Patent Publication Number: US-2018035744-A1

Title: Sound Producing Shoe Including Impact and Proximity Detectors

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 14/992,118. The parent application was filed on Jan. 11, 2016. It listed the same inventor. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of footwear. More specifically, the invention comprises a shoe that reproduces one or more pre-recorded sound upon the detection of one or more sensor inputs. 
     2. Description of the Related Art 
       FIG. 1  depicts a prior art shoe that uses an impact between the shoe&#39;s sole and the ground to trigger a flashing light. This feature can provide enhanced safety for persons running in low light conditions. It can also provide entertainment, primarily for young users who enjoy the flashing of the light with each step. In the version shown, impact sensor  16  is located in the area beneath the ball of the foot. Controller  12  includes the electronics needed to receive the impact signal from impact sensor  16  and activate the desired output (generally a single flash from LED  18 ). Power source  14  provides electrical energy to the components shown. In this version the power source is simply a pair of hearing aid batteries connected in series. An access port is provided in the bottom of the shoe so that the batteries may be replaced. 
     There are several different types of light-producing shoes known in the market. In other versions the impact sensor is located proximate the user&#39;s heel. The sensor then tends to be actuated by a stomping motion rather than a normal running motion. 
     Sound-producing shoes are also known. These employ a triggering sensor as for the shoe of  FIG. 1  but they produce a sound effect instead of the pulsing light output. The sound effect may be a simple chirp or may be a more complex sequence of pre-recorded sounds. 
     It is preferable for these sound and light-producing shoes to retain the desirable characteristics of a conventional shoe, such as shock-cushioning and pliability. It may therefore benefit the reader&#39;s understanding to explore some of the features of a conventional shoe before turning to the descriptions of the present invention.  FIGS. 2 and 3  depict some of the internal features of present-day running shoes. 
       FIG. 2  is a sectional elevation view through the heel  20  region of the shoe. Sole  22  is made of an abrasion-resistant material that gives good surface adhesion as well. Midsole  24  is made of a much softer material intended primarily for shock absorption. Open or close-cell foams are often used for the midsole. Bolster  26  surrounds and reinforces the rear of the shoe. It is often made of a material that is less stiff than sole  22  but more stiff than midsole  24 . The bolster is often configured to limit the rolling motion of a user&#39;s heel. 
     Upper  28  is the portion of the shoe that surrounds and captures the user&#39;s foot. It is often made as an assembly of multiple pieces and may also include multiple layers. Insole  30  is a removable and washable portion lying directly beneath the user&#39;s foot. 
       FIG. 3  is a sectional elevation view through the toe  32  portion of the same shoe. Midsole  24  tends to be much thinner in this region. In some constructions a different material is used for the midsole that lies beneath the ball of the foot versus the midsole lying beneath the heel. In still other constructions, additional shock absorbing “spring columns” are placed in the midsole beneath the heel. These existing structures are preferably considered and accommodated in the creation of the present invention. 
     BRIEF SUMMARY OF THE PRESENT INVENTION 
     The present invention comprises a pair of shoes that incorporates sound-reproducing equipment that is triggered by the detection of one or more conditions. One of the conditions is the impact of a shoe with the ground, such as when a user stomps the heel on the ground. Another condition is the proximity of a second shoe to a first shoe, such as when a user moves the left shoe of a pair close to the right shoe. The detection of an impact may be used to trigger the reproduction of any desired sound—such as the “chuff” sound of a steam locomotive. The detection of the proximity of another shoe along with an impact may be used to trigger the reproduction of a different sound—such as a steam whistle. 
     The proximity detection may be done using a variety of different methods. In a preferred embodiment, a magnet is placed in one shoe and the other shoe contains some type of magnetic switch. In another preferred embodiment, infrared light is transmitted by one shoe and reflected to a detector. Other embodiments are disclosed as well. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a side elevation view, showing some internal components of a prior art shoe that produces a light pulse with every step the user takes. 
         FIG. 2  is a sectional elevation view through the heel portion of a prior art shoe. 
         FIG. 3  is a sectional elevation view through the toe portion of a prior art shoe. 
         FIG. 4  is a side elevation view showing an embodiment of the present invention. 
         FIG. 5  is a plan view showing the embodiment of  FIG. 4  with the addition of a magnetic proximity sensor. 
         FIG. 6  is a perspective view, showing an embodiment incorporating a proximity detector based on infrared fight. 
