Patent Publication Number: US-2020289001-A1

Title: Wearable device with field replaceable band

Description:
BACKGROUND 
     Wearable devices may be affixed to a user with a band. For example, a watch may be held on a user&#39;s wrist with a watchband. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
       The detailed description is set forth with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items or features. 
         FIG. 1  is an illustrative wearable device comprising a housing and a field replaceable band, according to one implementation. 
         FIG. 2  is another view of the wearable device of  FIG. 1  showing the protrusions on the band and corresponding receptacles in the housing, according to one implementation. 
         FIG. 3  is a perspective view of the housing of the wearable device prior to installation of an upper cover, according to one implementation. 
         FIG. 4  is a perspective view of the housing of the wearable device, according to one implementation. 
         FIG. 5  is a plan view of the housing of the wearable device, according to one implementation. 
         FIGS. 6A and 6B  depict a cross sectional view of the housing including an enlargement of an interface between the upper cover and the housing, according to one implementation. 
         FIG. 7  is a cross sectional view of the housing, according to one implementation. 
         FIG. 8  depicts a view of the wearable device as worn by a user, according to one implementation. 
         FIG. 9  illustrates a block diagram of sensors and output devices that the wearable device may utilize, according to one implementation. 
         FIG. 10  is a view of components in the housing of the wearable device, according to one implementation. 
         FIG. 11  illustrates a block diagram of some components of the wearable device, according to one implementation. 
     
    
    
     While implementations are described herein by way of example, those skilled in the art will recognize that the implementations are not limited to the examples or figures described. It should be understood that the figures and detailed description thereto are not intended to limit implementations to the particular form disclosed but, on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include”, “including”, and “includes” mean “including, but not limited to”. 
     The structures depicted in the following figures are not necessarily according to scale. Furthermore, the proportionality of one component to another may change with different implementations. In some illustrations the scale or a proportionate size of one structure may be exaggerated with respect to another to facilitate illustration, and not necessarily as a limitation. 
     DETAILED DESCRIPTION 
     A wearable device may be used to provide a variety of functions to a user. These functions may include providing information, acquiring data using sensors, and so forth. The wearable device may operate alone or may utilize a communication link to operate in conjunction with another device such as a smartphone. 
     The wearable device may include output devices such as a haptic buzzer that provides haptic feedback to the user, a speaker to provide audio output, a light emitting diode (LED) to provide a visual indicator, and so forth. 
     The sensors on the wearable device may acquire data that helps the user perform various functions. For example, the wearable device may include a microphone, allowing the user to provide speech input to an application running on the smartphone. Other sensors such as accelerometers, heart rate monitors, and so forth may be used to acquire data about the user&#39;s activity level, physical condition, and so forth. This data may then help the user. For example, information about how much the user is moving may be compared to a goal and used to provide an output that informs the user and helps them increase their activity level. 
     The wearable device may include two parts: a housing and a band. The housing contains at least some of the electronics of the wearable device, such as the output devices and the sensors. The housing may be sealed to prevent water, dirt, or other foreign materials from entering the housing. 
     The band retains the housing proximate to the user. In some implementations a bottom surface of the housing may be in contact with the user&#39;s skin. Various sizes and types of band may be used, allowing for the housing to be worn on an arm, leg, abdomen, neck, and so forth. For example, the wearable device may be worn as a wristband, with the band holding the housing near the user&#39;s wrist. In another example, the wearable device may be worn as an anklet, with the band holding the housing near the user&#39;s ankle. 
     It is advantageous to be able to affix different bands to a given housing. Different bands may be chosen for one or more of aesthetic or functional reasons depending on the situation. For example, a band what is waterproof may be selected when the user expects to be in a wet environment. In another example, a band that is decorative may be selected when the user is going to be socializing. In another example, a band made from a specific material may be selected by a user to avoid contact dermatitis. In still another example, a band may become worn and require replacement. 
     The combination of the band and the housing should also be comfortable for extended wear. For example, the user should be able to wear the wearable device without experiencing pinching, gouging, undue pressure, and so forth. 
     Traditional mechanisms for affixing a band to a device may utilize various arrangements, such as spring-loaded pins or a “NATO” style watch strap in which the band passes through loops. Spring-loaded pins and other arrangements require the use of tools and significant dexterity to join or separate the band from the device. As a result, a user may be unable to easily change the band, limiting the frequency and utility of the wearable device. The NATO style watch strap and other arrangements require that the strap be relatively thin to pass through the loops, constraining the types of bands that may be used. The NATO style watch strap also places the band between the device and the user&#39;s skin. This placement precludes the use of sensors in the device that require contact with or a view of the user&#39;s skin to operate. For example, an optical heart rate monitor that uses reflected light to measure the user&#39;s pulse cannot operate through a nylon NATO style watch strap. 
     Described in this disclosure is a wearable device that allows for easy and tool-free removal and installation of a band, with respect to a housing. Removal and installation may be performed by a user with limited physical dexterity. As described in this disclosure, a housing may comprise one or more receptacles. For example, the housing may include a pair of receptacles with one on each end of the housing. The opening for each receptacle is in an upper surface of the housing. During wear, a bottom surface of the housing is in contact with at least a part of the user. A retention ridge extends around a perimeter of the opening for each receptacle. As a result, the entrance to the receptacle is smaller along at least one dimension than the interior volume of the receptacle. 
     One or more pairs of protrusions extend from an inner surface of the band. For example, when the housing includes a pair of receptacles a pair of protrusions extend from the band. The protrusions may comprise an elastomeric material, such as silicone rubber. Each of these protrusions have an enlarged tip, presenting a bulbous profile. The enlarged portion of the tip is slightly larger than the entrance to the receptacle. The band is affixed to the housing by placing the inner surface of the band in contact with the upper surface of the housing. A protrusion is aligned to a receptacle, and the user applies a force to the band on the outer surface opposite the protrusion. The applied force causes the enlarged tip of the protrusion to deform, allowing it to pass into the receptacle. Once within the receptacle, the elastomeric material expands, securing part of the protrusion within the receptacle and thus the band to the housing. In some implementations an audible “pop” or other sound is produced, providing audible feedback to the user that the band and the housing have been adequately engaged. 
