Patent Publication Number: US-10762751-B2

Title: Output devices for fabric-based electronic equipment

Description:
This application is a continuation of patent application Ser. No. 14/861,371, filed Sep. 22, 2015, which claims the benefit of provisional patent application No. 62/054,590, filed Sep. 24, 2014, both of which are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices having output devices incorporated into fabric. 
     Fabric can be provided with metal wires and other conductive fibers. These fibers can be used to carry signals for electrical components. In some arrangements, an electronic device can be formed from a fabric that contains electrical components. In other arrangements, an electronic device may include fabric that does not contain any electrical components. The fabric-based electronic device may be worn or held by a user. 
     Electronic devices are often provided with the ability to obtain a user&#39;s attention through the use of an alert device. For example, an electronic device may include output devices such as vibrating motors, speakers, and/or lights to attract the user&#39;s attention. 
     Challenges may arise when mounting electrical components such as output devices to fabric. If care is not taken, stresses on the fabric will tend to dislodge the electrical components. Short circuits can develop if signal paths are not properly isolated. Overly prominent mounting arrangements may be unsightly. 
     It would be desirable to be able to address these concerns by providing improved techniques for incorporating output devices into fabric for an electronic device. 
     SUMMARY 
     A fabric-based electronic device may include fabric formed from intertwined fibers. The fabric may be coupled to an electronic device housing in which electrical components are mounted. The fabric may be used to hold the electronic device housing against a user&#39;s body. For example, the fabric may form a wrist band that holds the electronic device housing against the user&#39;s wrist. 
     The fabric-based electronic device may include one or more output devices that provides output (e.g., tactile output) to a user from the fabric. The output device may include a moveable element such as a moveable wire in the fabric. Control circuitry such as an electromechanical actuator may be mounted in the electronic device housing and may be configured to control the movement of the wire in the fabric. 
     The wire may be enclosed within a flexible tube. The flexible tube may be intertwined with fibers in the fabric. The wire may include a kink or other irregularity that presses against the inner surface of the flexible tube. When the wire is rotated or moved into an appropriate position, the kink may press against the inner surface of the tube, which in turn forms a protrusion on the fabric. The protrusion on the fabric may press against the user&#39;s body and may therefore be used to obtain the attention of the user that is wearing or holding the fabric-based electronic device. If desired, the wire may be rotated repeatedly to create a pulsing sensation from the fabric against the user&#39;s body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of illustrative electronic equipment having one or more output devices incorporated into fabric in accordance with an embodiment. 
         FIG. 2  is a perspective view of illustrative electronic equipment having one or more output devices incorporated into fabric in accordance with an embodiment. 
         FIG. 3  is a perspective view of illustrative fabric that includes an output device formed from a moveable structure that is incorporated into the fabric in accordance with an embodiment. 
         FIG. 4A  is a cross-sectional side view of an illustrative output device having a controller that rotates a wire within a flexible tube in accordance with an embodiment. 
         FIG. 4B  is a cross-sectional side view of the output device of  FIG. 4A  in an activated state in accordance with an embodiment. 
         FIG. 5A  is a cross-sectional side view of an illustrative output device having a controller that deforms a wire within a flexible tube in accordance with an embodiment. 
         FIG. 5B  is a cross-sectional side view of the output device of  FIG. 5A  in an activated state in accordance with an embodiment. 
         FIG. 6A  is a cross-sectional side view of an illustrative output device having a controller that changes the shape or size of an irregularity in a wire within a flexible tube in accordance with an embodiment. 
         FIG. 6B  is a cross-sectional side view of the output device of  FIG. 6A  in an activated state in accordance with an embodiment. 
         FIG. 7  is a side view of an illustrative wire having an angled protrusion that may be used to provide tactile output from a fabric to a user in accordance with an embodiment. 
         FIG. 8  is a side view of an illustrative wire having an rounded protrusion that may be used to provide tactile output from a fabric to a user in accordance with an embodiment. 
         FIG. 9  is a side view of an illustrative wire having a rectangular protrusion that may be used to provide tactile output from a fabric to a user in accordance with an embodiment. 
