Abstract:
Accelerometer-based orientation and/or movement detection for controlling wearable audio recorders, such as wrist-worn audio recorders, resulting in button-free operation of the audio recorders. Operating a button-free wearable audio recorder does not rely on conventional switches that are often small, difficult to operate, and not very reliable. A wrist-worn audio recorder can use an accelerometer to detect the natural orientation and/or movement of a user&#39;s wrist and subsequently activate a corresponding audio-recorder function, for instance recording or playback, without requiring the user to remember to activate the audio-recorder function. In addition, a wearable audio recorder with a vibration mechanism can use this method to remind a user of an undesirable repeated movement, such as restless leg movement. In such applications, and many others, accelerometer-based control of a wearable audio recorder offers significant advantages over conventional means of control, particularly in terms of ease of use and durability.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of provisional application Ser. No. 61/008,504, filed Dec. 19, 2007 by the present inventors. 
     FEDERALLY SPONSORED RESEARCH 
     Not Applicable 
     SEQUENCE LISTING OR PROGRAM 
     Not Applicable 
     BACKGROUND 
     1. Field 
     This application relates to using accelerometer-based orientation and/or movement sensing to control wearable devices, such as wrist-worn audio recorders and wristwatches. 
     2. Prior Art 
     Wrist-worn audio recorders can serve a wide range of uses, from recording memos and meetings for professionals to documenting dietary intake and physical activity for health-conscious individuals and chronicling a child&#39;s first words and actions for parents. Furthermore, recorded audio messages can be played back at preset times to remind or alert a user, as disclosed in U.S. Pat. No. 5,511,046 to Vanderpal (1996). 
     These wrist-worn audio recorders, wristwatches, and related devices are generally controlled through one or more of the following means: electromechanical switches, voice activation, and motion activation. 
     Switches are commonly used to control functions such as audio recording and playback on devices like electronic wristwatches (as described in U.S. Pat. No. 4,717,261 to Kita et al. (1988)) and, more recently, wrist-worn watch/MP3 players (for example, the Xonix MP3 recorder watches manufactured by Xonix Electronic Watch Co., Ltd., Zhuhai, China). They are also used to report the time in talking watches. However, these switches are often small, difficult to operate, and not very reliable, which may lead to premature failure of the audio recorder or talking watch. In addition, using switches can be inconvenient for recording many brief personal messages, because the user has to remember to turn the audio recorder on and off in order to record each message. 
     Voice-activated recording mechanisms offer more convenience since they facilitate convenient recording of personal messages only when the user wants to record, without relying on the user&#39;s active attention to physically turn the audio reorder on and off during a recording session. However, irrelevant audio signals in the surrounding can still turn on a voice-activated mechanism. 
     Finally, motion activation has also been used to operate wristwatches. U.S. Pat. No. 3,939,640 to Kahn (1976) describes using a motion-activated switch inside a wristwatch to turn on or off the illumination of a wristwatch display. A free-rolling heavy ball within the container of the switch strikes a spring to cause conduction of electrical current when the wrist rotates rapidly. Additionally, U.S. Pat. No. 4,115,995 to Brien (1978) discloses using a motion-activated switch secured within a wristwatch to set the display on the wristwatch (i.e. to a desired time and date), where quick snaps of the wrist dislodge a metal ball from a magnet and cause conduction of electrical current through the ball. Although these motion-activated switches can be used to turn on and off a wrist-worn device, such as an audio recorder, the rapid motion required to close the electrical switches is unnatural and can cause muscle strain, especially after many repeated actions. Furthermore, it is difficult to add more control functions to a wrist-worn device using only these simple motion-activated on-off switches. 
     The aforementioned mechanisms for controlling wrist-worn devices leave much to be desired in terms of ease of use and durability. Accelerometer-based methods would offer advantages in these senses, since control can be automatically activated through a user&#39;s natural movements, and the user does not need to directly interact with the electromechanical parts of the accelerometer. 
     In recent years, accelerometers produced with low-cost MEMS (micro-electro-mechanical systems) technology have been used for movement and orientation sensing. For example, the wristwatch described in U.S. Pat. No. 6,513,532 B2 to Mault et al. (2003) uses an accelerometer and a button-controlled audio recorder to monitor physical activity and record dietary consumption, respectively, and U.S. Pat. No. 6,956,564 B1 to Williams (2005) discloses a portable hand-held computer that incorporates two single-axis accelerometers for display control and gesture recognition with small fingertip switches for recording speech notes. In the field of animal behavior monitoring, U.S. Pat. No. 7,246,033 B1 to Kudo (2007) and U.S. Pat. No. 6,263,836 B1 to Hollis (2001) describe the use of accelerometers to monitor pet activity and train dogs, respectively, and both incorporate an audio recorder for recording and playback of a human&#39;s voice. However, all of the above accelerometer applications require conventional switches to operate audio recording, so that there still exists a need for the application of accelerometer technology to control recording, playback, time reporting, and other functionality in wrist-worn devices. 
     SUMMARY 
     The use of accelerometer-based orientation and movement sensing to control wearable devices, such as wrist-worn audio recorders and wristwatches, is illustrated through three embodiments. 
     In accordance with a first embodiment, a wrist-worn audio recorder comprises an accelerometer for sensing the orientation and/or movement of the audio recorder. In this embodiment, the audio recorder activates audio recording only when it is in a predetermined orientation and/or after it has completed a predetermined movement. Different predetermined orientations and/or movements (i.e. sequences of accelerometer data) of the audio recorder can be used to activate other functions of the recorder, such as playback, rewinding, or fast forwarding. 
     In accordance with a second embodiment, a wrist-worn audio recorder comprises an accelerometer for sensing the orientation and/or movement of the audio recorder. In this embodiment, a reminding audio message can be recorded in accordance with the first embodiment or in any other manner. When the audio recorder is worn on a wrist, a leg, or another part of the body, it plays back a reminding audio message after it detects a predetermined orientation and/or movement a predetermined number of times. 
     In accordance with a third embodiment, a wristwatch comprises an accelerometer for sensing the orientation and/or movement of the wristwatch. In this embodiment, the watch gives an audio report of the time after it detects a predetermined orientation and/or movement. 
     Although the above embodiments take the form of wrist-worn devices, the methods and apparatus they illustrate can be extended to wearable devices in general, by one skilled in the art and without departing from the spirit and scope of the invention. 