     The band may then be wrapped around an arm and secured using a hook and loop fastener. Once the band has been secured, the wearable device is securely retained on the arm of the user. 
     To separate the band from the housing, the process is reversed. The user unwraps the band from their arm and pulls the band to withdraw the protrusions from their respective receptacles. In some implementations an audible “pop” or other sound is produced, providing audible feedback to the user that the band and the housing have been separated. 
     Also described are the structures and techniques for joining the housing to an upper cover that seals an opening in the housing. A groove extends around an opening in the housing. Adhesive is placed within the groove. A first ridge extends from an inner surface of the upper cover. Upon installation, at least a portion of the first ridge is placed into the groove. A second ridge may also extend from the inner surface of the upper cover proximate to the perimeter of the opening. A gasket may also be employed between the second ridge and the housing. The upper cover may also include a lip on each end. When installed, each lip engages a corresponding recess on the end of the housing. 
     Illustrative System 
       FIG. 1  is an illustrative view of a wearable device  100 , according to one implementation. The wearable device  100  comprises a housing  102  and a band  104 . The housing  102  may comprise a body  106  and an upper cover  108 . The body  106 , upper cover  108 , and other components may comprise one or more of a metal, plastic, composite, ceramic, and so forth. 
     The body  106  may include one or more openings. For example, during assembly components may be placed within the body  106  through an opening that is then closed by the upper cover  108 . The body  106  and the upper cover  108  may be joined such that the resulting housing  102  is sealed. In the implementation shown here, an upper surface of the housing  102  is curved. During wear, the upper surface of the housing  102  faces away from the portion of the user to which the wearable device  100  is retained. A lower surface of the housing  102  is proximate to the portion of the user. For example, at least a portion of the lower surface may be in contact with the user while the wearable device  100  is being worn. 
     The body  106  includes one or more receptacles  110 . As illustrated here, the body  106  is generally rectangular when viewed from above, with two ends. In the implementation depicted here a first receptacle  110  is proximate to a first end of the body  106  while a second receptacle  110  is proximate to a second end of the body  106 . Each receptacle  110  has an opening on the upper surface of the housing  102 . For example, the receptacle  110  may be within the body  106  while the upper cover  108  includes apertures for each of the openings of the receptacles  110 . 
     Each receptacle  110  is configured such that the opening or entry to the receptacle  110  is smaller along at least one dimension than an interior volume of the receptacle  110 . For example, each receptacle  110  may include a retention ridge that is proximate to the opening in the receptacle  110 . The retention ridge introduces a constriction or narrowing. For example, in cross-section the receptacle  110  may appear to resemble a mushroom shape with a root or stalk that is narrower than a larger, bulbous tip. In some implementations the retention ridge may extend along the entire perimeter of the opening. 
     The housing  102  may include one or more apertures  112 . The body  106  may include several apertures  112  for microphone ports, light emitting diodes, air pressure sensors, and so forth. In this view, apertures  112 ( 1 ) and  112 ( 2 ) are shown on a first side of the housing  102 . For example, the aperture  112 ( 1 ) may comprise a pressure equalization port and the aperture  112 ( 2 ) may provide a port for a first microphone to receive sound from outside the housing  102 . 
     The band  104  may comprise a flexible member  114  having a first end and a second end. The flexible member  114  includes an inner surface and an outer surface. When the band  104  is affixed to the housing  102 , at least a part of the inner surface of the flexible member  114  is proximate to the upper surface of the housing  102 . 
     The flexible member  114  may comprise one or more of fabric, an elastomeric material, a plurality of links, and so forth. For example, the flexible member  114  may comprise an elastic fabric. A loop  116  may be arranged at the first end of the flexible member  114  while an endcap  118  is arranged at the second end. The loop  116  may be a rigid loop. For example, the loop  116  may comprise metal that is encased in plastic. In other implementations, the loop  116  may comprise a flexible material. 
     One or more protrusions  120  extend away from the inner surface of the flexible member  114 . In the implementation shown here, a first protrusion  120  extends from the inner surface of the flexible member  114  at a first location L 1  and a second protrusion  120  extends from the inner surface at a second location L 2 . 
     Each protrusion  120  is configured to maintain mechanical engagement after insertion into the receptacle  110 . The protrusions  120  may comprise an elastomeric material. In one implementation, the protrusions  120  may comprise silicone rubber having a hardness as measured using a durometer with a Shore A reading of between 70 and 90. 
     In one implementation, the protrusions  120  may comprise components that have been joined to the flexible member  114 . For example, the protrusions  120  may be formed and then joined to the flexible member  114  using one or more of an adhesive, mechanical fasteners, thread, and so forth. 
     In another implementation the protrusions  120  may be integral with at least a portion of the flexible member  114 . For example, the flexible member  114  and the protrusions  120  may comprise a unitary piece of elastomeric material. 
     A portion of each protrusion  120  is larger than the narrowest part of the opening into the receptacle  110 . For example, a first distance D 1  indicates the maximum width of the opening in the receptacle  110 . A second distance D 2  indicates the maximum interior width of interior space of the receptacle  110  at the widest point. Due to the constriction in the receptacle  110 , the first distance D 1  is less than the second distance D 2 . 
     A third distance indicates the maximum width of the protrusion  120  at its widest point. The third distance is greater than the first distance D 1 . For example, at the widest point the bulbous tip of the protrusion  120  is larger than the opening of the receptacle  110 . In one implementation, the third distance of the maximum width of the protrusion  120  may be at least 15% greater than the first distance D 1 . 
     In one implementation the third distance may be less than the second distance D 2 . For example, the widest point of the protrusion  120  may be smaller than the largest width of the receptacle  110 . In another implementation the uncompressed protrusion  120  may have a third distance that is greater than the second distance D 2 . For example, after insertion into the receptacle  110  the protrusion  120  may expand and exert some pressure on the interior surface of the receptacle  110  as the elastomeric material attempts to resume a prior shape. In this implementation the portion of the protrusion  120  that is within the receptacle  110  remains at least slightly compressed. 
