximate deck portion  116 ), and a second side of the resilient material may be coupled to deck portion  120  (or board  104  proximate deck portion  120 ). A resiliency of the resilient material between the first and second sides may bias fender  240  away from tire  132  to provide adequate spacing between fender  240  and tire  132 , as shown in  FIGS. 7-10 . The adequate spacing may prevent the tire from contacting the fender. 
     Fender  240  (e.g., portion  240   c ) may be compressible toward tire  132 , if for example, vehicle  100  happens to flip over such that portion  240   c  is in contact with the ground. When vehicle  100  is restored to a suitable riding position, such as that shown in  FIG. 7 , the resiliency of the resilient material may restore the fender to a position providing the adequate spacing. 
     Fender  240  may extend across an overall width of tire  132  in a direction parallel to pitch axis A 1 , in a manner similar to that of partial fender portion  228  is shown extending in  FIG. 1 . Similarly, partial fender portion  232  may extend across the overall width of tire  132  in the direction of pitch axis A 1 . 
     As indicated in  FIG. 4 , the one or more electrical components of vehicle  100  may include a power supply  250 , a motor controller  254 , a rider detection device  262 , a power switch  266 , and a charge plug  268 . Power supply  250  may include one or more batteries which may be re-chargeable, such as one or more lithium batteries that are relatively light in weight and have a relatively high power density. For example, power supply  250  may include one or more lithium iron phosphate batteries, one or more lithium polymer batteries, one or more lithium cobalt batteries, one or more lithium manganese batteries, or a combination thereof. For example, power supply  250  may include sixteen (16) A123 lithium iron phosphate batteries (e.g., size 26650). The batteries of power supply  250  may be arranged in a 16S1P configuration. A microcontroller  269  and/or one or more sensors (or at least one sensor)  270  may be included in or connected to motor controller  254  (see  FIG. 5 ). At least one of sensors  270  may be configured to measure orientation information (or an orientation) of board  104 . For example, sensors  270  may be configured to sense movement of board  104  about and/or along the pitch, roll, and/or yaw axes. The motor may be configured to cause rotation of wheel  132  based on the orientation of board  104 . In particularly, motor controller  254  may be configured to receive orientation information measured by the at least one sensor of sensors  270  and to cause motor assembly  254  to propel the electric vehicle based on the orientation information. For example, motor controller  254  may be configured to drive hub motor  144  based on received sensed movement of board  104  from sensors  270  via microcontroller  269  to propel and/or actively balance vehicle  100 . 
     One or more of the electrical components may be integrated into board  104 . For example, board  104  may include a first environmental enclosure that may house power supply  250 , and a second environmental enclosure that may house motor controller  254 , and rider detection device  262 . The environmental enclosures may protect the one or more electrical components from being damaged, such as by water ingress. 
     Vehicle  100  may include one or more light assemblies, such as one or more headlight and/or taillight assemblies. For example, a first headlight/taillight assembly (or first light assembly)  272  may be disposed on or at (and/or connected to) a first end portion of board  104  (e.g., at a distal end portion of first deck portion  116 ), and a second headlight/taillight assembly  276  may be disposed on or at (and/or connected to) a second end portion of board  104  (e.g., at a distal end portion of second deck portion  120 ). The second end portion of board  104  may be opposite the first end portion. 
     Headlight/taillight assemblies  272 ,  276  may be configured to reversibly light vehicle  100 . For example, assemblies  272 ,  276  may indicate the direction that vehicle  100  is moving by changing color. For example, the headlight/taillight assemblies may each include one or more high output red and white LEDs (or other suitable one or more illuminators)  278  configured to receive data from microcontroller  269  (and/or a pitch sensor of sensors  270 , such as a 3-axis gyro  280 —see  FIG. 5 ) and automatically change color from red to white (or white to red, or a first color to a second color) based on the direction of movement of vehicle  100 , with white LEDs (or a first color) shining in the direction of motion and red LEDs (or a second color) shining backward (e.g., opposite the direction of motion). For example, one or more of the headlight/taillight assemblies (e.g., their respective illuminators) may be connected to microcontroller  269  via an LED driver  282  (see  FIG. 5 ), which may be included in or connected to motor controller  254 . In some embodiments, the illuminators may include RGB/RGBW LEDs. 
     Illuminators  278  may be located in and/or protected by skid pads  208 ,  212 , as shown in  FIG. 4 . For example, skid pads  208 ,  212  may include respective apertures  286 ,  290 . Illuminators  278  may be disposed in and shine through respective apertures  286 ,  290 . Apertures  286 ,  290  may be dimensioned to prevent illuminators  278  from contacting the ground. For example, apertures  286 ,  290  may each have a depth that is greater than a height of illuminators  278 . In some embodiments, the illuminators may be separable from the associated skid pad, so that the skid pads may be removed without removing the illuminators. 
     As shown in  FIG. 4 , first skid pad  208  and a first illuminator  278  are disposed at a distal end of first deck portion  116 , and second skid pad  212  and a second illuminator  278  are disposed at a distal end of second deck portion  120 . Each of skid pads may include an aperture (e.g., skid pad  208  may include aperture  286 , and skid pad  212  may include aperture  290 , as mentioned above) configured to allow light from the corresponding illuminator to shine through while preventing the illuminator from contacting the ground. 
     Illustrative Electrical System 
       FIG. 5  shows a block diagram of the one or more electrical components of vehicle  100 . The electrical components may include a power supply management system  300 , a direct current to direct current (DC/DC) converter  304 , a brushless direct current (BLDC) drive logic  306 , a power stage  310 , a 3-axis accelerometer  314 , one or more hall sensors  318 , and a motor temperature sensor  322 . DC/DC converter  304 , BLDC drive logic  306 , and power stage  310  may be included in and/or connected to motor controller  254 . Accelerometer  314  may be included in sensors  270 . 
     Active balancing (or self-stabilization) of the electric vehicle may be achieved through the use of a feedback control loop or mechanism, which may be implemented in the one or more electrical components. The feedback control mechanism may include sensors  270  connected to (and/or included in) motor controller  254 . 
     Preferably, the feedback control mechanism includes a Proportional-Integral-Derivative (PID) control scheme using one or more gyros (e.g., gyro  280 ) and one or more accelerometers (e.g., accelerometer  314 ). Gyro  280  may be configured to measure pivotation of foot deck  104  about the pitch axis. Gyro  280  and accelerometer  314  may be collectively configured to estimate (or measure, or sense) a lean angle of board  104 , such as an orientation of the foot deck about the pitch, roll and yaw axes. In some embodiments, the gyro and accelerometer  314  may be collectively configured to sense orientation information sufficient to estimate the lean angle of frame  104  including pivotation about the pitch, roll and yaw axes. 
     As mentioned above, orientation information of board  104  may be measured (or sensed) by gyro  280  and accelerometer  314 . The respective measurements (or sense signals) from gyro  280  and accelerometer  314  may be combined using a complementary or Kalman filter to estimate a lean angle of board  104  (e.g., pivotation of board  104  about the pitch, roll, and/or yaw axes, with pivotation about the pitch axis corresponding to a pitch angle, pivotation about the roll axis corresponding to a roll or heel-toe angle, and pivotation about the yaw axis corresponding to a yaw angle) while filtering out the impacts of bumps, road texture and disturbances due to steering inputs. For example, gyro  280  and accelerometer  314  may be connected to microcontroller  269 , which may be configured to correspondingly measure movement of board  104  about and along the pitch, roll, and yaw axes (see  FIG. 1 ). Alternatively, the electronic vehicle may include any suitable sensor and feedback control loop configured to self-stabilize a vehicle, such as a 1-axis gyro configured to measure pivotation of the board about the pitch axis, a 1-axis accelerometer configured to measure a gravity vector, and/or any other suitable feedback control loop, such as a closed-loop transfer function. However, additional accelerometer and gyro axes may allow improved performance and functionality, such as detecting if the board has rolled over on its side or if the rider is making a turn. 
     The feedback control loop may be configured to drive motor  144  to reduce an angle of board  104  with respect to the ground. For example, if in  FIG. 1  the rider was to angle board  104  downward, so that first deck portion  116  was ‘lower’ than second deck portion  120  (e.g., if the rider pivoted board  104  clockwise about pitch axis A 1 ), then the feedback loop may drive motor  144  to cause clockwise rotation of tire  132  about pitch axis A 1  (see  FIG. 9 ) and a counter-clockwise force on board  104 . 
     Thus, motion of the electric vehicle may be achieved by the rider leaning their weight toward their ‘front’ foot. Similarly, deceleration may be achieved by the rider leaning toward their ‘back’ foot. Regenerative braking can be used to slow the vehicle. Sustained reverse operation may be achieved by the rider maintaining their lean toward their ‘back’ foot. 
     As indicated in  FIG. 5 , microcontroller  269  may be configured to send a signal to BLDC drive logic  306 , which may communicate information relating to the orientation and motion of board  104 . BLDC drive logic  306  may then interpret the signal and communicate with power stage  310  to drive motor  144  accordingly. Hall sensors  318  may send a signal to the BLDC drive logic to provide feedback regarding a substantially instantaneous rotational rate of the rotor of motor  144 . Motor temperature sensor  322  may be configured to measure a temperature of motor  144  and send this measured temperature to logic  306 . Logic  306  may limit an amount of power supplied to motor  144  based on the measured temperature of motor  144  to prevent motor  144  from overheating. 
     Certain modifications to the PID loop or other suitable feedback control loop may be incorporated to improve performance and safety of the electric vehicle. For example, integral windup may be prevented by limiting a maximum integrator value, and an exponential function may be applied to a pitch error angle (e.g., a measure or estimated pitch angle of board  104 ). 
     Alternatively or additionally, some embodiments may include neural network control, fuzzy control, genetic algorithm control, linear quadratic regulator control, state-dependent Riccati equation control or other control algorithms. In some embodiments, absolute or relative encoders may be incorporated to provide feedback on motor position. 
     As mentioned above, during turning, the pitch angle can be modulated by the heel-toe angle (e.g., pivotation of the board about the roll axis—see  FIG. 11 ), which may improve performance and prevent a front inside edge of board  104  from touching the ground. In some embodiments, the feedback loop may be configured to increase, decrease, or otherwise modulate the rotational rate of the tire if the board is pivoted about the roll and/or yaw axes. This modulation of the rotational rate of the tire may exert an increased normal force between a portion of the board and the rider, and may provide the rider with a sense of ‘carving’ when turning, similar to the feel of carving a snowboard through snow or a surfboard through water. 
     Once the rider has suitably positioned themselves on the board, the control loop may be configured to not activate until the rider moves the board to a predetermined orientation. For example, an algorithm may be incorporated into the feedback control loop, such that the control loop is not active (e.g., does not drive the motor) until the rider uses their weight to bring the board up to an approximately level orientation (e.g., 0 degree pitch angle—as shown in  FIG. 8 ). Once this predetermined orientation is detected, the feedback control loop may be enabled (or activated) to balance the electric vehicle and to facilitate a transition of the electric vehicle from a stationary mode (or configuration, or state, or orientation) to a moving mode (or configuration, or state, or orientation). 
     Referring back to  FIG. 5 , the one or more electrical components may be configured to manage power supply  250 . For example, power supply management system  300  may be a battery management system configured to protect batteries of power supply  250  from being overcharged, over-discharged, and/or short-circuited. System  300  may monitor battery health, may monitor a state of charge in power supply  250 , and/or may increase the safety of the vehicle. Power supply management system  300  may be connected between charge plug  268  and power supply  250 . The rider (or other user) may couple a charger to plug  268  and re-charge power supply  250  via system  300 . 
     In operation, power switch  266  may be activated (e.g., by the rider). Activation of switch  266  may send a power-on signal to converter  304 . In response to the power-on signal, converter  304  may convert direct current from a first voltage level provided by power supply  250  to one or more other voltage levels. The other voltage levels may be different than the first voltage level. Converter  304  may be connected to the other electrical components via one or more electrical connections to provide these electrical components with suitable voltages. 
     Converter  304  (or other suitable circuitry) may transmit the power-on signal to microcontroller  269 . In response to the power-on signal, microcontroller may initialize sensors  270 , and rider detection device  262 . 
     The electric vehicle may include one or more safety mechanisms, such as power switch  266  and/or rider detection device  262  to ensure that the rider is on the board before engaging the feedback control loop. In some embodiments, rider detection device  262  may be configured to determine if the rider&#39;s feet are disposed on the foot deck, and to send a signal causing motor  144  to enter an active state when the rider&#39;s feet are determined to be disposed on foot deck  104 . 
     Rider detection device  262  may include any suitable mechanism, structure, or apparatus for determining whether the rider is on the electric vehicle. For example, device  262  may include one or more mechanical buttons, one or more capacitive sensors, one or more inductive sensors, one or more optical switches, one or more force resistive sensors, and/or one or more strain gauges. The one or more mechanical buttons may be located on or under either or both of first and second deck portions  116 ,  120  (see  FIG. 1 ). The one of more mechanical buttons may be pressed directly (e.g., if on the deck portions), or indirectly (e.g., if under the deck portions), to sense whether the rider is on board  104 . The one or more capacitive sensors and/or the one or more inductive sensors may be located on or near a surface of either or both of the deck portions, and may correspondingly detect whether the rider is on the board via a change in capacitance or a change in inductance. Similarly, the one or more optical switches may be located on or near the surface of either or both of the deck portions. The one or more optical switches may detect whether the rider is on the board based on an optical signal. The one or more strain gauges may be configured to measure board or axle flex imparted by the rider&#39;s feet to detect whether the rider is on the board. In some embodiments, device  262  may include a hand-held “dead-man” switch. Various embodiments and aspects relating to device  262  are discussed further below, in the section titled Illustrative Rider Detection Devices, Systems, and Methods. 