    
    
     
       DRAWINGS—FIGURES 
         FIG. 1  shows a front view of a wrist-worn audio recorder incorporating a three-axis accelerometer in accordance with the first embodiment, illustrating the X- and Y-axes of the accelerometer. 
         FIG. 2  shows a side view of the wrist-worn audio recorder of  FIG. 1 , illustrating the Y- and Z-axes of the accelerometer. 
         FIG. 3  is a schematic block diagram of the wrist-worn audio recorder of  FIG. 1 , in accordance with the first embodiment. 
         FIG. 4  is a view of the wrist-worn audio recorder in accordance with the first embodiment, schematically illustrating communication between the audio recorder and a processor, and between the audio recorder and an earphone. 
         FIG. 5  is a flow diagram illustrating the orientation and/or movement detection operation of a recorder controller of the wrist-worn audio recorder, in accordance with the first embodiment. 
         FIG. 6  is a graphical illustration of a possible orientation of the wrist-worn audio recorder for activating audio recording, in accordance with the first embodiment. 
         FIG. 7  is a graphical illustration of a possible orientation of the wrist-worn audio recorder for activating playback, in accordance with the first embodiment. 
         FIG. 8  is a graphical illustration of possible movements of the wrist-worn audio recorder for activating rewinding and fast forwarding, in accordance with the first embodiment. 
         FIG. 9  is a schematic block diagram of a wrist-worn audio recorder, in accordance with the second embodiment. 
         FIG. 10  is a flow diagram illustrating the orientation and/or movement detection operation of a recorder controller of the wrist-worn audio recorder, in accordance with the second embodiment. 
         FIG. 11  is a graphical illustration of using a wrist-worn audio recorder to remind the user of eating too many snacks, in accordance with the second embodiment. 
         FIG. 12  is a graphical illustration of using a wrist-worn audio recorder to sense restless leg movement of the user and transmit a reminding audio message to the caregiver of the user, in accordance with the second embodiment. 
         FIG. 13  shows a front view of a wristwatch incorporating a three-axis accelerometer in accordance with the third embodiment, illustrating the X- and Y-axes of the accelerometer. 
         FIG. 14  shows a side view of the wristwatch of  FIG. 13 , illustrating the Y- and Z-axes of the accelerometer. 
         FIG. 15  is a schematic block diagram of the wristwatch of  FIG. 13 , in accordance with the third embodiment. 
         FIG. 16  is a flow diagram illustrating the orientation and/or movement detection operation of a wristwatch controller of the wristwatch, in accordance with the third embodiment. 
         FIG. 17  is a graphical illustration of a possible orientation of the wristwatch for activating audio time reporting, in accordance with the third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 ,  2 ,  3 , and  4 —First Embodiment 
     The use of accelerometer-based orientation and/or movement sensing to control a wearable device is illustrated in a first embodiment with a wrist-worn audio recorder. The wrist-worn audio recorder incorporates an accelerometer for sensing the orientation and/or movement (i.e. either orientation or movement or both) of the audio recorder, and it is activated to record audio messages only when it is in a predetermined orientation and/or after it has completed a predetermined movement. In this embodiment we describe the predetermined orientation and/or movement to be the natural orientation and/or movement for the user to record personal audio messages, so that the user does not need to actively remember to turn the audio recorder on and off, but the predetermined orientation and/or movement can be any other orientation and/or movement. The wrist-worn audio recorder may usually also contain a real-time clock, so that the recorder can provide additional time-keeping function, and in this case the recorded audio data can be synchronized with other time-stamped data, such as video data or accelerometer data from other devices. 
       FIG. 1  shows a front view of a wrist-worn audio recorder  30  incorporating a three-axis accelerometer  32  inside a housing  33  of audio recorder  30 . Three-axis accelerometer  32  is commonly also called a triaxial accelerometer, and it senses acceleration in the three orthogonal axes X, Y, and Z. In  FIG. 1 , the accelerometer  32  is illustrated by a dotted outline, and the Z-axis points out of the figure. Wristband  31  secures audio recorder  30  on top of the user&#39;s right wrist (although audio recorder  30  could also be secured on top of the user&#39;s left wrist). A display  34  on the front surface of audio recorder  30  shows the time of day (hours, minutes, seconds), the date (month, date, day), or the current status (recording, playback, etc.) of audio recorder  30 . Alternatively, the hands for the hours, minutes, and seconds of an analog wristwatch may be used to show the time of day, in place of display  34 . Wrist-worn audio recorder  30  can function without a real-time clock, although the inclusion of a real-time clock enables time-stamping of the recorded audio data and facilitates data archiving, data searching, or time synchronization of the data with time-stamped data from other devices. 
     A microphone  36  is used for audio recording, and a speaker  38  is used for playing back the recorded audio data. When audio recorder  30  is activated for audio recording, indicators  40   a ,  40   b ,  40   c  at the front of housing  33  may be used to inform the user whether the recording is started at the beginning, the end, or somewhere in the middle of the audio-data record. Recording audio data at the beginning or between the beginning and the end of the audio-data record will overwrite previously recorded audio data. Recording at the end is the usual mode of audio recording and will append additional audio data to the end of the audio-data record. Indicators  40   a ,  40   b ,  40   c  can be miniature LEDs (light-emitting diodes), and flashing of an indicator can be used to signal the user that audio recording is in process. Alternatively, the functions of indicators  40   a ,  40   b ,  40   c  can be incorporated into display  34 , so that separate indicators  40   a ,  40   b ,  40   c  are not needed. 
