Patent Publication Number: US-9431189-B2

Title: Configurable buttons for electronic devices

Description:
This application is a continuation patent application of U.S. patent application Ser. No. 13/909,919, filed Jun. 4, 2013 and titled “Configurable Buttons for Electronic Devices,” now U.S. Pat. No. 8,717,199, which is a continuation patent application of U.S. patent application Ser. No. 12/239,652, filed Sep. 26, 2008 and titled “Configurable Buttons for Electronic Devices,” now U.S. Pat. No. 8,456,330, the disclosures of which are hereby incorporated herein in their entireties. 
    
    
     BACKGROUND 
     This invention relates generally to electronic devices, and more particularly, to buttons whose behavior may be modified in real time based on sensor readings. 
     Electronic devices often contain input-output devices such as buttons. The buttons may be, for example, keys in a keypad or keyboard, power buttons, menu buttons, or dedicated or multipurpose buttons that serve other functions on an electronic device. 
     Electronic devices such as portable electronic devices are becoming increasingly popular. Examples of portable electronic devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type. Popular portable electronic devices that are somewhat larger than traditional handheld electronic devices include laptop computers and tablet computers. 
     Electronic devices that contain buttons are often manipulated by a user. For example, a user of a device may press against the device with a finger or other object when interacting with movable structures that make up the device. 
     In situations such as these, it might be desirable to be able to reconfigure a button on the device in real time to avoid unintentional operation of the button. It might also be desirable to be able to make other real time adjustments to the way in which a button operates. 
     SUMMARY 
     In accordance with embodiments of the present invention, configurable buttons for electronic devices are provided. Electronic devices that use the configurable buttons may include, for example, portable electronic devices such as wearable media players. 
     A user often desires to physically manipulate a portion of an electronic device without activating buttons on the device. For example, a user of a small portable media player that has a clip might desire to squeeze the clip to attach the media player device to an article of clothing. 
     In situations such as these, the user&#39;s finger may inadvertently touch a portion of a button. A touch sensor that is associated with the button may determine when a user is attempting to physically manipulate a clip, lid, cover, or other portion of an electronic device without intending to operate the button. When this condition is detected, control circuitry within the electronic device can direct an actuator to momentarily restrict motion of the button relative to the device. This temporary restriction of the button&#39;s movement helps to avoid situations in which a button is inadvertently depressed even though a user only intended to open a clip or otherwise physically manipulate a portion of an electronic device and did not intend to operate the button. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative portable electronic device with a configurable button in accordance with an embodiment of the present invention. 
         FIG. 2  is a side view of an illustrative portable electronic device with a configurable button of the type shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 3  is a circuit diagram of an illustrative electronic device having a configurable button in accordance with an embodiment of the present invention. 
         FIG. 4  is a cross-sectional side view of an illustrative portable electronic device with a configurable button in accordance with an embodiment of the present invention. 
         FIG. 5  is cross-sectional side view of an illustrative electronic device of the type shown in  FIG. 4  showing an illustrative shape that may be used for a button support structure in accordance with an embodiment of the present invention. 
         FIG. 6  is a perspective view of an illustrative button support structure of the type shown in cross-section in  FIG. 5  in accordance with an embodiment of the present invention. 
         FIG. 7  is a top view of an illustrative button support structure of the type shown in cross-section in  FIG. 5  in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of an illustrative button having a touch sensor with multiple segments in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of an illustrative button of the type shown in  FIG. 8  having a touch sensor with fewer segments in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional side view of an illustrative button having a single-element touch sensor in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional side view of an illustrative button showing how a touch sensor may be mounted along a curved lower portion of the button in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of an illustrative button having externally mounted sensor electrodes in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional side view of an illustrative button with externally mounted sensor components such as pressure sensor elements in accordance with an embodiment of the present invention. 
         FIG. 14  is a perspective view of an illustrative electronic device having a generally rectangular configurable button in accordance with an embodiment of the present invention. 
         FIG. 15  is a cross-sectional side view of an illustrative electronic device having a sensor for a configurable button that is not mounted directly to the button in accordance with an embodiment of the present invention. 