     If device  262  detects that the rider is suitably positioned on the electric vehicle, then device  262  may send a rider-present signal to microcontroller  269 . The rider-present signal may be the signal causing motor  144  to enter the active state. In response to the rider-present signal (and/or the board being moved to the level orientation), microcontroller  269  may activate the feedback control loop for driving motor  144 . For example, in response to the rider-present signal, microcontroller  269  may send board orientation information (or measurement data) from sensors  270  to logic  306  for powering motor  144  via power stage  310 . 
     In some embodiments, if device  262  detects that the rider is no longer suitably positioned or present on the electric vehicle, device  262  may send a rider-not-present signal to microcontroller  269 . In response to the rider-not-present signal, circuitry of vehicle  100  (e.g., microcontroller  269 , logic  306 , and/or power stage  310 ) may be configured to reduce a rotational rate of the rotor relative to the stator to bring vehicle  100  to a stop. For example, the electric coils of the rotor may be selectively powered to reduce the rotational rate of the rotor. In some embodiments, in response to the rider-not-present signal, the circuitry may be configured to energize the electric coils with a relatively strong and/or substantially continuously constant voltage, to lock the rotor relative to the stator, to prevent the rotor from rotating relative to the stator, and/or to bring the rotor to a sudden stop. 
     In some embodiments, the vehicle may be configured to actively drive motor  144  even though the rider may not be present on the vehicle (e.g., temporarily), which may allow the rider to perform various tricks. For example, device  262  may be configured to delay sending the rider-not-present signal to the microcontroller for a predetermined duration of time, and/or the microcontroller may be configured to delay sending the signal to logic  306  to cut power to the motor for a predetermined duration of time. 
     The electric vehicle may include other safety mechanisms, such as a buzzer mechanism. The buzzer mechanism may be configured to emit an audible signal (or buzz) to the rider if circuitry within the electric vehicle detects an error. For example, the buzzer mechanism may emit an error signal to the rider if circuitry within the electric vehicle does not pass a diagnostic test (see  FIG. 6 ). 
     Illustrative Operational Method 
       FIG. 6  depicts multiple steps of a method (or operations), generally indicated at  600 , which may be performed by and/or in conjunction with vehicle  100 . Although various steps of method  600  are described below and depicted in  FIG. 6 , the steps need not necessarily all be performed, and in some cases may be performed in a different order than the order shown. 
     As shown, method  600  may include an initialization procedure, a standby procedure, and an operation procedure. The initialization procedure may include a step  602  of activating a power switch. For example, at step  602 , the rider may press switch  266  (see  FIG. 4 ). The initialization procedure may then flow to a step  604  of performing one or more diagnostics. For example, circuitry of vehicle  100  may perform one or more diagnostic tests to determine whether the one or more electrical components are properly operational. For example, at step  604 , motor controller  254  may perform a self-diagnostic to determine whether components thereof, such as the power stage, are operational. 
     The initialization procedure may include a step  606  of determining whether the diagnostics performed at step  606  were passed. If it is determined at step  606  that the diagnostics were not passed, then method  600  may flow to a step  608  of emitting an error signal, and a step  610  of disabling the vehicle. For example, vehicle  100  may emit an audible buzz via the buzzer mechanism or emit a light signal (e.g., by flashing illuminators  278 ) if it is determined that the diagnostics were not passed, and may prevent motor controller  254  from powering motor  144 . In some embodiments, disabling the vehicle may involve locking the rotor relative to the stator. For example, the motor controller may continuously energize the electric coils of the stator with a substantially constant current to prevent the rotor from rotating relative to the stator. However, if it is determined at step  606  that the diagnostics were passed, then the initialization procedure may flow to a step  612  of initializing sensors  270 . 
     As shown in  FIG. 6 , the initialization procedure may then flow to the standby procedure. The standby procedure may include a step  614  of determining whether a rider is detected. For example, circuitry of vehicle  100  may determine whether the rider is detected as being suitably positioned on board  104  (e.g., with one foot on first deck portion  116 , and the other foot on second deck portion  120 , as shown in  FIG. 7 ), based on a received signal from rider detection device  262 . If it is determined at step  614  that the rider is not detected on the vehicle, then step  614  may be repeated until a rider is detected. In some embodiments, device  262  may substantially continuously send the rider-present signal to the circuitry when the rider is positioned on the vehicle, and/or may substantially continuously send the rider-not-present signal to the circuitry when the rider is not positioned on the vehicle. In some embodiments, device  262  may intermittently send these signals based on the position of the rider. 
     If it is determined at step  614  that a rider is detected as suitably positioned on board  104 , as is shown in  FIG. 7 , then the standby procedure may flow to a step  616  of reading or acquiring one or more measurements (e.g., orientation information) from sensors  270  (e.g., gyro  280  and accelerometer  314 ). 
     The standby procedure may include a step  618  of determining whether board  104  is in the level orientation (or other predefined and/or predetermined orientation). Circuitry of vehicle  100  may determine whether board  104  is in the level orientation based on the measurements acquired from sensors  270  at step  616 . If it is determined at step  618  that board  104  is not in the level orientation, as is shown in  FIG. 7 , then the standby procedure may return to step  614 . 
     However, if it is determined at step  618  that board  104  is in the level orientation, as is shown in  FIG. 8 , then the standby procedure may flow to the operation procedure (e.g., to initialize self-balancing of the vehicle) via the feedback control loop, an example of which is generally indicated at  620  in  FIG. 6 . Loop  620  may be a closed-loop balancing routine, which may be repeated until the rider is no longer detected. 
     Loop  620  may include a step  622  of reading or acquiring one or more measurements from sensors  270 . For example, at step  622 , microcontroller  269  (or other circuitry) may acquire acceleration measurements of board  104  along the pitch, roll, and yaw axes from accelerometer  314 , and may acquire position measurements of board  104  about the pitch, roll, and yaw axes from gyro  280 . 
     Loop  620  may include a step  624  of applying sensor offsets to one or more of the measurements acquired at step  622 . For example, offsets for the accelerometer and the gyro may be determined at step  612  during initialization, which may be applied at step  624  to the measurements acquired at step  622  to substantially correct sensor bias. 
     Loop  620  may include a step  626  of combining sensor values. For example, at step  626 , microcontroller  269  may combine measurements from accelerometer  314  and gyro  280  acquired at step  622  (including or not including the applied offsets) with the complementary or Kalman filter. 
     Loop  620  may include a step  628  of calculating (or determining) the lean angle of board  104 . At step  628 , microcontroller  628  may determine the lean angle based on the combined measurements from accelerometer  314  and gyro  280 . 
     As described above, the lean angle may include the pitch, roll, and yaw angles of board  104 . As shown in  FIG. 9 , the rider may pivot board  104  about pitch axis A 1  to produce a pitch angle θ 1 , in which case at step  630 , the microcontroller may determine that board  104  has pitch angle θ 1  based on combined measurements (e.g., orientation information) from accelerometer  314  and gyro  280 . As shown, the pitch angle may be determined based on an orientation of board  104  with respect to the level orientation. The level orientation may be determined or calculated based on a measured gravity vector. 
     Loop  620  may include a step  630  of calculating an error angle. The error angle may be an estimate or calculation of a displacement of the board from the level orientation based on orientation information from sensors  270 . For example, in the orientation shown in  FIG. 9 , the microcontroller may determine that pitch angle θ 1  is the error angle. At step  630 , microcontroller  269  may calculate (or determine) the error angle with respect to a gravity vector measurement acquired from accelerometer  314 . 
     Loop  620  may include a step  632  of calculating P, I, and D values for the PID control scheme. These values may be used to filter out impacts from bumps on the ground, road texture, and/or disturbances due to unintentionally sudden steering inputs. 
     Loop  620  may include a step  634  of sending a motor command (or motor control signal) to motor  144 . At step  634 , the motor controller may generate the motor control signal in response to the orientation information received sensors  270 . Motor  144  may be configured to receive the motor control signal from motor controller  254  and to rotate wheel  132  in response to the orientation information. 
     For example, at step  634 , microcontroller  269  may send a signal to logic  306  including information corresponding to the calculated lean angle, the calculated error angle (which may be the calculated lean angle or a percentage thereof), and/or the calculated P, I, D values. Based on this information, BLDC drive logic  306  may determine how to accordingly drive motor  144 . For example, logic  306  may determine that the rotor of motor  144  should be driven in a clockwise direction (in  FIG. 9 ) at a first rate, based on pitch or error angle  61 , to attempt to move board  104  back to the level orientation, and send a corresponding motor command to power stage  310 . Power stage  310  may then accordingly power motor  144  via phase wires  202  (see  FIG. 3 ). If the rider maintains downward pressure on deck portion  116 , the clockwise rotation of the rotor of motor  144  may result in rightward propulsion of vehicle  100  in  FIG. 9 . 
     As shown in  FIG. 9 , in response to the motor command, illuminators  278  coupled to deck portion  116  may emit white light WL, and illuminators  278  coupled to deck portion  120  may emit red light RL, as vehicle  100  moves rightward. 
     Referring back to  FIG. 6 , loop  620  may include a step  636  of determining whether the rider is detected (e.g., as suitably positioned on board  104 ). The microcontroller may make this determination based on a signal from the rider detection device, for example, in a manner similar to that of step  614 . In some embodiments, the determination of whether the rider is detected may be based on motor torque (e.g., a reduction of motor torque below a predefined threshold), or vehicle orientations that may indicate that the electric vehicle is not under rider control (e.g., excessive pitch, roll, and/or yaw angle or modulation thereof). 
     At step  636 , if it is determined that the rider is not detected (e.g., has fallen, jumped, or otherwise dismounted the electric vehicle), then the operation procedure may flow to a step  638  of stopping motor  144 , and return to step  614 . At step  638 , stopping the motor may involve locking the rotor relative to the stator, such that the ground-contacting element (e.g., the tire) stops rotating around the pitch axis relative to the board. For example, at step  638 , the motor controller may energize the electric coils of the stator with a substantially continuous, constant, and/or relatively strong electric current to produce a substantially constant and/or strong electromagnetic field for stopping rotation of the magnets of the rotor around the pitch axis relative to the stator. 
     However, if it is determined at step  363  that the rider is detected (e.g., is still suitably positioned on the electric vehicle), then loop  620  may return to step  622 , and loop  620  may be repeated. For example, in a subsequent repetition of loop  620 , the rider may have moved board  104  to an orientation having a pitch angle θ 2  (see  FIG. 9 ). Pitch angle θ 2  may correspond to further pivotation of board  104  about pitch axis A 1  relative to the orientation of board  104  shown in  FIG. 9 , such that deck portion  116  has been moved further below the level orientation, and deck portion  120  has been moved further above the level orientation. In this subsequent repetition of loop  620 , circuitry of vehicle  100  may power the rotor in a clockwise direction at a second rate, based on pitch angle θ 2 , to attempt to move board  104  back to the level orientation. The second rate may be greater than the first rate. 
     In another subsequent repetition of loop  620 , the rider may have moved board  104  to an orientation having a pitch angle θ 3  (see  FIG. 10 ). As shown, pitch angle  83  corresponds to pivotation of board  104  about pitch axis A 1 , such that deck portion  120  has been moved below the level orientation, and deck portion  116  has been moved above the level orientation. In this subsequent repetition of loop  620 , circuitry of vehicle  100  may power the rotor of motor  144  to rotate in a counter-clockwise direction (as indicated in  FIG. 10 ) at a third rate, based on pitch angle θ 3 , to attempt to move board  104  back to the level orientation. If the rider maintains downward pressure on deck portion  120 , the counter-clockwise rotation of the rotor of motor  144  may result in leftward propulsion of vehicle  100  in  FIG. 10 . An absolute value of the third rate may correspond to a greater rate than an absolute value of the first rate, as angle θ 3  in  FIG. 10  is shown to have a larger magnitude than angle θ 1  in  FIG. 9 . Similarly, an absolute value of the third rate may correspond to a lesser rate than an absolute value of the second rate, as angle θ 3  is shown to have a smaller magnitude than angle θ 2  in  FIG. 9 . 
     As mentioned above, the light assemblies may switch color when vehicle  100  reverses direction. For example, as shown in  FIG. 10 , in response to the reversed direction of movement of vehicle  100  (relative to the direction of movement shown in  FIG. 9 ), illuminators  278  coupled to deck portion  116  may switch from illuminating white light to emitting red light RL, and illuminators  278  coupled to deck portion  120  may switch from emitting red light to emitting white light RL, as vehicle  100  moves leftward. 
     In particular, illuminators  278  of the first light assembly (e.g., disposed at the first end portion of board  104  on the right-hand side of  FIG. 9 ) may be configured to output light of a first color (e.g., white) when board  104  is being propelled generally in a first direction (e.g., indicated in  FIG. 9  as to the right), and to output light of a second color (e.g., red) when board  104  is being propelled generally in a second direction (e.g., to the left in  FIG. 10 ). 