         FIG. 7  is a perspective view, showing an embodiment incorporating a proximity detector based on a paddle switch. 
         FIG. 8  is a plan view, showing an embodiment incorporating a proximity detector based on RFID technology. 
         FIG. 9  is a perspective view, showing an embodiment incorporating a removable battery and an external charging port. 
         FIG. 10  is a detailed elevation view, showing an embodiment incorporating an inductive charging antenna. 
         FIG. 11  is a schematic view, showing one possible arrangement for the electronic components of the present invention. 
         FIG. 12  is a plan view, showing an embodiment in which each shoe contains a magnet and a magnetic sensor. 
         FIG. 13  is a flow chart showing some exemplary operations carried out by the controller in the inventive shoes. 
         FIG. 14  is a plan view, showing an embodiment in which each shoe contains an infrared emitter and an infrared detector. 
     
    
    
     REFERENCE NUMERALS IN THE DRAWINGS 
       10  shoe 
       12  controller 
       14  power source 
       16  impact sensor 
       18  LED 
       20  heel 
       22  sole 
       24  midsole 
       26  bolster 
       28  upper 
       30  insole 
       32  toe 
       34  speaker 
       36  right shoe 
       38  left shoe 
       40  magnetic sensor 
       42  magnet 
       44  IR emitter 
       46  IR detector 
       48  reflector/filter 
       50  paddle switch 
       52  RFID transceiver 
       54  RFID response module 
       56  battery 
       58  receiver 
       60  hatch 
       62  charge controller 
       64  inductive charge antenna 
       66  charging port 
       68  power bus 
       70  input 
       72  processor 
       74  memory 
       76  sensor  1   
       78  sensor  2   
       80  I/O port 
       82  D/A converter 
       84  amplifier 
       86  output driver 
       88  rotary input 
       90  index, mark 
       92  medial side 
       94  lateral side 
       96  start of cycle 
       98  first decision point 
       100  second decision point 
       102  second sound trigger step 
       104  playback completion step 
       106  first sound trigger step 
       108  playback completion step 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 4 and 5  illustrate a first exemplary embodiment of the present invention.  FIG. 4  depicts a side elevation view of shoe  10  incorporating the inventive components. Controller  12  and power source  14  are located within the shoe&#39;s midsole. Impact sensor  16  is located in this example at the junction between the midsole and the sole. The impact sensor may be configured to detect any desired level of impact. For example, it could be configured to detect every normal step or configured to detect only a hard “stomp” of the user&#39;s heel. 
     Many different types of sensing material may be used for impact sensor  16 . As a first example, a simple normally-open contact switch may be used. As a second example, a planar piezoelectric element could be used. The piezoelectric element has the advantage of no moving parts. As those skilled in the art will know, the gain of a piezoelectric element may be selectively adjusted to give varying sensitivity. 
     Controller  12  incorporates multiple components. In the preferred embodiment, a processor running software is included in the controller. An associated memory is also present. The controller and its associated memory are able to store a recorded sound sequence (preferably in a digital format). The controller also monitors for a triggering event (such as the detection of an impact). When the triggering event occurs, the controller retrieves a desired digital sound file, sends it through a digital to analog converter, amplifies the resulting analog signal, and feeds the analog signal to speaker  34 . 
     Speaker  34  converts the electrical signal to sound energy so that it may be heard by the shoe&#39;s wearer and other persons nearby. In the embodiment shown, the speaker is located in the rear portion of shoe  10 . It may of course be located in other portions. The speaker preferably includes weather-resistant features as it will likely be exposed to moisture and variable temperatures. 
     Power source  14  provides electrical power to all the components within the shoe. The power source may be a simple stack of hearing aid batteries connected in series. It may also be a more complex assembly, such as a lithium ion pack connected to a charge controller. The power source may be replenished by any suitable method. In the case of a stack of hearing aid batteries, an access port may be provided to facilitate the removal and replacement of the batteries. In the case of a more complex assembly, an inductive charge antenna may be connected to the charge controller. A simple electrical plug may also be provided so that the shoe can be connected to an external charger when not in use. 
     All the components within the shoe are preferably made as thin and flat as possible. This allows the components to reside within the pliable components of the shoe without causing discomfort to the user. They may in fact be potted within a semi-pliable polymer to provide structural reinforcement. The placement of the components in the aft portion of the shoe minimizes bending stress. Even so, it is preferable to use components that can repeatedly undergo some bending without failure. As an example, the electrical connection may be made using fiat flex circuits rather than simple wiring. 