       FIG. 2  shows a side view of wrist-worn audio recorder  30  with accelerometer  32  (illustrated by a dotted outline) mounted inside housing  33  to sense the orientation and/or movement of audio recorder  30 . Audio recorder  30  is secured on top of the wrist, using wristband  31 , and the X-axis points out of the figure. Three-axis accelerometers such as accelerometer  32  may be constructed with MEMS (micro-electro-mechanical systems) technology using capacitance measurement to determine the amount of acceleration, and they are available from Freescale Semiconductor, Inc., of Austin, Tex., or other companies. The X-, Y-, and Z-axis signals from a three-axis accelerometer provide information about the accelerometer&#39;s movement (which may be determined by a sequence of accelerometer data, for example), and can also be separated into components of the vertical gravitational acceleration G to determine orientation when the accelerometer is at rest, so that a three-axis accelerometer can serve as both an orientation and movement sensor. In this way, audio recorder  30  uses the X-, Y-, and Z-axis acceleration signals of accelerometer  32  to detect specific orientations and/or movements of audio recorder  30  and subsequently activate the corresponding audio-recorder functions. For example, if the user stretches his or her arm out forwards, with the palm of his or her hand facing vertically downwards, accelerometer  32  (as illustrated in  FIG. 2 ) will sense an acceleration of −9.8 meter/sec 2  (the gravitational acceleration G is 9.8 meter/sec 2  vertically downward) along its Z-axis, because the Z-axis is pointing vertically upward in this orientation. The acceleration signals are zero along its X- and Y-axes, because they are orthogonal to the direction of G. Likewise, an acceleration of 9.8 meter/sec 2  (i.e. G) will be sensed along the accelerometer&#39;s Z-axis if the palm is facing upwards instead. Other orientations of the wrist will produce acceleration signals with different signs and magnitudes in the X-, Y-, and Z-axis components of accelerometer  32 , and the orientation can be computed using standard vector analysis. 
       FIG. 3  is a schematic block diagram of wrist-worn audio recorder  30  ( FIG. 1 ). Each of the X-, Y- and Z-axis analog signal components of accelerometer  32  is selected by an analog multiplexer  42  at predetermined time intervals, under the control of a recorder controller  48 . Recorder controller  48  also activates an analog-to-digital converter  46 , which uses a sample -and-hold circuit  44  to sample and hold the selected analog signal component. Analog-to-digital converter  46  converts the sampled analog signal component to the corresponding digital datum and sends the digital datum to recorder controller  48 , which stores the digital datum in an accelerometer-data memory  50 . Although  FIG. 3  shows that accelerometer  32  senses accelerometer signal components in three orthogonal axes, accelerometer  32  may sense signal components in a different number of axes for detection of different predetermined orientations and/or movements. Sample-and-hold circuit  44  and analog-to-digital converter  46  are not required for an accelerometer that produces digital output data for the signal components, and analog multiplexer  42  should be replaced with a digital multiplexer in this case. Furthermore, if accelerometer  32  is a single-axis accelerometer that produces only one signal component, the analog or digital multiplexer is not needed. 
     A system clock  52  provides the operation timing for recorder controller  48 , which is usually a microprocessor. Recorder controller  48  can be configured to perform mathematical computation, logic operation, timer function, storing and retrieving data using an audio-data memory  56  and accelerometer-data memory  50 , and reading and sending data through a communication port  60 , etc., as well known in the art. A real-time clock  54  provides time-keeping function, and recorder controller  48  can also use real-time clock  54  to time-stamp each section of recorded audio message. In certain designs, real-tine clock  54  is derived from system clock  52 , so that a dedicated real-time clock  54  is not required. 
     A user records audio messages into microphone  36 , and the analog audio signal from microphone  36  is converted to digital audio data by a sample-and-hold circuit  62  and an analog-to-digital converter  64 . Recorder controller  48  stores the digital audio data in audio-data memory  56 , and it can subsequently send the digital audio data to a digital-to-analog converter  66  for playback from speaker  38 . Through communication port  60 , recorder controller  48  can also send the recorded audio data to a processor (not shown in  FIG. 3 ) for data archiving, data searching, or time synchronization of the data with other time-stamped data, or to an earphone (not shown in  FIG. 3 ) for playback. Audio-data memory  56  and accelerometer-data memory  50  can be RAM (random-access memory), flash memory, removable memory cards, or other types of digital memory. A user interface  68 , which includes display  34  (FIG.  1 ), indicators  40   a ,  40   b ,  40   c  ( FIG. 1 ), and switches if necessary (not shown in  FIG. 1 ), facilitates communication between audio recorder  30  and the user. 
     Communication port  60  facilitates communication between audio recorder  30  and a processor (not shown in  FIG. 3 ), such as a personal computer, and can send recorded audio data to the processor for playback, data archiving, data searching, or time synchronization of the data with other time-stamped data. Communication port  60  also facilitates transmission of recorded audio data to an earphone (not shown in  FIG. 3 ) for playback. Communication port  60  can be a wired or wireless USB (Universal-Serial-Bus) port, a Bluetooth® (a digital wireless protocol) wireless communication port, or any other wired or wireless communication port. 
       FIG. 4  illustrates communication between audio recorder  30  and a processor  70  through a communication link  72 , which can be a wired or wireless data link. Communication link  72  can be used to transmit data between audio recorder  30  and processor  70 , or for other uses such as sending clock-setting commands from processor  70  to audio recorder  30  to set real-time clock  54  ( FIG. 3 ) of audio recorder  30  to an accurate real-time clock reading. Audio recorder  30  can also transmit recorded audio data to an earphone  71  through a wired or wireless data link  73 , such as a Bluetooth® data link. Processor  70  can be a personal computer, a PDA, a cellular phone, or another digital device. Although  FIG. 4  shows audio recorder  30 , with housing  33 , secured to the right wrist by wristband  31 , audio recorder  30  can communicate with processor  70  and earphone  71  without being secured to a wrist. 
     Speech recognition of recorded speech notes is useful in applications such as recording food intake or physical activity, because it minimizes the time and inconvenience otherwise involved if the user needs to manually enter this food and activity data into a processor such as processor  70  to analyze his or her energy balance or fitness status. In these cases, either recorder controller  48  ( FIG. 3 ) can perform the speech recognition, or it can send the audio data to processor  70  for processor  70  to perform the speech recognition. If audio recorder  30  performs the speech recognition, then the time-stamped text messages (obtained from speech recognition of time-stamped audio data) can be stored in audio-data memory  56  ( FIG. 3 ) along with other audio data and sent to processor  70  at a later time. 