     Similarly, illuminators  278  of the second light assembly (e.g., disposed at the second end portion of board  104  on the left-hand side of  FIG. 9 ) may be configured to output light of the second color (e.g., red) when board  104  is being propelled generally in the first direction (e.g., indicated in  FIG. 9  as to the right), and to output light of the first color (e.g., white) when board  104  is being propelled generally in the second direction (e.g., to the left in  FIG. 10 ). 
     Vehicle  100  may include a turn compensation feature. The turn compensation feature may adjust a rate at which motor  144  is driven based on the roll angle of board  104 . For example, the rider may pivot board  104  from the level orientation to a rolled orientation about roll axis A 2 , as shown in  FIG. 11 , by changing heel and/or toe pressure applied to board  104 , resulting in a roll angle θ 4 , in which case, step  628  of  FIG. 6  may involve calculating roll angle θ 4  based on orientation information from sensors  270 . If board  104  is also pivoted about the pitch axis (e.g. has pitch angle θ 1  or θ 3 , as shown respectively in  FIGS. 9 and 10 ), then at step  634  of  FIG. 6 , the circuitry may send an increased amount of power to motor  144  based on roll angle θ 4  to increase the rotational rate of the rotor and thus tire  132 . A magnitude of the increased amount of power may be based on a magnitude of the roll angle, with a greater roll angle magnitude corresponding to a greater increase in power, and a lesser roll angle magnitude corresponding to a lesser increase in power. 
     Similarly, the turn compensation feature may adjust a rate at which motor  144  is driven based on a change in the yaw angle of board  104 . For example, the rider may pivot board  104  from a first orientation (as shown in dash double dot lines in  FIG. 12 ) to a second orientation (as shown in solid lines in  FIG. 12 ) about yaw axis A 3 , resulting in a yaw angle change θ 5 . If in this second orientation, board  104  is also oriented to have a pitch angle, then at step  634  of  FIG. 6 , the circuitry may send an increased amount of power to motor  144  based on yaw angle change θ 5  to increase the rotational rate of the rotor and thus tire  132 . 
       FIGS. 7-12  show a process of operating vehicle  100 .  FIG. 7  shows the rider on board  104  in a starting orientation. The starting orientation may correspond to one of the rider&#39;s feet pressing downward on deck portion  120  to brace deck portion  120  against the ground, and the other of the rider&#39;s feet positioned on deck portion  116 . As shown, the rider&#39;s right foot is pressing downward on deck portion  120 , and the rider&#39;s left foot is contacting deck portion  116 . However, board  104  may be configured to allow the rider to operate vehicle  100  in a “switch” stance, with their left foot on deck portion  120 , and their right foot on deck portion  116 . In (or prior to) the starting position, the rider may power-on vehicle  100  by pressing switch  266  (see  FIG. 4 ). In the starting position, circuitry of vehicle  100  may prevent or hinder rotation of the rotor relative to the stator (see  FIG. 3 ), for example, by powering the electric coils with a relatively strong and substantially continuously constant current (and/or mechanically locking and/or creating increased friction between the rotor and the stator), which may assist the rider in moving board  104  to the level orientation. The circuitry of vehicle  100  may be configured to remove this rotational hindrance when orientation information from the sensors indicates that board  104  has been moved to the level orientation. 
     The rider may move board  104  to the level orientation, as shown in  FIG. 8 , by shifting their weight to pivot board  104  about pitch axis A 1 . Movement of board  104  to the level orientation may initialize active balancing of vehicle  100  via control loop  620  (see  FIG. 6 ). In some embodiments, circuitry of vehicle  100  may be configured to initialize (or proceed to) loop  620  after board  104  has been maintained in the level orientation (or a range of orientations near the level orientation) for a predetermined duration of time (e.g., 1 second), which may provide adequate delay for ensuring that the rider is in control of vehicle  100 . 
     As indicated in  FIG. 9 , the rider may pivot board  104  about pitch axis A 1  by angle  81  to move vehicle  100  “forward” (that is to the to the right in  FIG. 9 ) via clockwise rotation provided by motor  144 . The rider may increase the clockwise rotation of motor  144 , and thus the forward speed of vehicle  100  by further pivoting board  104  in a clockwise direction, for example to produce pitch angle θ 2 . 
     As the rider increases the speed of vehicle  100  by pressing deck portion  116  further toward the ground (e.g., to pitch angle  82 ), the power output of motor  144  may approach a maximum power output. At the maximum output of motor  144 , pressing deck portion  116  further toward the ground may result in a front end of the board contacting the ground at a relatively high speed, which may result in an accident. To prevent a likelihood of such an accident, vehicle  100  may include a power margin indication feature configured to indicate to the rider a margin between a current power output of motor  144  and the maximum power output of motor  144 . For example, when the current power output of motor  144  reaches a predetermined headroom threshold near the maximum power output (e.g., if motor  144  is being driven at a relatively high speed or rate and the rider pivots board  104  to pitch angle  82 ), circuitry of vehicle  100  may be configured to send an increased pulse of power (e.g., in excess of the headroom threshold, but less than or equal to the maximum power output) to motor  144  to push back the rider and move the board  104  back toward (and/or to) the level orientation (or in some embodiments, even further back). In some embodiments, the power margin indicator may communicate a relationship between the current power output and the maximum power output by emitting an audio signal (e.g., from the buzzer) or a visual signal (e.g., from a tachometer). In some embodiments, the power margin indicator may be configured to similarly indicate a margin (or ratio) between the current power output and the maximum power output when vehicle  100  is propelled in reverse, as shown in  FIG. 10 . 
     While pivoting board  104  to have a pitch angle with respect to the level orientation, as shown in  FIGS. 9 and 10 , the rider may pivot board  104  about roll axis A 2 , as is shown in  FIG. 11 , to modulate power to the motor. 
     Similarly, while pivoting board  104  to have a pitch angle with respect to the level orientation, the rider may pivot board  104  about yaw axis A 3 , as is shown in  FIG. 12 , to modulate power to the motor. 
     Illustrative Peripheral Systems and Software 
     In some embodiments, one or more electric vehicles, which may each be similar to and/or include vehicle  100 , may be monitored, altered, and/or controlled by one or more peripheral devices. Examples of such systems and components thereof are shown in  FIGS. 13-22 . 
       FIG. 13  shows an illustrative system, generally indicated at  700 . System  700  may include vehicle  100  in communication with a wireless electronic device  710 . Device  710  may be any suitable wireless electronic device including a transmitter TX and/or a receiver RX. For example, device  710  may be a smartphone, a tablet computer, or any other wireless electronic device capable of wirelessly transmitting and/or receiving data. 
     Device  710  may be configured to wirelessly upgrade and/or alter firmware of vehicle  100  (e.g., of microcontroller  269 ). For example, device  710  may download an encrypted firmware package from a server  720  over a network, such as a cloud network. Device  710  may transmit the package from a transmitter TX of device  710  to a receiver RX of vehicle  100 . In some embodiments, vehicle  100  may include a transmitter TX for transmitting data regarding the operational status of vehicle  100  to a receiver RX of device  710 . Reception of the data by device  710  may prompt device  710  to download the package from server  720 . 
     Device  710  may include a processor (or processor unit—see  FIG. 23 ), a storage device (see  FIG. 23 ), and a program (or software application)  800  comprising a plurality of instructions stored in the storage device. The plurality of instructions may be executed by the processor to receive data transmitted from vehicle  100 , display the received data from vehicle  100  on a graphical user interface (GUI) of device  710 , display a component configuration of vehicle  100  on the GUI of device  710 , transmit data to vehicle  100 , reconfigure (or alter) one or more components of vehicle  100 , control one or more components of vehicle  100 , and/or perform one or more of the features depicted in  FIGS. 14-20 . 
       FIG. 14  depicts a schematic block diagram of various features which may be included in application  800 . Application  800  may include a riding mode selector feature  802 . Feature  802  may be configured to allow the rider (or other user) to select and/or change a riding mode of vehicle  100 . For example, feature  802  may include a top speed limit selector  804 , a top acceleration limit selector  806 , a control loop gain selector  808 , and/or a turn compensation parameter selector  810 . Selector  804  may allow a top speed limit of vehicle  100  (e.g., of the rotor relative to the stator) to be selected (and/or set). For example, the rider may be a novice, in which case selector  804  may be used to set the top speed limit to a relatively low speed, such as 2 miles per hour (MPH). At a later time and/or as the rider becomes more proficient in operating the electric vehicle, the rider may use selector  804  to increase the top speed limit (e.g., to 8 MPH). In another example, the electric vehicle may be used by multiple users, at least one of which may be a novice, and at least one of which may be more experienced. Selector  804  may be used to set the top speed limit to a lower speed for the novice, and to a higher speed for the more experienced rider. Similarly, selector  806  may be used to select a top acceleration limit of the electric vehicle (e.g., of the rotor relative to the stator). 
     Selector  808  may be configured to allow a gain of the control loop of the electric vehicle (e.g., see feedback control loop  620  in  FIG. 6 ) to be decreased, increased, or otherwise modulated. For example, the gain may determine a rate at which the rotational rate of the rotor of motor  144  is changed based on how much the lean angle (e.g., pitch angle) of board  104  has been changed. By using selector  808  to set the gain to a lower level, a first change in the pitch angle may correspond to a smaller acceleration of the electric vehicle. By using selector to set the gain to a higher level, the first change in the pitch angle may correspond to a larger acceleration of the electric vehicle. Setting the gain may include changing one or more gains of the PID control loop, such as a proportional gain (Kp), an integral gain (Ki), and/or a derivative gain (Kd). However, changing the proportional gain may more dramatically change a riding feel of the vehicle, as compared to changing the integral gain and/or the derivative gain. 
     Selector  810  may be configured to allow one or more turn compensation parameters to be selected and/or set. For example, selector  810  may allow the user to select whether the roll angle is used to modulate the motor command, and/or set a gain corresponding to a relationship between the roll angle and modulation of the motor command. Similarly, selector  810  may allow the user to select whether a yaw angle change is used to modulate the motor command, and/or set a gain corresponding to a relationship between the yaw angle change and modulation of the motor command. 
     Application  800  may include a battery status feature  812 . Feature  812  may display on the GUI, or otherwise communicate to the user, an amount of available power remaining in the power supply (e.g., the one or more batteries) of the electric vehicle. For example, feature  812  may display remaining battery power as a percentage, and/or a distance corresponding to how far the remaining power may propel the electric vehicle. If the electric vehicle is plugged into a recharging device for recharging the power supply, then feature  812  may display (or communicate) a duration of time until the power supply is fully recharged. 
     Application  800  may include an odometer feature  814 . Feature  814  may display (or otherwise communicate) a total distance that the electric vehicle has been ridden or operated. For example, circuitry of the electric vehicle may transmit data representative of a total number of revolutions of the tire of the electric vehicle to the wireless electronic device. The wireless electronic device may then display (or update) the distance communicated by feature  814  based on the transmitted data. 
     Application  800  may include a lighting mode selector  816 . The electric vehicle may include a plurality of lighting modes, such as a first, second, third, fourth, and fifth lighting modes. The first lighting mode may be configured to reversibly light the headlight/taillight assemblies (e.g., switch the color of the illuminators of the assemblies based on the direction of movement of the electric vehicle). The second lighting mode may be configured to not reversibly light the headlight/taillight assemblies (e.g., not switch the colors based on the direction of movement). The third lighting mode may be configured to emit brighter light from the headlight/taillight assemblies (e.g., for night time riding). The fourth lighting mode may be configured to emit dimmer light from the headlight/taillight assemblies (e.g., for daytime riding). The fifth lighting mode may be configured to flash the illuminators of one or both of the headlight/taillight assemblies (e.g., to increase visibility of the electric vehicle). 
     Selector  816  may allow selection of one or more modes of the plurality of lighting modes. For example, the rider may use selector  816  to select the first lighting mode and the third lighting mode, resulting in the headlight/taillight assemblies being reversibly lit and emitting a greater amount of light. The rider may subsequently use selector  816  to deselect the third lighting mode, and select the fourth lighting mode to decrease power consumption of the electric vehicle. In some embodiments selector  816  may be used to switch the headlight/taillight assemblies between ON and OFF modes. 
     Application  800  may include an informational feature  818 . Feature  818  may be configured to acquire diagnostic, service, error, and/or debugging information from the electric vehicle, and display (or otherwise communicate) this information to the user. For example, feature  818  may acquire and/or display information (or data) representative of, indicative of, corresponding to, and/or associated with battery voltage, current amps, total amp-hours, regenerated or regen amp-hours (e.g., an amount of electric energy recovered through regenerative braking), a current lean angle of the board, a safety margin (e.g., representative of the current power output of the motor relative to the maximum power output of the motor, such as the current power output represented as a percentage of the maximum power output), a current motor temperature, a history of motor temperatures, total battery cycles, and/or an indication of an operational status of any of the foregoing. 
     Application  800  may include a security feature  820 . Feature  820  may be configured to prevent unauthorized use of the electric vehicle. For example, feature  820  may be configured to toggle the electric vehicle between an enabled mode and a disabled mode. The enabled mode may allow the motor of the electric vehicle to be powered. The disabled mode may prevent the motor of the electric vehicle from being powered (and/or electrically and/or mechanically lock the rotor relative to the stator). 
