Abstract:
A method of waterproof testing an electronic device at a rated water depth is provided. The method may comprise the steps of assembling the electronic device; subjecting the electronic device to a test vacuum pressure associated with the rated water depth; measuring a leak rate of the electronic device after the electronic device is subjected to the test vacuum pressure; rejecting the electronic device if the leak rate is above an allowable leak rate; and accepting the electronic device if the leak rate is below the allowable leak rate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of application Ser. No. 11/222,163, filed Sep. 8, 2005, the entire contents of which is expressly incorporated herein, which claims the benefits of U.S. Provisional Application No. 60/608,856, filed Sep. 10, 2004, the entire contents of which are incorporated herein by reference. 
     
    
     STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT  
       [0002]     Not Applicable  
       BACKGROUND  
       [0003]     The present invention relates to a process for assembling and/or testing a waterproof and/or shock resistant electronic device and also to machinery for assembling and/or testing the waterproof and/or shock resistant electronic device.  
         [0004]     Active people, hikers, surfers, snowboarders and the like, enjoy listening to music while engaging in vigorous physical activities which may include the risk on inevitability of getting wet. One method for the participant to listen to his/her favorite music while engaged in the vigorous physical activity is to listen to a compact disk. However, a CD player has many inherent problems such as the weight, track skipping, and size. Additionally, for snowboarding and swimming, participants may not be able to listen to music with CD players because CD players are not water resistant. Moreover, CD players are typically too large and too heavy for the active person to carry while engaging in the vigorous physical activity.  
         [0005]     Accordingly, there is a need in the art for an improved music playing device wherein a user may listen to music while participating in vigorous physical activity including water related sports. Moreover, there is a need in the art for an assembly process and a machine for assembling the improved music playing device. Additionally, there is a need in the art for a method and machine to test whether the music player will function (e.g., waterproof) while the participant engages in vigorous physical activity and/or water related activities.  
       BRIEF SUMMARY  
       [0006]     The present invention addresses the needs discussed above, those discussed below and those that are known in the art.  
         [0007]     A waterproof test machine is described herein. The waterproof test machine may comprise a leak test chamber, a rigid tube in fluid communication with the leak test chamber and a vacuum pump. The vacuum pump may be activated via a computer to apply vacuum pressure within the leak press chamber to determine whether the music player is waterproof.  
         [0008]     The waterproof test machine may subject the music player or electronic device to a waterproof test process. The test process subjects the music player to various vacuum pressures. The vacuum pressure in the leak test chamber is then measured over a period of time to determine a leak rate. If the leak rate is below an allowable leak rate, then the music player is determined to be waterproof at a rated water depth. If the leak rate is above the allowable leak rate, then the music player is failed, disassembled and salvaged.  
         [0009]     The rated water depth corresponds to the test vacuum pressure. In particular, if the rated depth of the music player is 10 feet, then the test vacuum pressure is about 5.3 psig. The reason is that the music player will be subjected to about 5 psig at a water depth of 10 feet. A 0.3 psig safety factor is used. The leak rate of the music player is measured after the leak test chamber is subjected to the corresponding test vacuum pressure of the rated water depth. The music player is passed or failed based on the leak rate, as discussed above.  
         [0010]     In an aspect of the steps to assemble the music player, one of the steps comprises the step of inserting a rigid member into a flexible member. During use of the music player, the user controls operation of the music player by pushing the flexible member which subsequently traverses the rigid member to operate switches connected to a printed circuit board. The flexible member creates a waterproof seal such that water does not enter the music player via a button aperture formed to receive the flexible member/button.  
         [0011]     In another aspect of the steps to assemble the music player, one of the steps comprises placing an o-ring about a plug. The o ring is disposed in matching grooves of upper and lower housings. The o ring and the grooves form a waterproof seal such that water does not enter through the plug aperture of the housing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:  
         [0013]      FIG. 1  is an illustration of a swimmer listening to music with a water resistant and shock resistant music player wherein the music player is engaged to the participant&#39;s arm via an arm band;  
         [0014]      FIG. 2  is a perspective view of the music player removed from the arm band and an earphone removed from an earphone plug of the music player;  
         [0015]      FIG. 3  is an exploded perspective view of the music player illustrating four buttons and the earphone plug wherein rim portions of buttons and a ring disposable about the plug are respectively received into rim grooves and a ring groove to make the music player water resistant;  
         [0016]      FIG. 4  is a top view of the upper housing with alignment pins of the upper housing engaged to alignment holes of the PCB board and the ring disposed about the plug received into the ring groove of the upper housing;  
         [0017]      FIG. 5  is a cross sectional top view of the button in the button aperture illustrating a rim portion of a flexible member disposed within the rim groove for forming a water tight seal therebetween;  
         [0018]      FIG. 6  is a cross sectional front elevational view of the button in the button aperture illustrating a band disposed in recesses of the upper and lower housing periphery;  
         [0019]      FIG. 7  is a flow diagram for assembling the music player;  
         [0020]      FIG. 8  is a flow diagram for a step of applying a conformal coating step shown in  FIG. 7 ;  
         [0021]      FIG. 9  is a flow diagram for a step of attaching a transparent window step shown in  FIG. 7 ;  
         [0022]      FIG. 10  is a perspective view of a conformal coating machine;  
         [0023]      FIG. 11  is a perspective view of a sonic welding machine for sonically welding a transparent window to a housing of the music player;  
         [0024]      FIG. 12  illustrates the steps shown in  FIG. 7  of inserting a rigid member into a flexible member, inserting the flexible members into apertures of a band, disposing an O-ring about a plug, assembling a PCB on the band, aligning a button of a switch to a second distal end of the rigid member, disposing a compressible material in an upper housing and disposing the PCB on the upper housing;  
         [0025]      FIG. 13  illustrates the steps of placing the music player assembly into a fixture and traversing a horn downward recited in  FIG. 7 ;  
         [0026]      FIG. 14  illustrates a leak test chamber in an open position with a music player disposed therein; and  
         [0027]      FIG. 15  illustrates the leak test chamber and a leak test control unit for testing whether the music player is waterproof. 