         FIG. 16  is a flow chart of illustrative steps involved in using equipment with a configurable button in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates to configurable buttons for electronic devices. 
     The buttons may be keys in a keypad or keyboard, dedicated buttons such as power on-off buttons, sleep buttons, menu buttons, or volume buttons, or may be multipurpose buttons such as buttons that perform one function when pressed once and another function when pressed twice or that perform different functions depending on context. With one suitable arrangement, a user may press the button when it is desired to make selections such as selections of media playback functions in a media player (e.g., selections of which songs to play, whether to play or pause a particular track, etc.). This is, however, merely illustrative. The configurable buttons of the present invention may be used to control any suitable functions in an electronic device if desired. 
     The electronic devices may include any suitable equipment that uses one or more configurable buttons. For example, configurable buttons may be used in electronic accessories and peripherals such as headsets, keyboards, computer mice, remote controls, speaker systems, monitors, printers, etc. Configurable buttons may also be used in audio-visual equipment, computers, appliances, and other stand-alone equipment. Portable equipment that may include configurable buttons includes, for example, portable electronic devices such as laptop computers or small portable computers of the type that are sometimes referred to as ultraportables. Configurable buttons may also be used in somewhat smaller portable electronic devices. Examples of smaller portable electronic devices that may include configurable buttons include wrist-watch devices, pendant devices, headphone and earpiece devices, and other wearable and miniature devices. If desired, electronic devices with configurable buttons such as portable electronic devices may be wireless electronic devices. 
     Electronic devices with configurable buttons may include, for example, handheld devices such as cellular telephones, media players, media players with wireless communications capabilities, handheld computers (also sometimes called personal digital assistants), remote controllers, global positioning system (GPS) devices, and handheld gaming devices. Electronic devices with configurable buttons may also include hybrid devices that combine the functionality of multiple conventional devices. Examples of hybrid portable electronic devices include a media player with wireless communications capabilities, a cellular telephone that includes media player functionality, a media player with gaming functionality, a gaming device that includes a wireless communications capability, a cellular telephone that includes game and email functions, a portable device that receives email, supports mobile telephone calls, has music player functionality and supports web browsing. These are merely illustrative examples. 
     An illustrative portable electronic device in accordance with an embodiment of the present invention is shown in  FIG. 1 . Device  10  of  FIG. 1  may be, for example, a media player. If desired, device  10  may include wireless communications functions. Optional wireless communications circuitry in device  10  may, for example, be used to support communications with wireless Bluetooth® headphones or WiFi® (IEEE 802.11) local area network equipment. 
     As shown in  FIG. 1 , device  10  may include one or more buttons such as button  14 . In the  FIG. 1  example, there is a single button  14  mounted within device housing  12 . This is merely illustrative. Device  10  may include any suitable number of buttons (e.g., two buttons, three buttons, more than three buttons, etc.). One, some, or all of such buttons may be configurable. 
     Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including, plastic, glass, ceramics, metal, other suitable materials, or a combination of these materials. In some situations, housing  12  or portions of housing  12  may be formed from a dielectric or other low-conductivity material, so as not to disrupt the operation of conductive antenna elements that are located in proximity to housing  12 . An advantage of forming housing  12  from a dielectric material such as plastic is that this may help to reduce the overall weight of device  10  and may avoid potential interference with wireless operations. An advantage of forming housing  12  from materials such metal is that metal may be durable and may provide an attractive finish. In scenarios in which housing  12  is formed from metal elements, one or more of the metal elements may be used as part of the antennas in device  10 . For example, metal portions of housing  12  may be shorted to an internal ground plane in device  10  to create a larger ground plane element for that device  10 . 
     When a button is configurable, its properties may be altered in real time (e.g., based on sensor input). If, for example, the presence of a user&#39;s finger is detected, the amount of travel that is permitted for all or part of the button may be restricted. Solenoids and other actuators may be used to alter the allowed range of motion and other mechanical properties of a configurable button. Restriction of a button&#39;s range of motion in certain circumstances may help to prevent unintended operation of button  14 . For example, a user who is manipulating a part of device  10  may necessarily risk operating button  14 , even when button operation is not intended. Selective restriction of the button&#39;s motion may help to reduce this risk. 