     One of the important features of the present invention is its ability to sense an interaction between two shoes (as opposed to just the actions of a single shoe).  FIG. 5  shows a plan view of a preferred embodiment including this ability. Right shoe  36  includes the components illustrated in  FIG. 4  (controller  12 , power source  14 , impact sensor  16 , speaker  34 ). It also includes magnetic sensor  40 . Magnetic sensor  40  is configured to detect magnetic phenomena, such as the proximity of a magnetic field or a rate of change of a magnetic field. 
     Left shoe  38  includes magnet  42 . In this version, magnet  42  is positioned so that it will lay proximate magnetic sensor  40  when the heel of left shoe  38  is brought near the heel of right shoe  36 . Magnetic sensor  40  will then detect the presence of magnet  42 . 
     The controller and sensors may be configured to create a virtually endless variety of sound effects. One simple example will benefit the reader&#39;s understanding. Young children, sometimes enjoy the sounds of a steam locomotive. The controller may be used to store the “chuff” sound made by the driving cylinder of a steam locomotive when moving at low speed. Impact sensor  16  may be configured to trigger the “chuff” sound every time the child stomps the heel of the right shoe down. 
     The controller may also be used to store the sound of a steam train whistle. Magnetic sensor  40  may be configured to trigger the steam whistle sound every time the heel of left shoe  38  is brought near the heel of right shoe  36 . The child then walks forward while bringing the heel of the right shoe down abruptly to create a rhythmic chuffing or “chugging” sound. When the child swings the left heel closely by the right heel a steam train whistle is also produced. 
     Many other sound effects can be added as well. For example, the controller may log a series of impact sensor actuations in order to gauge the user&#39;s walking speed. The nature of the steam train sounds may then be changed according to speed. Other sounds may be added as well—such as the clanging of a train bell or the hissing of steam letting off when the user stops moving. 
     Left shoe  38  in the embodiment of  FIG. 5  is shown as containing only a magnet, but this will not always be the case. In some embodiments, left shoe  38  will contain a separate controller, power supply, impact sensor, speaker, etc. It may then be used to create its own synchronized “chuff” sound every time the left heel is brought down. In this version the user will create a chuff with the right heel and the left heel. The steam train whistle may still be triggered by the magnetic sensor. 
     Magnetic sensor  40  may assume many forms. A simple version might use a magnetic reed switch that is normally open and that will close when magnet  42  comes near. A more complex version might use a Hall effect sensor. As those skilled in the art will know, a Hall effect sensor varies its output voltage in response to a magnetic field. A Hall effect sensor may be configured to act as a switch (having only an on/off mode). It may also be configured to detect the rate of change of a magnetic field. In this latter case, the triggering event for the steam train whistle might not be the simple placement of the left heel near the right heel but rather the “swiping” of the left heel rapidly past the right heel. Such a swiping motion would create a rapid increase and subsequent decrease in the output of the Hall effect sensor. Software running on controller  12  could interpret this as the triggering “swipe” of the left heel. 
     The proximity detection, functions of the present invention may also be based on non-magnetic sensors.  FIGS. 6-8  illustrate additional embodiments using other sensor types. In FIG.  6 , infrared emitter  44  and infrared detector  46  are placed in right shoe  36 . The IR emitter projects infrared light and the IR detector is triggered when a reflection of that infrared light is received. Left shoe  38  is provided with reflector/filter  48 . This panel filters light wavelengths other than that emitted by IR emitter  44  and reflects light within the band of IR emitter  44 . When the heel of left shoe  38  is placed near right shoe  36 , the infrared light from emitter  44  is reflected back to IR detector  46  and the controller within right shoe  36  is thereby “informed” that left shoe  38  is close by. As for the prior example, the detection of proximity may be used to trigger a desired effect, such as the sounding of a steam train whistle. 
       FIG. 7  depicts an embodiment incorporating a much simpler form of proximity detection. Paddle switch  50  is provided on the side of right shoe  36 . The user activates this switch by sliding the left shoe along the side of the right shoe. The switch may be configured to have a neutral middle position that is held in place by centering springs. The user can then activate the switch by swiping the left shoe forward or backward along the side of the right shoe. 