     
    
     DETAILED DESCRIPTION  
       [0028]     Referring now to the drawings which are for the purposes of illustrating the preferred embodiments of the present invention and not for the purposes of limiting the same,  FIG. 1  illustrates a user  10  listening to a music player  12  while swimming. The music player  12  is inserted into an armband  14  wrapped and secured to a left arm  16  of the person  10 . An ear phone  18  is also shown having an ear bud  20  and a jack  22 . The jack  22  is connected to the music player  12  and the ear bud  20  is inserted into an ear  24  of the user  10 . The music player  12  permits the user  10  to simultaneously swim and listen to music.  
         [0029]      FIG. 2  illustrates the armband  14 , the music player  12  and the earphone  18 . The armband  14  may comprise a strap  26 , pouch  28  and a closing flap  30 . The strap  26  may be fabricated from a neoprene material and sized and configured to fit around the user&#39;s arm  16 . The distal ends  32   a, b  of the strap  26  may have hooks  34  and loops  36  respectively attached to ends  32   a, b.  The strap  26  may be wrapped around the user&#39;s arm  16 , and the hooks  34  and loops  36  may engage each other to attach the armband  14  to the user&#39;s arm  16 .  
         [0030]     The pouch  28  may be attached to a central portion  38  of the strap  26  on its outside surface. The pouch  28  may also be fabricated from a neoprene material sized and configured to the general shape of a casing  40  of the music player  12 . In particular, the pouch  28  may be fabricated to have a rounded top portion  42  and tapered bottom portion  44 . The pouch  28  may further define an entrance/exit or opening  46  through which the music player  12  may be inserted into or removed from the pouch  28 . The opening  46  may be smaller than the music player  12  such that the opening  46  must be stretched open to insert the music player  12  into the pouch  28  or to remove the music player  12  from the pouch  28 . This provides additional capture of the music player  12  inside the pouch  28  in addition to the closing flap  30 . The pouch  28  may further have button openings  48  on the left and right hand sides of the pouch  28  sized, configured and positioned to allow the user  10  to feel and depress buttons  50   a - d  of the music player  12 . The closing flap  30  may be attached to an outside surface of the pouch  28  and removably attachable to an inside surface of the strap  26 . The closing flap may a jack aperture  52  sized and configured to receive the jack  22  of the earphone  18 , as shown in  FIGS. 1 and 2 . The inside surface of the strap  26  and the inside surface of the closing flap  30  may be respectively lined with hooks  54  and loops  56  such that the closing flap  30  may cover the opening  46  when the closing flap  30  is in a closed position (see  FIG. 1 ) and the hooks  54  and loops  56  lined on the inside surfaces of the strap  26  and closing flap  30  may be engaged to each other. In the closed position, the jack aperture  52  may be aligned to a plug  58  of the music player  12  such that the jack  22  of the earphone  18  may be plugged into the plug  58  when the flap  30  is in the closed position. To remove the music player  12  from the pouch  28 , the user  10  may remove the jack  22  from the plug  58 . The loops  56  may be disengaged from the hooks  54 , and the music player  12  may be slipped out of the pouch  28  through opening  46 .  
         [0031]     The discussion of the operation of the music player  12  itself is exemplary and not meant to limit the present invention. It is also contemplated that other operation schemes may be employed in conjunction with the various aspects of the music player  12  discussed herein. The music player  12  may be turned on by pressing the on/off button  50   c  for three seconds while the jack  22  of the earphone  18  (i.e., output devices) is attached to the plug  58 . The music player  12  may be turned off by disengaging the jack  22  from the plug  58 . Alternatively, and more preferably, the music player  12  may be turned off by depressing the on/off button  50   c  for three seconds. While the music player  12  is on, a subsequent song or previous song may be played by depressing either the next track button  50   c  or the previous track button  50   d,  respectively. To replay the current song, the previous track button  50   d  may be depressed. To adjust the volume, the increase or decrease volume buttons  50   a, b  may be depressed. These buttons  50   a - d  activate the switches  60   a - d  (see  FIG. 3 ) formed on a PCB  62  to control the music player  12 .  