     Detection Operation— FIGS. 5 ,  6 ,  7 , and  8   
       FIG. 5  is a flow diagram illustrating the orientation and/or movement (i.e. sequence of acceleration data) detection operation of recorder controller  48  ( FIG. 3 ). In  FIG. 5 , after analog multiplexer  42 , under the control of recorder controller  48 , selects an acceleration signal component (X, Y, or Z) at step  74 , recorder controller  48  activates analog-to-digital converter  46  ( FIG. 3 ) to use sample-and-hold circuit  44  ( FIG. 3 ) to sample and hold the selected signal component at step  76 . At step  78 , analog-to-digital converter  46  converts the sampled analog signal component to its corresponding digital datum and sends the digital datum to recorder controller  48 , which stores the digital datum in accelerometer-data memory  50  ( FIG. 3 ) at step  80 . At step  82 , recorder controller  48  repeats this process for the next accelerometer signal component, until the X, Y, and Z signal components have all been selected. If audio recorder  30  does not move too fast over each cycle of accelerometer-data acquisition, the acquired and stored X, Y, and Z signal data in each cycle are approximately simultaneous. Alternatively, separate data acquisition subsystems, each including a sample-and-hold circuit and an analog-to-digital converter, can be used for each of the three accelerometer-signal components to obtain more precisely simultaneous X, Y, and Z accelerometer signal data. At step  84 , recorder controller  48  uses the data stored in accelerometer-data memory  50  to compute the orientation and/or movement of audio recorder  30  and activates an audio-recorder function, such as audio recording, playback, or rewinding (the operation of the audio-recorder function is not illustrated in  FIG. 5 ), only if a predetermined orientation and/or movement is detected. At step  86 , if the user does not stop the accelerometer-data acquisition, recorder controller  48  waits for a predetermined time interval at step  88  and then returns to step  74  to repeat the above process. 
       FIG. 6  illustrates a possible orientation of audio recorder  30  during audio recording, with audio recorder  30  secured on top of the wrist, using wristband  31 . The user naturally positions audio recorder  30  in front of his or her mouth (typically within 8 inches of the mouth, for example), with the front surface of housing  33  of audio recorder  30  facing the mouth. In this specific orientation of audio recorder  30 , the Y component of the gravitational acceleration G is small (the Y-axis points away from the figure and is nearly horizontal). Since the angle between the X-axis and the direction of the gravitational acceleration G is about 45 degrees, the X component of the gravitational acceleration G is approximately G cosine 45°, which is equal to 0.707 G, as illustrated in the vector diagram in  FIG. 6 . Similarly, the angle between the Z-axis and the gravitational acceleration G is about 135°, so that tile Z component of the gravitational acceleration G is G cosine 135°, which is −0.707 G. Recorder controller  48  ( FIG. 3 ) detects this combination of X, Y, and Z signal components to activate audio recording. Alternatively, and for more robust detection, recorder controller  48  can use a machine learning algorithm or other suitable method to detect a predetermined movement, such as the natural movement of lifting the arm upwards from a resting position (i.e. from the side of the body or from in front of the lower end of the torso) and tilting the wrist towards the mouth to activate audio recording. 
     In the first embodiment, the audio recording function of audio recorder  30  turns on automatically when the user positions audio recorder  30  in a predetermined orientation, such as the natural orientation for recording shown in  FIG. 6 , and/or after audio recorder  30  has completed a predetermined movement, and an indicator ( 40   a ,  40   b , or  40   c  shown in  FIG. 1 ) simultaneously turns on to inform the user that he or she may begin audio recording. A voice-activated mechanism can be added to minimize accidental activation, so that recording is activated only when audio recorder  30  is in the predetermined orientation and/or has completed the predetermined movement and the user begins talking to it. In addition, recorder controller  48  ( FIG. 3 ) of audio recorder  30  can be designed to take the user&#39;s position or posture into consideration, so that it activates audio recording after sensing any in a range of signal outputs from accelerometer  32 . This range may encompass, for example, audio recorder  30 &#39;s natural recording orientation in front of the mouth (as shown in  FIG. 6 ) for a range of user postures from standing upright (the posture illustrated in  FIG. 6 ) to lying down. Using these same concepts, recorder controller  48  can also be designed to detect the natural recording orientation of audio recorder  30  for a user who wears audio recorder  30  on the other side (i.e. the bottom) of the wrist. In all cases, the audio recording is stopped as soon as the user moves audio recorder  30  away from the predetermined orientation, so that recording of irrelevant audio information is minimized without requiring the user to consciously turn off the audio recording. Furthermore, a different type of accelerometer, such as a two-axis (also called biaxial) or a single-axis (also called uniaxial) accelerometer, or a combination of the same or different types of accelerometers, can also be used to detect a predetermined orientation of audio recorder  30 , instead of using a three-axis accelerometer as illustrated here. 
       FIG. 7  illustrates a possible orientation of audio recorder  30  for activating playback of recorded audio data when audio recorder  30  is secured on the top of the right wrist by wristband  31 . The user simply positions audio recorder  30  (illustrated by a dotted circle in  FIG. 7 ) close to his or her ear, with the front surface of housing  33  (not shown in  FIG. 7 ) of audio recorder  30  facing the ear. In this predetermined orientation of audio recorder  30 , the sound volume of speaker  38  ( FIGS. 1 and 3 ) is automatically adjusted to the appropriate level for listening to the recorded audio data in close proximity. The Z accelerometer signal component of the gravitational acceleration G here is almost zero (the Z-axis points into the figure and is nearly horizontal). Since the angle between the accelerometer X-axis and the direction of the gravitational acceleration G is about 45 degrees, the X accelerometer signal component of G is approximately G cosine 45°, which is equal to 0.707 G, as illustrated in the vector diagram in  FIG. 7 . Similarly, the angle between the accelerometer Y-axis and the gravitational acceleration G is about 135°, so that the Y accelerometer signal component is approximately G cosine 135°, which is −0.707 G. After sensing this combination of accelerometer signal components, recorder controller  48  ( FIG. 3 ) of audio recorder  30  activates playback of a section of audio recording before the end of the audio-data record through speaker  38 . A proximity sensor (not shown in  FIG. 3 ), such as a capacitive, pyroelectric, pressure-sensitive, or electrical-conductive sensor, can be added to minimize accidental activation, so that playback only begins when audio recorder  30  is in this predetermined orientation and in close proximity (within 3 inches, for example) of or in contact with the skin of the ear or around the ear. Besides the orientation illustrated in  FIG. 7 , recorder controller  48  can also be designed to activate playback after detecting an orientation where the user positions audio recorder  30  close to his or her other ear for listening, where the user wears audio recorder  30  on the other side (i.e. the bottom) of the wrist, or where the user positions audio recorder  30  towards the ear of another person. When audio recorder  30  is playing back the audio-data record, the user can use predetermined patterns of wrist and arm movement to activate rewinding or fast forwarding as discussed below. 
