Abstract:
This document describes methods and apparatus for reducing a magnetic field emitted by an earpiece assembly from extending substantially outside a device associated with the earpiece assembly. Where the earpiece assembly is susceptible to ingress of magnetically attractable particles into the earpiece assembly such a reduction can prolong an operational life of the earpiece assembly. By insert molding magnetically permeable materials throughout an enclosure that surrounds and supports a permanent magnet of the earpiece assembly, a portion of a magnetic field emanating from the permanent magnet that extends outside the device can be substantially reduced or redirected so that the magnetic field ceases to draw the magnetically attractable particles into the earpiece assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International PCT Application No. PCT/US15/10333, filed Jan. 6, 2015, and claims priority to U.S. Provisional Patent Application No. 62/047,441, filed Sep. 8, 2014, and entitled “EARPIECE INTEGRATED MAGNETIC SHIELDING FOR MITIGATING INGRESS OF MAGNETIC PARTICLES”, which is herein incorporated by reference in its entirety. 
     This application is related to (i) U.S. Provisional Patent Application No. 62/047,567, filed Sep. 8, 2014, and entitled “ACOUSTIC MESH AND METHODS OF USE FOR ELECTRONIC DEVICES”, and (ii) U.S. Provisional Patent Application No. 62/047,561, filed Sep. 8, 2014, and entitled “SHIELD FOR ACOUSTIC DEVICE”. 
    
    
     FIELD 
     The described embodiments relate generally to methods for preventing contaminates from entering a device housing. More particularly, the present embodiments relate to methods and apparatus for preventing or at least reducing a rate at which a magnetic element of a voice coil motor draws magnetically attractable particles into the device housing. 
     BACKGROUND 
     As an electronic device assumes progressively thinner profiles, internal electronic components suitable for performing various tasks can be forced closer towards various openings of the electronic device. In some cases, a magnet responsible for generating audio signals is purposefully placed near an opening in the electronic device to optimize an emitted audio signal. Unfortunately, a magnetic field emitted by such a magnet can cause various magnetically attractable particles to be drawing through the opening. These magnetically attractable contaminates can accumulate within the electronic device to a point at which functionality of internal components of the electronic device suffer degradation and in some cases complete failure. While a protective screen positioned across the opening can be effective to keep larger particles out, reduction in aperture of the screen below a certain threshold can substantially degrade the passage of signals along the lines of audio signals. For this reason, modern designs often allow small particles on the order of below 10 microns to pass into the electronic device. In some embodiments, a build up of the small particles can inhibit movement of audio generating components, thereby degrading and in some cases preventing operation of the audio components. 
     SUMMARY 
     This paper describes various embodiments that relate to methods and apparatus for preventing ingress of magnetically attractable particles through an audio port. 
     A speaker assembly for an electronic device is disclosed. The speaker assembly includes at least the following: a speaker that includes a magnetic element that emits a magnetic field used to actuate an acoustic membrane that generates audio signals; and a speaker enclosure substantially surrounding the speaker assembly and defining an opening that provides an outlet for the audio signals produced by the acoustic membrane. The speaker enclosure includes magnetically permeable material positioned proximate the opening in a manner that shapes the magnetic field such that magnetically attractable particles from an external environment are inhibited from being magnetically drawn through the opening. 
     A speaker assembly configured to be affixed to an interior surface of a housing of an electronic device is disclosed. The speaker assembly includes at least the following: a speaker enclosure defining an opening leading towards a position at which an opening in the interior surface of the housing is positioned when the speaker assembly is affixed to the interior surface of the housing, the speaker enclosure including magnetically permeable material arranged around the opening defined by the speaker enclosure; a magnet disposed within and substantially surrounded by the speaker enclosure; an electrically conductive ring electrically coupled with a power supply that supplies the electrically conductive ring with modulated current during operation of the speaker assembly; and a diaphragm coupled with and disposed across the electrically conductive ring. The electrically conductive ring and the magnet cooperate to vibrate the electrically conductive ring so that the diaphragm generates an audio signal that is transmitted through the opening defined by the speaker enclosure, and the magnetically permeable material is positioned to redirect a portion of the magnetic fields extending outside of the electronic device without obstructing the opening defined by the speaker enclosure. 