     In some embodiments, an owner and/or an authorized rider of a particular electric vehicle (or set of electric vehicles) may be issued a personal identification number (PIN) corresponding that particular electric vehicle (or set of electric vehicles), in which case feature  820  may allow the owner and/or the authorized rider to input the PIN to toggle the electric vehicle between the enabled and disabled modes. In some embodiments, a predefined relatively close proximity of a wireless electronic device with an authorized PIN to a corresponding electric vehicle may toggle the electric vehicle to the enable mode. In some embodiments, removal of the wireless electronic device with the authorized PIN from the predefined relatively close proximity may toggle the electric vehicle to the disable mode. 
     Feature  820  may allow the predefined relatively close proximity to be adjusted. For example, feature  820  may allow the authorized user to switch the proximity between a relatively short distance (e.g., 5 meters) and a relatively long distance (e.g., 50 meters). Setting the proximity to the short distance may be suitable for personal use. Setting the proximity to the long distance may be suitable for situations in which the electric vehicle is being used by another party, such a renter or a friend. In some embodiments, feature  820  may toggle the electric vehicle to the disable mode when a measured distance between the wireless electronic device and the electronic vehicle is indicative of the wireless electronic device not being carried by a rider of the electronic vehicle. Proximity of the wireless electronic device (or distance there between) may be measured or estimated by any suitable apparatus, mechanism, device, or system, such as a global positioning system (GPS) or one or more other suitable proximity sensors. 
     Application  800  may include a notification feature  822 . Feature  822  may receive a notification from the electric vehicle that the electric vehicle has been turned on (or powered-up). Feature  822  may receive a notification from the electric vehicle when power in the power supply reaches a predefined level, such as at or below 20%. Feature  822  may display (or otherwise communicate) one or more of these notifications to the user. 
     Application  800  may include a navigation feature  824 . Feature  824  may display a map of routes taken by the electric vehicle. The map may include vehicle statistics, such as average speed for one or more of the routes, a top speed for one or more of the routes, a top cornering speed for one or more of the routes, and/or a top acceleration for one or more of the routes. The routes may be identified based at least in part on GPS tracking of either the vehicle or the wireless electronic device, or tracking via another suitable system. The vehicle statistics may be determined based at least in part on motor controller information transmitted from the vehicle to the wireless electronic device. 
     Feature  824  may allow the user to share the map, one or more particular routes, and/or data corresponding thereto with one or more other parties via one or more social networks, such as FACEBOOK® or TWITTER®. Feature  824  may display a map of a user&#39;s current location, and overlay on the map of a circle (or other shape) indicative of how far the electric vehicle can travel (e.g., vehicle range) given a current power level in of the power supply. The map may show locations of nearby charging stations. The charging stations may include public electric vehicle charging stations and/or locations of individual electric vehicle enthusiasts who have been previously identified as allowing others to plug into electrical outlets at their respective homes or businesses. 
     Application  800  may include a training feature  826 . Feature  826  may be configured to guide a rider through a learning progression regarding various features of the electric vehicle. The learning progression may include a series of instructional videos. Each of the instructional videos may be related to a different feature of the electric vehicle. Each video may be followed by one or more guided exercises. If the rider successfully completes the one or more guided exercises, then feature  826  may unlock a new feature of the electric vehicle. The new feature may be a feature that was previously unavailable to the rider. 
       FIG. 15  shows an exemplary screenshot of a home screen  900  of the software application. As shown, screen  900  may include a field  902 . Field  902  may show a percentage of battery power remaining (in this example 88%), and may depict this percentage in a bar graph. Screen  900  may include a field  904  displaying an estimated vehicle range (in this case 5.3 miles) that the electric vehicle may travel based on the percentage of battery power remaining. Fields  902  and/or  904  may be an example of feature  812 . 
     Screen  900  may include a riding mode selector field  906 . Field  906  may be an example of feature  802 . Field  906  may allow the user to select one of a plurality of riding modes, such as a learn mode, a speed mode, or a trick mode. The learn mode may be suitable for use by a novice rider when learning how to operate the electric vehicle. For example, the learn mode may correspond to a lower top speed limit, a lower top acceleration limit, and/or relatively low (or no) turn compensation. The speed (or commute) mode may be suitable for riders who desire to quickly travel on the electric vehicle from one place to another. For example, the speed mode may correspond to a higher top speed limit, a higher top acceleration limit, and/or moderate turn compensation. The trick mode may be suitable for riders who desire to perform various tricks on the electric vehicle. For example, the trick mode may correspond to a moderate top speed limit, a higher top acceleration limit, and/or higher turn compensation. 
     The user may select the learn mode by tapping on a learn field  908 , the user may select the speed mode by tapping on the speed field  910 , and the user may select the trick mode by tapping on a trick field  912 . Selection of one of the modes may correspond to a de-selection of one or more of the other modes. 
     Selection of a riding mode may result in display of a field  914 . Field  914  may show one or more operational parameters of the selected riding mode. For example, if the speed mode is selected, as shown in  FIG. 15 , then field  914  may show a top speed field  916 , an acceleration field  918 , a corning field  920 , and a range field  922 . Field  916  may depict a top speed limit for the speed mode and/or enable the user to set the top speed limit for the speed mode. Field  918  may depict a top acceleration limit for the speed mode and/or enable the user to set the top acceleration limit for the speed mode. Field  920  may depict and/or enable the user to set a rate at which modulation of the roll angle and/or the yaw angle is factored into modulation of the rotational rate of the rotor about the pitch axis. Field  922  may depict how one or more operational parameters (or settings) of the speed mode may affect a range that the electric vehicle can travel. For example, if the operational parameters consume a greater amount of energy, then field  922  may indicate a shorter range, as shown. Similarly, field  914  may depict and/or enable one or more similar operational parameters to be set for the learn and trick modes. 
     Screen  900  may include a lighting mode field  924 . Field  924  may be an example of feature  816 . Field  924  may enable the user to toggle the headlight/taillight assemblies between two or more lighting modes, such as an OFF mode and an ON mode. The OFF mode may correspond to the illuminators of the headlight/taillight assemblies not emitting light. The ON mode may correspond to the illuminators of the headlight/taillight assemblies emitting light. 
     Screen  900  may include an indicator  926 . Indicator  926  may indicate how or through what protocol device  710  is connected to vehicle  100  (see  FIG. 13 ). As indicated in  FIG. 15 , device  710  may be connected to (e.g., in communication with) vehicle  100  via Bluetooth protocol. However, in other embodiments, the wireless electronic device may connect to the electric vehicle via another protocol suitable for transmitting data, preferably wirelessly, from one circuit to another. 
     Screen  900  (and other screens of application  800 ) may include one or more icons that allow a user to switch between various features of application  800 . For example, the screens of application  800  may include icons  928 ,  930 ,  932 ,  934 . Icon  928  may be a riding-mode/home screen icon, which when tapped (or otherwise selected) by the user may switch application  800  to screen  900 . Icon  930  may be a navigation icon, which when selected by the user may switch application  800  to one or more navigation screens. For example, selection of icon  930  may result in display of a menu that allows the user to choose either of screens  1000  or  1100  (see  FIGS. 16 and 17 ). Icon  932  may be a configuration icon, which when selected by the user may display features  818  and/or  820  (see  FIG. 14 ) on a screen  1200  (see  FIG. 18 ). Icon  934  may be a training icon, which when selected by the user may switch application  800  to one or more training screens. The one or more training screens may progress through one or more operations, examples of which are shown in  FIGS. 19 and 20 . 
     In  FIG. 16 , screen  1000  depicts an example of navigation feature  824  (see  FIG. 14 ). As shown in  FIG. 16 , screen  1000  may display a map, generally indicated at  1004 . Map  1004  may show one or more routes traveled by vehicle  100 , such as a first route  1008  (shown in dash double dot lines), a second route  1012  (shown in dash dot lines), and a third route  1016  (shown in dashed lined). For one or more of the routes, map  1004  may display one or more statistics for the electric vehicle along the respective route. For example, map  1004  may display an average speed statistic (e.g., 6 MPH) for the electric vehicle along route  1008 , a location at which the electric vehicle achieved a top (or maximum) cornering speed, a location at which the electric vehicle achieved a top acceleration, and a location at which the electric vehicle achieved a top speed. Values of the top cornering speed, acceleration, and speed may be displayed on map  1004  (e.g., proximal the associated locations). Similarly, map  1004  may display statistics for routes  1012 ,  1016 . In some embodiments, map  1004  may simultaneously display statistics for all of the routes shown. In some embodiments, map  1004  may display statistics for only a subset of the routes, which may be selected by the user. In some embodiments, map  1004  may allow selective display and/or sharing of specific routes (e.g., by tapping on a specific route to access display and/or sharing controls for that specific route). 
     In  FIG. 17 , screen  1100  depicts another example of navigation feature  824  (see  FIG. 14 ). As shown in  FIG. 17 , screen  1100  may display a map, generally indicated at  1104 . Map  1104  may show a current position of the electric vehicle. Feature  824  may overlay a circle  1108  (or other shape, outline, or perimeter) on map  1104  to indicate how far the electric vehicle can travel (e.g., a range of the electric vehicle) based on a current power level in the power supply of the electric vehicle. Map  1104  may depict locations (and/or proximities) of one or more charging stations. For example, map  1104  shows two charging stations located within circle  1108 , and one charging station located outside of circle  1108 . Display of the current position of the electric vehicle, the locations of the charging stations, and/or circle  1108  may help the user to determine a direction of travel, and/or whether to visit a particular charging station to re-charge the power supply of the electric vehicle. For example, based on map  1104 , the user may decide to travel to one of the charging stations located within circle  1108 . 
     In some embodiments, map  1104  of  FIG. 17  may include map  1004  of  FIG. 16 . For example, map  1104  may include a display of routes taken by the electric vehicle and statistics for those routes. 
       FIG. 18  is a schematic of screen  1200  including features  818 ,  820 . Screen  1200  (and/or other screens of the application) may include an image  1204 , which may rotate based on the lean angle (e.g., pivot, roll, and/or yaw angles) of the electric vehicle. For example, rotation of image  1204  may be based on sensor information (or orientation information) from the electric vehicle gyro and accelerometer. For example, the software application may receive a signal indicative of sensor information corresponding to the electric vehicle moving from the orientation shown in  FIG. 7  to the orientation shown in  FIG. 8 . In response to this signal, the software application may correspondingly rotate a display of image  1204  from a first position (shown in solid lines) to a second position (shown in dashed double dot lines). The software application may similarly rotate image  1204  to indicate movement about the roll axis and/or the yaw axis. As shown in  FIG. 18 , image  1204  is an image of the electric vehicle. However, in other embodiments, the image may be an image of another object or shape, or an image of a texture. 
     Rotation of image  1204  may enable the user to remotely view movement of the electric vehicle, and/or conveniently visualize an accuracy of sensor information. For example, rotation of image  1204  may enable the user to verify and/or otherwise interpret information provided by feature  818 . As described above, feature  818  may display diagnostic, service, error, and/or debugging information to the user. For example, the user may manually tilt the electric vehicle, and visually verify that circuitry in the electric vehicle is accurately calculating the lean angle by visually comparing a tilt of image  1204  to the actual electric vehicle. 
     Rotation of image  1204  may increase a security of the electric vehicle. For example, rotation of image  1204  may indicate that an unauthorized party is moving the electric vehicle, in which case the user may access feature  820  to toggle the electric vehicle from the enable mode to the disable mode to prevent unauthorized use of the electric vehicle. 
     In some embodiments image  1204  may be a background image of the software application. For example, image  1204  may be displayed “behind” either of features  818 ,  820 . In some embodiments, image  1204  may appear on one or more of the screens of the software application when the software application receives a signal indicating that the electric vehicle has been powered on, which may increase the security of the electric vehicle. In some embodiments, image  1204  may disappear from one or more of the screens of the software application when the software application receives a signal indicating that the electric vehicle has been powered off. 
     First Illustrative Method for Instructing a User 
       FIG. 19  depicts multiple steps of a method, generally indicated at  1300 , which may be performed by the software application, such as by training feature  826  (see  FIG. 14 ). Although various steps of method  1300  are described below and depicted in  FIG. 19 , the steps need not necessarily all be performed, and in some cases may be performed in a different order than the order shown. 
     Method  1300  may include a step  1302  of providing a first set of instructions to the user. The first set of instructions may relate to a first product feature of the electric vehicle, such as basic balancing. The first set of instructions may include text, audio, and/or video instructions provided by the software application on the wireless electronic device to the user. For example, providing the first set of instructions may involve displaying an instructional video to the user to educate the user in how to execute a first process related to basic balancing, such as pivoting the board from a starting position (see  FIG. 7 ) with one end of the board on the ground, to the level orientation (see  FIG. 8 ) to activate the feedback control loop. 
     Method  1300  may include a step  1304  of guiding the user through a first exercise related to the first product feature. For example, at step  1304 , the software application may (through text, audio, and/or video) direct the user to execute the first process. For example, at step  1304  the software application may be configured to emit voice instructions through a speaker in the wireless electronic device. The voice instructions may direct the user to position the board in the starting position, place their feet on the first and second footpads, and/or move the board to the level orientation. 
     Method  1300  may include a step  1306  of determining whether the first exercise was successfully performed (or completed). At step  1306  a signal may be sent from the electric vehicle to the wireless electronic device. The signal may include information from which the software application may determine whether the first exercise was successfully performed, such as sensor information and/or other information from the microcontroller of the electric vehicle. Based on the signal, the software application may determine whether the first exercise was successfully performed. 