     In  FIG. 7 , rotating of the wrist (and audio recorder  30 ) back and forth in a direction  92  in front of the ear (the rotating movement of the wrist is illustrated by the arrows at each end of direction line  92 ) produces a pattern of X- and Z-axis accelerometer signal changes while the Y-axis accelerometer signal remains essentially unchanged, because the angle between the Y-axis and the vertically downward direction of the gravitational acceleration G is nearly constant during this movement. Recorder controller  48  ( FIG. 3 ) can detect these predetermined signal changes to activate rewinding for a short duration. Record controller  48  can also detect several back-and-forth rotations of the wrist in direction  92  in close succession to activate rewinding for a much longer duration. Likewise, moving the wrist side-to-side in a direction  94  in front of the ear (the side-to-side movement of the wrist is illustrated by having an arrow at each end of direction line  94 ) produces a pattern of X- and Y-axis accelerometer signal changes while the Z-axis accelerometer signal component remains essentially unchanged, because the angle between the Z-axis and the vertically downward direction of gravitational acceleration G is nearly constant during this movement (the Z-axis points into the page and is nearly horizontal). Recorder controller  48  can detect these predetermined signal changes to activate fast forwarding for a short duration. Recorder controller  48  can also detect multiple side-to-side movements of the wrist in direction  94  in close succession to activate fast forwarding for a much longer duration. Similarly, recorder controller  48  can be designed to detect other movements of the wrist and arm to activate rewinding or fast forwarding. In all these cases, machine-learning algorithms can be used for more accurate and robust detection of predetermined movements from accelerometer signals. 
     For the case illustrated in  FIG. 7 , playback stops as soon as audio recorder  30  is moved away from the predetermined orientation in close proximity of the ear, and an indicator ( 40   a,    40   b , or  40   c  in  FIG. 1 ) informs the user whether the playback stopped at the beginning, the end, or somewhere in the middle of the audio-data record. As in a typical audio recorder, starting audio recording before the end of tile audio-data record will overwrite previously stored audio data. When the audio data stored in audio recorder  30  is digital, as discussed above, and each section of recorded audio message is time-stamped by real-time clock  54  ( FIG. 3 ), rewinding and fast forwarding can be accomplished almost instantly. 
       FIG. 8  illustrates some other possible movements of the wrist and the forearm (and hence of audio recorder  30 ) for activating rewinding and fast forwarding of audio recorder  30 . Audio recorder  30 , with housing  33 , is secured on top of the wrist here using wristband  31 . In  FIG. 8 , the user positions his forearm at an angle of about 135 degrees between the forearm and the vertically downward direction of the gravitational acceleration G. Counterclockwise circular movement of the wrist (and also the hand and forearm) along a path  95  (in the direction of the arrow) produces a pattern of Y- and Z-axis accelerometer signal changes while the X-axis accelerometer signal component of the gravitational acceleration G is small, because the X-axis points away from the figure and is nearly horizontal. Recorder controller  48  ( FIG. 3 ) can detect these predetermined signal changes to activate rewinding all the way to the beginning of the audio-data record, and an indicator ( 40   a ,  40   b , or  40   c  in  FIG. 1 ) turns on to inform the user of this action. Likewise, recorder controller  48  can detect clockwise circular movement of the wrist and forearm along path  95  (in the opposite direction of the arrow) to activate fast forwarding all the way to the end of the audio-data record, and a different indicator ( 40   a ,  40   b , or  40   c  in  FIG. 1  ) turns on to inform the user of this action. To minimize accidental activation of these audio-recorder functions by normal daily activities, recorder controller  48  can be designed to activate an audio-recorder function such as recording or playback only after audio recorder  30  remains in a static position for a predetermined period of time after a predetermined wrist and arm movement pattern has been detected. 
     FIGS.  9 —Second Embodiment 
     The use of accelerometer-based orientation and/or movement sensing in a second embodiment for controlling a wearable electronic device is illustrated with a wearable audio recorder in  FIG. 9 , which is a block diagram of the audio recorder. The audio recorder of the second embodiment incorporates an accelerometer for sensing the orientation and/or movement (i.e. sequence of acceleration data) of the audio recorder, and a predetermined orientation and/or movement of the audio recorder activates playback of a reminding message. The reminding messages can be audio messages (i.e. voice messages, musical sounds, songs, alarms, or computer generated audio tones or messages) recorded in accordance with the first embodiment or in any other way, or they can be non-audio, such as vibration of the audio recorder. 
     In  FIG. 9 , a wrist-worn audio recorder  170  incorporates a three-axis accelerometer  172  for sensing the orientation and/or movement of audio recorder  170 , and two switches  202 ,  204  for recording and verifying a reminding audio message. A recorder controller  174  plays back a reminding audio message when a predetermined orientation and/or movement of audio recorder  170  is detected. Each of the X, Y and Z analog signal components of accelerometer  172  is selected by an analog multiplexer  176  at predetermined time intervals, under the control of a recorder controller  174 . Recorder controller  174  also activates an analog-to-digital converter  180 , which uses a sample-and-hold circuit  178  to sample and hold the selected analog signal component. Analog-to-digital converter  180  converts the sampled analog signal component to the corresponding digital datum and sends the digital datum to recorder controller  174 , which stores the digital datum in an accelerometer-data memory  182 . 
     A microphone  194  is used for recording a reminding audio message when the user activates switch  202  to cause signal  206  at an input of record controller  174  to change from logic low to logic high (or vice versa). Under the control of recorder controller  174 , the analog audio signal from microphone  184  is converted to digital audio data by a sample-and-hold circuit  186  and an analog-to-digital converter  188 , and the digital audio data of the reminding audio message is stored in an audio-data memory  190 . Audio-data memory  190  and accelerometer-data memory  182  can be RAM (random-access memory), flash memory, removable memory cards, or other types of digital memory. When recorder controller  174  detects a predetermined orientation and/or movement of audio recorder  170  a predetermined number of times, it sends the reminding audio message for the predetermined orientation and/or movement from audio-data memory  190  to a digital-to-analog converter  191  and a speaker  192  for playback. Tile user can also verify (i.e. manually use a switch to play back) a recorded reminding audio message by activating switch  204  to cause signal  208  at an input of record controller  174  to change from logic low to logic high (or vice versa). Additional switches may be used for recording and verifying more reminding audio messages. Instead of playing back a reminding audio message through speaker  192 , recorder controller  174  can send the reminding audio message to an earphone or a processor (not shown in  FIG. 9 ) through a communication port  198 , or vibrate the audio recorder if a vibration mechanism (not shown in  FIG. 9 ) is incorporated. 