     In the implementation depicted here, the each of the two protrusions  120  extending from the inner surface of the flexible member  114  has a corresponding receptacle  110 . The band  104  is affixed to the housing  102  by placing the inner surface of the flexible member  114  in contact with the outer surface of the upper cover  108 , placing the band  104  atop the housing  102 . For example, the inner surface of the flexible member  114  between L 1  and L 2  may be in contact with the upper cover  108 . 
     Each protrusion  120  is aligned to a respective receptacle  110  and a force is applied to the flexible member  114  on the outer surface opposite the protrusion  120 . The applied force causes the enlarged portion of the protrusion  110  to temporarily deform, allowing it to pass into the cavity of the receptacle  110 . In some implementations an audible “pop” or other sound is produced, providing audible feedback to the user that the band  104  and the housing  102  have been adequately engaged. Once within the receptacle  110 , the elastomeric material expands, securing part of the protrusion  120  within the receptacle  110 . The band  104  is now affixed to the housing  102 . 
     To separate the band  104  from the housing  102 , the process is reversed. A pull may be applied to the flexible member  114 . Under the influence of the pull, the protrusion  120  temporarily deforms and is able to be withdrawn from the receptacle  110 . In some implementations an audible “pop” or other sound is produced, providing audible feedback to the user that the band  104  and the housing  102  have been separated. 
     In one implementation, the one or more receptacles  110  in the housing  102  may be configured with the same dimensions. Likewise, the one or more protrusions  120  on the band  104  may be configured with the same dimensions. In this implementation, the relative orientation of the housing  102  with respect to the band  104  may be easily changed. For example, a left-handed user may wish to reverse the orientation of the housing  102  with respect to the band  104  to allow improved access to one or more controls on the housing  102 . In other implementations the dimensions of one or more of the receptacles  110  or the protrusions  120  may differ, enforcing a particular orientation of the band  104  with respect to the housing  102 . 
     Instead of an elastomeric material, the protrusions  120  may comprise a one or more spring elements. For example, the protrusions  120  may comprise a metal or plastic element that forms a living hinge. In another example, the protrusions  120  may comprise one or more features that are biased using one or more compression springs. 
     With the housing  102  and the band  104  attached, the wearable device  100  may be worn by a user. The flexible member  114  may include on the outer surface a loop portion  122  comprising a plurality of loops and a hook portion  124  comprising a plurality of hooks. To affix the wearable device  100  to the user, the second end of the flexible member  114  having the endcap  118  is passed through the loop  116 . The user may place their forearm into the loop formed by the flexible member  114 . The second end of the flexible member  114  may then be pulled such that the inner surface is in comfortable contact with the user&#39;s forearm, and the hook portion  124  is then pressed against the loop portion  122 , securing the flexible member  114 . 
     In other implementations, other mechanisms may be used to secure the wearable device  100  to the user. For example, the flexible member  114  may utilize a buckle, a folding clasp, butterfly closure, and so forth. In another example, the flexible member  114  may comprise a contiguous loop of elastomeric material, allowing the user to pass their hand through the loop and which then contracts to hold the wearable device  100  in place. 
     At least a portion of the flexible member  114  between the first location L 1  and the second location L 2  may comprise an elastomeric material. A distance between the receptacles  110  may be slightly greater than the distance between L 1  and L 2 . In this implementation, during and after installation the portion of the band  104  between L 1  and L 2  is under tension from the elastomeric material of the flexible member  114  attempting to resume a prior shape. This tension provides a biasing force that assists in keeping the inner surface of the flexible member  114  in contact with the upper surface of the housing  102 . By maintaining contact, the flexible member  114  is not wrinkled or otherwise protruding, thus preventing snags, preventing contaminants from accumulating in between the two, and improving the aesthetics of the wearable device  100 . 
     In some implementations the housing  102  may include one or more output devices on the upper surface. For example, a display device may be arranged on the upper surface between the receptacles  110  to provide visual output to the user. At least a portion of the flexible member  114  that is between the first location L 1  and the second location L 2  may be transparent, contain one or more holes, or another opening to allow at least a portion of the display device to be visible. For example, the flexible member  114  may comprise a transparent material such as silicone rubber. In another example, the flexible member  114  may comprise an opening or aperture that is coincident with the display device. In another example, the flexible member  114  may comprise a plurality of holes, perforations, or spaces between threads that allow at least a portion of light from the display device to pass through. 
       FIG. 2  is another view of the wearable device  100  of  FIG. 1  with the band  104  not yet affixed to the housing  102 , according to one implementation. In this view, the inner surface  202  and the outer surface  204  of the flexible member  114  are shown. In this view additional apertures  112 ( 3 ) and  112 ( 4 ) are shown. For example, the aperture  112 ( 3 ) may provide a path for light from an LED to exit the housing  102  while the aperture  112 ( 4 ) may provide a port for a second microphone to receive sound from outside the housing  102 . 
     A button  206  is also present on this side of the housing  102  between the apertures  112 ( 3 ) and  112 ( 4 ). The button  206  may be used to activate a switch to allow for user input. 
     A sensor window  208  is arranged on a bottom surface of the housing  102 . The sensor window  208  may be transparent to one or more wavelengths of light. For example, the sensor window  208  may be transparent to visible and infrared light. The sensor window  208  may be used by one or more sensors to obtain information about the user. A field of view of one or more sensors may pass through the sensor window  208 . For example, an optical heart rate monitor may comprise an LED that emits light which passes through the sensor window  208  and to the arm of the user. Reflected or scattered light returns through the sensor window  208  where it is measured by a photodetector. In another example a camera may have a field of view that passes through the sensor window  208  to obtain images of a portion of the user&#39;s arm. 
     In some implementations, the portion of the bottom surface of the housing  102  that includes the sensor window  208  may protrude away from the remainder of the bottom surface. 
     One or more electrical contacts  210  may also be present on the bottom surface of the housing  102 . The electrical contacts  210  may be used to transfer data, provide electrical power, and so forth. In some implementations the electrical contacts  210  may be recessed with respect to the bottom surface. 