     At step  1306 , if it is determined that the first exercise was not successfully performed (e.g., that the board was not moved to the level orientation), then method  1300  may return to step  1302  and the first set of instructions and/or a set of instructions similar to the first set may be provided to the user on the wireless electronic device by the software application. 
     However, if it is determined at step  1306  that the first exercise was successfully performed, then method  1300  may proceed to a step  1308  of unlocking a second product feature of the electric vehicle. The second product feature may be a feature of the electric vehicle that was previously disabled. The second product feature may be generally more difficult to operate than the first product feature, and/or a product feature that is more complex and/or builds upon a function of the first product feature. For example, the second product feature may be a sustained forward motion feature that involves maintaining a pitch angle of the board to propel the board forward, as is shown in  FIG. 9 . 
     As shown in  FIG. 19 , method  1300  may include a step  1310  of providing a second set of instructions to the user. The second set of instructions may relate to the second product feature. For example, at step  1310 , the software application may provide an instructional video on the wireless electronic device that shows the user how to hold the front foot pad down to drive the electric vehicle forward, and how to allow the board to return to the level orientation to bring the electric vehicle to a stop. 
     Similar to respective steps  1304 ,  1306 , method  1300  may include a step  1312  of guiding the user through a second exercise related to the second product feature, and a step  1314  of determining whether the second exercise was successfully performed. At step  1314 , if it is determined that the second exercise was not successfully performed, then method  1300  may return to step  1310 . However, if it is determined at step  1314  that the second exercise was successfully performed, then method  1300  may proceed to a step  1316  of unlocking a third product feature. The third product feature may be more complex than the first and second product features, and/or may require operational knowledge of the first and/or second product features in order to be safely performed. 
     Second Illustrative Method for Instructing a User 
       FIGS. 20A and 20B  are respective first and second parts a flowchart, and are referred to collectively as  FIG. 20 . 
       FIG. 20  depicts multiple steps of a method, generally indicated at  1400 , which may be performed by the software application, such as by training feature  826  (see  FIG. 14 ). For example, method  1400  may be an embodiment of method  1300  of  FIG. 19 . Although various steps of method  1400  are described below and depicted in  FIG. 20 , the steps need not necessarily all be performed, and in some cases may be performed in a different order than the order shown. 
     As shown, method  1400  may include a step  1402  of displaying a basic balancing instructional video. At step  1402 , the basic balancing instructional video may be displayed on the wireless electronic device by the software application to the rider (or user). 
     Method  1400  may include a step  1404  of guiding the rider through a basic balancing exercise. For example, at step  1404 , the software application may direct the rider to perform the basic balancing exercise on the electric vehicle. In some embodiments, the software application may determine whether the basic balancing exercise was successfully performed. 
     Method  1400  may include a step  1406  of unlocking a slow-speed (e.g., 2 MPH) forward motion feature and a stopping feature. In some embodiments, the software application may unlock the slow-speed forward motion feature after (or only after) it has been determined that the basic balancing exercise was successfully performed (or completed). 
     Method  1400  may include a step  1408  of displaying a forward motion and stopping instructional video, and a step  1410  of guiding the rider through a forward motion and stopping exercise. In some embodiments, the software application may determine whether the forward motion and stopping exercise was successfully performed. 
     Method  1400  may include a step  1412  of unlocking a toe-side turning feature, such as modulation of the rotational rate of the rotor of the motor based on pivotation of the board about the roll axis in a direction opposite to that shown in  FIG. 11 . In some embodiments, the software application may unlock the toe-side turning feature after (or only after) it has been determined that the forward motion and stopping exercise was successfully performed. 
     Method  1400  may include a step  1414  of displaying a toe-side turning instructional video, and a step  1416  of guiding the rider through a toe-side turning exercise. In some embodiments, the software application may determine whether the toe-side turning exercise was successfully performed. 
     Method  1400  may include a step  1418  of unlocking a higher speed feature, such as forward motion at a speed of up to 8 MPH. In some embodiments, the software application may unlock the higher speed feature after (or only after) it has been determined that the toe-side turning exercise was successfully performed. 
     Method  1400  may include a step  1420  of displaying a speed modulation instructional video. For example, the speed modulation instructional video may show the rider a speed modulation process of increasing the pitch angle to increase the speed of the electric vehicle, and decreasing the pitch angle to decrease the speed of the electric vehicle. 
     Method  1400  may include a step  1422  of guiding the rider through a speed modulation exercise. For example, at step  1422 , the software application may direct the rider to perform one or more steps of the speed modulation process. 
     Method  1400  may include a step  1424  of unlocking a reversing feature, such as reverse motion as a result to maintaining the rear foot pad below the level orientation, as shown in  FIG. 10 . In some embodiments, the software application may unlock the reverse motion feature after (or only after) it has been determined that the speed modulation exercise was successfully performed. 
     Method  1400  may include a step  1426  of displaying a reversing instructional video, and a step  1428  of guiding the rider through a reversing exercise. In some embodiments, the software application may determine whether the reversing exercise was successfully performed. 
     Similar to step  1412 ,  1414 ,  1416 , method  1400  may include a step  1430  of unlocking a heel-side turning feature, a step  1432  of displaying a heel-side turning instructional video, and a step  1434  of guiding the rider through a heel-side turning exercise, an example of which is shown in  FIG. 11 . 
     Method  1400  may include a step  1436  of unlocking a full speed feature, such as forward and/or reverse motion at a speed of up to 12 MPH. In some embodiments, the software application may unlock the full speed feature after (or only after) it has been determined that the heel-side turning exercise was successfully performed. 
     Method  1400  may include a step  1438  of displaying a carving instructional video, which may show the rider how to make high-speed turns using modulation of one or more of the roll and yaw angles to module the rotational rate of the rotor relative to the stator. 
     Method  1400  may include a step  1440  of guiding the rider through a carving exercise, in which the rider may be instructed to complete a plurality of turns at relatively high speeds through modulation of the roll and/or yaw angles. 
     Method  1400  may include a step  1442  of awarding a certificate of training completion (or virtual certificate) to the rider. Awarding the certificate may be based upon whether it was determined by the software application that the carving exercise, and/or any of the other exercises, were successfully completed. In some embodiments, method  1400  may include awarding a certificate based on successful performance of one or more of the previously performed exercises, at any of steps  1404 ,  1410 ,  1416 ,  1422 ,  1428 ,  1434 . For example, step  1418  may include unlocking the higher speed feature and awarding a certificate based on successful completion of the toe-side turning exercise. 
     Illustrative Communication Systems 
       FIG. 21  shows a system, generally indicated at  1500 . System  1500  may include electric vehicle  100  and an electric vehicle  1502 , which may be similar to vehicle  100 , in communication with wireless electronic device  710 . For example, vehicle  1502  may include a transmitter and a receiver similar to those of vehicle  100  (see  FIG. 13 ), that are capable of establishing a wireless data-communication link between device  710  and vehicle  1502 . System  1500  may be desirable in a situation in which one user wishes to wirelessly connect to both of vehicles  100 ,  1502  to monitor and/or alter a configuration of either of vehicles  100 ,  1502 . For example, the one user may be a parent who may be riding vehicle  100 , and a child of the parent may be riding vehicle  1502 . The wireless data-communication link formed between device  710  and vehicles  100 ,  1502  may enable the parent, while riding with the child, to alter the riding mode of vehicle  1502  to match the abilities of the child and to alter the riding mode of vehicle  100  to match a power consumption of vehicle  100  to that of vehicle  1502 . 
     System  1500  may enable device  710  to monitor and/or alter the respective configurations of vehicles  100 ,  1502 , either independently or substantially simultaneously. For example, a technician may operate device  710  to update the respective firmware of vehicles  100 ,  1502  at substantially the same time, or may enable the technician to sequentially update vehicles  100 ,  1502 . 
     In some embodiments, system  1500  may enable the technician or other user, to reconfigure the electrical components of vehicle  1502  to match a configuration of the electrical components of vehicle  100 . For example, a rider of vehicle  1502  may be friends with a rider of vehicle  100 . Vehicle  100  may have a configuration (e.g., a particular gain, and/or other settings) that the rider of vehicle  1502  desires to apply to vehicle  1502 , in which case, either of the riders may use device  710  to read the configuration of vehicle  100  (e.g., via the software application), and to reconfigure vehicle  1502  accordingly. In some embodiments, the software application may include a feature that automatically reconfigures vehicle  1502  to match a configuration of vehicle  100 . 
       FIG. 22  shows a system, generally indicated at  1600 . System  1600  may include vehicle  100  in communication with device  710 , and a wireless electronic device  1610 . A first wireless data-communication link may be formed between device  710  and vehicle  100 , and a second wireless data-communication link may be formed between device  1610  and vehicle  100 . Device  1610  may be similar to device  710 . For example, device  1610  may be running a software application similar to application  800  (see  FIG. 14 ). 
     System  1600  may be useful for coaching a rider of vehicle  100 . For example, a trainee may be holding device  710  and may be positioned on vehicle  100 , and a trainer may be holding device  1610  and may be positioned remote from vehicle  100 . The trainee may use the software application running on device  710  to monitor and/or alter a configuration of vehicle  100  and/or receive training information via feature  826  (see  FIG. 14 ). The trainer may use the software application running on device  1610  to similarly monitor and/or alter a configuration of vehicle  100  and/or send training information to device  710  via vehicle  100 . In some embodiments, devices  710 ,  1610  may be in direct communication with one another via one or more wireless data-communication links, and the trainee and the trainer may monitor and/or alter a configuration of vehicle  100  through a mutual data-communication link established between one of the devices and the electric vehicle, and/or mutually share training information. 
     Illustrative Data Processing System 
       FIG. 23  depicts a data processing system  2300 , also referred to as a computer, in accordance with aspects of the present disclosure. In this example, data processing system  2300  is an illustrative data processing system for implementing one or more of the operations and/or functions depicted in  FIGS. 1-22, and 24-29  and/or described in relation thereto. More specifically, in some examples, devices that are embodiments of data processing systems (e.g., onboard computers, chips, and electronic systems) may be programmed or otherwise configured to carry out functions such as motor control, hysteresis algorithms, rider presence information signal processing, power supply management, microcontroller operations, and/or sensor control. 
     Data processing system  2300  may include a communications framework  2302 . Communications framework  2302  provides communications between a processor unit  2304 , a memory  2306 , a persistent storage  2308 , a communications unit  2310 , an input/output (I/O) unit  2312 , and a display  2314 . Memory  2306 , persistent storage  2308 , communications unit  2310 , input/output (I/O) unit  2312 , and display  2314  are examples of resources accessible by processor unit  2304  via communications framework  2302 . 
     Processor unit  2304  serves to run instructions for software that may be loaded into memory  2306 . Processor unit  2304  may be a number of processors, a multi-processor core, or some other type of processor, depending on the particular implementation. Further, processor unit  2304  may be implemented using a number of heterogeneous processor systems in which a main processor is present with secondary processors on a single chip. As another illustrative example, processor unit  2304  may be a symmetric multi-processor system containing multiple processors of the same type. 
     Memory  2306  and persistent storage  2308  are examples of storage devices  2316 . A storage device is any piece of hardware that is capable of storing information, such as, for example, without limitation, data, program code in functional form, and other suitable information either on a temporary basis or a permanent basis. 
     Storage devices  2316  also may be referred to as computer readable storage devices in these examples. Memory  2306 , in these examples, may be, for example, a random access memory or any other suitable volatile or non-volatile storage device. Persistent storage  2308  may take various forms, depending on the particular implementation. 
     For example, persistent storage  2308  may contain one or more components or devices. For example, persistent storage  2308  may be a hard drive, a flash memory, a rewritable optical disk, a rewritable magnetic tape, or some combination of the above. The media used by persistent storage  2308  also may be removable. For example, a removable hard drive may be used for persistent storage  2308 . 
     Communications unit  2310 , in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit  2310  is a network interface card. Communications unit  2310  may provide communications through the use of either or both physical and wireless communications links. 
     Input/output (I/O) unit  2312  allows for input and output of data with other devices that may be connected to data processing system  2300 . For example, input/output (I/O) unit  2312  may provide a connection for user input through a keyboard, a mouse, and/or some other suitable input device. Further, input/output (I/O) unit  2312  may send output to a printer. Display  2314  provides a mechanism to display information to a user. 
     Instructions for the operating system, applications, and/or programs may be located in storage devices  2316 , which are in communication with processor unit  2304  through communications framework  2302 . In these illustrative examples, the instructions are in a functional form on persistent storage  2308 . These instructions may be loaded into memory  2306  for execution by processor unit  2304 . The processes of the different embodiments may be performed by processor unit  2304  using computer-implemented instructions, which may be located in a memory, such as memory  2306 . 
     These instructions are referred to as program instructions, program code, computer usable program code, or computer readable program code that may be read and executed by a processor in processor unit  2304 . The program code in the different embodiments may be embodied on different physical or computer readable storage media, such as memory  2306  or persistent storage  2308 . 
     Program code  2318  is located in a functional form on computer readable media  2320  that is selectively removable and may be loaded onto or transferred to data processing system  2300  for execution by processor unit  2304 . Program code  2318  and computer readable media  2320  form computer program product  2322  in these examples. In one example, computer readable media  2320  may be computer readable storage media  2324  or computer readable signal media  2326 . 