     Consider, as an example, the illustrative situation of  FIG. 1  in which device  10  is provided with a mechanical structure such as clip  16 . A user may open and close clip  16  when it is desired to fasten device  10  to a user&#39;s clothing. As shown in  FIG. 1 , clip  16  may be mounted to device  10  using a hinge structure such as hinge structure  18 . Hinge structure  18  may support clip  16  for rotational motion about rotational axis  20 . When supported in this way, end  26  of clip  16  may move in direction  24  when end  32  of clip  16  moves in direction  28 , whereas end  26  of clip  16  may move in direction  22  when end  32  of clip  16  moves in direction  30 . Hinge structure  18  may include a spring that biases end  26  of clip in direction  22  against the lower surface of housing  12  when a user is not pressing on end  32 . When a user desires to open clip  16 , the user may press on end  32  of clip  16  to press end  32  upwards in direction  28 . This causes end  26  of clip  16  to open, so that device  10  may be attached to a suitable object such as the user&#39;s clothing. 
     In a typical scenario, a user may press clip  16  upwards in direction  28  by squeezing end  32  of clip  16  and end  34  of device  10  between two opposing fingers. While convenient for a user, this type of squeezing operation may inadvertently cause a portion of one of the user&#39;s fingers to contact a portion of button  14 . A conventional button on a device of this type might therefore be accidentally depressed, even in situations in which the user only intended to open a clip and did not intend to operate the device. 
     Configurable buttons in accordance with the present invention can be configured in real time to prevent unintended activation by a user. As shown in  FIG. 2 , device  10  may contain a sensor such as sensor  36 . Sensor  36  may be, for example, a capacitive touch sensor. Sensors readings from sensor  36  may be used to control the operation of button  14  in real time. 
     When a user desires to open clip  16 , a user may squeeze end  34  of device  10  between opposing fingers such as fingers  40  and  38 . In general, device  10  and its button  14  and other structures may be manipulated using any suitable animate or inanimate members. For example, these structures may be manipulated by a user&#39;s fingers or other body parts, by a stylus or other pointer, or using any other suitable external source of force. For clarity, the present invention is sometimes described in the context of scenarios in which device  10  is being manipulated by a user&#39;s fingers. This is, however, merely illustrative. 
     A user may desire to open clip  16  or may desire to otherwise manipulate device  10 . For clarity, the present invention is sometimes described in the context of users who desire to open clip  16 . If desired, however, the unintended pressure on button  14  may arise from a desire to manipulate device  10  in other ways. For example, a user may be picking up device  10 , may be opening a cover of device  10 , may be placing device  10  into a protective case, may be adjusting the orientation of device  10  on a stand or other support structure, or may be touching device  10  for other reasons. The description of users who unintentionally press against button  14  in device  10  to open clip  16  is merely illustrative. 
     As the user squeezes fingers  38  and  40  towards each other, finger  40  tends to move in direction  44 , thereby pressing end  32  of clip  16  upwards in direction  28 . This causes clip  16  to pivot about axis  20 , so that end  26  of clip  16  moves in direction  24  from position  17  into the position shown in  FIG. 2 . At the same time, finger  38  presses downward in direction  42  against the upper portion of device  10 . During this operation, finger  38  may press against button  14 . Most typically, finger  42  will press against button  14  in region  46  of the upper surface of button  14  (to the left of vertical axis  50  passing through the pivot of hinge  18 ), rather than in region  48  (to the right of vertical axis  50 ). 