     Communication port  198  facilitates wired or wireless communication between the audio recorder  170  and a processor, such as a personal computer or an earphone. Communication port  198  can be a wired or wireless USB port, a Bluetooth® wireless communication port, or any other wired or wireless communication port. Although  FIG. 9  shows that accelerometer  172  senses accelerometer signal components in three orthogonal axes X, Y, and Z, accelerometer  172  may sense accelerometer signal components in a different number of axes to detect different predetermined orientations and/or movements. Sample-and-hold circuit  178  and analog-to-digital converter  180  are not required for an accelerometer that produces digital output data for the accelerometer signal components, and analog multiplexer  176  should be replaced with a digital multiplexer in this case. Furthermore, if accelerometer  172  is a single-axis accelerometer that produces only one signal component, the analog or digital multiplexer is not needed. 
     A user interface  194 , which usually includes a display, LED indicators, and conventional switches, facilitates communication between audio recorder  170  and the user. A system clock  196  provides the operation timing for recorder controller  174 , which is usually a microprocessor. Recorder controller  174  can be configured to perform mathematical computation, logic operation, timer function, storing and retrieving data using audio-data memory  190  and accelerometer-data memory  182 , and reading and sending data through communication port  198 , etc., as well known in the art. A real-time clock  200  provides time-keeping function, although audio recorder  170  can function without a real-time clock. In certain designs, real-time clock  200  is derived from system clock  196 , so that a dedicated real-time clock  200  is not required. 
     In  FIG. 9 , two switches  202 ,  204  are used for recording and verifying a reminding audio message. Instead of switches  202 ,  204 , accelerometer  172  may also be used to record a reminding audio message. For example, audio recorder  170  may activate recording after using accelerometer  172  to detect that it is in a predetermined orientation, as discussed in the first embodiment, or that it has completed a predetermined movement of the wrist, such as rotating the wrist (and thus audio recorder  170 , located on the wrist) back and forth three times in close succession while audio recorder  170  is in front of the mouth (as illustrated in  FIG. 6 ). If audio recorder  170  is also used as a regular audio recorder, the recorded reminding audio messages may be stored in a dedicated location of audio-data memory  190 , so that they will not be overwritten by other recorded audio data. Furthermore, reminding audio messages can be recorded in audio recorder  170  during the manufacturing process of audio recorder  170  or received from a computer through communication port  198 . 
     In the second embodiment, a recorded reminding audio message can be played back to remind the user of a predetermined type of physical activity, especially an undesired type of physical activity. For example, recorder controller  174  can be designed to detect the pattern of changes of X, Y, and Z accelerometer signal components produced by the wrist and arm movement of a user&#39;s hand when he or she puts snacks into his or her mouth, provided that the user wears audio recorder  170  on the wrist to detect such movement. When the wrist movement is repeated a predetermined number of times in a preset time window, recorder controller  174  activates playback of a reminding audio message to warn the user that he or she is eating too many snacks. With real-time clock  200  incorporated in audio recorder  170 , recorder controller  174  can also be designed to play back a reminding audio message only when such repeated wrist movement is detected during the usual snack time of the user. In another example, wrist-worn audio recorder  170  can play back a different reminding audio message when the user has not moved his or her wrist (and audio recorder  170  on the wrist) very much over a period of time because of inactivity, such as when the user is watching television. This reminding audio message can help remind the user to stay active to prevent obesity, for instance. 
     After reminding messages are stored in audio-data memory  190  of audio recorder  170 , audio recorder  170  can be attached to any part of the user&#39;s body, such as the waist or one of the lower extremities, to detect physical activity or inactivity there. For example, when audio recorder  170  is attached to the leg of a user who has restless leg syndrome, audio recorder  170  can play back a reminding audio message to the user when his or her leg is moving restlessly. Instead of playing back a reminding audio message through speaker  192 , recorder controller  174  can also send the message to a wireless earphone (not shown in  FIG. 9 ) such as a Bluetooth® earphone, through communication port  198 , or activate a vibration mechanism (not shown in  FIG. 9 ) if one is incorporated, so that the user is not embarrassed by unwanted people hearing the reminding audio message. 
     Detection Operation— FIGS. 10 ,  11 , and  12   
       FIG. 10  is a flow diagram illustrating the orientation and/or movement detection operation of recorder controller  174  ( FIG. 9 ) for playing back a reminding audio message when a predetermined orientation and/or movement of audio recorder  170  ( FIG. 9 ) is detected a predetermined number of times. In  FIG. 10 , after analog multiplexer  176  ( FIG. 9 ), under the control of recorder controller  174 , selects an accelerometer signal component (X, Y, or Z) at step  210 , recorder controller  174  activates analog-to-digital converter  180  to use sample-and-hold circuit  178  ( FIG. 9 ) to sample and hold the accelerometer signal component at step  212 . At step  214 , analog-to-digital converter  180  converts the sampled analog signal to the corresponding digital datum and sends the digital datum to recorder controller  174 , which stores the digital datum in accelerometer-data memory  182  ( FIG. 9 ) at step  216 . At step  218 , recorder controller  174  repeats this process for the next accelerometer signal component, until the X, Y, and Z accelerometer signal components have all been selected. If audio recorder  170  does not move too fast over each cycle of accelerometer-data acquisition, the acquired and stored X, Y, and Z signal data in each cycle are approximately simultaneous. Alternatively, separate data acquisition subsystems, each including a sample-and-hold circuit and an analog-to-digital converter, can be used for each of the three accelerometer-signal components to obtain more precisely simultaneous X, Y, and Z accelerometer signal data. At step  220 , recorder controller  174  uses the data stored in accelerometer-data memory  182  to compute the orientation and/or movement of audio recorder  170  to playback a reminding audio message if the orientation and/or movement matches a predetermined orientation and/or movement for a predetermined number of times. At step  222 , if the user does not stop accelerometer-data acquisition, recorder controller  174  waits for a predetermined time interval at step  224  and then returns to step  210  to repeat the above process. 