         FIG. 10  is a side view of an illustrative wire that may be used to provide tactile output from a fabric to a user in which the wire includes multiple protrusions distributed along the length of the wire in accordance with an embodiment. 
         FIG. 11  is a side view of an illustrative wire that may be used to provide tactile output from a fabric to a user in which the wire includes multiple protrusions distributed with different densities along the length of the wire in accordance with an embodiment. 
         FIG. 12  is a side view of an illustrative group of wires that may be used to provide tactile output from a fabric to a user in which each wire in the group of wires includes a protrusion in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A schematic diagram of an illustrative fabric-based system that may include output devices incorporated into fabric is shown in  FIG. 1 . Fabric-based electronic equipment  24  of  FIG. 1  may include an electronic device such as electronic device  10  and fabric such as fabric  20 . Electronic device  10  and fabric  20  may be integral with one another, may be detachable or non-detachable from one another, and/or may be physically separate from one another while maintaining the ability to communicate with each other. 
     In one illustrative arrangement, fabric  20  in system  24  may be an accessory for electronic device  10 . For example, fabric  20  may be a removable external case for electronic equipment, may be a strap, may be a wrist band or head band, may be a removable cover for a device, may be a case or bag that has straps or that has other structures to receive and carry electronic equipment and other items, may be a necklace or arm band, may be a wallet, sleeve, pocket, or other structure into which electronic equipment or other items may be inserted, may be part of a chair, sofa, or other seating, may be part of an item of clothing, or may be any other suitable fabric-based item. If desired, fabric  20  may be used in forming part of an electronic device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which fabric-based equipment is mounted in a kiosk, in an automobile or other vehicle, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     Fabric  20  may form all or part of electronic device  10 , may form all or part of a housing wall for electronic device  10 , may form internal structures in electronic device  10 , or may form other fabric-based structures. Fabric-based device  24  may be soft (e.g., the device may have a fabric surface that yields to a light touch), may have a rigid feel (e.g., the surface of the device may be formed form a stiff fabric), may be coarse, may be smooth, may have ribs or other patterned textures, and/or may be formed as part of a device that has portions formed from non-fabric structures of plastic, metal, glass, crystalline materials, ceramics, or other materials. 
     As shown in  FIG. 1 , electronic device  10  may include control circuitry  16 . Control circuitry  16  may include storage and processing circuitry for controlling the operation of device  10 . Control circuitry  16  may, for example, include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Control circuitry  16  may include processing circuitry based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio codec chips, application specific integrated circuits, etc. 
     Input-output devices  12  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. Input-output devices  12  may also include input-output components with which a user can control the operation of device  10 . A user may, for example, supply commands through input-output devices  12  and may receive status information and other output from device  10  using the output resources of input-output devices  12 . 
     Input-output devices  12  may include sensors and status indicators such as an ambient light sensor, a proximity sensor, a temperature sensor, a pressure sensor, a magnetic sensor, an accelerometer, a touch sensor, a fingerprint sensor, and light-emitting diodes and other components for gathering information about the environment in which device  10  is operating and providing information to a user of device  10  about the status of device  10 . Audio components in devices  12  may include speakers and tone generators for presenting sound to a user of device  10  and microphones for gathering user audio input. Devices  12  may include one or more displays such as display  14 . Displays may be used to present images for a user such as text, video, and still images. Sensors in devices  12  may include a touch sensor array that is formed as one of the layers in display  14 . During operation, user input may be gathered using buttons and other input-output components in devices  12  such as touch pad sensors, buttons, joysticks, click wheels, scrolling wheels, touch sensors such as a touch sensor array in a touch screen display or a touch pad, key pads, keyboards, vibrators, cameras, and other input-output components. The input-output output devices of device  10  may include wired and wireless communications circuitry (e.g., circuitry to support digital data communications, a radio-frequency transceiver and antennas for supporting wireless communications, etc.). 