       FIG. 3  is a perspective view of the housing  102  of the wearable device  100  prior to installation of the upper cover  108 , according to one implementation. The upper cover  108  may have one or more receptacle holes  302 . The receptacle holes  302  provide clearance for the receptacle  110  when the upper cover  108  is joined to the housing  102 . 
     A groove  304  extends around a perimeter of an upper portion of the housing  102 . For example, the groove  304  is arranged around the opening into the interior of the housing  102 . The upper cover  108  includes a ridge along an underside. To join the upper cover  108  and the housing  102 , adhesive  306  may be placed into the groove  304 . For example, a liquid dispense adhesive (LDA) may be dispensed into the groove  304 . The upper cover  108  is place onto the housing  102  and at least a portion of this ridge fits within the groove  304  and comes into contact with the adhesive  306 . This interface is described in more detail with regard to  FIGS. 6A and 6B . 
     The housing  102  may include one or more recesses  308  that retain excess adhesive  306  that may be displaced during assembly. For example, as the upper cover  108  is pressed down onto the housing  102 , excess adhesive  306  may be displaced into the recesses  308 . 
     Within the housing  102  an internal stiffener  310  is visible. The internal stiffener  310  provides mechanical support to the upper cover  108 . The internal stiffener  310  may be fabricated as a separate piece and then joined to the upper cover  108 . In other implementations the internal stiffener  310  and the upper cover  108  may comprise a single structure. 
       FIG. 4  is a perspective view of the housing  102  of the wearable device  100 , according to one implementation. The receptacles  110  and the groove  304  are visible. Also shown are the apertures  112 ( 1 )-( 4 ) on the sides of the housing  102 . A sensor window aperture  402  is shown in the bottom of the housing  102 . A contact aperture  404  is shown in the bottom of the housing, proximate to one end of the housing  102 . A button aperture  406  is shown on a side of the housing  102  between apertures  112 ( 3 ) and  112 ( 4 ). 
       FIG. 5  is a plan view of the housing  102  of the wearable device  100 , according to one implementation. In this view a mounting feature  502  is shown. For example, a temperature sensor may be mounted at the mounting feature  502 . The temperature sensor may provide information such as the temperature of the user&#39;s body as transferred through the portion of the housing  102  that is proximate to the mounting feature  502 . 
       FIGS. 6A and 6B  depict a cross-sectional view of the housing  102  along line A-A (as shown in  FIG. 1 ) including an enlargement in  FIG. 6B  of an interface between the upper cover  108  and the housing  102 , according to one implementation.  FIG. 6A  shows the cross section including the button  206 , the housing  102 , and the upper cover  108  joined to the housing  102 . Also visible is the sensor window  208  installed within the sensor window aperture  402 . 
       FIG. 6B  shows an enlargement of a portion of the interface between the upper cover  108  and the housing  102 . The housing  102  comprises a groove  304  having a lip  602 . Within the groove  304  is the adhesive  306 . The upper cover  108  includes a ridge  604  that is configured to fit within the groove  304 . When installed, a portion of the ridge  604  comes into contact with the adhesive  306 . The adhesive  306  joins the ridge  604  of the upper cover  108  to the housing  102 . The adhesive  306  may form a seal to prevent the outside environment from reaching the interior of the housing  102 . The lip  602  may act as a hard stop with respect to the upper cover  108 . 
     In some implementations the upper cover  108  may include a second ridge  606  that is arranged to be adjacent to the lip  602  of the housing  102  when joined. A gasket  608  may be placed between the lip  602  and the second ridge  606  to provide an additional seal. 
       FIG. 7  is a cross sectional view of the housing  102  along line B-B (as shown in  FIG. 1 .), according to one implementation. In this view the upper cover  108  is shown separate from the housing  102 . 
     The receptacles  110  are visible here. Each receptacle  110  has a retention ridge  702  proximate to the entry of the receptacle  110 . In another implementation other engagement features may be used. For example, teeth may extend from the housing  102 . The opening of the receptacle  110 , the retention ridge  702 , and the interior cavity of the receptacle  110  may be rounded or otherwise avoid sharp edges. Rounding of these features may facilitate controlled installation and removal of the protrusion  110  and may also improve lifespan of the protrusion  120  by preventing tearing. 
     The first distance D 1  indicates the maximum width of the opening in the receptacle  110 , as constrained by the retention ridge  702  or other feature. The second distance D 2  indicates the maximum interior width of the receptacle  110  at the widest point of the interior space within the receptacle  110 . Due to the constriction in the receptacle  110 , the first distance D 1  is less than the second distance D 2 . 
     The upper cover  108  may include a first lip  704  and a second lip  704 . The first lip  704  may be proximate to a first end of the upper cover  108  while the second lip  704  may be proximate to a second end of the upper cover  108 . The first lip  704  and the second lip  704  extend from an inside surface of the upper cover  108 . For example, in cross section the upper cover  108  may resemble a “C”. 
     The housing  102  may also include one or more recesses  706 . For example, the housing  102  may include a first recess  706  that is proximate to the first end the housing  102  and a second recess  706  that is proximate to the second end of the housing  102 . The recess  706  is configured to accept the corresponding lip  704  and retain the upper cover  108  to the housing  102 . For example, during assembly, the adhesive  306  is placed with the groove  304  and the upper cover  108  is moved into contact with the housing  102 . Upon application of a force bringing the upper cover  108  and the housing  102  together, the ridge  604  enters the groove  304  and the first lip  704  enters the first recess  706  and the second lip  704  enters the second recess  706 . 
     A metal chassis  708  is also shown. Various components may be mounted to the metal chassis  708 . A first end of the metal chassis  710  and a second end of the metal chassis  712  may include features to facilitate mounting of other components. For example, the metal chassis  708  may include holes that permit the passage of a mechanical fastener such as a screw. 
     A battery  714  may be placed within the housing  102 . The battery  714  may be used to provide electrical power to the components of the wearable device  100 . The battery  714  may be rechargeable. A battery contact block  716  provides electrical connections between contacts on the battery  714  and the electronics of the wearable device  100 . A flexible printed circuit (FPC)  718  provides one or more electrical traces to transfer one or more of power or data between components of the wearable device  100 . 