         [0032]     The music player  12  may be manufactured to be water resistant such that the user  10  may engage in water sports while listening to his or her favorite music. Additionally, the music player  12  may be shock resistant such that the user  10  may engage in vigorous physical activity without interruption of the music being played. To this end, as shown in  FIG. 3 , the music player  12  may have a plurality of electronic components  64  formed on the printed circuit board (PCB)  62 . The PCB  62  and the electronic components  64  may cooperate with each other to play music. The electronic components  64  may include a battery which may be rechargeable and a flash memory (by way of example and not limitation, 128 megabyte, 256 megabyte and 1 gigabyte). The electronic components  64  may include software embedded on an IC chip to play music downloaded onto the flash memory. The software may play MP3 formatted music as well as all common music formats.  
         [0033]     The plug  58  may also be attached to the PCB  62  at a distal end thereof. The plug  58  may be a 3.5 mm plug and may also be waterproof. The plug  58  may be connected to output devices such as amplified speakers, headphones, earphones  18 , and the like. The plug  58  may also be connected to a USB cable adaptor. The USB cable adaptor may have a cable jack and USB connector with a cable connecting the cable jack and the USB connector. The cable jack may be inserted into the plug  58  and the USB connector may be connected to a USB port of a computer to permit downloading of music files from the computer to the music player  12 , and more particularly, to the flash memory of the music player  12 . Additionally, the USB cable adaptor may provide power to the music player  12  for recharging the battery of the music player  12 .  
         [0034]     The music player  12  may have an upper housing  66 , a lower housing  68  and a band  70  disposed therebetween which when assembled together forms a cavity to contain the electronic components  64  and resists water from entering into the cavity. The lower housing  68  may have a transparent window  72  such that a light emitting diode (LED) may emit light through the transparent window  72 . The LED may be one of the electronic components  64  attached to the PCB  62 . The LED functions to indicate a status of the MP3 player  12  such as whether a song is being played or whether the battery of the music player  12  is being charged. The band  70 , upper housing  66  and lower housing  68  may contact each other to form a water tight seal therebetween. For example, the upper housing  66 , lower housing  68  and the band  70  disposed therebetween may be sonically welded to each other. The band  70  may have a plurality of apertures  74   a - d  for receiving the buttons  50   a - d  (see  FIG. 4 ) and the plug  58 . In particular, an upper portion of the band  70  may have a plug aperture  74   e  sized and configured to receive the plug  58  therethrough. Left and right portions of the band  70  may have two button apertures  74   a, b  and  74   c, d  on each portion. The button apertures  74   a - d  may be sized and configured to receive buttons  50   a - d,  respectively. The buttons  50   a - d  may be operative to control switches  60   a - d,  respectively, attached to the PCB board  62 . A center line  76 a-d of the button apertures  74   a - d,  respectively, may be aligned to the switches  60   a - d  attached to the PCB board  62  when the MP3 player  12  is assembled. The buttons  50   a - d  may have flexible members  78  which permit minute movements of rigid members  80  through the apertures  74   a - d.  The rigid member  80  may be disposed through a core of the button  50   a - d.  As shown in  FIG. 5 , the rigid member  80  may be aligned to the switch  60  and in contact therewith and extend into the distal tip of the button  50 . Depressing the flexible member  78  in the direction of arrow  82  by the user&#39;s fingers is operative to traverse the rigid member  80  against the switch  60  and depress the switch  60  to control the operation of the music player  12 , as shown in  FIG. 6 .  
         [0035]     The upper and lower housings  66 ,  68  may have a cup-shaped configuration. A periphery of each of the upper and lower housings  66 ,  68  may define an interface surface  84   a, b  (see  FIGS. 3 and 4 ). The upper housing  66  may be disposed above the lower housing  68  with the interface surface  84   a  of the upper housing  66  in alignment with the interface surface  84   b  of the lower housing  68 . When the interface surfaces  84   a, b  of the upper housing  66  and the lower housing  68  are in contact with each other, a cavity is formed therebetween which houses the electronic components  64 . When the interface surfaces  84   a, b  of the upper and lower housings  66 ,  68  are sonically welded, a watertight seal is formed therebetween. However, the upper and lower housings  66 ,  68  form button apertures  86   a - e  for the buttons  50   a - d  and the plug  58 . As such, water may still enter the cavity through button and plug apertures  86   a - e  but is prevented as discussed below.  
         [0036]     The button and plug apertures  86   a - e  permit the user  10  of the music player  12  to insert a jack  22  of an earphone  18  into a plug  58  attached to the PCB board  62  and to depress buttons  50   a - d  to control the switches  60   a - d.  More particularly, the plug  58  may be attached to the PCB board  62  and extend through sidewall portions  88   a, b  (see  FIG. 3 ) of the upper and lower housings  66 ,  68 . The plug  58  may have a generally circular configuration. The plug aperture  86 e may be sized to be slightly larger than a diameter of the plug  58  such that the plug  58  may be inserted therethrough. The plug aperture  86   e  may be defined by a semi-circularly shaped depression formed in the lower housing  68  which mates with a corresponding semi-circularly shaped depression in the upper housing  66 . When the interface surface  84   a  of the upper housing  66  mates with the interface surface  84   b  of the lower housing, then plug aperture  68   e  is formed.  