     Computer readable storage media  2324  may include, for example, an optical or magnetic disk that is inserted or placed into a drive or other device that is part of persistent storage  2308  for transfer onto a storage device, such as a hard drive, that is part of persistent storage  2308 . Computer readable storage media  2324  also may take the form of a persistent storage, such as a hard drive, a thumb drive, or a flash memory, that is connected to data processing system  2300 . In some instances, computer readable storage media  2324  may not be removable from data processing system  2300 . 
     In these examples, computer readable storage media  2324  is a physical or tangible storage device used to store program code  2318  rather than a medium that propagates or transmits program code  2318 . Computer readable storage media  2324  is also referred to as a computer readable tangible storage device or a computer readable physical storage device. In other words, computer readable storage media  2324  is a media that can be touched by a person. 
     Alternatively, program code  2318  may be transferred to data processing system  2300  using computer readable signal media  2326 . Computer readable signal media  2326  may be, for example, a propagated data signal containing program code  2318 . For example, computer readable signal media  2326  may be an electromagnetic signal, an optical signal, and/or any other suitable type of signal. These signals may be transmitted over communications links, such as wireless communications links, optical fiber cable, coaxial cable, a wire, and/or any other suitable type of communications link. In other words, the communications link and/or the connection may be physical or wireless in the illustrative examples. 
     In some illustrative embodiments, program code  2318  may be downloaded over a network to persistent storage  2308  from another device or data processing system through computer readable signal media  2326  for use within data processing system  2300 . For instance, program code stored in a computer readable storage medium in a server data processing system may be downloaded over a network from the server to data processing system  2300 . The data processing system providing program code  2318  may be a server computer, a client computer, or some other device capable of storing and transmitting program code  2318 . 
     The different components illustrated for data processing system  2300  are not meant to provide architectural limitations to the manner in which different embodiments may be implemented. The different illustrative embodiments may be implemented in a data processing system including components in addition to and/or in place of those illustrated for data processing system  2300 . Other components shown in  FIG. 23  can be varied from the illustrative examples shown. The different embodiments may be implemented using any hardware device or system capable of running program code. As one example, data processing system  2300  may include organic components integrated with inorganic components and/or may be comprised entirely of organic components excluding a human being. For example, a storage device may be comprised of an organic semiconductor. 
     In another illustrative example, processor unit  2304  may take the form of a hardware unit that has circuits that are manufactured or configured for a particular use. This type of hardware may perform operations without needing program code to be loaded into a memory from a storage device to be configured to perform the operations. 
     For example, when processor unit  2304  takes the form of a hardware unit, processor unit  2304  may be a circuit system, an application specific integrated circuit (ASIC), a programmable logic device, or some other suitable type of hardware configured to perform a number of operations. With a programmable logic device, the device is configured to perform the number of operations. The device may be reconfigured at a later time or may be permanently configured to perform the number of operations. Examples of programmable logic devices include, for example, a programmable logic array, a programmable array logic, a field programmable logic array, a field programmable gate array, and other suitable hardware devices. With this type of implementation, program code  2318  may be omitted, because the processes for the different embodiments are implemented in a hardware unit. 
     In still another illustrative example, processor unit  2304  may be implemented using a combination of processors found in computers and hardware units. Processor unit  2304  may have a number of hardware units and a number of processors that are configured to run program code  2318 . With this depicted example, some of the processes may be implemented in the number of hardware units, while other processes may be implemented in the number of processors. 
     In another example, a bus system may be used to implement communications framework  2302  and may be comprised of one or more buses, such as a system bus or an input/output bus. Of course, the bus system may be implemented using any suitable type of architecture that provides for a transfer of data between different components or devices attached to the bus system. 
     Additionally, communications unit  2310  may include a number of devices that transmit data, receive data, or both transmit and receive data. Communications unit  2310  may be, for example, a modem or a network adapter, two network adapters, or some combination thereof. Further, a memory may be, for example, memory  2306 , or a cache, such as that found in an interface and memory controller hub that may be present in communications framework  2302 . 
     The flowcharts and block diagrams described herein illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various illustrative embodiments. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function or functions. It should also be noted that, in some alternative implementations, the functions noted in a block may occur out of the order noted in the drawings. For example, the functions of two blocks shown in succession may be executed substantially concurrently, or the functions of the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. 
     Illustrative Rider Detection Devices, Systems, and Methods 
     As shown in  FIGS. 24-28 , this section describes illustrative rider detection systems and methods. These rider detection systems and methods relate to various examples of the rider detection device described above (i.e., device  262 ). 
       FIGS. 24 and 25  depict an illustrative pressure-sensing transducer suitable for use in a rider detection system.  FIG. 26  is an overhead view of a similar pressure-sensing transducer.  FIG. 27  is an overhead view of an electric vehicle, including multiple such transducers in corresponding deck portions.  FIG. 28  is a schematic sectional view of the system of  FIG. 27 . 
     In general, a rider detection device, system, or sensor for a personal electric vehicle having zero or more ground-contacting elements (e.g., wheels) may comprise a flexible, resilient, or rigid circuit having one or more sensing elements integrated into a single substrate. The rider detection sensor includes a pressure-sensing transducer configured to convert a sensed force or pressure into an electrical signal. A pressure-sensing transducer may have one or more fully conductive layers and/or one or more partially conductive layers. In some examples, a partially conductive layer may be proportionally conductive, such that the conductivity of the layer is proportional to the applied pressure or force. In some examples, e.g., where one or more of the layers are partially conductive, the sensing element(s) may include a force-sensitive resistor, such as the Force Sensing Resistor® produced by Sensitronics, LLC. A layer in this context may have a width and length substantially greater than its thickness or depth. Accordingly, such a layer may be described as an expanse. 
     A force-sensitive resistor (FSR) includes a material or layer that predictably changes electrical resistance in response to a force being applied to the layer. More specifically, the electrical resistance of a force-sensitive resistor decreases as force is applied, e.g., proportionally. Force-sensitive resistors may include one or more conductive polymers. In some examples, a force-sensitive resistor material may take the form of a polymer sheet, a polymer layer, or a printable ink. Printable force-sensitive resistor inks may be screen printed or otherwise applied onto a film substrate, such as a polyethylene terephthalate (PET) film. In some examples, the term FSR may be used to describe the specific layer of a transducer that includes, for example, the conductive polymer. In some examples, the term FSR may be used to refer to a transducer that includes one or more layers of FSR material. 
     The rider detection sensor, which may be constructed using printed circuit fabrication processes, may include a transducer having one or more conductive layers. For example, a pair of fully and/or proportionally conductive layers may be spaced from and face each other. At least one of the two layers may be resilient or flexible, such that the layer is displaced when a force is applied, thereby contacting the other layer and completing an electrical circuit. As mentioned above, one of the layers may include a force-sensitive resistor, such that the electrical conductivity of that layer is variable depending on the force applied (e.g., the layer resistance is proportional to the force applied). In examples that include a force sensitive resistor, the transducer as a whole will be proportionally responsive to an applied pressure. In examples that include only fully conductive layers, the transducer response will be substantially binary (i.e., on/off). 
     A layer of the rider detection sensor may have relatively small displacement, such that the displacement is not detectable by the rider. For example, deflection or displacement of a sensor may be in a range of about 0.005 to 0.020 inches. More specifically, when a rider applies activation force or pressure to a sensor, a separation distance between layers may be reduced by about 0.005 to 0.020 inches. This amount is for illustration only, and other separation and/or displacement distances may be appropriate. Deactivation of the rider detection sensor element (e.g., by removal of activation pressure or force) may result in the associated conductive layers moving relative to one another to restore the separation distance. For example, as described above, one or both layers may comprise a resilient material. 
     In some examples, an FSR-type transducer will be used to facilitate a more robust rider sensing system. For example, various factors may cause a baseline amount of pressure to be placed upon the rider detection sensor, such as the application of additional layers of material above and/or below the sensor. One advantage an FSR will have in this situation, as opposed to a purely binary sensor, is its proportional response. Although the sensor may be activated to some degree by the baseline pressure, the FSR will only become partially conductive. Accordingly, a threshold level can be set, above which the sensor will indicate a rider&#39;s presence, and below which the sensor will indicate that no rider is present. This threshold can be set above the baseline level, to avoid false positive readings. 
     In some examples, the rider detection sensor may be made weather-resistant by encasing the rider detection sensor or transducer element in a waterproof enclosure, e.g., using waterproof bonding. An air- or vapor-permeable, water-impermeable vent, such as a Gore vent, may be included to allow the rider detection sensor to equilibrate to changes in atmospheric pressure while maintaining waterproof sealing. One suitable example of such a vent is a TEMISH® venting system, S-NTF series, produced by the Nitto Denko Corporation. 
     In some examples, multiple sensing zones (e.g., each defined by a respective sensing transducer) may be included on a single rider detection sensor. The use of multiple zones may enable increased accuracy, better responsiveness to different sources of pressure, and/or can allow different conditions to begin operation, continue operation, and/or halt operation of the vehicle. 
     In one example, a vehicle such as a self-stabilizing skateboard may include first and second sensor zones having associated active areas under the rider&#39;s heel and toe. For example, the first and second sensor zones may be separated from one another by a gap or other region extending substantially parallel to a direction of travel of the skateboard and/or substantially perpendicular to a pitch axis of a centrally disposed wheel of the skateboard. In other words, one pressure-sensing transducer may be adjacent to and laterally spaced from another pressure-sensing transducer, such that the pressure-sensing transducers are configured to be disposed beneath a front portion and a rear portion, respectively, of the foot of the rider. In some embodiments, the rider detection sensor may be fabricated with highly durable polycarbonate/PET materials and sealed with a wide waterproof border. 
     In an exemplary operation, active balancing may be initialized or initiated in response to both zones being pressed. Depression of only one (or at least one) zone may permit continued riding (e.g., continued active balancing). Such an operational configuration may permit relatively aggressive heel-side and toe-side turns, where the rider may lift a heel or toe, while maintaining the other part of the foot in contact with the skateboard deck (e.g., thereby depressing an associated sensor zone). 
     In some examples, when the rider slows the skateboard (or other type of vehicle incorporating the rider detection sensor) below a safe speed specified by software or firmware (such as that which may be included in an associated motor controller), the system may be configured to stop actively balancing the vehicle if the user lifts or otherwise removes a heel or toe from the board. Accordingly, removing pressure from an associated sensor zone may permit the vehicle to come to a stop. Vehicle speed may be measured or sensed by any suitable device or method. For example, a speed sensing device may be associated with the rotational speed of a wheel of the vehicle. 
     In some examples, the rider detection sensor may be made using circuit printing processes typical in the membrane keypad industry and/or the force-sensitive resistor (FSR) industry. In some embodiments, printed conductor layers may be separated by a spacer layer, which may prevent the rider detection sensor from being triggered when not loaded. 
     In some embodiments, the rider detection sensor may be located on a rigid part of a footpad of the vehicle, and sandwiched between a slip-resistant (e.g., grip tape) layer disposed over the rider detection sensor and a rigid part of the footpad disposed under the rider detection sensor. Such a configuration may improve sensor reliability. For example, in such a configuration, the rider detection sensor may have no moving parts, or the parts may not move significantly relative to one another. Due to the printed nature of some sensors (and/or other factors), additional sensor zones can be added without significantly increasing costs. 
     Turning to  FIGS. 24 and 25 , an illustrative rider detection system  2400  is shown in exploded and assembled views. System  2400  comprises an example of rider detection device  262 , and is suitable for use in the system described above, with respect to  FIG. 5 . System  2400  includes a pressure-sensing transducer  2402  disposed (e.g., sandwiched) between a slip-resistant layer  2404  and a deck portion  2404  of an electric skateboard, such as vehicle  100  described above. 
     Pressure-sensing transducer  2402 , interchangeably referred to as a force-sensing or force-sensitive transducer, may include any suitable structure and/or device configured to convert a sensed mechanical force into an electrical signal. In the example shown in  FIG. 24 , pressure-sensing transducer comprises an upper force-sensitive resistor (FSR) layer  2408  and a lower conductive layer  2410 , separated by a gapping or spacer layer  2412 . In this example, the spacer layer includes two portions, a first spacer portion  2412 A and a second spacer portion  2412 B. 
     FSR layer  2408  may include any suitable layer having an electrical resistance that changes predictably in response to an applied force. For example, FSR layer  2408  may include a conductive polymer ink applied to a PET film substrate. In some examples, the substrate may comprise a conductive polymer rather than the printed ink. FSR layer  2408  may be referred to as partially conductive and/or variably conductive. 
     Conductive layer  2410  may include any suitable conductive material, such as a partial electrical circuit. For example, conductive layer  2410  may include a pattern of silver or copper printed or otherwise applied to a film substrate. In some examples, the pattern may include interlocking or interdigitated portions (e.g., fingers). 