     Fabric  20  may be formed from intertwined fibers. Fibers that form fabric  20  may be single-strand filaments or may be threads, yarns, or other fibers that have been formed by intertwining single-strand filaments. Fibers may be formed from polymer, metal, glass, graphite, ceramic, natural materials such as cotton or bamboo, or other organic and/or inorganic materials and combinations of these materials. Conductive coatings such as metal coatings may be formed on non-conductive fiber cores. Fibers may also be formed from single filament metal wire or stranded wire. Fibers may be insulating or conductive. Fibers may be conductive along their entire length or may have conductive segments (e.g., metal portions that are exposed by locally removing polymer insulation from an insulated conductive fiber). Threads and other multi-strand fibers that have been formed from intertwined filaments may contain mixtures of conductive fibers and insulating fibers (e.g., metal fibers or metal coated fibers with or without exterior insulating layers may be used in combination with solid plastic fibers or natural fibers that are insulating). One or more output devices  18  may be incorporated into fabric  20 . A user may receive status information, alerts, and other output from system  24  using output devices  18 . 
     Path  22  may form a mechanical, electrical, and/or wireless connection between fabric  20  and housing  24 . For example, path  22  may be an attachment structure that physically attaches fabric  20  to electronic device  10  and/or path  22  may be or may include conductive pathways that convey electrical signals between electronic device  10  and fabric  20 . 
     Control circuitry  16  may be used to run software on device  10  such as operating system code and applications. During operation of system  24 , the software running on control circuitry  16  may display images for a user on display  14  and may use other devices within input-output devices  12  and output devices  18 . For example, the software running on control circuitry  16  may be used to process input from a user using one or more sensors (e.g., capacitive touch sensors, mechanical sensors, thermal sensors, force sensors, switches, buttons, touch screen displays, and other components) and may be used to provide status indicator output and other visual and/or audio output. Control circuitry  16  may use devices  12  and/or devices  18  to provide vibrations, pressure, and/or other physical output (e.g., haptic output). Devices  18  may, for example, include solenoids, vibrators, or other components that provide physical feedback (e.g., vibrations) to a user in conjunction with a button press, touch input, or other user activity. Changes in fabric attributes such as fabric temperature, texture, size, and shape may also be produced using devices  18  to convey output to a user. 
     In some scenarios, it may be desirable to provide physical output from fabric  20  without attaching a large actuator to fabric  20 . For example, motors and other actuators that provide sensory output to a user may be easily housed within device  10  but may be difficult to incorporate into fabric  20  without adding undesirable bulk to the fabric. To provide fabric  20  with output capabilities, output devices  18  may include output structures that are remotely actuated using a controller in device  10  (e.g., a controller that forms part of control circuitry  16 ). By using electronic device  10  to house the control circuitry and power circuitry that operate output structures  18  in fabric  20 , the weight and size of fabric  20  can be minimized and the device may be more comfortably worn or carried by a user. 
     A perspective view of an illustrative fabric-based system in which an electronic device is coupled to and controls output devices in fabric is shown in  FIG. 2 . As shown in  FIG. 2 , fabric-based system  24  may include fabric  20  and electronic device  10 . In the illustrative example of  FIG. 2 , fabric  20  is attached to housing  50  of electronic device  10  and may, for example, be used to attach electronic device  10  to some part of a user&#39;s body. For example, fabric  20  may form a wrist band, an arm band, a head band, a waist band, or other article that can be secured against a user&#39;s body and that can support or hold electronic device  10  in place (e.g., against a user&#39;s skin). The arrangement of  FIG. 2  is, however, merely illustrative. In general, electronic device  10  and fabric  20  may be integrated with or attached to one another in any suitable fashion. Arrangements in which fabric-based system  24  includes an electronic device  10  attached to a band  20  are sometimes described herein as an example. 
     System  24  may include output devices such as output device  18  for providing physical output to a user. Output device  18  may include a moveable element such as wire  30  and a controller such as controller  26  that controls the movement of wire  30 . Wire  30  may be embedded in fabric  20  and may be configured to move within fabric  20  to obtain a user&#39;s attention through tactile sensation. For example, movement of wire  30  may result in vibration of fabric  20  against a user&#39;s body, pulsing of fabric  20  against a user&#39;s body, pressing of fabric  20  against a user&#39;s body, and/or other physical or tactile output from fabric  20  against a user&#39;s body. 