         [0037]     The semi-circularly shaped depressions may have donut shaped grooves  90   a, b  (see  FIG. 3 ) sized and configured to receive a ring  92  disposable about the plug  58 . During assembly, the PCB board  62  with the plug  58  attached thereto may have the ring  92  disposed about the plug  58 . The PCB board  62  may be disposed within the upper housing  66  with the plug  58  disposed in the semi-circularly shaped depression of the upper housing  66 . Moreover, the ring  92  disposed around the plug  58  may be disposed in groove  90   a  of the upper housing  66 . The interface surface  84   a  of the upper housing  66  may be aligned and placed in contact with the interface surface  84   b  of the lower housing  68 . Moreover, in this position, the depression formed in the sidewall portion of the lower housing  68  also receives the plug  58 , and the groove  90   b  receives the ring  92  disposed around the plug  58 . The interface surfaces  84   a, b  of the upper and lower housings  66 ,  68  may be sonically welded to each other to assemble the music player  12 . When assembled, the ring  92  being slightly larger than the grooves  90   a, b  is snugly fitted within the grooves  90   a, b  of the lower and upper housings  66 ,  68 . The snug fit between the ring  92  and the grooves  90   a,b  of the housings  66 ,  68  forms a watertight seal therebetween. In this manner, a jack  22  of the earphone  18  may be plugged into the plug  58  for receiving electronic signals from the music player  12  and delivering such signals to the ear bud  20  of the earphone  18  such that the user  10  may enjoy listening to the music being played while in wet conditions.  
         [0038]     The buttons  50   a - d  which control the operations of the music player  12  may be inserted into button apertures  86   a - d  so as to form a water tight seal therewith. In particular, the buttons  50   a - d  may have the flexible member  78  and the rigid member  80 , as shown in  FIG. 3 . The flexible member  78  may have a hat-shaped configuration defined by a nub portion  94  and a rim portion  96 . The nub and rim portions  94 ,  96  may have cylindrical configurations (see  FIG. 3 ) wherein a central axis of the nub portion  94  and a central axis  96  of the rim portion  96  are aligned with each other. The nub portion  94  and the rim portion  96  may be fabricated from a unitary material such as rubber or other elastomeric material. The button apertures  86   a - d  for receiving the buttons  50   a - d  may be defined by semi-circularly shaped depressions formed in the upper and lower housings  66 ,  68 . The button apertures  86   a - d  may be sized and configured to receive the nub and rim portions  94 ,  96  of the flexible member  78  and the rigid member  80 , as shown in  FIG. 5 . The semi-circularly shaped depressions formed in the upper and lower housings  66 ,  68  may also have donut shaped grooves  98   a, b  (see  FIGS. 3 and 4 ). Groove  98   a  of the upper housing  66  is best shown in  FIG. 4 , and groove  98   b  of the lower housing  68  is best shown in  FIG. 3 . The donut shaped grooves  98   a, b  of the upper and lower housings  66 ,  68  may collectively receive the rim portion  96  of the flexible member  78 . When the rim portion  96  is received in the grooves  98   a, b  of the upper and lower housings  66 ,  68  and the interface surfaces  84   a, b  of the upper and lower housings  66 ,  68  are assembled (e.g., sonic welding, etc.), a watertight seal is formed between the interface surfaces  84   a, b  of the upper and lower housings  66 ,  68  as well as between the button  50  and the button aperture  86 .  
         [0039]     The button apertures  86   a - d  (see  FIG. 3 ) may also define a central axis which is in alignment with the switches  60   a - d  attached to the PCB board  62 , as shown in  FIG. 5 . Additionally, a hole may be formed through the rim portion  96  and the nub portion  94  of the flexible member  78 . The hole may extend through the rim portion  96  and extend to the nub portion  94 . However, the hole should not extend through the entire nub portion  94  so as to make a hole through the button  50  such that water does not enter the housing through such hole.  
         [0040]     The hole and rigid member  80  may be sized and configured such that the rigid member  80  may snuggly fit within the hole but may also be slidable therethrough. A first distal end  100  of the rigid member  80  may have a bulbous configuration with an edge  102  (see  FIG. 5 ) to prevent the rigid member  80  from being pulled out of the hole. The first distal end  100  of the rigid member  80  may be inserted into the hole until the first distal end  100  contacts a bottom  104  of the hole. The rigid member  80  may be longer than a depth  106  of the hole and a second distal end  108  of the rigid member  80  may be disposed adjacent to a switch  60 . When the upper and lower housings  66 ,  68  are assembled with the buttons  50   a - d  and PCB board  62 , the user  10  may press the button  50  in direction  82  to slide the rigid member  80  through the hole such that the second distal end  108  of the rigid member  80  depresses the switch  60  (see  FIG. 6 ). This controls the operation of the music player  12 . When the user&#39;s finger releases the button  50 , the switch  60  springs outwardly and traverses the rigid member  80  back to its normal position (see  FIG. 5 ).  