     An electronic device is disclosed and includes at least the following: a device housing defining a speaker opening; and a speaker assembly affixed to an interior facing surface of the device housing that includes the speaker opening. The speaker assembly includes at least the following: a speaker enclosure defining an opening oriented towards the speaker opening in the interior surface of the device housing, the speaker enclosure comprising magnetically permeable material distributed around the opening defined by the speaker enclosure; a magnet disposed within and substantially surrounded by the speaker enclosure; and an acoustic membrane stretched over an electrically conductive ring, the electrically conductive ring configured to emit a shifting magnetic field that cooperates with a magnetic field emitted by the magnet to cause the acoustic membrane to generate an audio output that is transmitted through the opening of the speaker enclosure and the speaker opening. 
     Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1  shows perspective views of an electronic device suitable for use with the described embodiments; 
         FIG. 2  shows a close up top view of an upper portion of the electronic device depicted in  FIG. 1 ; 
         FIG. 3  shows a partial cross-sectional view of the electronic device in accordance with section line A-A; 
         FIGS. 4A-4B  show partial cross-sectional side views of the electronic device of  FIG. 2  in accordance with section line B-B, overlaid by representations of magnetic field lines emanating from a magnet; 
         FIG. 5  shows an alternative embodiment in which additional magnetically permeable material along the lines of mu-metal is added within the electronic device and above a magnetic component of an earpiece assembly; 
         FIG. 6  shows a graph representing a strength of a magnetic field present along a top surface of the electronic device just above a magnetic component of an earpiece speaker assembly; 
         FIGS. 7A-7E  show various alternative embodiments suitable for preventing magnetically attractable particles from accumulating on a diaphragm of the earpiece speaker assembly; 
         FIG. 8  shows a flow diagram representing a method for preventing the ingress of magnetically attractable particles into an electronic device; and 
         FIG. 9  shows a block diagram representing an electronic device suitable for controlling operations of internal components in accordance with the described embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     This application is related to another provisional patent application entitled, “Acoustic mesh features of an electronic device” that discusses a number of acoustic and cosmetic mesh embodiments to include various stackups 0 , mesh stiffener elements and three dimensional mesh configurations. 
     Representative applications of methods and apparatus according to the present application are described in this section. These examples are being provided solely to add context and aid in the understanding of the described embodiments. It will thus be apparent to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the described embodiments. Other applications are possible, such that the following examples should not be taken as limiting. 
     In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments in accordance with the described embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the described embodiments, it is understood that these examples are not limiting; such that other embodiments may be used, and changes may be made without departing from the spirit and scope of the described embodiments. 
     Audio components often use magnetic elements for converting a signal that includes auditory information into sound waves. By modulating an amount of current circulating through an electrically conductive coil a shifting magnetic field can be created that interacts with a magnetic field associated with a permanent magnet. The electrically conductive coil and a diaphragm attached thereto can then move in response to a changing magnetic force caused by interactions between the magnetic fields to produce audio waves. Depending upon a position of the permanent magnet within a device housing, the magnetic field emitted by the permanent magnet can continuously attract magnetically attractable particles external to the housing. Because the permanent magnet is generally arranged close to an opening in the housing to facilitate exit of the audio waves generated by the audio components, the magnetically attractable particles tend to be drawn into the housing through the opening. Although such an opening is typically covered with a porous mesh, small magnetically attractable particles with a diameter smaller than the pores of the porous mesh can be drawn through the porous mesh. Once the magnetically attractable particles enter the housing they are drawn towards the permanent magnet and tend to build up on the diaphragm, especially given that the diaphragm is typically positioned just above the permanent magnet. Over time the build up of even small magnetically attractable particles can degrade or even prevent movement of the diaphragm. 
     One solution to this problem is to place a magnetically permeable material between the permanent magnet and a wall of the device housing through which the magnetic field of the permanent magnet extends. The magnetically permeable material can be arranged around a pathway between the opening and the permanent magnet so that a flow of audio waves out of the housing remains unimpeded. Notwithstanding the opening, the magnetically permeable material can redirect the magnetic field of the permanent magnet so that the magnetic field is less concentrated just above the opening leading into the device. In this way, the ingress of magnetically attractable particles can be reduced to a level at which magnetically attractable particles are less likely to prevent or degrade movement of the diaphragm. With the exception of an open audio pathway leading out of an earpiece enclosure surrounding the audio component, magnetically permeable material can be insert-molded within the earpiece enclosure so that the permanent magnet is substantially surrounded by magnetically permeable material. The inclusion of generous amounts of magnetically permeable material immediately around the permanent magnet can also reduce a likelihood of the permanent magnet interfering with other internal electrical components disposed within the housing. It should be noted that in addition to reducing the effect of the external magnetic field, by insert-molding robust magnetically permeable material into the earpiece enclosure a thickness of the earpiece enclosure can be considerably reduced, when compared with a plastic earpiece enclosure, without impairing a structural soundness of the earpiece enclosure. The thinned earpiece enclosure walls can also enhance audio performance of the audio component by increasing the volume available to the transducer. 