     Wire  30  may be moveable between a first position in which no tactile output is felt by the user (sometimes referred to as a deactivated state) and a second position in which tactile output is felt by the user (sometimes referred to as an activated state). When wire  30  is in the first position, the surface of fabric  20  that rests against a user&#39;s skin or body such as interior surface  20 I may be relatively smooth, without protrusions or bumps. When wire  30  is in the second position, fabric  20  may have one or more protrusions or bumps that press against the user&#39;s skin or body. For example, portions of wire  30  such as portion  28  may press fabric  20  against a user&#39;s skin or body when wire  30  is in the second position. Portion  28  may be a kink, curve, twist, bump, protrusion, or other irregularity in wire  30  that, when oriented towards interior surface  20 I of fabric  20 , forms a corresponding irregularity on interior surface  20 I of fabric  20  that can be felt by the user. 
     In some arrangements, irregularity  28  in wire  30  may be a permanent irregularity in wire  30  or may be an irregularity that is produced in response to control signals from controller  26 . In embodiments where portion  28  is a permanent irregularity in wire  30 , wire  30  may transition from a first state in which irregularity  28  is oriented away from a user&#39;s skin or body such that interior surface  20 I of fabric  20  is completely smooth to a second state in which irregularity  28  is oriented towards a user&#39;s body such that interior surface  20 I of fabric  20  has a bump that presses against the user&#39;s body. In embodiments where irregularity  28  is not permanent, wire  30  may transition from a first state in which wire  30  is completely smooth (without any bumps or kinks) such that interior surface  20 I of fabric  20  is completely smooth to a second state in which wire  30  includes one or more irregularities such as kink  28  such that interior surface  20 I of fabric  20  has a bump that presses against the user&#39;s body. 
     Wire  30  may be formed from a solid metal, metal fibers, metal fibers that are completely or partly coated with plastic, solid plastic, plastic fibers that are coated with metal or that have metal portions, intertwined fibers (e.g., conductive and/or dielectric fibers), or other suitable conductive and/or insulating materials. Wire  30  may, for example, be formed from a thin, string-like piece of metal. Wire  30  may be stiff, may be flexible, or may have both rigid and flexible portions. If desired, wire  30  may be formed from a shape memory substance (e.g., nitinol or other shape memory metal alloys, shape memory polymers, etc.). 
     Movement of wire  30  may be controlled by controller  26 . In some arrangements, controller  26  may be an electromechanical actuator (e.g., an electromechanical actuator such as a linear actuator, a rotary actuator, an actuator based on one or more solenoids, motors, or piezoelectric elements, etc.) that controls the state of wire  30  by physically moving wire  30  within fabric  20 . For example, actuator  26  may be a rotary actuator that rotates wire  30  within fabric  20 , which in turn rotates protrusion  28  between a position facing towards the user&#39;s body to a position facing away from the user&#39;s body. In other embodiments, actuator  26  may be a shape memory metal actuator that controls the state of wire  30  using shape memory effects (e.g., the two-way shape memory effect). In this type of arrangement, actuator  26  may control the state of wire  30  by controlling the temperature of wire  30  (e.g., by passing current through shape memory material in wire  30  using a heating element). When wire  30  is maintained at room temperature, the shape memory material of wire  30  may have a first shape that places fabric  20  (or a portion of fabric  20 ) in a first state (e.g., in which interior surface  20 I of fabric  20  is smooth and uniform). When the shape memory material of wire  30  is heated to an elevated temperature (e.g., a temperature above room temperature), the shape memory material of wire  30  may have a second shape that places fabric  20  (or a portion of fabric  20 ) in a second state (e.g., in which interior surface  20 I of fabric  20  includes bumps or other irregularities that are felt by a user wearing fabric  20 ). 
     As shown in  FIG. 2 , controller  26  may be mounted in housing  50  of electronic device  10  and may be coupled to wire  30  in fabric  20 . In some arrangements, wire  30  and controller  26  may be detachable from one another so that fabric  20  can be detached from electronic device  10 . In other arrangements, wire  30  in fabric  20  may be permanently coupled to controller  26  in electronic device  10 . The arrangement of  FIG. 2  is merely illustrative, however. If desired, controller  26  may be mounted to or incorporated into fabric  20 . 