       FIG. 11  is a graphical illustration of using audio recorder  170  (behind the right wrist in  FIG. 11 , and illustrated by a dotted outline) to remind a user of eating too many snacks. When the user puts snacks into his or her mouth, recorder controller  174  ( FIG. 9 ) of audio recorder  170  worn on the wrist detects the pattern of accelerometer signal changes of the X, Y, and Z components produced by a wrist movement  227  (the alternating movement of the wrist is illustrated by the arrows at each end of direction line  227 ). When wrist movement in direction  227  is repeated a predetermined number of times in a preset time window, recorder controller  174  activates playback of a reminding audio message to remind the user that he or she might be eating too many snacks. In  FIG. 11 , recorder controller  174  sends the reminding audio message through communication port  198  ( FIG. 9 ) and the corresponding communication link  228  (wired or wireless) to an earphone  229 , such as a Bluetooth® earphone, worn by the user, although recorder controller  174  may also play back the reminding audio message through speaker  192  ( FIG. 9 ) or vibrate audio recorder  170  if a vibrate mechanism (not shown in  FIG. 9 ) is incorporated. Alternatively, recorder controller  174  may send the reminding audio message to a wireless earphone worn by another person (not shown in  FIG. 11 ), such as the parent of a child or the caregiver of an elderly, instead of the child or the elderly who wears audio recorder  170 . Furthermore, recorder controller  174  can use real-time clock  200  ( FIG. 9 ) to enable playback of a reminding audio message only when wrist movement  227  is detected a predetermined number of times during a predetermined time window, such as during the usual snack time for the person who wears audio recorder  170 . 
       FIG. 12  is a graphical illustration of using audio recorder  170  to play back a reminding audio message when restless leg movement is detected. After an appropriate reminding audio message has been recorded in audio recorder  170 , audio recorder  170  is attached to the user&#39;s right lower leg, as illustrated in  FIG. 12 . When the user moves his or her right leg restlessly in a direction  230  (the alternating movement of the leg is illustrated by the arrows at each end of direction line  230 ), recorder controller  174  ( FIG. 9 ) detects the pattern of accelerometer signal changes of the X, Y, and Z components produced by the leg movement in direction  230 . When leg movement in direction  230  is repeated a predetermined number of times in a predetermined time window, recorder controller  174  activates playback of the reminding audio message. Recorder controller  174  sends the reminding audio message through communication port  198  ( FIG. 9 ) and the corresponding communication link  232  (wired or wireless) to an earphone  234  (a Bluetooth® earphone, for example) worn by another person, such as the parent of a child or the caregiver of an elderly, instead of the child or the elderly who wears audio recorder  170  on his or her right lower leg. Alternatively, recorder controller  174  may play back the reminding audio message through speaker  192  ( FIG. 9 ), send the reminding audio message to an earphone worn by the person who wears audio recorder  170  on his or her right lower leg, or vibrate audio recorder  170  if a vibrate mechanism (not shown in  FIG. 9 ) is incorporated. Furthermore, recorder controller  174  can use real-time clock  200  ( FIG. 9 ) to enable playback of the reminding audio message only when leg movement is detected a predetermined number of times during a predetermined time window, such as during the usual rest time for the person who wears audio recorder  170 . 
       FIGS. 13 ,  14 , AND  15 —Third Embodiment 
     The use of accelerometer-based orientation and/or movement sensing in a third embodiment for controlling a wearable device is illustrated with a wristwatch. The wristwatch incorporates an accelerometer for sensing the orientation and/or movement of the wristwatch, and a predetermined orientation and/or movement of the wristwatch, such as the user moving it up and towards the ear, activates audio reporting of the time. This accelerometer-based time-reporting function can also be incorporated in other wrist-worn devices such as the voice recorder described in the first embodiment. 
       FIG. 13  shows a front view of a wristwatch  330  incorporating a three-axis accelerometer  332  inside a housing  333  of wristwatch  330 . Three-axis accelerometer  332  is commonly also called a triaxial accelerometer, and it senses acceleration in the three orthogonal axes X, Y, and Z. In  FIG. 13 , accelerometer  332  is illustrated by a dotted outline, and the Z-axis points out of the page. Wristband  331  secures wristwatch  330  on top of the user&#39;s right wrist, although wristwatch  330  could also be secured on top of the user&#39;s left wrist. A display  334  on the front surface of wristwatch  330  shows the time of day (hours, minutes, seconds) or date (month, date, day) of wristwatch  330 . Alternatively, the hands for the hours, minutes, and seconds of an analog display may be used to show the time of the day, in place of display  334 . A speaker  338  is used for audio reporting of the time, and buttons  341   a  and  341   b  are used for functional control of the wristwatch, such as re-setting the time or setting an alarm. Microphone  339  allows the user to record personalized audio time components (i.e. “three”, “forty”, “minutes”, “PM”, etc.) for use in the audio time reporting, so that the reporting can be in a desired voice or language. Alternatively, standard time components recorded during manufacturing may be used for the audio time reporting. Other button arrangements and watch face displays may also be used. 
       FIG. 14  shows a side view of wristwatch  330  with accelerometer  332  (illustrated by a dotted outline) mounted inside housing  333  to sense the orientation and/or movement of wristwatch  330 , and the X-axis points out of the page. Wristwatch  330  is secured on top of the wrist, using wristband  331 . The X-, Y-, and Z-axis signals from a three-axis accelerometer such as accelerometer  332  provide information about the accelerometer&#39;s movement (which may be determined by a sequence of accelerometer signals, for example), and can also be separated into components of the vertical gravitational acceleration G to determine orientation when the accelerometer is at rest, so that a three-axis accelerometer can serve as both an orientation and movement sensor. In this way, wristwatch  330  uses the X-, Y-, and Z-axis acceleration signals of accelerometer  332  to detect specific orientations and/or movements of wristwatch  330  and subsequently activate the audio time reporting function of wristwatch  330 . 
       FIG. 15  is a schematic block diagram of wristwatch  330  ( FIGS. 13 ,  14 ). Each of the X-, Y-, and Z-axis analog signal components of accelerometer  332  is selected by an analog multiplexer  342  at predetermined time intervals, under the control of wristwatch controller  348 . Wristwatch controller  348  also activates an analog-to-digital converter  346 , which uses a sample-and-hold circuit  344  to sample and hold the selected analog signal component. Analog-to-digital converter  346  converts the sampled analog signal component to the corresponding digital datum and sends the digital datum to wristwatch controller  348 , which stores the digital datum in an accelerometer-data memory  350 . 