     The wearable device  100  may utilize a system in package (SIP) construction, as shown with the SIP  720 . The SIP  720  may comprise a processor, memory, power conditioning, or other components. The FPC  718  or other FPCs, wiring harnesses, and so forth may be used to interconnect the components in the wearable device  100 . 
     A FPC  722  may provide be used as a transmission line to transfer radio frequency signals between the SIP  720  and one or more antenna contacts  726 . When the upper cover  108  is installed on the housing  102  the antenna contacts  726  provide an electrical connection between the FPC  722  and a portion of an antenna trace  728 . The antenna trace  728  may extend along a portion of an inner surface of the upper cover  108 . 
     Also shown in this view is a window barrier  724  that is located between the sensor window  208  and the interior of the housing  102 . For example, the electronics in the wearable device  100  may include an optical heart rate monitor that uses an LED to emit light and a photodetector to detect the light reflected or scattered by the arm of the user. The window barrier  724  may provide an opaque barrier between the LED and the photodetector to prevent the emitted light from intruding on and saturating the photodetector. The window barrier  724  also provides mechanical support to the sensor window  208 . 
     Also shown are the contacts  210 . 
       FIG. 8  depicts a view of the wearable device  100  as worn by a user, according to one implementation. In this view a portion of the user&#39;s wrist  802  is shown, with the band  104  wrapped around the wrist  802 . 
       FIG. 9  illustrates a block diagram of sensors  902  and output devices  904  that the wearable device  100  may utilize, according to one implementation. The sensors  902  may generate sensor data during operation. 
     The one or more sensors  902  may be integrated with or internal to the wearable device  100 . For example, one or more of the sensors  902  may be built-in to the wearable device  100  during manufacture. In another example, one or more of the sensors  902  or a portion thereof may be incorporated into a band  104 . In other implementations, the sensors  902  may be part of another device. For example, the sensors  902  may comprise a device external to, but in communication with, the wearable device  100  using Bluetooth, Wi-Fi, 3G, 4G, LTE, ZigBee, Z-Wave, or another wireless or wired communication technology. 
     The one or more sensors  902  may include one or more switches  902 ( 1 ) that are configured to accept input from the user. The switches  902 ( 1 ) may comprise mechanical, capacitive, optical, or other mechanisms. For example, the switches  902 ( 1 ) may comprise mechanical switches configured to accept an applied force as transferred by the button  206  to generate an input signal. 
     A blood pressure sensor  902 ( 2 ) may be configured to provide sensor data that is indicative of the user&#39;s blood pressure. For example, the blood pressure sensor  902 ( 2 ) may comprise a camera that acquires images of blood vessels and determines the blood pressure by analyzing the changes in diameter of the blood vessels over time. In another example, the blood pressure sensor  902 ( 2 ) may comprise a sensor transducer that is in contact with the skin of the user that is proximate to a blood vessel. 
     A heart rate monitor  902 ( 3 ) may be configured to provide sensor data that is indicative of a cardiac pulse rate and data indicative of oxygen saturation of the user&#39;s blood. For example, an optical heart rate monitor  902 ( 3 ) may use one or more light emitting diodes (LEDs) and corresponding detectors to determine changes in apparent color of the blood of the user resulting from oxygen binding with hemoglobin in the blood, providing information about oxygen saturation. Changes over time in apparent reflectance of light emitted by the LEDs may be used to determine cardiac pulse. 
     The sensors  902  may include one or more touch sensors  902 ( 4 ). The touch sensors  902 ( 4 ) may use resistive, capacitive, surface capacitance, projected capacitance, mutual capacitance, optical, Interpolating Force-Sensitive Resistance (IFSR), or other mechanisms to determine the position of a touch or near-touch of the user. For example, the IFSR may comprise a material configured to change electrical resistance responsive to an applied force. The location within the material of that change in electrical resistance may indicate the position of the touch. 
     One or more microphones  902 ( 5 ) may be configured to acquire information about sound present in the environment. In some implementations, a plurality of microphones  902 ( 5 ) may be used to form a microphone array. The microphone array may implement beamforming techniques to provide for directionality of gain. 
     A temperature sensor (or thermometer)  902 ( 6 ) may provide information indicative of a temperature of an object. The temperature sensor  902 ( 6 ) in the wearable device  100  may be configured to measure ambient air temperature proximate to the user, the body temperature of the user, and so forth. The temperature sensor  902 ( 6 ) may comprise a silicon bandgap temperature sensor, thermistor, thermocouple, or other device. In some implementations, the temperature sensor  902 ( 6 ) may comprise an infrared detector configured to determine temperature using thermal radiation. For example, the temperature sensor  902 ( 6 ) may be mounted on the housing  102  within the mounting feature  502 . 
     The sensors  902  may include one or more light sensors  902 ( 7 ). The light sensors  902 ( 7 ) may be configured to provide information associated with ambient lighting conditions such as a level of illumination. The light sensors  902 ( 7 ) may be sensitive to wavelengths including, but not limited to, infrared, visible, or ultraviolet light. In contrast to a camera, the light sensor  902 ( 7 ) may typically provide a sequence of amplitude (magnitude) samples and color data while the camera provides a sequence of two-dimensional frames of samples (pixels). 
     One or more radio frequency identification (RFID) readers  902 ( 8 ), near field communication (NFC) systems, and so forth, may also be included as sensors  902 . The user, objects around the wearable device  100 , locations within a building, and so forth, may be equipped with one or more radio frequency (RF) tags. The RF tags are configured to emit an RF signal. In one implementation, the RF tag may be a RFID tag configured to emit the RF signal upon activation by an external signal. For example, the external signal may comprise a RF signal or a magnetic field configured to energize or activate the RFID tag. In another implementation, the RF tag may comprise a transmitter and a power source configured to power the transmitter. For example, the RF tag may comprise a Bluetooth Low Energy (BLE) transmitter and battery. In other implementations, the tag may use other techniques to indicate its presence. For example, an acoustic tag may be configured to generate an ultrasonic signal, which is detected by corresponding acoustic receivers. In yet another implementation, the tag may be configured to emit an optical signal. 