         [0041]     As shown in  FIG. 6 , the band  70  may be interposed between the upper and lower housings  66 ,  68 . In particular, the upper and lower housings  66 ,  68  may be formed with a recess  110   a, b  about peripheries of the upper and lower housings  66 ,  68 , as shown in  FIGS. 3 and 4 . More particularly, as shown in  FIGS. 4 and 6 , the upper housing  66  may be formed with a recess  110   a  about the periphery thereof. Also, as shown in  FIGS. 3 and 6 , the lower housing  68  may be formed with a recess  110   b  about the periphery thereof. The recesses  110   a, b  may be sized and configured to receive the band  70  therein such that the band  70  is substantially flush with an exterior of the upper and lower housings  66 ,  68 , as shown in  FIGS. 2 and 6 . The band  70  may also have four button apertures  74   a - d  (see  FIG. 3 ) which may be sized and configured to receive the nub portion  94  of the buttons  50   a - d,  as shown in  FIG. 4 . The band  70  with the buttons  50   a - d  inserted into the button apertures  74   a - d  may be placed into the recess  110   a  of the upper housing periphery with the rim portions  96  of the buttons  50   a - d  received into the grooves  98   a.  Additionally, the plug  58  with the ring  92  disposed thereabout may be inserted into aperture  74   e.  The interface surfaces  84   a, b  of the upper and lower housings  66 ,  68  may be aligned and sonically welded to each other, as shown in  FIG. 6 .  
         [0042]     To assemble the music player  12 , the ring  92  may be disposed about the plug  58 . Alignment pins  112  (see  FIG. 3 ) formed in the upper housing  66  may then be inserted into alignment holes  114  (see  FIG. 3 ) formed in the PCB board  62 , as shown in  FIG. 4 . At this time, the ring  92  is disposed in groove  90   a  of the upper housing  66 . The rigid member  80  may be inserted into the holes of the flexible member  78  to assemble the button  50 . The buttons  50   a - d  may be inserted into the button apertures  74   a - d  of the band  70 , as shown in  FIG. 4 . Thereafter, the band  70  may be placed on the recess  110   a  of the upper housing periphery with the nub portions  94  of the buttons  50   a - d  placed into the semi-circularly shaped depressions of the upper housing  66  and the rim portions  96  placed into the grooves  98   a.  The interface surface  84   b  of the lower housing  68  may be aligned and engaged (e.g., sonically welded, etc.) to the interface surface  84   a  of the upper housing  66 . The engagement of the interface surfaces  84   a, b  of the upper and lower housings  66 ,  68  creates a water tight seal therebetween. The ring  92  and the rim portions  96  of the buttons  50   a - d  create a water tight seal with the grooves  90   a, b  and  98   a, b  of the upper and lower housings  66 ,  68 . Hence, water does not enter the cavity formed by the upper and lower housings  66 ,  68  thereby protecting the PCB board  62  from water damage.  
         [0043]     Referring now to  FIGS. 7-15 , the water and shock resistant music player  12  may be assembled in the following manner and assembled utilizing the machine shown in  FIGS. 10, 11 , and  13 - 15 . As shown in  FIG. 7 , a first step  200  for assembling the music player  12  is to apply  200  a conformal coating to the printed circuit board  62  and/or the electronic components  64 . The conformal coating assists the music player  12  to withstand all water forms such as water, ice, snow, humidity, condensation and the like that may cause an electrical short of the electronic system of the music player  12 . By way of example and not limitation, the electronic components  64  may initially be attached to the printed circuit board  62  so as to electrically interconnect the electronic components  64  to each other. With the electronic components  64  attached to the printed circuit board  62 , the electronic components  64  and the printed circuit board  62  may be prebaked  202  (see  FIG. 8 ) for about four hours at a temperature of about 55 degrees Celsius or about 131 degrees Fahrenheit. After the prebake step  202  (see  FIG. 8 ), the connectors (e.g., switches  60  and plug  58 ; see  FIG. 3 ) may be masked off  204 . For example, the exposed hole  152  (see  FIG. 3 ) of the plug  68  as well as the moving mechanical parts (e.g., buttons  128 ; see  FIG. 3 ) of the switches  60   a - d  may be masked off to prevent the conformal coating from covering the electrical contact in the plug  58  or operation of the switches  60   a - d.  Otherwise, the plug  58  and/or the switches  60  may become inoperative due to the conformal coating. After the masking off step  204 , both sides of the printed circuit board  62  may be sprayed  206  with a conformal coating material such as humisel 1B31 type AR. After the spraying step  206 , the conformal coating material may be air cured  208 . After the curing step  208 , the mask may be removed  210  from the connectors.  