     Sensor  36  may be used to detect the presence of finger  38 . When, for example, finger  38  touches button  14  in region  46  or when finger  38  approaches close to button  14  (e.g., when finger  38  is less than a millimeter or other suitable distance away from the upper surface of button  14 ), sensor  36  can detect this event. When sensor  36  detects that the user&#39;s finger is present in region  46  (and, if desired, also detects that no finger is present in region  48 ), control circuitry within device  10  may automatically configure button  14  in real time to adjust the mechanical properties of button  14 . For example, one or more solenoids or other actuator equipment may be used to prevent motion of all or part of button  14  relative to housing  12  along axis  50 . Once finger  38  is no longer present in region  46 , button  14  may be returned to its normal configuration in which travel along direction  50  is permitted. The user may then press against button  14  in region  48  to operate button  14  as needed. If desired, when sensor  36  detects that the user&#39;s finger is present in region  46  (and, if desired, also detects that no finger is present in region  48 ), control circuitry within device  10  may disable the functionality of button  14  (e.g., device  10  may ignore any input received by button  14  when the user&#39;s finger is present in region  46 ). 
     Circuitry  52  in device  10  is shown in  FIG. 3 . As shown in  FIG. 3 , circuitry  52  may include control circuitry  56 . Control circuitry  56  may include storage  58  and processing circuitry  60 . Storage  58  may include one or more different types of storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory), volatile memory (e.g., battery-based static or dynamic random-access-memory), etc. Processing circuitry  60  may be used to control the operation of device  10  (e.g., by running software instructions stored in storage  58 ). Processing circuitry  60  may be based on a processor such as a microprocessor and other suitable integrated circuits. With one suitable arrangement, processing circuitry  60  and storage  58  are used to run software on device  10  such as media playback software. 
     Input-output devices  62  may be coupled to control circuitry  56 . Devices  62  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Examples of input-output devices that may optionally be used in device  10  include displays, light-emitting diodes, buttons, microphones, and speakers. Input-output devices  62  may also include connectors such as audio jacks (e.g., for connecting headphones to device  10 ), video jacks, universal serial bus connectors, connectors for other digital and analog ports, etc. In larger devices, input-output devices  62  may include displays, touch screens, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, cameras, etc. 
     Button sensor  36  may be used to detect when a user&#39;s fingers or other object is present in the vicinity of button  14  (e.g., in region  46  of  FIG. 2 ). Actuator  54  may be used to control the mechanical properties of button  14  such as the permitted travel of button  14  with respect to case  12  and thereby serves as a controllable mechanism for enabling and disabling button  14 . Actuator  54  may include one or more solenoids or other suitable electrically controllable actuator components. 
     A user can control the operation of circuitry  52  and device  10  by supplying commands through user input devices  62 . Control circuitry  56  may also run software that performs actions automatically. For example, control software may be implemented on circuitry  56  that directs circuitry  56  to receive sensor data from button sensor  36  and to control actuator  54  in real time based on the sensor data. 
     A cross-sectional view of an illustrative device  10  having a configurable button is shown in  FIG. 4 . As shown in  FIG. 4 , button  14  of device  10  may include a button member  74 , sensor  36 , and button support structure  68 . Button member  74  may be formed of glass, plastic, or any other suitable material. One or more structures may be used in forming button member  74 . Button member  74  may be attached to sensor  36  using any suitable attachment mechanism. As an example, pressure-sensitive adhesive (e.g., double-sided adhesive-coated tape) such as tape  72  may be used to attach button member  74  to the upper surface of sensor  36 . Sensor  36  may also be mounted to support  68  using double-sided adhesive-coated tape such as tape  70 . Support  68  may be formed from plastic, metal, or other suitable materials. Portions  82  of support  68  may protrude into openings in housing  12  such as annular groove  80 . When protruding into groove  80 , portions  82  may be captured between upper groove surface  76  and lower groove surface  78 . This limits the vertical travel of button  14 . Support  68  may have tabs, slots, and other features that allow support  68  to accommodate radial expansion and compression during assembly. This allows support  68  to be pressed into groove  80  when mounting support  68  and button  14  into device  10 . 
     Structures  64  may include circuitry such as circuitry  52  of  FIG. 3  mounted on one or more rigid and flexible printed circuit boards (e.g., fiberglass-filled epoxy printed circuit boards and flex circuits formed from flexible dielectrics such as polyimide). Structures  64  may also include a battery, mounting structures, internal mechanical structures such as frame structures, etc. 