     One or more RF receivers  902 ( 9 ) may also be included as sensors  902 . In some implementations, the RF receivers  902 ( 9 ) may be part of transceiver assemblies. The RF receivers  902 ( 9 ) may be configured to acquire RF signals associated with Wi-Fi, Bluetooth, ZigBee, Z-Wave, 3G, 4G, LTE, or other wireless data transmission technologies. The RF receivers  902 ( 9 ) may provide information associated with data transmitted via radio frequencies, signal strength of RF signals, and so forth. For example, information from the RF receivers  902 ( 9 ) may be used to facilitate determination of a location of the wearable device  100 , and so forth. 
     The sensors  902  may include one or more accelerometers  902 ( 10 ). The accelerometers  902 ( 10 ) may provide information such as the direction and magnitude of an imposed acceleration, tilt relative to local vertical, and so forth. Data such as rate of acceleration, determination of changes in direction, speed, tilt, and so forth, may be determined using the accelerometers  902 ( 10 ). 
     A gyroscope  902 ( 11 ) provides information indicative of rotation of an object affixed thereto. For example, the gyroscope  902 ( 11 ) may indicate whether the device has been rotated, rate of rotation, direction of rotation, and so forth. 
     A magnetometer  902 ( 12 ) may be used to determine an orientation by measuring ambient magnetic fields, such as the terrestrial magnetic field. For example, output from the magnetometer  902 ( 12 ) may be used to determine whether the device containing the sensor  902 , such as the wearable device  100 , has changed orientation or otherwise moved. In other implementations, the magnetometer  902 ( 12 ) may be configured to detect magnetic fields generated by another device. 
     A glucose sensor  902 ( 13 ) may be used to determine a concentration of glucose within the blood or tissues of the user. For example, the glucose sensor  902 ( 13 ) may comprise a near infrared spectroscope that determines a concentration of glucose or glucose metabolites in tissues. In another example, the glucose sensor  902 ( 13 ) may comprise a chemical detector that measures presence of glucose or glucose metabolites at the surface of the user&#39;s skin. 
     A location sensor  902 ( 14 ) is configured to provide information indicative of a location. The location may be relative or absolute. For example, a relative location may indicate “kitchen”, “bedroom”, “conference room”, and so forth. In comparison, an absolute location is expressed relative to a reference point or datum, such as a street address, geolocation comprising coordinates indicative of latitude and longitude, grid square, and so forth. The location sensor  902 ( 14 ) may include, but is not limited to, radio navigation-based systems such as terrestrial or satellite-based navigational systems. The satellite-based navigation system may include one or more of a Global Positioning System (GPS) receiver, a Global Navigation Satellite System (GLONASS) receiver, a Galileo receiver, a BeiDou Navigation Satellite System (BDS) receiver, an Indian Regional Navigational Satellite System, and so forth. In some implementations, the location sensor  902 ( 14 ) may be omitted or operate in conjunction with an external resource such as a cellular network operator providing location information, or Bluetooth beacons. 
     A fingerprint sensor  902 ( 15 ) is configured to acquire fingerprint data. The fingerprint sensor  902 ( 15 ) may use an optical, ultrasonic, capacitive, resistive, or other detector to obtain an image or other representation of features of a finger. For example, the fingerprint sensor  902 ( 15 ) may comprise a capacitive sensor configured to generate an image of the fingerprint of the user. 
     A proximity sensor  902 ( 16 ) may be configured to provide sensor data indicative of one or more of a presence or absence of an object, a distance to the object, or characteristics of the object. The proximity sensor  902 ( 16 ) may use optical, electrical, ultrasonic, electromagnetic, or other techniques to determine a presence of an object. For example, the proximity sensor  902 ( 16 ) may comprise a capacitive proximity sensor configured to provide an electrical field and determine a change in electrical capacitance due to presence or absence of an object within the electrical field. 
     An image sensor  902 ( 17 ) comprises an imaging element to acquire images in visible light, infrared, ultraviolet, and so forth. For example, the image sensor  902 ( 17 ) may comprise complementary metal oxide (CMOS) imaging element or a charge coupled device (CCD). 
     The sensors  902  may include other sensors  902 (S) as well. For example, the other sensors  902 (S) may include strain gauges, anti-tamper indicators, and so forth. For example, strain gauges or strain sensors may be embedded within the wearable device  100  and may be configured to provide information indicating that at least a portion of the wearable device  100  has been stretched or displaced such that the wearable device  100  may have been donned or doffed. 
     In some implementations, the sensors  902  may include hardware processors, memory, and other elements configured to perform various functions. Furthermore, the sensors  902  may be configured to communicate by way of a network or may couple directly with the other devices. 
     The wearable device  100  may include or may couple to one or more output devices  904 . The output devices  904  are configured to generate signals which may be perceived by the user, detectable by the sensors  902 , or a combination thereof. 
     Haptic output devices  904 ( 1 ) are configured to provide a signal, which results in a tactile sensation to the user. The haptic output devices  904 ( 1 ) may use one or more mechanisms such as electrical stimulation or mechanical displacement to provide the signal. For example, the haptic output devices  904 ( 1 ) may be configured to generate a modulated electrical signal, which produces an apparent tactile sensation in one or more fingers of the user. In another example, the haptic output devices  904 ( 1 ) may comprise piezoelectric or rotary motor devices configured to provide a vibration that may be felt by the user. 
     One or more audio output devices  904 ( 2 ) are configured to provide acoustic output. The acoustic output includes one or more of infrasonic sound, audible sound, or ultrasonic sound. The audio output devices  904 ( 2 ) may use one or more mechanisms to generate the acoustic output. These mechanisms may include, but are not limited to, the following: voice coils, piezoelectric elements, magnetorestrictive elements, electrostatic elements, and so forth. For example, a piezoelectric buzzer or a speaker may be used to provide acoustic output by an audio output device  904 ( 2 ). 
     The display devices  904 ( 3 ) may be configured to provide output that may be seen by the user or detected by a light-sensitive detector such as the image sensor  902 ( 17 ) or light sensor  902 ( 7 ). The output may be monochrome or color. The display devices  904 ( 3 ) may be emissive, reflective, or both. An emissive display device  904 ( 3 ), such as using LEDs, is configured to emit light during operation. In comparison, a reflective display device  904 ( 3 ), such as using an electrophoretic element, relies on ambient light to present an image. Backlights or front lights may be used to illuminate non-emissive display devices  904 ( 3 ) to provide visibility of the output in conditions where the ambient light levels are low. 