         [0044]     The step of applying  200  (see  FIGS. 7 and 8 ) the conformal coating to the printed circuit board  62  and/or the electronic component  64  may be accomplished with a conformal coating machine  116  (see  FIG. 10 ). The conformal coating machine  116  may be hand operated, manually operated, mechanically operated, computer operated, etc. The conformal coating machine  116  may have a spray gun  154  fluidically connected to container fitted with the conformal coating material. The spray gun  154  pumps the material through the spray gun and onto the printed circuited board  62  and the electronic components  64 . A grip  168  of the conformal coating machine  116  manipulates (e.g., flips, turns, rotates, etc.) the PCB  62  with respect to the spray gun  154  so as to cover the entire PCB  62  with the conformal coating material.  
         [0045]     In a second step  212  (see  FIGS. 7, 9  and  11 ), the transparent widow  72  (see  FIG. 11 ) is formed  212  into the lower housing  68 . In particular, the lower housing  68  may have a window aperture  156  at or about the upper portion thereof, as shown in  FIGS. 2, 3  and  11 . The transparent window  72  may be sized and configured to contact the entire periphery  158  of the window aperture  156  formed in the lower housing  68 . The transparent window  72  may define a base portion  120  and a nub portion  122 .  
         [0046]     To attach  212  the transparent window  72  to the window aperture  156  of the lower housing  68 , the lower housing  68  may be placed in a fixture  124  (see  FIG. 11 ) sized and configured to receive the lower housing  68 . The inner cavity  160  of the fixture  124  may have a substantially mirror configuration as the exterior surface of the lower housing  68  such that the lower housing  68  does not move or wiggle within the inner cavity  160  of the fixture  124 . The lower housing  68  may be placed  214  (see  FIG. 9 ) into the fixture  124  with the exterior surface of the lower housing  68  contacting the interior cavity  160  of the fixture  124 . After placing  214  the lower housing  68  into the fixture  124 , the transparent window  72  may be placed adjacent to the window aperture  156  of the lower housing  68 . In particular, the base portion  120  of the transparent window  72  may contact the periphery  158  of the window aperture  156 . The nub portion  122  may have a cylindrical configuration and be positioned so as to be oriented in an upward direction (see  FIG. 11 ). After positioning  216  the transparent window  72  into the lower housing  68 , a sonic weld horn  126  may be traversed downward and onto the transparent window  72 . The sonic weld horn  126  may also have a recess for receiving the nub portion  122  of the transparent window  72 . The transparent window  72  may now be sonically welded  217  to the lower housing  68  at the window aperture  156  of the lower housing  68 . The sonic welding  217  (see  FIG. 9 ) of the transparent window  72  to the lower housing  68  creates an airtight and watertight seal such that water and air cannot pass through the window aperture  156  of the lower housing  68 .  
         [0047]     As shown in  FIG. 12 , the rigid member  80  may be inserted  218  (see  FIG. 7 ) into the flexible member  78 . In particular, the first distal end  100  of the rigid member  80  may be inserted  218  into the hole of the flexible member  78  until the first distal end  100  contacts a bottom  104  of the flexible member hole (see  FIG. 12 ).  
         [0048]     After inserting  218  the rigid member  80  into the flexible member  78 , the flexible member  78  may be inserted  220  (see  FIG. 7 ) through the button aperture  74  of the band  70 . Each button aperture  74   a - d  may have one flexible member  78  inserted therethrough  74 . After inserting  220  the flexible member  78  into the button aperture  74 , the O-ring  92  is disposed  222  (see  FIG. 7 ) about the plug  58 . After disposing  222  the o-ring  92  about the plug  58 , the printed circuit board  62  is assembled  224  within the band  70 , as shown in  FIG. 12 . In particular, the plug  58  is pushed through the plug aperture  74   e  of the band  70 . The second distal end  108  of the rigid members  80  are aligned  226  (see  FIG. 7 ) to the buttons  128  of the switches  60 . Each of the buttons  50  may be depressed to assure proper functioning of the switches  60 .  
         [0049]     A compressible material  162  (see  FIG. 12 ) may be disposed  228  (see  FIG. 7 ) against the interior surface of the upper housing  66 . The compressible material  162  may be sufficiently thick so as to press against the electronic components  64  and/or circuit board  62 . During use, the compressible material  162  absorbs any shock to prevent damage to the electronic components  64  and the printed circuit board  62 . Preferably, the compressible material  162  is a foam strip adhered onto the interior surface of the upper housing  66 .  
         [0050]     After disposing  228  the compressible material into the upper housing  66 , the band  70  and the printed circuit board  62  are disposed  230  into the upper housing  66  (see  FIG. 12 ). The electronic components  64  may compress the compressible material to prevent or absorb shock experienced by the music player  12 . The band  70  and the printed circuit board  62  is disposed  230  into the upper housing  66  in the following manner. The band  70  contacts the recess  110   a  of the upper housing  66  (see  FIGS. 6 and 12 ). The O-ring  92  is disposed within the groove  90   a  of the upper housing  66 . Also, the rim portions  96  of the flexible member  78  of the buttons  50   a - d  are disposed within respective grooves  98 a of the upper housing  66 . At this point, the rigid members  80  should still be aligned to the buttons  128  of the switches  60 . If not, then the rigid members  80  should be readjusted such that the rigid members  80  are aligned to the buttons  128  of the switches  60  such that depression of the buttons  50   a - d  actuates the switches  60 .  