       FIG. 3  is a perspective view of an illustrative configuration for fabric  20 . In the example of  FIG. 3 , fabric  20  is a woven fabric having fibers  40  (e.g., warp fibers and weft fibers) woven in a plain weave. In general, fabric  20  may include any intertwined fibers  40  (woven, knitted, braided, etc.). The plain weave fabric of  FIG. 3  is merely illustrative. Fabric  20  may contain conductive fibers, may contain a mixture of conductive and insulating fibers, or may be formed exclusively from insulating fibers. 
     As shown in  FIG. 3 , wire  30  of output device  18  may be enclosed within a hollow tube such as tube  32  having cylindrical inner walls that define an opening such as opening  34  in which wire  30  is located. Tube  32  may be formed from a flexible material such as polytetrafluoroethylene (PTFE), polyethylene, other flexible polymer, an elastomeric material such as silicone elastomer, or other suitable materials. Forming tube  32  from a flexible or deformable material allows the interior and exterior surfaces of tube  32  to be deformed in response to movement of wire  30  and kink  28 . By enclosing wire  30  within tube  32 , movement of wire  30  does not induce any relative motion between fabric  20  and a user&#39;s body (e.g., fabric  20  does not rub or slide on a user&#39;s skin in response to movement of wire  30 ). 
     In the example of  FIG. 3 , tube  32  is intertwined (e.g., interwoven) with fibers  40  of fabric  20 . This is, however, merely illustrative. If desired, tube  32  may be sandwiched between two layers of fabric  20 , may be stitched into fabric  20 , may be attached to the surface of edge of fabric  20 , or may be integrated with fabric  20  using any other suitable method. There may be only one tube  32  containing a moveable wire  30  in fabric  20  or fabric  20  may include multiple tubes  32 , each with an associated moveable wire  30 . Tubes  32  may be separated into multiple layers of fabric  20  or may be formed in a single layer of fabric  20 . Tubes  32  may be stacked (e.g., may overlap each other in fabric  20 ) or may be formed in different regions of fabric  20  (e.g., a first tube  32  may be formed in a first portion of fabric  20  and a second tube  32  may be formed in a second portion of fabric  20 ). 
     The diameter D 2  of opening  34  (sometimes referred to as a bore) in tube  32  may be about equal to the diameter D 1  of wire  30  or may be slightly greater than the diameter D 1  of wire  30 . The diameter D 2  of opening  34  in tube  32  may, for example, be chosen such that irregularity  28  in wire  30  is able to touch the inner surface of tube  32  and deform the outer surface of tube  32  in response to control signals from controller  26  ( FIG. 2 ). 
     The surface of fabric  20  that rests against a user&#39;s skin or body such as interior surface  201  of fabric  20  may have different surface features depending on the state of output device  18 . For example, interior surface  20 I may be smooth and uniform when wire  30  is not actuated and may include bumps or protrusions when wire  30  is actuated (e.g., during an alert). When it is desired to provide physical output from fabric  20  to a user, controller  26  may actuate output device  18  to move wire  30  such that irregularity  28  forms a corresponding irregularity in fabric  20  that can be physically felt by a user wearing or carrying fabric  20 . 
     In some embodiments, controller  26  may actuate output device  18  to provide output to a user by rotating wire  30  about its longitudinal axis  42  (e.g., in direction  44  of  FIG. 3  or in a direction opposite to direction  44 ). This in turn causes protrusion  28  to also rotate about longitudinal axis  42  of wire  30 . When protrusion  28  is rotated so as to face away from interior surface  20 I of fabric  20  (e.g., to face towards exterior surface  20 E of fabric  20 ), interior surface  201  may be smooth against the user&#39;s body. When protrusion  28  is rotated so as to face towards interior surface  20 I of fabric  20 , interior surface  20 I may include a corresponding protrusion that aligns with protrusion  28  of wire  30 . This protrusion (extending upward in the z-direction relative to surface  201 ) may be physically felt by the user wearing or holding fabric  20  and may therefore serve as a means of obtaining the user&#39;s attention (e.g., during an alert such as an incoming telephone call alert, a message alert, a timer done alert, an alarm alert, etc.). 