       FIG. 8  depicts still another embodiment incorporating a different proximity-detecting mechanism. Left shoe  38  includes RFID response module  54 . Right shoe  36  incorporates RFID transceiver  52  connected to controller  12 . This embodiment is based on the well-known “RFID tag” technology. It can be passive or active. In the passive version, RFID transceiver  52  transmits an exciting signal. If RFID response module  54  is close enough, this exciting signal activates it and the response module then transmits its own modulated signal RFID transceiver  52  receives the response signal and thereby detects the presence of left shoe  38 . 
     As those skilled in the art will know, the response signal can contain additional information specifically identifying the RFID response module. In fact each RFID module installed in a shoe could be given, a unique response signal. In this way, controller  12  could be informed of specifically which shoe is in close proximity. This feature allows additional interactions beyond just between a single user&#39;s left and right shoes. The proximity of a shoe belonging to a different user could be detected and this event could be used to trigger still another sound effect—such as the sound of the closing of a mechanical railroad coupler. 
     The presence of a radio frequency transceiver connected to controller  12  allows other features as well. It may be desirable from time to time to change some of the parameters stored in the software running on controller  12  or to update the software itself. An external programmer can be used to transmit radio frequency signals to the transceiver. As one example, the pressure threshold for impact sensor  16  may need to be adjusted depending on the weight of the user. An external programmer may be used for this purpose. 
     Those skilled in the art will also realize that an external programmer need not rely on radio frequency signals to communicate. Light or sound could also be used with a suitable receiver placed in the shoe. 
     Whenever form the impact sensor (first sensor) and proximity sensor (second sensor) take, it is important that each send a signal to the controller upon the occurrence of the event they are configured to detect. The term “signal” in this context just means something that informs the controller that an event has been detected, if, for example, the second sensor is a magnetic reed switch, the “signal” may simply be the fact that the circuit has been made by the closing of the switch. If the second sensor is a Hall effect sensor, the signal may be a change in voltage output resulting from an increasing (or decreasing) magnetic field. 
     Returning now to  FIG. 4  the reader will recall that power source  14  provides electrical energy to the various components of the invention. The stored electrical energy must be replenished from time to time to keep the invention functioning.  FIG. 9  shows two approaches to replenishment. In the first approach, a rechargeable battery  56  is used. Receiver  58  receives the battery. Hatch  60  secures the battery in position. When the battery is depleted, the user opens the hatch, removes the battery, and places the battery in a separate charger. 
     The second approach shown in  FIG. 9  is charging port  66 . This port provides an electrical connection to an internal charge controller. A separate charger is plugged into charging port  66  in order to recharge the battery. 
     FIB.  10  shows still another embodiment. Charge controller  62  regulates the charging condition of battery  56 . Inductive charge antenna  64  inductively receives electrical energy from an external source and feeds it to charge controller  62 . In this version the shoe is placed on a charging, pad when not in use. The charging pad emits a low level charging signal that is received by inductive charge antenna  64  and conveyed to charge controller  62 . This version has the advantage of needing no external portals or connectors. All the components can be sealed within the shoe. 
     Manual features may also be provided in some embodiments for adjusting the shoe&#39;s operating parameters.  FIG. 7  shows one such device. Rotary input  88  surrounds the external speaker on the rear of the shoe. The user is able to unlock this rotary dial and turn it to indicate different settings. Index mark  90  is provided as a fixed reference. As one example, the controller could be configured so that four stomps in quick succession causes it to enter the programming mode. Turning rotary input  88  would then alter a selected parameter. Parameters could be announced using instructive recorded sequences such as a voice saying “programming mode entered” or “turn the dial to set sensitivity.” Rotary input  88  could thereby be used to adjust the sensitivity of the impact sensor, the magnetic sensor, or any other parameter. 
     The impact or magnetic sensors themselves could also be used as input devices. If four stomps put the device in programming mode, then additional stomps could be used to index the parameter being adjusted. Likewise, moving the second shoe next to the magnetic sensor and away again could produce one input pulse for programming purposes. 
     Those skilled in the art will know that controller  12  may assume many different forms.  FIG. 11  depicts one exemplary embodiment among the many different possibilities. Many of the components shown may be included in a single chip or made as an assembly of multiple chips. The reader should therefore properly view the example of  FIG. 11  as one possibility among many others. 