     The display mechanisms of display devices  904 ( 3 ) may include, but are not limited to, micro-electromechanical systems (MEMS), spatial light modulators, electroluminescent displays, quantum dot displays, liquid crystal on silicon (LCOS) displays, cholesteric displays, interferometric displays, liquid crystal displays, electrophoretic displays, LED displays, and so forth. These display mechanisms are configured to emit light, modulate incident light emitted from another source, or both. The display devices  904 ( 3 ) may operate as panels, projectors, and so forth. 
     The display devices  904 ( 3 ) may be configured to present images. For example, the display devices  904 ( 3 ) may comprise a pixel-addressable display. The image may comprise at least a two-dimensional array of pixels or a vector representation of an at least two-dimensional image. 
     In some implementations, the display devices  904 ( 3 ) may be configured to provide non-image data, such as text or numeric characters, colors, and so forth. For example, a segmented electrophoretic display device  904 ( 3 ), segmented LED, and so forth, may be used to present information such as letters or numbers. The display devices  904 ( 3 ) may also be configurable to vary the color of the segment, such as using multicolor LED segments. 
     Other output devices  904 (T) may also be present. 
       FIG. 10  is a view of components in the housing  102  of the wearable device  100 , according to one implementation. The top cover  108  is shown. A frame  1002  is shown that assists in alignment and retention of the internal stiffener  310 . 
     The battery  714  may be arranged within a battery cover  1004 . For example, the battery cover  1004  may comprise a mylar sheath that is arranged around at least a portion of the battery  714 . 
     A battery flexible printed circuit (FPC)  1006  is shown that provide electrical connectivity between the battery contact block  716  and the SIP  720 . 
     An adhesive  1008  affixes the battery cover  1004  to an upper side of the metal chassis  708 . For example, the adhesive  1008  may comprise a sheet or layer of a pressure sensitive adhesive (PSA). 
     Mechanical fasteners  1010 , such as screws, are shown that join the metal chassis  708  to the housing  102 . In other implementations other techniques may be used to join the metal chassis  708  to the housing  102 . For example, the metal chassis  708  may include one or more mechanical engagement features such as ridges, tabs, and so forth that engage features on the housing  102 . 
     An adhesive  1012  affixes a lower side of the metal chassis  708  to the SIP  720 . For example, the adhesive  1012  may comprise a sheet or layer of PSA. 
     Also shown in this figure is the FPC  718  that provides connectivity between the various components in the wearable device  100 . For example, the FPC  718  extends around a perimeter of an interior of the housing  102 . The SIP  720 , one or more sensors  902 , output devices  904  such as LEDs, and so forth may be connected to the FPC  718 . For example, the microphones  902 ( 5 ) are shown attached to the FPC  718 . 
     An adhesive  1014  affixes an upper side of the sensor window  208  to a lower side of the metal chassis  708 . For example, the adhesive  1014  may comprise a sheet or layer of PSA. 
     The window barrier  724  arranged on an upper side of the sensor window  208  is also shown. The contacts  210  are also depicted. 
     One of the receptacles  110  in the housing  102  are also shown. While a pair of receptacles  110  are depicted, in other implementations other arrangements may be used. For example, the housing  102  may comprise a single receptacle  110  while the band  104  features a corresponding single protrusion  120 . In another example, the housing  102  may comprise three receptacles  110  while the band  104  features three corresponding protrusions  120 . 
       FIG. 11  illustrates a block diagram of some components of the wearable device  100 , according to one implementation. 
     One or more power supplies  1102  are configured to provide electrical power suitable for operating the components in the wearable device  100 . In some implementations, the power supply  1102  may comprise a rechargeable battery, fuel cell, photovoltaic cell, power conditioning circuitry, wireless power receiver, thermocouple, and so forth. 
     The wearable device  100  may include one or more hardware processors  1104  (processors) configured to execute one or more stored instructions. The processors  1104  may comprise one or more cores. One or more clocks  1106  may provide information indicative of date, time, ticks, and so forth. For example, the processor  1104  may use data from the clock  1106  to generate a timestamp, trigger a preprogrammed action, and so forth. 
     The wearable device  100  may include one or more communication interfaces  1108  such as input/output (I/O) interfaces  1110 , network interfaces  1112 , and so forth. The communication interfaces  1108  enable the wearable device  100 , or components thereof, to communicate with other devices or components. The communication interfaces  1108  may include one or more I/O interfaces  1110 . The I/O interfaces  1110  may comprise interfaces such as Inter-Integrated Circuit (I2C), Serial Peripheral Interface bus (SPI), Universal Serial Bus (USB) as promulgated by the USB Implementers Forum, RS-232, and so forth. 
     The I/O interface(s)  1110  may couple to one or more I/O devices  1114 . The I/O devices  1114  may include input devices such as one or more of the sensors  902 . The I/O devices  1114  may also include output devices  904  such as one or more of an audio output device  904 ( 2 ), a display device  904 ( 3 ), and so forth. In some embodiments, the I/O devices  1114  may be physically incorporated with the wearable device  100  or may be externally placed. 
     The network interfaces  1112  are configured to provide communications between the wearable device  100  and other devices, such as the sensors  902 , routers, access devices, and so forth. The network interfaces  1112  may include devices configured to couple to wired or wireless personal area networks (PANs), local area networks (LANs), wide area networks (WANs), and so forth. For example, the network interfaces  1112  may include devices compatible with Ethernet, Wi-Fi, Bluetooth, ZigBee, 4G, 5G, LTE, and so forth. 
     The wearable device  100  may also include one or more busses or other internal communications hardware or software that allow for the transfer of data between the various modules and components of the wearable device  100 . 