     In operation, FSR layer  2408  may be displaced toward conductive layer  2410  by an applied mechanical force (i.e., pressure), such as by the foot of a rider. Contact between the two layers results in a completion of an electrical circuit, allowing a signal to be generated indicating that a rider is present. Because the FSR layer has a variable resistance, additional information may be communicated or measured, e.g., based on the amount of current flowing through the circuit. In some cases, as described above, a certain baseline level of activation may be caused by squeezing the FSR and conductive layers between slip-resistant layer  2404  and deck portion  2404 . As shown in  FIG. 24 , conductive layer  2410  may include a portion that passes through an aperture  2414  in deck portion  2406  to connect with a suitable electrical connector  2416 . Connector  2416  may include any suitable electrical connector configured to place transducer  2402  in communication with a controller, such as motor controller  254  and/or microcontroller  269  (see  FIG. 5 ). 
     Spacer  2412  may include any suitable non-conductive, e.g., dielectric, material configured to keep FSR layer  2408  and conductive layer  2410  separated absent an applied force. In some examples, spacer  2412  may include one or more layer portions (e.g., portion  2412 A and  2412 B) having a thickness greater than that of conductive layer  2410  and placed on opposing lateral sides of the conductive layer, thereby holding FSR layer  2408  above the conductive layer. In some examples, spacer  2412  may include one or more portions configured to be sandwiched between FSR layer  2408  and conductive layer  2410 , such that the spacer portions are disposed only on a periphery of the layers, thereby leaving central or middle portions of each layer free to interact. 
     Slip-resistant layer  2404  may be disposed above transducer  2402 , and may include any suitable material configured to provide a durable, traction-enhancing surface for a rider&#39;s foot. For example, slip-resistant layer  2404  may include a non-skid material, grip tape, a textured layer, and/or the like, or any combination of these. Slip-resistant layer  2404  may be similar in size or larger than transducer  2402 , such that the transducer is also protected to some degree by the slip-resistant layer. Slip-resistant layer  2404  may be an example of portions  124 ,  128 , described above. 
     FSR layer  2408  has been described as being disposed above conductive layer  2410 . However, some examples may have this arrangement reversed, such that the FSR layer is the lower layer. Some examples may include more or fewer of each type of layer. For example, a transducer/sensor may include only a single FSR layer. Any suitable combination of layers may be utilized. 
       FIG. 26  depicts an illustrative pressure- or force-sensing sensor region  2420  suitable for use in a rider detection system such as system  2400 . Similar to transducer  2402 , sensor region  2420  may be incorporated into such a system, for example, by sandwiching the sensor region between a grip tape layer and a rigid portion of the vehicle&#39;s board or deck. As described further below, sensor region  2420  may include a plurality of side-by-side pressure- or force-sensing transducers, each of which defines a different active area or discrete sensing zone. 
     As depicted in  FIG. 26 , sensor region  2420  includes a first pressure-sensing transducer  2422  defining a first active area (or discrete zone)  2424 ; a second pressure-sensing transducer  2426  defining a second active area (or discrete zone)  2428 ; a waterproof housing or enclosure  2430  enclosing transducers  2422  and  2424 ; a vent  2432  configured to permit barometric equilibrium of an internal space inside enclosure  2430  with an exterior environment; and electrical contacts  2434 ,  2436 ,  2438  in electrical communication with the transducers. 
     Each of transducers  2422  and  2426  may include at least partially conductive first and second layers separated by a spacer layer. In some examples, one or both transducers include a resilient first conductive layer spaced from and facing a second conductive layer, such that a force applied to the first conductive layer causes the first conductive layer to contact the second conductive layer. In some examples, one or both transducers include an FSR layer, similar to that described above with respect to  FIGS. 24-25 . 
     Contacts  2434  and  2436  may be electrically connected to transducers  2422  and  2426 , respectively. Contact  2438  may be a ground connection. When force or pressure is applied to first zone  2424  (e.g., by a rider&#39;s foot), thereby reducing or closing a separation distance between the first and second layers of transducer  2422 , rider presence information (e.g., a rider-present signal) may be output on contact  2434 . Similarly, force or pressure applied to second zone  2428  may cause a similar output on contact  2436 . These signals may be communicated to the motor controller, which may use the rider presence information to determine an appropriate state for the motor assembly of the vehicle (e.g., stopping, or rotating the wheel in a forward or reverse direction). In some examples, contact  2434  may be a drive line (e.g., a toe drive line) associated with first transducer  2422 ; contact  2436  may be a drive line (e.g., a heel drive line) associated with second transducer  2426 ; and contact  2438  may be a sense line. 
     In an exemplary use of sensor region  2420 , the sensor region may be positioned or embedded in a platform of a self-stabilizing vehicle (e.g., vehicle  100 ), such that first zone  2424  registers with a first portion of a user&#39;s foot (e.g., a toe region), and second zone  2428  registers with a second portion of the user&#39;s foot (e.g., a heel region). Simultaneously activation of zones  2424  and  2428  may initialize active balancing of the vehicle, for example, via reception of the rider-presence information from respective contacts  2434  and  2436  by a motor controller. Once the vehicle is in an active balancing mode or state, the user may tilt the deck (e.g., in a direction substantially perpendicular to a heel-toe direction) to propel the vehicle along a direction of travel. 
     After the vehicle achieves a predetermined or selected threshold speed (e.g., 3 MPH), the motor controller (or other controller) may be configured to continue active balancing of the vehicle, e.g., by driving the motor, even if pressure is removed from one or more of zones  2424  and  2428 . This may occur, for example, while performing heel and/or toe side turns. However, when the vehicle is being operated below the predetermined or selected threshold speed, removal of pressure from one or both zones may be configured to stop and/or slow active balancing of the vehicle. For example, removal of pressure from zone  2428  (e.g., associated with the rider&#39;s heel) may be configured to send a rider-not-present signal to the motor controller via contact  2436 . If the vehicle is traveling below the threshold speed, rider presence information indicating absence of the rider may cause the motor controller to de-energize the motor and/or send a drive signal to the motor sufficient to bring the vehicle to rest. In a similar manner, removal of pressure from zone  2424  may be configured to bring the vehicle to rest when traveling below the predetermined speed, even if zone  2428  is activated (or vice versa). 
     A controller or control circuit for the motor may incorporate hysteresis to more predictably or more intuitively change modes of the vehicle. For example, a control circuit similar to or incorporating a Schmitt trigger may be used to bias the vehicle toward continued operation at higher speeds and biased toward non-operation at lower speeds. A voltage threshold and/or time-off setting may be adjustable for this purpose. See below for additional description of an illustrative method of operation. 
       FIGS. 27 and 28  depict a rider detection system  2500  having aspects similar to rider detection system  2400  and sensor region  2420 , and suitable for use in an electric vehicle such as vehicle  100 . System  2500  comprises an example of rider detection device  262 , and is suitable for use in the system described above, with respect to  FIG. 5 . System  2500  may include a vehicle such as a self-stabilizing skateboard  2502  having a wheel assembly  2504  coupled to a deck  2506 . This wheel assembly and deck are substantially similar to those described above, with respect to vehicle  100 , wheel assembly  112 , and deck  104 . 
     As depicted in  FIGS. 27 and 28 , a first rider detection unit  2508  (also referred to as a rider detection device, sensing region, or sensor region) may be integrated into, coupled to, connected to, embedded in, or disposed on a first footpad  2510  of deck  2506 . Rider detection unit  2508  may be similar to sensor region  2420  of  FIG. 26 . For example, unit  2508  may include first and second sensing transducers  2512  and  2514  encased in a waterproof enclosure  2516  having a vent  2518  (similar to vent  2432 ) configured to permit barometric equilibrium between an internal space and an external environment. 
     As shown in  FIG. 28 , unit  2508  may be sandwiched between a slip-resistant layer  2520 , such as grip tape, and a board portion  2522  of deck  2506 . Board portion  2522  is a substantially rigid portion of deck  2506 . For example, board portion  2522  may comprise plywood, fiberglass, and/or other substantially rigid material. In some examples, enclosure  2516  may be bonded in a waterproof fashion to slip-resistant layer  2520  and/or board portion  2522 . 
     Transducer  2512  may include a first and a second conductive layer  2524 ,  2526  separated by a spacer layer  2528 . Similarly, transducer  2514  may include a third and a fourth conductive layer  2530 ,  2532  separated by a spacer layer  2534 . As described above, these conductive layers may include one or more FSR layer(s). Each transducer may be configured to provide a variable output signal (e.g., force-proportional), to provide a binary on/off signal, or to be selectable between these two modalities. 
     In the example depicted in  FIG. 28 , vent  2518  is disposed in an interface region between enclosure  2516  and board portion  2522 . However, in some examples, the vent may be positioned in other suitable positions adjacent or peripheral to enclosure  2516 . In some embodiments, a hole or aperture  2535  may be formed in board portion  2522  directly under vent  2518  (or in another suitable location), thereby placing vent  2518  in fluid communication with the exterior environment. This arrangement may facilitate greater airflow into and out of the interior space of rider detection unit  2508 , in which interior space transducers  2512  and  2514  are disposed. 
     As depicted in  FIG. 28 , a rider&#39;s foot may press down on rider detection unit  2508  with a force that is generally balanced variably between two force vectors. More specifically, a toe force vector  2536  describes the normal force applied to foot pad  2510  (and thus to unit  2508 ) by a front or toe portion of the rider&#39;s foot. Similarly, a heel force vector  2538  describes the normal force applied to foot pad  2510  by a rear or heel portion of the rider&#39;s foot. In some examples, the board or deck portion of the vehicle may have a shape other than flat. For example, a deck portion and/or footpad may be concave, convex, or otherwise non-planar. Although a planar deck is described herein, with associated normal forces, similar functionality applies to non-planar arrangements. 
     During use of the vehicle, the rider&#39;s foot, indicated at  2540  in  FIG. 28 , may press down on unit  2508  with force applied by both heel and toe. In other words, force may be applied through force vectors  2536  and  2538  simultaneously. Accordingly, transducers  2512  and  2514  may both be activated, causing them to communicate respective rider-presence information signals to a motor controller associated with wheel assembly  2504 . Reception of such signals by the motor controller may be configured to initiate active balancing of skateboard  2502 . 
     Once skateboard  2502  is traveling at or above a selected threshold speed, the motor controller may continue sending drive signals to the motor (e.g., for continued active balancing) even if the motor controller receives a rider-not-present signal from one of the pressure-sensing transducers (i.e., transducer  2512  or  2514 ). Transducer  2512  and/or  2514  may be deactivated or cease sending a signal as a result of the rider removing pressure from the respective area of the footpad, e.g., by lifting a toe or heel portion of the foot. However, when skateboard  2502  is traveling below the selected threshold speed, the motor controller may be configured to bring the vehicle to rest (e.g., by de-energizing the motor) when one or more of the sensor transducers are deactivated (e.g., not pressed). 
     With reference to  FIG. 27 , a second rider detection unit  2542 , substantially identical to first unit  2508 , may be integrated into, coupled to, connected to, embedded in, or disposed on a second footpad  2544  of deck  2506 . For example, unit  2542  may include first and second sensing transducers  2546  and  2548  encased in a waterproof enclosure  2550  having a vent  2552  configured to permit barometric equilibrium between an internal space and an external environment. Furthermore, unit  2542  may be sandwiched between a slip-resistant layer  2554 , such as grip tape, and a relatively rigid board portion  2556  of deck  2506 . All of these components are substantially similar to the corresponding components of first unit  2508 . In some examples, second unit  2542  is absent. 
     In some embodiments, deactivation of a selected number (e.g., one) of the pressure-sensing transducers, or a predetermined configuration of selected transducers may be configured to bring the vehicle to rest when traveling below the threshold speed. In some embodiments, active balancing may be initialized when all of transducers  2512 ,  2514 ,  2546 ,  2548  (or other predetermined number or configuration thereof) are activated. In some embodiments, activation and/or deactivation of the transducers may be configured to modulate drive signals to the motor of wheel assembly  2504  via the motor controller when skateboard  2502  is traveling at or above the threshold speed. 
     Additional Illustrative Operational Method 
     This section describes an illustrative method for operating an electric vehicle such as vehicle  100  having a rider detection system such as system  2400 ; see  FIG. 29 . Aspects of rider detection devices and systems described above may be utilized in the method steps described below. Where appropriate, reference may be made to previously described components and systems that may be used in carrying out each step. These references are for illustration, and are not intended to limit the possible ways of carrying out any particular step of the method. 
       FIG. 29  is a flowchart illustrating steps performed in an illustrative method, and may not recite the complete process or all steps of the process.  FIG. 29  depicts multiple steps of a method, generally indicated at  3000 , which may be performed in conjunction with vehicles having rider detection systems according to aspects of the present disclosure. Although various steps of method  3000  are described below and depicted in  FIG. 29 , the steps need not necessarily all be performed, and in some cases may be performed in a different order than the order shown. Additionally, steps of method  3000  may be combined with one or more method steps described above with respect to system  2400  and/or method  600 . 
     At step  3002 , the control system of an electric vehicle, which may include a processor and/or controller, detects the presence of a rider on the electric vehicle. For simplicity, the electric vehicle will be referred to as a board. Any suitable vehicle may be used, such as vehicle  100  described above. Detection of the rider may be performed in any suitable manner. For example, the rider may be detected using one or more pressure-sensing transducers, such as transducer  2402 . As explained above, such a pressure-sensing transducer may include a force-sensitive resistor (FSR), and may therefore have a proportional response to an applied force or pressure, such as the rider&#39;s foot. Furthermore, as described with respect to  FIGS. 27-28 , the transducer may include two sensing zones, one associated with a front or toe portion of the foot and another associated with a rear or heel portion of the foot. In this example, detection of rider presence does not change the status of an active balancing system on the vehicle. 