     To configure the mechanical properties of button  14  in real time, device  10  may include actuator  54 . In the example of  FIG. 4 , actuator  54  is shown as being formed from solenoids. The solenoids may have at least two states. In a first state, plungers  84  are allowed to reciprocate freely within solenoid bodies  86 , thereby allowing button  14  to move freely. In a second state, free movement of plungers  84  is fully or partially inhibited, so that the motion of structure  68  and therefore button  14  is restricted. Depending on the desired configuration for button  14 , motion of structure  68  may be completely prevented or structure  68  may be allowed to travel within groove  80  to a lesser extent than would otherwise be possible, thereby modifying the mechanical behavior of button  14 . Motion may be restricted by increasing friction (resistance to motion), by establishing hard limits on travel, by using combinations of such arrangements, or by using other suitable technique. 
     In the  FIG. 4  example, two solenoids are shown as bearing against structure  68 . This is merely illustrative. One or more actuating devices of any suitable type may be used to adjust the behavior of button  14  based on sensor readings from sensor equipment such as sensor  36 . The arrangement of  FIG. 4  in which two or more solenoids are used to arrest the motion of button  14  is an example of one suitable arrangement, but other arrangements may be used if desired (e.g., with fewer solenoids, with more solenoids, with actuators of other types, with combinations of different actuators, etc.). The solenoids or other actuating elements may be operated in concert (e.g., so both are in the same state at the same time) or may be operated independently. 
     A dome switch such as dome switch  66  or other suitable switch element may be operated when button  14  is depressed. Dome switch  66  may have an associated nub  88  that bears against button  14  to provide crisp button operation. Nub  88  may be formed from plastic, epoxy, or any other suitable material. If desired, switch structures that use other types of switches (i.e., non-dome switches) may be used for button  14  if desired. With one suitable arrangement, these switches may allow button  14  to be placed in two different states. When depressed, button  14  is placed into a first state. When released and not depressed, button  14  may be placed in a second state. The first state may represent a closed position and the second state may represent an open position or vice versa. If desired, button  14  may be provided with switch structures that allow the button to be placed in three or more operational states. 
     Spring action for button  14  may be provided by the spring force of the switch structure (e.g., dome switch  66 ). Spring action may alternatively or in addition be provided by other spring structures. These springs may, for example, be formed on or under support  68 . 
     In the illustrative arrangement of device  10  that is shown in  FIG. 5 , support  68  has bent tabs such as tabs  90  and  92 . These tabs may allow for a desired range of motion of button  14 . Springs on support  68  (not shown in  FIG. 5 ) may bias support  68  so that the lower surface of tab  90  is registered against the lower surface of groove  80 , whereas the upper surface of tab  92  is registered against the upper surface of groove  80 . When solenoid  54  is placed into a first state in which free motion of plunger  84  within body  86  is permitted, the button may be depressed to press tab  92  downwards in direction  94 , thereby allowing support  68  to activate dome switch. When solenoid  54  is placed into a second state in which free motion of plunger  84  within body  86  is prevented or otherwise restricted, button motion in direction  94  will also be prevented or otherwise restricted. This may make it more difficult or impossible for the button depression to activate dome switch  66 . 
       FIG. 6  shows a perspective view of an illustrative support  68  having two downwardly bent tabs  90  and two upwardly bent tabs  92 . One or more features such as slot  96  may allow support  68  to flex so that support  68  may be press fit within groove  80  or other suitable opening in housing  12 . When assembled within device  10 , springs  98  may bear against the upper surface of groove  80 . This biases tabs  90  downwards against the lower surface of groove  80 . Dome switch  66  or additional springs formed in support  68  may be used to provide an upward bias in the vicinity of tabs  92 , so that the upper surfaces of tabs  92  register against the upper surface of groove  80 . A top view of an illustrative support such as support  68  of  FIG. 6  is shown in  FIG. 7 . 
     In arrangements of the type shown in  FIGS. 6 and 7 , spring members  98  are formed as an integral portion of support  68 . If desired, springs may be attached to support  68  (e.g., using fasteners, welds, adhesive, etc.). Springs  98  may be formed from stainless steel or other suitable resilient material. 