     These and other embodiments are discussed below with reference to  FIGS. 1-9 ; however, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. 
       FIGS. 1A-1B  show perspective views of electronic device  100  suitable for use with the described embodiments. Electronic device  100  includes display assembly  102 . Display assembly  102  can be utilized to present a touch based user interface to a user of electronic device  100 . In some embodiments, electronic device  100  also includes another user interface element along the lines of button  104 . Button  104  can be configured to perform specific functions depending on an operating state of electronic device  100 . In some embodiments, button  104  can be configured to return electronic device  100  to a higher level menu and/or terminate use of a currently selected application. In other embodiments, a function of button  104  can be user configurable. It should be noted that electronic device  100  can include many other buttons and or user interface elements not specifically discussed. A top surface of electronic device  100  can be covered by cover glass  106 . Cover glass  106  can define an opening  108  associated with an audio port configured to generate audio signals generated within electronic device  100  that exit electronic device  100  through opening  108 . In some embodiments, the audio signals can be along the lines of audio signals associated with telephone conversations. In other embodiments, media files can be played back through the audio port. Opening  108  can be covered by a layer or multiple layers of mesh that prevents most contaminates from entering into electronic device  100 , while allowing audio signals to pass through the layers of mesh substantially unhindered. In some embodiments, the mesh layer(s) can have openings no larger than about 10 microns in diameter. 
       FIG. 2  shows a close up top view of an upper portion of electronic device  100 . In particular, opening  108  of the audio port is depicted. Close up x-ray view  202  shows a number of internal components associated with the audio port relative to opening  108 . Snout region  204  represents an aperture through which audio signals generated by vibratory motion associated with components interacting with magnet  206  exit electronic device  100 . Earpiece enclosure  208  substantially surrounds magnet  206  and acts as a shunt to substantially prevent a magnetic field associated with magnet  206  from affecting objects external to electronic device  100  when enclosure  208  includes magnetically permeable material. This can be particularly important when magnet  206  is a permanent magnet as the magnetic field associated with magnet  206  would be persistently present. Enclosure  208  doesn&#39;t extend over snout region  204 , so that audio signals can pass unhindered through snout region  204 . While leaving snout region  204  open can reduce an effectiveness of enclosure  208  as a shielding member for magnet  206 , earpiece enclosure  208  can still attenuate enough of the magnetic field emitted from magnet  206  to prevent the magnetic field from extending substantially outside electronic device  100 . Positioning enclosure  208  between magnet  206  and cover glass/protective cover  106  can limit or in certain embodiments preclude an amount of electromagnetic radiation from leaving electronic device  100  even though enclosure  208  doesn&#39;t completely cover magnet  206 . 
       FIG. 3  shows a partial cross-sectional view of electronic device  100  in accordance with section line A-A that includes earpiece assembly  300 . Earpiece assembly  300  is anchored within opening  108  defined by cover glass  106 . Cosmetic mesh  302  covers opening  108  and provides an overlay that presents a cosmetically pleasing cover for earpiece assembly  300 . Cosmetic mesh  302  can also be useful for preventing some contaminates from entering electronic device  100 . Cosmetic mesh  302  can be affixed to an inside surface of cover glass  106  in various ways. For example, cosmetic mesh can be adhesively coupled to an inside surface of cover glass  106 . In some embodiments, a frame member can be used to keep cosmetic mesh  302  stretched across opening  108 . A remaining portion of earpiece assembly  300  can also be adhered to cover glass  106 . In some embodiments, an injection molded portion  304  can suspend down from the cover glass to define a channel depicted as snout region  204 . Snout region  204  can be covered by acoustic mesh  306  that can in cooperation with cosmetic mesh  302  operate to prevent contaminates from passing into a portion of earpiece assembly  300  that includes contaminate sensitive components along the lines of audio components. In some embodiments, injection molded portion  304  can be formed around magnetically permeable material  308  along the lines of high carbon steel. Magnetically permeable material  308  redirects a portion of a magnetic field emitted from magnet  206  so the magnetic field does not extend substantially past cover glass  106 , which will be illustrated in  FIGS. 4A-4B . In some specific embodiments, magnetically permeable material  308  can take the form of magnetically permeable stainless steel along the lines of SUS-430, which provides a good balance between strength and magnetic permeability. In this way, SUS-430 can provide both robust structural support for earpiece enclosure  208  that substantially surrounds magnet  206  and magnetic field shielding to at least mitigate a strength of a magnetic field proximate to opening  108 . It should also be noted that because magnetically permeable material  308  can provide robust structural support that a thickness of earpiece enclosure  208  can be reduced. The reduced thickness can allow earpiece enclosure  208  to fit in a tighter space and accommodate somewhat larger components to surround it. In some embodiments the thinned walls can also help to enhance an output of audio components disposed within earpiece enclosure  208  as vibration of the walls can be improved which can improve acoustic transmission of audio waves outside electronic device  100 . 