     At step  3004 , the control system detects that the board has been substantially leveled. In other words, a tilt angle of the board has reached a state or range that is defined as “level” or “no longer at rest” by the system. For example, a rider may place both feet on the board and cause the foot deck to become generally parallel to the ground. Detection of board angle may be performed by any suitable method using any suitable sensor and/or detector, as described above with respect to  FIGS. 5 and 6 . 
     At step  3006 , when the control system is satisfied that the rider is present and the board is in a level position, active balancing may be engaged. Active balancing and riding of the vehicle is described above, for example, with respect to method  600 . 
     At steps  3008  and  3010 , the system may detect a change in rider presence, and respond accordingly. At step  3008 , the system may detect that the entire foot of the rider has been removed from the board. For example, the pressure sensors in both the toe zone and the heel zone of one foot pad may no longer be activated. In this case, the system may assume that the rider is no longer on the vehicle, and may halt the vehicle motor at step  3012 , either immediately or after some selected delay. At step  3010 , on the other hand, the system may detect that only a portion of the rider&#39;s foot has been removed from the board. For example, only the toe sensing zone or only the heel sensing zone may stop being activated. This may occur, for example, during a turn when a ride lifts his or her toes (or heels) to maintain balance. In response to this partial loss of rider detection, step  3014  includes checking the vehicle speed. If vehicle speed is above a selected threshold, the board will continue operating in active mode. If vehicle speed is below the threshold (e.g., three miles per hour), the system may halt vehicle operation at step  3012 . 
     Although a single sensor region has been described, i.e., under a single foot, with multiple sub-zones, some examples may also use a second sensor region under the other foot of the rider. Any suitable combination of sensor regions and/or zones may be utilized. Additionally, any suitable type of sensor or transducer may be used, such as a FSR-type transducer and/or a fully conductive transducer. 
     Selected Examples and Embodiments 
     The following describes additional aspects and features of disclosed embodiments, presented without limitation as a series of numbered paragraphs. Each of these paragraphs can be combined with one or more other paragraphs, and/or with disclosure from elsewhere in this application, including the materials incorporated by reference in the Cross-References, in any suitable manner. Some of the paragraphs below expressly refer to and further limit other paragraphs, providing without limitation examples of some suitable combinations. 
     A. An electric vehicle comprising a board including first and second deck portions each configured to receive a left or right foot of a rider; a wheel assembly disposed between the first and second deck portions and including a ground-contacting element; a motor assembly mounted to the board and configured to rotate the ground-contacting element around an axle to propel the electric vehicle; at least one sensor configured to measure orientation information of the board; and a motor controller configured to receive orientation information measured by the sensor and to cause the motor assembly to propel the electric vehicle based on the orientation information; wherein the electric vehicle includes exactly one ground-contacting element. 
     A1. The vehicle of paragraph A, wherein the motor assembly includes a hub motor. 
     A2. The vehicle of paragraph A1, wherein the hub motor is internally geared. 
     A3. The vehicle of paragraph A1, wherein the hub motor is direct-drive. 
     A4. The vehicle of paragraph A, further comprising a first light assembly disposed at a first end portion of the board; and a second light assembly disposed at a second end portion of the board; wherein the first light assembly is configured to output light of a first color when the board is being propelled generally in a first direction and to output light of a second color when the board is being propelled generally in a second direction; and wherein the second light assembly is configured to output light of the second color when the board is being propelled generally in the first direction and to output light of the first color when the board is being propelled generally in the second direction. 
     A5. The vehicle of paragraph A4, wherein the first color is white and the second color is red. 
     A6. The vehicle of paragraph A, wherein the at least one sensor includes a gyro and an accelerometer collectively configured to estimate a lean angle of the board. 
     B. An electric skateboard comprising a foot deck having first and second deck portions each configured to support a rider&#39;s foot; exactly one ground-contacting wheel disposed between the first and second deck portions and configured to rotate about an axle to propel the skateboard; at least one sensor configured to measure an orientation of the foot deck; and an electric motor configured to cause rotation of the wheel based on the orientation of the foot deck. 
     B1. The skateboard of paragraph B, wherein the motor is a hub motor. 
     B2. The skateboard of paragraph B, further comprising a first light assembly disposed at a distal end of the first deck portion; and a second light assembly disposed at a distal end of the second deck portion; wherein the first light assembly is configured to output light of a first color when the board is being propelled generally in a first direction and to output light of a second color when the board is being propelled generally in a second direction; and wherein the second light assembly is configured to output light of the second color when the board is being propelled generally in the first direction and to output light of the first color when the board is being propelled generally in the second direction. 
     B3. The skateboard of paragraph B, wherein the at least one sensor includes a gyro configured to measure pivotation of the foot deck about a pitch axis. 
     B4. The skateboard of paragraph B3, wherein the at least one sensor further includes an accelerometer, and wherein the gyro and the accelerometer are collectively configured to measure orientation of the foot deck about pitch, roll and yaw axes. 
     B5. The skateboard of paragraph B, further including a rider detection device configured to determine if a rider&#39;s feet are disposed on the foot deck, and to send a signal causing the motor to enter an active state when the rider&#39;s feet are determined to be disposed on the foot deck. 
     C. A self-balancing electric vehicle comprising a frame defining a plane; a first deck portion mounted to the frame and configured to support a first foot of a rider; a second deck portion mounted to the frame and configured to support a second foot of a rider; a wheel mounted to the frame between the deck portions, extending above and below the plane and configured to rotate about an axis lying in the plane; at least one sensor mounted to the frame and configured to sense orientation information of the frame; a motor controller configured to receive the orientation information from the sensor and to generate a motor control signal in response to the orientation information; and a motor configured to receive the motor control signal from the motor controller and to rotate the wheel in response, thus propelling the skateboard. 
     C1. The electric vehicle of paragraph C, wherein the motor is an electric direct-drive hub motor. 
     C2. The electric vehicle of paragraph C, wherein the at least one sensor includes a gyro and a 3-axis accelerometer collectively configured to sense orientation information sufficient to estimate a lean angle of the frame including pivotation about pitch, roll and yaw axes. 
     C3. The electric vehicle of paragraph C, further comprising a first skid pad and a first illuminator disposed at a distal end of the first deck portion and a second skid pad and a second illuminator disposed at a distal end of the second deck portion, wherein each skid pad includes an aperture configured to allow light from the corresponding illuminator to shine through while preventing the illuminator from contacting the ground. 
     C4. The electric vehicle of paragraph C3, wherein the first illuminator is configured to output light of a first color when the frame is being propelled generally in a first direction and to output light of a second color when the frame is being propelled generally in a second direction, and wherein the second illuminator is configured to output light of the second color when the frame is being propelled generally in the first direction and to output light of the first color when the frame is being propelled generally in the second direction. 
     C5. The electric vehicle of paragraph C, further comprising a fender attached to at least one of the deck portions and configured to prevent water traversed by the wheel from splashing onto a rider. 
     C6. The electric vehicle of paragraph C5, wherein the fender is attached to both of the first and second deck portions and substantially entirely separates the wheel from the rider. 
     D0. An electric vehicle, comprising: 
     a board including first and second deck portions each configured to receive a left or right foot of a rider oriented generally perpendicular to a longitudinal axis of the board; 
     a wheel assembly including a ground-contacting element disposed between and extending above the first and second deck portions; 
     a motor assembly mounted to the board and configured to rotate the ground-contacting element around an axle to propel the electric vehicle; 
     at least one orientation sensor configured to measure orientation information of the board; 
     a first sensing region disposed in the first deck portion, the first sensing region including a first pressure-sensing transducer; and 
     a motor controller configured to receive board orientation information measured by the orientation sensor and rider presence information based on an output of the first pressure-sensing transducer, and to cause the motor assembly to propel the electric vehicle based on the board orientation information and the rider presence information. 
     D1. The vehicle of paragraph D0, wherein the first sensing region further includes a second pressure-sensing transducer adjacent to and laterally spaced from the first pressure-sensing transducer, such that the first pressure-sensing transducer and the second pressure-sensing transducer are configured to be disposed beneath a front portion and a rear portion, respectively, of the left or right foot of the rider. 
     D2. The vehicle of any of paragraphs D0 through D1, wherein the first pressure-sensing transducer is embedded in an upper surface of the first deck portion. 
     D3. The vehicle of paragraph D2, wherein the first pressure-sensing transducer is sandwiched between a slip-resistant layer and a rigid layer of the first deck portion. 
     D4. The vehicle of any of paragraphs D0 through D3, wherein the first pressure-sensing transducer is encased in a waterproof enclosure. 
     D5. The vehicle of paragraph D4, wherein the waterproof enclosure includes an air-permeable, water-resistant vent. 
     D6. The vehicle of any of paragraphs D0 through D5, wherein the first pressure-sensing transducer comprises a force-sensitive resistor. 
     D7. The vehicle of any of paragraphs D0 through D6, wherein the first pressure-sensitive transducer comprises a resilient first conductive layer spaced from and facing a second conductive layer, such that a force applied to the first conductive layer causes the first conductive layer to contact the second conductive layer. 
     E0. An electric skateboard, comprising: 
     a foot deck having first and second deck portions each configured to support a rider&#39;s foot oriented generally perpendicular to a longitudinal axis of the foot deck; 
     exactly one ground-contacting wheel disposed between and extending above the first and second deck portions and configured to rotate about an axle to propel the skateboard; 
     at least one orientation sensor configured to measure an orientation of the foot deck; 
     a pressure-sensing transducer disposed on the first deck portion; and 
     an electric motor configured to cause rotation of the wheel based on the orientation of the foot deck and an output of the pressure-sensing transducer. 
     E1. The skateboard of paragraph E0, wherein the pressure-sensing transducer comprises a spacer layer disposed between a force-sensitive resistor layer and an electrical circuit layer. 
     E2. The skateboard of paragraph E0, wherein the pressure-sensing transducer comprises a spacer layer disposed between an electrically conductive layer and a partially electrically conductive layer having a conductivity proportional to a force applied thereon. 
     E3. The skateboard of any of paragraphs E0 through E2, wherein the pressure-sensing transducer comprises a resilient first conductive layer spaced from and facing a second conductive layer, such that the first conductive layer is displaceable to electrically contact the second conductive layer, thereby producing the output of the pressure-sensing transducer. 
     E4. The skateboard of any of paragraphs E0 through E3, wherein the pressure-sensing transducer is in communication with a motor controller configured to control the electric motor. 
     E5. The skateboard of paragraph E4, further including a speed sensor configured to provide wheel speed information to the motor controller, wherein the motor controller is configured to control the motor based on the output of the pressure-sensing transducer and the wheel speed information. 
     E6. The skateboard of any of paragraphs E0 through E5, wherein the pressure-sensing transducer is encased in a waterproof enclosure. 
     E7. The skateboard of any of paragraphs E0, through E6, wherein the pressure-sensing transducer includes a force-sensitive resistor. 
     F0. A self-balancing electric vehicle, comprising: 
     a frame defining a plane and having a longitudinal axis; 
     a first deck portion mounted to the frame and configured to support a first foot of a rider oriented generally perpendicular to the longitudinal axis of the frame; 
     a second deck portion mounted to the frame and configured to support a second foot of a rider oriented generally perpendicular to the longitudinal axis of the frame; 
     a wheel mounted to the frame between the deck portions, extending above and below the plane and configured to rotate about an axis lying in the plane; 
     at least one orientation sensor mounted to the frame and configured to sense orientation information of the frame; 
     a pressure-sensing transducer disposed on the first deck portion and configured to sense rider presence information based on a force applied to the first deck portion; 
     a motor controller configured to receive the orientation information and the rider presence information and to generate a motor control signal in response; and 
     a motor configured to receive the motor control signal from the motor controller and to rotate the wheel in response, thereby propelling the skateboard. 
     F1. The electric vehicle of paragraph F0, wherein the motor controller is configured to permit motor rotation when the pressure-sensing transducer senses that the force is presently applied to the first deck portion. 
     F2. The electric vehicle of any of paragraphs F0 through F1, wherein the pressure-sensing transducer is a first pressure-sensing transducer, the vehicle further comprising a second pressure-sensing transducer laterally adjacent to the first pressure-sensing transducer, wherein the first and the second pressure-sensing transducers comprise a first discrete sensing zone and a second discrete sensing zone, respectively. 
     F3. The electric vehicle of any of paragraphs F0 through F2, wherein the pressure-sensing transducer includes at least one partially electrically conductive layer. 
     F4. The electric vehicle of paragraph F3, wherein the pressure-sensing transducer comprises a force-sensitive resistor. 
     F5. The electric vehicle of any of paragraphs F0 through F4, wherein the pressure-sensing transducer is encased in a waterproof enclosure. 
     F6. The electric vehicle of any of paragraphs F0 through F5, wherein the pressure-sensing transducer is sandwiched between an upper slip-resistant layer and a rigid portion of the first deck portion. 
     CONCLUSION 
     The disclosure set forth above may encompass multiple distinct examples with independent utility. Although each of these has been disclosed in its preferred form(s), the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. To the extent that section headings are used within this disclosure, such headings are for organizational purposes only. The subject matter of the examples includes all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. Other combinations and subcombinations of features, functions, elements, and/or properties may be claimed in applications claiming priority from this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.