     Controller  26  may rotate wire  30  once during an alert such that protrusion  28  presses fabric  20  against the user&#39;s body only once, or controller  26  may rotate wire  30  repeatedly during an alert such that protrusion  28  pulses fabric  20  against the user&#39;s body repeatedly. The time between pulses (moments of pressure against the user&#39;s skin on which interior surface  20 I rests) may be controlled and adjusted by adjusting the speed at which wire  30  is rotated. If desired, controller  26  may rotate wire  30  a different number of times and/or at different speeds for different types of alerts. For example, controller  26  may rotate wire  30  at a relatively low speed for one type of alert and at a relatively high speed for another type of alert. Some alerts may be presented using only one rotation of wire  30 , while others may be presented using multiple rotations of wire  30 . 
     Cross-sectional side views of output device  18  illustrating the operation of output device  18  according to one suitable arrangement are shown in  FIGS. 4A and 4B . In the example of  FIG. 4A , output device  18  is in a deactivated state in which interior surface  20 I of fabric  20  is smooth and uniform against object  36  (e.g., a portion of a user&#39;s body). In the deactivated state, controller  26  has rotated wire  30  such that protrusion  28  faces away from object  36 . If desired, protrusion  28  may deform exterior surface  20 E of fabric  20  when rotated away from interior surface  20 I, or exterior surface  20 E of fabric  20  may remain smooth even when protrusion  28  faces towards exterior surface  20 E. A smooth, unaffected surface may be achieved by adjusting the position of wire  30  within tube  32  or by forming one or more fabric layers over tube  32  to form exterior surface  20 E of fabric  20 . 
     When it is desired to obtain the user&#39;s attention using output device  18 , controller  26  may rotate wire about longitudinal axis  42  to place output device  18  in activated state, as shown in  FIG. 4B . In the activated state, wire  30  has been rotated such that protrusion  28  faces towards object  36 . When faced towards object  36 , protrusion  28  presses the wall of tube  32  outward to form a protrusion on the exterior surface of tube  32 . This in turn forms a corresponding protrusion  44  on the interior surface  20 I of fabric  20  that aligns with protrusion  28 . Protrusion  44  may press against the user&#39;s body and may therefore serve as a means of obtaining the user&#39;s attention. If desired, the outer surface of tube  32  may press directly against object  36  or the outer surface of tube  32  may press against fibers or a layer of fabric that in turn presses against object  36 . 
     Cross-sectional side views of output device  18  illustrating the operation of output device  18  according to another suitable arrangement are shown in  FIGS. 5A and 5B . In the example of  FIG. 5A , output device  18  is in a deactivated state in which interior surface  20 I of fabric  20  is smooth and uniform against object  36  (e.g., a portion of a user&#39;s body). In the deactivated state, controller  26  has placed wire  30  in a straight configuration in which wire  30  does not press against the walls of tube  32 . Wire  30  may, for example, be formed from shape memory material such as nitinol. When the shape memory material that forms wire  30  is maintained at a first temperature (e.g., room temperature), wire  30  may have a first shape (e.g., the straight shape shown in  FIG. 5A ). When the shape memory material that forms wire  30  is heated to an elevated temperature (e.g., a temperature above room temperature), the shape memory material may have a second shape (e.g., the bent shape as shown in  FIG. 5B ). The temperature (and shape) of wire  30  may be controlled by controlling how much current flows through wire  30  using controller  26  (e.g., using a heating element in controller  26 ). 
     When it is desired to obtain the user&#39;s attention using output device  18 , controller  26  may adjust the shape of wire  30  (e.g., by heating wire  30  to an elevated temperature) to place output device  18  in activated state, as shown in  FIG. 5B . In the activated state, wire  30  has a protrusion  28  that faces towards object  36 . When faced towards object  36 , protrusion  28  presses the wall of tube  32  outward to form a protrusion on the exterior surface of tube  32 . This in turn forms a corresponding protrusion  44  on the interior surface  20 I of fabric  20  that aligns with protrusion  28 . Protrusion  44  may press against the user&#39;s body and may therefore serve as a means of obtaining the user&#39;s attention. If desired, the outer surface of tube  32  may press directly against object  36  or the outer surface of tube  32  may press against fibers or a layer of fabric that in turn presses against object  36 . 