     Sensors such as sensor  36  may include any suitable number of sensor segments. An illustrative example in which sensor  36  has nine individual segments is shown in  FIG. 8 . With this type of arrangement, the presence of a user&#39;s finger or other object may be detected with a precision of one part in nine along horizontal dimension  102  on the exposed upper surface of button member  74 . If desired, more segments or a two-dimensional array of segments may be used in sensor  36 . Each segment may be formed, for example, by a respective conductive (e.g., metal) electrode that detects capacitance changes induced by the close proximity or touch of a user&#39;s finger or other object. 
     If desired, sensors  36  may be implemented with fewer individual elements. As shown in the example of  FIG. 9 , sensor  36  may have three independent segments  100 , each of which may independently be used to produce a sensor signal to indicate the presence of a finger or other object on an adjacent portion of button member  74 . 
     The example of  FIG. 10  shows how sensor  36  may have only a single element such as sensor element  100 . With this type of arrangement, the element may be placed under region  46 , but not under region  48 . 
     With a sensor arrangement of the type shown in  FIG. 10 , button travel can be restricted whenever the single sensor under region  46  detects the presence of a finger. This allows a user to manipulate structures on device  10  such as opening clips such as clip  16 , without inadvertently activating button  14 . With a sensor arrangement of the type shown in  FIGS. 8 and 9 , which offer more sensor element granularity, the control circuitry in the device can determine when the user&#39;s finger is touching region  46  of button and is not touching region  48 . If desired, button motion can be permitted when the finger is touching both regions  46  and  48 , as this may be indicative of an intentional button press operation, whereas button motion can be restricted when the finger is touching only region  46 . 
     In the examples of  FIGS. 8, 9, and 10 , button sensor  36  is shown as being formed on a flat lower surface of button member  74 . If desired, button member  74  may have a curved lower surface or a lower surface with other suitable shapes, as shown in  FIG. 11 . In arrangements of this type, an additional button member that serves as a support may be mounted under sensor segments  100 . 
     Sensor  36  may, if desired, have exposed electrodes on the exposed upper surface of button member  74 . As shown in  FIG. 12 , exposed surface electrodes  104  may be electrically separated from each other by interposed dielectric regions  106 . Electrodes  104  may be formed from metal or other suitable conductive materials. Dielectric regions  106  may be formed from epoxy, polyimide, plastic, or other suitable dielectric materials. Conductive paths such as vias  108  may be used to interconnect electrodes  104  to contact pads  110 . Pads  110  may, in turn, be connected to sensor circuitry. 
       FIG. 13  shows an illustrative arrangement for sensor  36  in which segments  100  are formed from sensor elements that do not use capacitive sensor technology. Segments  100  may, for example, include pressure-sensitive diaphragms, as shown schematically by dotted lines  112 . Segments such as segments  100  may also be implemented using resistive sensor arrangements in which changes in resistance (through contact or pressure) may be measured and used to detect the presence of a user&#39;s finger or other object. Conductive paths such as via-based paths  114  and pads  116  may be used to route signals from sensor segments  100  to sensor circuitry. 
     If desired, device  10  may have shapes other than the roughly circular shape shown in  FIG. 1 . As an example, device  10  may have a rectangular outline as shown in  FIG. 14 . With this type of arrangement, configurable button  14  may also have a rectangular outline. Button  14  may, in general, have any suitable shape (e.g., a shape with straight sides, a shape with curved sides, a circular shape, a square, triangular, rectangular, or other polygonal shape, a shape with a mixture of curved and straight portions, a domed shape, a flat-topped shape, etc.). 
     Sensor  36  need not be mounted on button  14 . As shown in  FIG. 15 , for example, sensor  36  may be mounted on clip  16 . When a user&#39;s finger or other object is present, sensor  36  may inform the control circuitry in device  10  accordingly, so that button  14  may be configured (e.g., by locking the travel of button  14  so long as sensor  36  is being contacted). In the  FIG. 15  example, sensor  36  is shown as being mounted on clip  16 . If desired, sensor  36  may be located on an exterior portion of housing  12  or other structures associated with device  10 . As described in connection with  FIGS. 8, 9, and 10 , sensors of this type may have any suitable number of segments  100 . 