         [0051]     After disposing  230  the printed circuit board and band  70  into the upper housing  66 , the lower housing  68  may be disposed  232  on the band  70 , printed circuit board  62  and the upper housing  66 . In particular, the lower housing  68  is aligned to the band  70 , printed circuit board  62  and the upper housing  66  when the rim portions  96  are disposed within the respective grooves  98   b  (see  FIG. 3 ) of the lower housing  68 . Additionally, the O-ring  92  is disposed within the groove  90   b  (see  FIG. 3 ) of the lower housing  68 . At this point, the band also contacts the recess  110   b  (see  FIG. 3 ) of the lower housing  68 .  
         [0052]     The assembled but loose upper housing  66 , printed circuit board  62 , band  70  and the lower housing  68  are placed  234  (see  FIGS. 7 and 13 ) into a fixture  130  (see  FIG. 13 ) sized and configured to receive the upper housing  66 . By way of example and not limitation, the internal cavity  164  of the fixture  130  may have a reverse configuration as the exterior surface of the upper housing  66 . The internal cavity  164  of the fixture  130  should be sized and configured to the exterior surface of the upper housing  66  such that the assembled but loose music player  12  does not unduly move or wiggle within the fixture  130 . After placing  234  the assembled but loose music player  12  into the fixture  130  a horn  132  is traversed downward onto the lower housing  68 . The upper housing  66 , lower housing  68  and the band  70  are sonically welded to each other. The horn  132  may be custom made to fit the design of the music player  12  to provide precise welding of the parts to insure airtight, waterproof component manufacture. By way of example and not limitation, the horn  132  may provide pressure about the periphery of the lower housing  68  such that the interface surfaces  84   a - b  (se  FIG. 3 ) are sonically welded to each other. Also, the band  70  may be sonically welded to interface surfaces  110   a, b.    
         [0053]     After sonically welding  234 ,  236  (see  FIG. 7 ) the upper housing  66  to the lower housing  68 , the assembled and attached music player  12  is leak tested  238  (see  FIGS. 7, 14  and  15 ). In particular, the music player  12  may be placed within a leak test chamber  134  (see  FIGS. 14 and 15 ). The leak test chamber  134  may comprise a base member  136  of the leak test chamber  134 . The base member  136  may have an internal cavity  166  sized and configured to receive the music player  12 . A gasket  138  may be formed about the periphery of the internal cavity  166  of the leak test chamber  134 . The gasket  138  may protrude out of a top surface  140  of the base member  136 . More particularly, the music player  12  may be disposed at a lower elevation compared to the gasket  138 . A lid member  142  may be rotated and closed over the internal cavity  166  of the base member  136 . A bottom surface  144  of the lid member  142  contacts the gasket  138 . A clamp  146  (see  FIG. 15 ) may be used to apply downward pressure on the lid member  142  such that there is an airtight seal between the top surface  140  of the base member  136  and the bottom surface  144  of the lid member  142  via the gasket  138 .  
         [0054]     The internal cavity  166  of the leak test chamber  134  may be in fluid communication with a vacuum pump. The vacuum pump is operative to create a vacuum within the internal cavity  166  of the leak test chamber  134 . By way of example and not limitation, a through hole may be formed in the base member  136  of the leak test chamber  134 . A rigid tube  150  may be fitted into the through hole and also connected to a leak test control unit  148 . The leak test control unit  148  may contain the vacuum pump. The leak test unit  148  controls the vacuum pump to apply a vacuum pressure to the internal cavity  166  of the leak test chamber  134  as described below. Through such procedures, the music player  12  is waterproof tested without the application of water. The leak test unit  148  will indicate whether the music player  12  is waterproof or not based on a pass/fail signal. If the music player does not pass the leak test process or step  238  (see  FIG. 7 ), then the music player  12  is disassembled and the boards are salvaged and retested.  
         [0055]     For those music players  12  that pass the leak test  238 , they  12  undergo a functionality and performance test  240  (see  FIG. 7 ). The music player  12  is plugged into headphones or personal computer speakers and tested to insure that all switches, buttons and functions are working properly and that music is played back.  
         [0056]     The sonic welder machine may be Dukane Sonic Welder.  
         [0057]     Another advantage of the music player  12  is that the music player  12  is resistant to shocks. The user  10  may be engaged in vigorous physical activity such as surfing or cycling. The user  10  may be violently tumbled by the waves or may ride over bumps in the road. Nonetheless, the music player  12  continuously plays music without skipping. Moreover, the solid construction of the music player  12  prevents the shocks from destroying the music player  12 .  