     Cross-sectional side views of output device  18  illustrating the operation of output device  18  according to another suitable arrangement are shown in  FIGS. 6A and 6B . In the example shown in  FIGS. 6A and 6B , controller  26  adjusts the output provided by output device  18  by adjusting the height of the protrusion  28  and the height of the corresponding protrusion  44  on interior surface  20 I of fabric  20 . For example, in the configuration of  FIG. 6A , protrusion  44  has a height H 1  relative to the smooth (non-raised) portion of interior surface  201 . In the configuration of  FIG. 6B , protrusion  44  has a height H 2  relative to the smooth (non-raised) portion of interior surface  20 I, where H 2  is greater than H 1 . Wire  30  may, for example, be formed from shape memory material such as nitinol. When the shape memory material that forms wire  30  is maintained at a first temperature (e.g., room temperature), wire  30  may have a first shape (e.g., with a smaller protrusion  28  as shown in  FIG. 6A ). When the shape memory material that forms wire  30  is heated to an elevated temperature (e.g., a temperature above room temperature), the shape memory material may have a second shape (e.g., with a larger protrusion  28  as shown in  FIG. 6B ). The temperature (and shape) of wire  30  may be controlled by controlling how much current flows through wire  30  using controller  26  (e.g., using a heating element in controller  26 ). 
     The configurations of  FIGS. 6A and 6B  may be used to provide different types of output to a user from fabric  20 . For example, some alerts (e.g., less urgent alerts) may be presented by lightly pulsing the smaller protrusion  28  of  FIG. 6A  against object  36 , whereas other alerts (e.g., more urgent alerts) may be presented by pulsing the larger protrusion  28  of  FIG. 6B  against object  36 . 
       FIGS. 7, 8, and 9  show illustrative shapes that irregularity  28  in wire  30  may have. In the example of  FIG. 7 , wire  30  is bent to form a triangular shaped kink  28  in wire  30 . With this type of arrangement, a minimal amount of surface area A 1  of wire  30  comes into contact with the inner walls of tube  32  ( FIG. 3 ). The angled kink  28  of  FIG. 7  may therefore be used to produce small points of pressure against the user&#39;s body. 
     In the example of  FIG. 8 , wire  30  is bent to form a curved (e.g., semicircular) bump  28  in wire  30 . With this type of arrangement, the surface area A 2  of wire  30  that comes into contact with the inner walls of tube  32  ( FIG. 3 ) may be somewhat larger than that of the angled kink  28  of  FIG. 7 . The curved bump  28  of  FIG. 8  may be used to produce broader regions of pressure against the user&#39;s body. 
     In the example of  FIG. 9 , wire  30  is bent to form a rectangular shaped kink  28  in wire  30 . With this type of arrangement, the surface area A 3  of wire  30  that comes into contact with the inner walls of tube  32  ( FIG. 3 ) may be larger than that of the rounded bump  28  of  FIG. 8 . The rectangular kink  28  of  FIG. 9  may be used to produce larger regions of continuous pressure against the user&#39;s skin or body. 
       FIGS. 10, 11, and 12  show illustrative patterns of irregularities that may be formed in wire  30 . In the example of  FIG. 10 , a single wire  30  includes multiple bumps  28 . Bumps  28  in wire  30  may be uniformly or non-uniformly distributed along the length of wire  30 . With this type of arrangement, actuation of wire  30  may create the sensation of a line of pressure against the user&#39;s body. 
     In the example of  FIG. 11 , a single wire  30  includes multiple bumps  28  formed with different densities along the length of wire  30 . For example, some regions of wire  30  may include one bump  28  in a given length of wire  30 , while other regions of wire  30  may include a series of closely spaced bumps  28  in a given length of wire  30 . 
     In the example of  FIG. 12 , multiple wires  30  are arranged adjacently to one another (e.g., in parallel lines) and each wire  30  includes one or more bumps  28 . For example, bumps  28  may be laterally offset from one another (e.g., may not be directly aligned or overlapping with one another, as shown in the example of  FIG. 12 ) or may, if desired, be directly aligned and overlapping with one another. With this type of arrangement, the simultaneous actuation of bumps  28  may create the sensation of a line of pressure against the user&#39;s body or skin. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.