     Also depicted in  FIG. 3  is diaphragm  310 . Diaphragm  310  can be a semi-rigid acoustic membrane formed from material that provides excellent properties for providing high quality auditory output. In some embodiments, the material can be paper; however, any number of materials can be alternatively employed, such as for example paper composites, polypropylene, mineral/fiber filled polypropylene, thermoplastic polyurethane (TPU), thermoplastic elastomers (TPE), and polyether ether ketone (PEEK). Diaphragm  310  is positioned across electrically conductive coil  312 . Electrically conductive coil  312  can provide a platform across which diaphragm  310  can be stretched or at least secured. In some embodiments, electrically conductive coil  312  can be formed from copper. Although not depicted, coil  312  can be electrically coupled with a power supply that provides a changing amount of electricity. A longitudinal axis of electrically conductive coil  312  can be substantially aligned with a longitudinal axis of magnet  206  to facilitate interaction between magnetic fields emitted by the two elements. By changing an amount of electricity routed through coil  312  a shifting magnetic field can be emitted from electrically conductive coil  312  that interacts with a magnetic field emanating from magnet  206 . 
     In some embodiments, earpiece assembly  300  can include an additional electrically conductive coil  314 . Electrically conductive coil  314  can be utilized to provide an additional magnetic field that interacts with the magnetic field produced by magnet  206  and the magnetic field produced by electrically conductive coil  312 . In some embodiments, all three magnetic fields can cooperate to create magnetic signatures not otherwise possible. For example, current in both electrically conductive coils  312  and  314  can run in opposite directions while being modulated in different patterns. In other embodiments, current modulations and amplitudes can be at least partially synchronized. Because diaphragm  310  is only flexibly connected to the enclosure by flexible connectors  316 , diaphragm  310  can be vertically displaced to generate sound waves  318  in the direction indicated by the arrows over diaphragm  310 . The vertical displacement can be driven at a frequency that causes sound waves  318  to match audio content specified in data stored and/or received by electronic device  100 . In some embodiments, flexible connectors  316  can be configured to electrically couple electrically conductive coil  312  to the power supply. In other embodiments, electrically conductive coil  312  can be electrically coupled to the power supply by a separate electrical connector (not depicted). Regardless of how the coils are powered, the varying Lorentz force produced by modulating current through the electrically conductive coil or coils can cause vertical displacement to occur in a desired pattern that corresponds to audio information received by electronic device  100 . It should be noted that in addition to insert molding magnetically permeable material  308  into components surrounding magnet  206 , magnetic shunt  322  can be positioned directly below magnet  206 . In some embodiments, magnetic shunt  322  can be configured to snap into and be held within an opening defined by an insert-molded portion of earpiece enclosure  208 . Magnetic shunt  322  can substantially prevent magnetic radiation from extending directly below magnet  206 . This can be particularly beneficial where magnetically sensitive components along the lines of a printed circuit board are located below magnetic shunt  322 . 
       FIGS. 4A-4B  show partial cross-sectional side views of electronic device  100  in accordance with section line B-B overlaid by representations of a magnetic field emanating from magnet  206 .  FIG. 4A  shows a representation of magnetic fields  402  and  404  resulting when no magnetically permeable shielding material is included in enclosure  208 . For example, when SUS-304 is utilized to surround and strengthen an enclosure surrounding magnet  206 , the magnetic field emitted from magnet  206  is substantially unaffected.  FIG. 4B  shows a representation of magnetic fields  406  and  408  emanating from magnet  206 . Noticeably, a portion  410  of magnetic field  408 , made up of a number of magnetic field lines, bends substantially away from cover glass  106  as a result of magnetically permeable material insert molded within earpiece enclosure  208  surrounding magnet  206 . 