     As shown in  FIG. 11 , the wearable device  100  includes one or more memories  1116 . The memory  1116  comprises one or more computer-readable storage media (CRSM). The CRSM may be any one or more of an electronic storage medium, a magnetic storage medium, an optical storage medium, a quantum storage medium, a mechanical computer storage medium, and so forth. The memory  1116  provides storage of computer-readable instructions, data structures, program modules, and other data for the operation of the wearable device  100 . A few example functional modules are shown stored in the memory  1116 , although the same functionality may alternatively be implemented in hardware, firmware, or as a system on a chip (SOC). 
     The memory  1116  may include at least one operating system (OS) module  1118 . The OS module  1118  is configured to manage hardware resource devices such as the I/O interfaces  1110 , the network interfaces  1112 , the I/O devices  1114 , and provide various services to applications or modules executing on the processors  1104 . The OS module  1118  may implement a variant of the FreeBSD operating system as promulgated by the FreeBSD Project; other UNIX or UNIX-like operating system; a variation of the Linux operating system as promulgated by Linus Torvalds; the Windows operating system from Microsoft Corporation of Redmond, Wash., USA; the Android operating system from Google Corporation of Mountain View, Calif., USA; the iOS operating system from Apple Corporation of Cupertino, Calif., USA; or other operating systems. 
     Also stored in the memory  1116  may be a data store  1120  and one or more of the following modules. These modules may be executed as foreground applications, background tasks, daemons, and so forth. The data store  1120  may use a flat file, database, linked list, tree, executable code, script, or other data structure to store information. In some implementations, the data store  1120  or a portion of the data store  1120  may be distributed across one or more other devices. 
     A communication module  1122  may be configured to establish communications with one or more of other devices, the sensors  902 , and so forth. The communications may be authenticated, encrypted, and so forth. The communication module  1122  may also control the communication interfaces  1108 . 
     The memory  1116  may also store a data acquisition module  1124 . The data acquisition module  1124  is configured to acquire sensor data. In some implementations the data acquisition module  1124  may be configured to operate the one or more sensors  902 , the microphone array  902 ( 5 ), and so forth. For example, the data acquisition module  1124  may determine that the sensor data satisfies a trigger event. The trigger event may comprise values of sensor data for one or more sensors  902  exceeding a threshold value. 
     In another example, the data acquisition module  1124  on the wearable device  100  may receive instructions from another device, such as a smartphone, to acquire sensor data at a specified interval, at a scheduled time, and so forth. 
     A user interface module  1126  provides a user interface using one or more of the I/O devices  1114 . The user interface module  1126  may be used to obtain input from the user, present information to the user, and so forth. For example, the user interface module  1126  may accept input from the user via the switch  902 ( 1 ) and use the display device  904 ( 3 ) such as an LED to provide output to the user. 
     One or more other modules  1128  may also be stored in the memory  1116 . 
     Data  1130  may be stored in the data store  1120 . For example, the data  1130  may comprise the sensor data, user preferences, and so forth. 
     One or more acquisition parameters  1132  may be stored in the memory  1116 . The acquisition parameters  1132  may specify operation of the data acquisition module  1124 , such as data sample rate, sample frequency, scheduling, and so forth. 
     Threshold data  1134  may be stored in the memory  1116 . For example, the threshold data  1134  may specify one or more thresholds used by the data acquisition module  1124  to determine whether sensor data is to be retained or discarded. 
     The wearable device  100  may maintain historical data  1136 . The historical data  1136  may be used to provide information about trends or changes over time. For example, the historical data  1136  may comprise data indicative of movement as measured by the accelerometer  902 ( 10 ) over several hours or days. 
     Other data  1138  may also be stored in the data store  1120 . 
     The wearable device  100  may operate in conjunction with one or more other devices. For example, sensor data may be sent from the wearable device  100  to a smartphone, server, or other computing device for processing. 
     Specific physical embodiments as described in this disclosure are provided by way of illustration and not necessarily as a limitation. Those having ordinary skill in the art readily recognize that alternative implementations, variations, and so forth may also be utilized in a variety of devices, environments, and situations. Although the subject matter has been described in language specific to structural features or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features, structures, and acts are disclosed as exemplary forms of implementing the claims. 
     Processes discussed herein may be implemented in hardware, software, or a combination thereof. In the context of software, the described operations represent computer-executable instructions stored on one or more non-transitory computer-readable storage media that, when executed by one or more processors, perform the recited operations. Generally, computer-executable instructions include routines, programs, objects, components, data structures, and the like that perform particular functions or implement particular abstract data types. Those having ordinary skill in the art will readily recognize that certain steps or operations illustrated in the figures above may be eliminated, combined, or performed in an alternate order. Any steps or operations may be performed serially or in parallel. Furthermore, the order in which the operations are described is not intended to be construed as a limitation. 
     Embodiments may be provided as a software program or computer program product including a non-transitory computer-readable storage medium having stored thereon instructions (in compressed or uncompressed form) that may be used to program a computer (or other electronic device) to perform processes or methods described herein. The computer-readable storage medium may be one or more of an electronic storage medium, a magnetic storage medium, an optical storage medium, a quantum storage medium, and so forth. For example, the computer-readable storage media may include, but is not limited to, hard drives, optical disks, read-only memories (ROMs), random access memories (RAMs), erasable programmable ROMs (EPROMs), electrically erasable programmable ROMs (EEPROMs), flash memory, magnetic or optical cards, solid-state memory devices, or other types of physical media suitable for storing electronic instructions. Further, embodiments may also be provided as a computer program product including a transitory machine-readable signal (in compressed or uncompressed form). Examples of transitory machine-readable signals, whether modulated using a carrier or unmodulated, include, but are not limited to, signals that a computer system or machine hosting or running a computer program can be configured to access, including signals transferred by one or more networks. For example, the transitory machine-readable signal may comprise transmission of software by the Internet. 
     Separate instances of these programs can be executed on or distributed across any number of separate computer systems. Thus, although certain steps have been described as being performed by certain devices, software programs, processes, or entities, this need not be the case, and a variety of alternative implementations will be understood by those having ordinary skill in the art. 
     Additionally, those having ordinary skill in the art will readily recognize that the techniques described above can be utilized in a variety of devices, environments, and situations. Although the subject matter has been described in language specific to structural features or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the claims.