     Controller  12  includes processor  72  and an associated memory  74 . The processor runs controlling software and the memory includes stored items, such as multiple digital sound files. When the processor determines that a particular sound file is to be played, it retrieves the file from memory, then outputs it to digital-to-analog converter  82 . This device transforms the file to an analog signal. Amplifier  84  then amplifies the analog signal and feeds it to speaker  34 , where it is converted to sound waves. 
     Multiple sensors  76 ,  78  provide information to the processor. Examples include an impact sensor and a proximity sensor as described previously. I/O port  80  allows for software updates to be loaded and for other output features (such as a listing of the current state of all the parameters stored in memory  74 ). Output driver  86  allows the processor to control higher-current external devices such as LED  18  (which may be used to create a visual flash as for prior art shoes). 
     Power source  14  is regulated by charge controller  62  and fed power from input  70 . In the view powers source  14  includes multiple output branch lines. These are intended to indicate that the power source in this example provides power to all the component shown. This feature may or may not involve multiple connections. As an example, everything shown within the outline of controller  12  might be integrated onto a single chip (an “Application-Specific Integrated Circuit”). On the other hand, there might be multiple separate components each needing a separate feed line. 
       FIGS. 12 through 14  depict additional embodiments of the present invention. One potential issue with the invention is the unintentional actuation of the proximity sensor (second sensor). It is preferable to provide a proximity sensor that is only actuated by a deliberate action on the part of the user. As an example of this issue, one may consider the embodiment depleted in  FIG. 5 . 
     The version shown in  FIG. 5  has a controller  12  and magnetic sensor  40  in right shoe  36 . Left shoe  38  contains only a magnet  42 . As explained previously, the proximity sensor (magnetic sensor  40 ) is actuated whenever magnet  42  is nearby. However, it is preferable to provide a controller and sound-playing functionality in both the left and right shoes. This is particularly true where the sound being played for each step taken is the “chuff” of a steam train. A user (typically a young child) wants a “chuff” sound to be emitted for each step taken—one for the right foot and one for the left foot. 
     This desired functionality presents a problem for the proximity sensor. Looking again at  FIG. 5 , if left shoe  38  is provided with all the same components as right shoe  36 , then each shoe will have a magnet  42  and magnetic sensor  40 . In addition, the magnet and magnetic sensor in each individual shoe will have to be close together. This fact will produce “false” triggering of the proximity sensor, as a shoe&#39;s own magnet will trigger its proximity sensors. For this reason, it is not preferable to make the right and left shoes true mirror images. 
       FIG. 12  shows an embodiment configured to avoid this concern. Right shoe  36  and left shoe  38  are both equipped with controllers  12  and speakers  34 . Both also have an impact sensor  16  and a power source  14 . However, the proximity sensor system is different for the left and right shoe. 
     Each shoe has a medial side  92  and a lateral side  94 . Each shoe also has a toe portion and a heel portion. The magnetic sensor  40  in left shoe  38  is located on the medial side  92  proximate the toe portion. The magnet  42  in right shoe  36  is located on the medial side  92  of the right shoe and is proximate the toe portion of the right shoe. 
     For right shoe  36  magnetic sensor  40  is located proximate the heel portion along medial side  92  of the right shoe. The magnet  42  in left shoe  38  is located proximate the heel portion in medial side  92  of the left shoe. 
     When a user brings both feet together (side by side), the magnetic, sensor in each shoe will be triggered by the magnet in the other shoe. However, when the feet are separated, the magnet in each shoe is far enough away from the magnetic sensor in the same shoe that no false triggering occurs. 
     This configuration allows the controller  12  in each shoe to create the desired functionality. The desired functionality is (1) A sound will be produced when impact sensor  16  is triggered; and (2) The sound produced will depend upon the state of the proximity detection system. 
       FIG. 13  depicts a flow chart of the process run by the software in each controller in order to carry out the desired functionality. The process in each controller can be run independently of the other controller. A detection cycle begins at  96 . The software checks at step  98  whether the impact sensor has been triggered. If the impact sensor has not been triggered the process returns to step  96  and starts again. If the impact sensor has been triggered then the process proceeds to step  100 . At step  100  the process checks whether the proximity sensor (such as magnetic sensor  40 ) has been triggered. If the proximity sensor has not been triggered, then the process proceeds to step  106 . A first sound (such as a steam engine “chuff”) is retrieved from memory and played. Playback is completed at step  108  and the process returns to step  96 . 