     If desired, changes in the capacitance of all or part of clip  16  may be sensed by monitoring clip  16  directly, in which case clip  16  serves as a sensor electrode. Case  12 , a portion of case  12 , or other electrically conductive structures associated with device  10  may also be used as sensor electrodes. 
     Device  10  may be provided with sensors that are mounted in diverse locations. For example, a first sensor may be mounted on clip  16  as shown in  FIG. 15 , whereas a second sensor may be mounted on button member  74  as shown in  FIG. 4 . In this type of configuration, button travel may be restricted only when fingers are detected as being present on both sensors simultaneously (as an example). Arrangements for device  10  of this type may use sensors in any suitable number of locations (e.g., one, two, three, more than three, etc.). Although arrangements with numerous diverse sensors and numerous sensor electrodes may be more complex than arrangements with fewer sensors and sensor segments, the improved accuracy in monitoring a user&#39;s interactions with device  10  and button  14  may be warranted in certain applications. 
     Illustrative steps involved in using a device  10  that has one or more configurable buttons such as button  14  are shown in  FIG. 16 . 
     At step  118 , one or more sensors such as sensor  36  may be monitored to detect the presence of a user&#39;s fingers and other objects. With capacitive touch sensor arrangements, the presence of an object such as a user&#39;s finger may be detected before the finger actually touches the sensor. This allows device  10  to configure button  14  proactively, as soon as the finger is detected within the vicinity of the sensor. Capacitive touch sensors also generate signals when touched by fingers and other objects. Other sensor arrangements (e.g., sensors based on resistance changes, sensors based on pressure-sensing diaphragms, etc.) may sometimes require actual contact (e.g., a touch by a finger or other object) before a positive sensor reading is generated. 
     Regardless of the particular type of sensor equipment that is used to detect presence of a finger or other object in the vicinity of device  10 , once the presence of the object is detected, processing may proceed to step  120 . During the operations of step  120 , sensor signals may be analyzed to determine which portion of the button is affected by the presence of the finger or other activating member. For example, it may be determined that the user&#39;s fingers are being used to squeeze clip  16  as described in connection with  FIG. 2 . In devices with other configurations, sensor signals may be used to ascertain when a user is opening a lid, moving a latch, closing a cover, or is otherwise physically manipulating structures associated with device  10  without intending to activate button  14 . 
     At step  122 , button  14  may be configured appropriately based on the measured sensor data. If, for example, it is determined that the user is attempting to operate button  14  normally, actuator  54  (e.g., the solenoids shown in  FIG. 4 ) may be directed to allow button  14  to reciprocate freely within housing  12 . If, however, it is determined that the user is attempting to manipulate a clip, lid, or other structure associated with device  10  but is not attempting to actuate button  14 , the movement of button  14  may be fully or partly restricted using actuator  54 . 
     As shown by line  124 , the operations of  FIG. 16  may be performed by control circuitry  52  of  FIG. 3  continuously while using device  10 . 
     With another suitable arrangement, button  14  may be formed in such as way that the button is not actuated when a user&#39;s finger presses against button  14  in region  46  and is actuated when the user&#39;s finger presses against button  14  in region  48 . For example, button support structure  68  may be configured such that tabs  90  ( FIG. 5 ) rest against lower groove surface  78  of groove  80  creating a pivot axis around which the button support structure pivots. With this type of arrangement, button  14  is not actuated when the user&#39;s finger presses against region  46  of button  14  (e.g., because the user&#39;s finger presses against a portion of button support structure  68  that is close to the pivot axis of the button support structure, the user&#39;s finger may not generate enough force on dome switch  66  to actuate button  14 ). In contrast, button  14  is actuated when the user&#39;s finger presses against region  48  of button  14  (e.g., because the user&#39;s finger presses against a portion of structure  68  that is away from the pivot axis, the user&#39;s finger generates enough force on switch  66  to actuate button  14 ). 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.