         [0058]     As discussed above, the music player  12  is leak tested  238  by placing the music player  12  in an internal cavity  166  of the leak test chamber  134 . The leak test chamber  134  is closed (see  FIG. 15 ) and a vacuum pressure cycle is applied to the leak test chamber  134  via the leak test machine  148 . The test sequence comprises two different tests which may be performed with a push of a start button on the leak test equipment  148 . In particular, the first test sequence comprises the steps of applying the test vacuum pressure to the internal cavity  166  of the leak test chamber  134 . Thereafter, the vacuum pressure in the internal cavity  166  is immediately sensed over a period of time (e.g.,  3  seconds) via a vacuum pressure sensor of the leak test unit  148 . A vacuum pressure drop in the leak test chamber  134  greater than an allowable vacuum pressure drop indicates a large leak in the music player  12  and the music player  12  is failed. If the music player  12  passes the first test sequence, then the music player  12  is subsequently subjected to a second test sequence which tests for smaller leaks. The second test sequence may comprise the steps of applying the test vacuum pressure to the internal cavity  166  of the leak test chamber  134 . The vacuum pressure within the internal cavity  166  of the leak test chamber  134  is then allowed to stabilize. After the vacuum pressure has stabilized in the leak test chamber  134 , the vacuum pressure is measured over a period of time. If the vacuum pressure drop (after stabilization) over the period of time in the leak test chamber  134  is greater than an allowable vacuum pressure drop, then the music player is failed and is not allowed to proceed to a next step of testing  240  the function and performance of the music player  12 .  
         [0059]     During the first and second test sequences discussed above, the leak test unit  148  may be calibrated to display a cubic centimeters per minute (i.e., ccm) leak rate based on the loss of vacuum pressure over a period of time. During the first and second test sequences discussed above, the leak rate is calculated based on the loss of vacuum pressure over a period of time. If the leak rate is greater than the allowable leak rate, then the music player  12  is failed and not allowed to pass to the next step. The allowable leak rate may be the same or different for the first or second test sequences. For example, during the first test sequence, the leak test chamber  134  is brought to the test vacuum pressure. Immediately thereafter, the vacuum pressure is sensed over a period of time. Based on the loss of pressure over the period of time, the leak rate is calculated. If the leak rate is greater than the allowable leak rate, then the music player  12  is failed and not allowed to pass to the next step. During the second test sequence, the leak test chamber is brought to the test vacuum pressure. The vacuum pressure is allowed to stabilize. After the vacuum pressure has stabilized, the vacuum pressure is sensed over a period of time. Based on the loss of pressure over the period of time, the leak rate is calculated. If the leak rate is greater than the allowable leak rate, then the music player  12  is failed and not allowed to pass to the next step.  
         [0060]     The vacuum pressure has stabilized when the vacuum loss over a period of time is approximately linear. Initially, when the leak test chamber  134  is brought to the test vacuum pressure, the rate of pressure loss in the leak test chamber  134  may be greater than a linear rate. After a period of time, the leak rate or rate of vacuum pressure loss will approach a constant value. The leak rate during the linear portion of the cycle is compared to the allowable leak rate to determine whether the music player  12  is waterproof.  
         [0061]     The leak test chamber  134  is brought to the test vacuum pressure during the first and second test sequences. The test vacuum pressure is derived from the rated water depth of the music player  12 . The rated water depth is the depth that the music player  12  may be submerged in water and able to withstand entry of water into the music player  12  during its intended use. By way of example and not limitation, if the music player&#39;s rated water depth is ten feet, then the pressure applied to the music player  12  at a water depth of 10 feet is approximately less than 5 psig. A 0.3 psig is used as a safety factor. As such, the leak test chamber is brought to a vacuum test pressure of about 5.3 psig. Preferably the vacuum test pressure is a vacuum rather than a positive air or water pressure. However, a positive pressure may also be used during the first and second test sequences discussed above. If the rate of vacuum pressure loss corresponds to a leak rate less than about 5 cubic centimeters per minute (ccm), then the music player  12  is waterproof at the rated depth of 10 feet. Preferably, the leak rate should be less than about 0.5 sccm.  
         [0062]     After the music player  12  is leak tested  238  via the leak test unit  148 , the dry music player  12  is weighed to determine the weight of the music player  12 . Thereafter, the music player  12  is submerged in water to the rated water depth (e.g., 10 feet) for approximately 48 hours. At the end of 48 hours, the music player  12  is removed from the water, dried and reweighed. If the weight of the music player  12  is the same before and after submersion of the music player  12  into the water, then the music player  12  is determined to be waterproof. This subsequent water submersion test may be performed on a small portion of music players  12  to sample the lot or on all of the music players  12 .  
         [0063]     The leak test unit  148  is programmable to operate the vacuum pump and sense the vacuum pressure within the leak test chamber  134  as discussed above such that with a push of a start button on the leak test unit  148 , the music player  12  may be subjected to the first test sequence and the second test sequence if the music player passes the first test sequence.  
         [0064]     In an aspect of the method and machinery, the leak test equipment may be a Uson Testra 1100.  
         [0065]     The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including various ways of engaging the interface surfaces  84   a, b  of the upper and lower housings  66 ,  68 . Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.