       FIG. 5  shows an alternative embodiment in which additional magnetically permeable material along the lines of mu-metal is added between cosmetic mesh  302  and magnet  206  of earpiece assembly  300 . For example, magnetically permeable material  502  is depicted in place below cosmetic mesh  302 . By placing additional magnetically permeable material  502  between magnet  206  and cosmetic mesh  302  a strength of a magnetic field extending outside electronic device  100  can be spread out and redirected, thereby further reducing a rate at which magnetically attractable particles are drawn into electronic device  100 . In this way, an intense magnetic field localized just above magnet  206  can be distributed more evenly, causing a much lower likelihood of magnetically attractable particles  320  from being drawn into electronic device  100 . In particular, by reducing a Z-component of the emitted magnetic field a force driving magnetically attractable particles  320  towards cosmetic mesh  302  can be commensurably reduced. 
       FIG. 6  shows a graph  600  representing a magnitude of a Z-component of a magnetic field present along a top surface of an electronic device just above a magnetic component of an earpiece speaker assembly. The Z-component of the magnetic field corresponds to an amount of force normal to the opening leading into the speaker assembly of the electronic device. Generally speaking, configurations having a greater Z-component will result in magnetically attractable particles being drawn into the electronic device at a greater rate. The depicted field lines represent the Z-component of the magnitude of the magnetic field immediately outside electronic device  100  for various shielding configurations. Line  602  represents one of the depicted configurations, where a material along the lines of SUS-304 (a metal with substantially no magnetic permeability) is used to surround the magnetic component and no additional shielding is utilized. In such a case the Z-component of the magnetic force is concentrated near the center of the magnet, which unfortunately is located above a point of entry leading directly towards the magnetic element emitting the magnetic field. Line  604  represents a configuration in which SUS-430 is utilized to surround the magnet. In such a case the Z-component just above a central portion of the magnet is reduced by about one third. Line  606  represents a configuration in which mu-metal is used to line the enclosure for the magnet. While mu-metal generally has greater magnetic permeability than SUS-430 it tends to have weaker mechanical properties, requiring a thicker enclosure than one having the same strength but formed from SUS-430. Finally, line  608  represents a configuration similar to that shown in  FIG. 5  where SUS-430 surrounds the magnet and mu-metals are included near the cosmetic mesh. By combining the magnetically permeable insert molding materials with the mu-metals near the surface of electronic device  100 , the Z-component of the magnetic field extending outside electronic device  100  can be substantially distributed across the outside of electronic device  100 . 
       FIGS. 7A-7E  show various alternative embodiments suitable for preventing ingressing magnetically attractable particles from accumulating on the diaphragm. In particular,  FIG. 7A  shows a configuration in which magnets  702  are positioned peripherally along the particle ingress path. In some embodiments, magnets  702  can attract magnetically attractable particles so they accumulate on magnets  702  as opposed to diaphragm  310 . It should be noted that a size and strength of magnets  702  can be optimized to prevent or at least ameliorate any negative effects caused by interference between magnets  702  and a magnetic field emitted by magnet  206  or a shifting magnetic field emanated by electrically conductive coil  312 .  FIG. 7B  another alternative embodiment in which a sacrificial magnet  704  is offset from snout region  204 . Sacrificial magnet  704  can draw magnetically attractable particles away from snout region  204  as depicted in the arrows designated as the particle ingress path. In this position, sacrificial magnet  704  can have a substantial magnetic field that can divert magnetically attractable particles otherwise destined to accumulate on diaphragm  310  to a location above sacrificial magnet  704 . 
       FIG. 7C  shows another alternative embodiment in which an acoustic baffle  706  is added below cosmetic mesh  302 . In some embodiments, cosmetic mesh stiffener  708  can be utilized to increase a stiffness of cosmetic mesh  302 . In some embodiments, cosmetic stiffener  708  can also be utilized to support acoustic baffle  706  just below cosmetic mesh  302 . By limiting ingress of magnetically attractable particles to a portion of the device that is not directly above snout region  204  an amount of magnetically attractable particles that arrive at diaphragm  310  can be reduced.  FIG. 7D  shows another alternative embodiment in which an acoustic baffle  710  is positioned directly above snout region  204 . In this way, an additional layer of protection is positioned directly between diaphragm  310  and cosmetic mesh  302 .  FIG. 7E  shows yet another alternative embodiment in which an acoustic baffle has relatively smaller openings than the previously described embodiments that are distributed across an area about the same as cosmetic mesh  302 . 