     However, if at step  100  the software determines that the proximity detector has been triggered, then the process proceeds to step  102 . At step  102  a second sound (such as a steam whistle) is retrieved from memory and played. Playback is completed at step  104  and the process returns to step  96 . Obviously there are other ways to implement the desired functionality and the flow diagram shown in  FIG. 13  should be viewed as exemplary. 
     With these principles in mind, the operation of the embodiment shown in  FIG. 12  will be described. In this example, the first recorded sound is the “chuff” of a steam engine and the second recorded sound is the whistle of a steam engine. As the user walks along, each shoe will emit a “chuff” when it strikes the ground. This chuffing will continue for as long as the user walks along. 
     If the user jumps with both feet placed together (side by side) then upon landing both shoes will emit the steam whistle sound. A third option exists: The user may keep one foot planted on the ground and then stomp the other foot down next to the planted foot. In this Case the planted foot will remain silent and the “stomped foot” will emit the steam whistle sound. 
     The invention is not limited to any particular sound effects, though naturally it is preferable to select sound effects that are related to each other. Examples include:
         (1) A steam chuff and a steam whistle (as explained previously);   (2) A horse hoof “clop” and a whinny;   (3) A car engine “revving” sound and a tire squeal; and   (4) The two-note theme music from the movie “Jaws” and a scream.       

     The asymmetric configuration of the proximity sensors in the embodiment of  FIG. 12  is not limited to magnetic sensors.  FIG. 14  shows still another embodiment in which light-based proximity sensors are used. Right shoe  36  has an infrared emitter  44  (such as an IR LED) located on its medial side near the heel. Left shoe  38  has an IR detector  46  located on its medial side near the heel. This detector in the left shoe detects the emitter in the right shoe when the two shoes are placed side by side. 
     Similarly, left shoe  38  has an infrared emitter  44  (such as an IR LED) located on its medial side near the toe. Right shoe  36  has an IR detector  46  located on its medial side near the toe. This detector in the right shoe detects the emitter in the left shoe when the two shoes are placed side by side. The functionality of this light-based embodiment is the same as the functionality described for the embodiment of  FIG. 12 . Other types of proximity sensors could be used as well. Including Hall effect sensors and RFID sensors. 
     In general, each shoe has a contact sensor configured to determine when the shoe has landed on the ground. Each shoe also has a proximity detector and a proximity trigger. A “proximity trigger” is a thing that will cause a proximity detector to send a signal when the proximity trigger comes near the proximity detector. The following have been described as proximity detectors; a magnetic read switch, a Hall-effect sensor, an RFID transceiver, and an IR detector. The following have been described as proximity triggers; a magnet, an RFID tag, and an IR emitter. 
     It is preferable to provide a variable gain on the proximity detectors so that their sensitivity can be adjusted. For many modern sensors, this variable gain can be set using software. It is also possible to provide a variable output for many types of proximity detectors, such as IR emitters. 
     The inventive shoe thus described will have many different applications. The embodiments disclosed pertained to the production of entertaining sounds intended for younger users. However, the shoe could also be useful in other fields. As one example, the shoe could be useful in dance instruction where music is played and the controller detects (1) whether impacts are detected at the correct time, and (2) whether the proximity of the other shoe is detected at the correct time. 
     These skilled in the art will realize that many other components and features could be added to the invention. These include: 
     1. An ultrasonic emitter and detector for the proximity detecting functions;
         2. A speaker in the side of the shoe rather than the rear;   3. An adjustment feature that adjusts the pace of sound playback on the basis of how fast the user is running, walking or dancing (by determining an average pace of ground impacts);   4. A capacitive proximity sensor;   5. A proximity sensor based on ambient light;   6. A proximity sensor based on Doppler detection of emitted sounds;   7. An inductive proximity sensor;   8. A radar-based proximity sensor;       

     9. A sonar-based proximity sensor;
         10. A Local area network based proximity sensor (such as Bluetooth);   11An impact sensor that is a simple mechanical switch; and   12. An impact sensor that includes a piezoelectric element.       

     Although the preceding description contains significant detail, it should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. Numerous other permutations and modifications will be apparent to those skilled in the art. As an example, the placement of the speaker in the rear of the shoe is not necessary to the invention and the speaker may in fact be placed in many other locations. These other embodiments are still within the scope of the invention. Thus, the scope of the invention should be fixed by the following claims rather than the examples given.