       FIG. 8  shows a block diagram representing a method for preventing the ingress of magnetically attractable particles into an electronic device. In a first step  802 , magnetically permeable material is insert molded into an enclosure configured to surround a magnet. In some embodiments, the magnetically permeable material can be SUS-430, which has good magnetic permeability and structural characteristics. The structural or mechanical characteristics allow the magnetically permeable material to reinforce the enclosure surrounding the magnet. In some embodiments, using material with good structural characteristics can help to reduce a size or thickness of the enclosure. At step  804 , additional magnetically permeable material can be added within the electronic device so that it is positioned between the magnet and an outside surface of the electronic device. The additional magnetically permeable material can be formed from a material chosen specifically for its high magnetic permeability, as the material need not perform or augment any structural features of the electronic device. In some embodiments, mu-metal can be used to fulfill this function. The mu-metal can be a nickel-iron alloy formed primarily from nickel but also including iron and smaller amounts of chromium or molybdenum. It should be noted that in addition to its high magnetic permeability, mu-metal tends to be ductile, which can make it easier for the material to be formed into a particular shape and location within the electronic device. 
       FIG. 9  is a block diagram of electronic device  900  suitable for controlling operations of internal components in accordance with the described embodiments. Electronic device  900  illustrates circuitry of a representative computing device. Electronic device  900  includes a processor  902  that pertains to a microprocessor or controller for controlling the overall operation of electronic device  900 . Electronic device  900  contains instruction data pertaining to manufacturing instructions in a file system  904  and a cache  906 . The file system  904  is, typically, a storage disk or a plurality of disks. The file system  904  typically provides high capacity storage capability for the electronic device  900 . However, since the access time to the file system  904  is relatively slow, the electronic device  900  can also include a cache  906 . The cache  906  is, for example, Random-Access Memory (RAM) provided by semiconductor memory. The relative access time to the cache  906  is substantially shorter than for the file system  904 . However, the cache  906  does not have the large storage capacity of the file system  904 . Further, the file system  904 , when active, consumes more power than does the cache  906 . The power consumption is often a concern when the electronic device  900  is a portable device that is powered by a battery  924 . The electronic device  900  can also include a RAM  920  and a Read-Only Memory (ROM)  922 . The ROM  922  can store programs, utilities or processes to be executed in a non-volatile manner. The RAM  920  provides volatile data storage, such as for cache  906 . 
     The electronic device  900  also includes a user input device  908  that allows a user of the electronic device  900  to interact with the electronic device  900 . For example, the user input device  908  can take a variety of forms, such as a button, keypad, dial, touch screen, audio input interface, visual/image capture input interface, input in the form of sensor data, etc. Still further, the electronic device  900  includes a display  910  (screen display) that can be controlled by the processor  902  to display information to the user. A data bus  916  can facilitate data transfer between at least the file system  904 , the cache  906 , the processor  902 , and a CODEC  913 . The CODEC  913  can be used to decode and play a plurality of media items from file system  904  that can correspond to certain activities taking place during a particular manufacturing process. The processor  902 , upon a certain manufacturing event occurring, supplies the media data (e.g., audio file) for the particular media item to a coder/decoder (CODEC)  913 . The CODEC  913  then produces analog output signals for a speaker  914 . The speaker  914  can be a speaker internal to the electronic device  900  or external to the electronic device  900 . For example, headphones or earphones that connect to the electronic device  900  would be considered an external speaker. 
     The electronic device  900  also includes a network/bus interface  911  that couples to a data link  912 . The data link  912  allows the electronic device  900  to couple to a host computer or to accessory devices. The data link  912  can be provided over a wired connection or a wireless connection. In the case of a wireless connection, the network/bus interface  911  can include a wireless transceiver. The media items (media assets) can pertain to one or more different types of media content. In one embodiment, the media items are audio tracks (e.g., songs, audio books, and podcasts). In another embodiment, the media items are images (e.g., photos). However, in other embodiments, the media items can be any combination of audio, graphical or visual content. Sensor  926  can take the form of circuitry for detecting any number of stimuli. For example, sensor  926  can include any number of sensors for monitoring various operating conditions of electronic device  900 , such as for example a Hall Effect sensor responsive to external magnetic field, a temperature sensor, an audio sensor, a light sensor such as a photometer, a depth measurement device such as a laser interferometer and so on. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.