     Audio-data memory  356  stores audio data for each of the time components needed to report time (i.e. “three”, “forty”, “minutes”, “PM”, etc.). Alternatively, the wristwatch of the third embodiment can be incorporated with the voice recording function of the first embodiment or a conventional voice recording function to allow personalized recording of each of these audio time components, for example in a different voice or language. In either of these cases, a user records the personalized audio time components into a microphone  336 , and the analog audio signal from microphone  336  is converted to digital audio data by a sample-and-hold circuit  362  and an analog-to-digital converter  364 . Wristwatch controller  348  stores the digital audio data in audio-data memory  356 , and it can subsequently send the digital audio data to a digital-to-analog converter  366  for personalized reporting of time from speaker  338 . Audio-data memory  356  and accelerometer-data memory  350  can be RAM (random-access memory), flash memory, removable memory cards, or other types of digital memory. When wristwatch controller  348  detects a predetermined orientation and/or movement of wristwatch  330  ( FIGS. 13 ,  14 ), such as moving the wristwatch towards the ear, it notes the current time from real-time clock  354  and sends the appropriate audio data (i.e. “two”, “fifty”, “one,” and “PM”, for 2:51 PM) from audio-data memory  356  to a digital-to-analog converter  366  and subsequently speaker  338  for audio time reporting to the user. 
     Although  FIG. 15  shows that accelerometer  332  senses accelerometer signal components in three orthogonal axes X, Y, and Z, accelerometer  332  may sense accelerometer signal components in a different number of axes to detect different predetermined orientations and/or movements. Sample-and-hold circuit  344  and analog-to-digital converter  346  are not required for an accelerometer that produces digital output data for the accelerometer signal components, and analog multiplexer  342  should be replaced with a digital multiplexer in this case. Furthermore, if accelerometer  332  is a single-axis accelerometer that produces only one signal component, the analog or digital multiplexer is not needed. 
     A user interface  368 , which usually includes a display  334  ( FIG. 13 ) and switches (such as switches  341   a ,  341   b  ( FIG. 13 ) and additional switches if necessary), facilitates communication between wristwatch  330  and the user, and provides a visual display of the time. A system clock  352  provides the operation timing for wristwatch controller  348 , which is usually a microprocessor. Wristwatch controller  348  can be configured to perform mathematical computation, logic operation, timer function, storing and retrieving data using audio-data memory  356  and accelerometer-data memory  350 , etc., as well known in the art. A real-time clock  354  provides time-keeping function. 
     Detection Operation— FIGS. 16 and 17   
       FIG. 16  is a flow diagram illustrating the orientation and/or movement detection operation of wristwatch controller  348  ( FIG. 15 ) for audio reporting of the time when a predetermined orientation and/or movement of wristwatch  330  ( FIGS. 13 ,  14 ) is detected. In  FIG. 16 , after analog multiplexer  342  ( FIG. 15 ), under the control of wristwatch controller  348 , selects an accelerometer signal component (X, Y, or Z) at step  374 , wristwatch controller  348  activates analog-to-digital converter  346  ( FIG. 15 ) to use sample-and-hold circuit  344  ( FIG. 15 ) to sample and hold the accelerometer signal component at step  376 . At step  378 , analog-to-digital converter  346  converts the sampled analog signal to the corresponding digital datum and sends the digital datum to wristwatch controller  348 , which stores the digital datum in accelerometer-data memory  350  ( FIG. 15 ) at step  380 . At step  382 , wristwatch controller  348  repeats this process for the next accelerometer signal component, until the X, Y, and Z accelerometer signal components have all been selected. If wristwatch  330  does not move too fast over each cycle of accelerometer data acquisition, the acquired and stored X, Y, and Z signal data in each cycle are approximately simultaneous. Alternatively, separate data acquisition subsystems, each including a sample-and-hold circuit and an analog-to-digital converter, can be used for each of the three accelerometer-signal components to obtain more precisely simultaneous X, Y, and Z accelerometer signal data. At step  384 , wristwatch controller  348  uses the data stored in the accelerometer-data memory  350  to compute the orientation and/or movement of wristwatch  330  and activates an audio time reporting function if a predetermined orientation and/or movement is detected. At step  386 , if the user does not stop accelerometer-data acquisition, wristwatch controller  348  waits for a predetermined time interval at step  388  and then returns to step  374  to repeat the above process. 
       FIG. 17  illustrates a possible orientation of wristwatch  330  for activating audio reporting of the current time when wristwatch  330  is secured on top of the right wrist by wristband  331 . The user simply positions wristwatch  330  (illustrated by a dotted circle in  FIG. 17 ) close to his or her ear, with the front surface of housing  333  (not shown in  FIG. 17 ) of audio recorder  330  facing the ear. In this predetermined orientation of audio recorder  330 , the sound volume of speaker  338  ( FIGS. 13 and 15 ) is automatically adjusted to the appropriate level for listening to audio time reporting in close proximity. The Z accelerometer signal component of the gravitational acceleration G here is almost zero (the Z-axis points into the page and is nearly horizontal). Since the angle between the accelerometer X-axis and the direction of the gravitational acceleration G is about 45 degrees, the X accelerometer signal component of G is approximately G cosine 45°, which is equal to 0.707 G, as illustrated in the vector diagram in  FIG. 17 . Similarly, the angle between the accelerometer Y-axis and the gravitational acceleration G is about 135°, so that the Y accelerometer signal component is approximately G cosine 135°, which is −0.707 G. After sensing this combination of acceleration signal components, wristwatch controller  348  ( FIG. 15 ) activates audio time reporting, so that the current time is reported using real-time clock information and standard or personalized time components from audio-data memory  356  ( FIG. 15 ) through speaker  338 . A proximity sensor (not shown in  FIG. 15 ), such as a capacitive, pyroelectric, pressure-sensitive, or electrical-conductive sensor, can be added to minimize accidental activation, so that time reporting only occurs when wristwatch  330  is in this predetermined orientation and is in close proximity (within 3 inches, for example) of or in contact with the skin of the ear or around the ear. Besides the orientation illustrated in  FIG. 17 , wristwatch controller  348  can also be designed to activate audio time reporting after detecting an orientation where the user positions wristwatch  330  close to his or her other ear for listening, where the user wears wristwatch  330  on the other side (i.e. the bottom) of the wrist, or where the user positions wristwatch  330  toward the ear of another person. 
     Although the description above contains many specificities, these should not be construed as limiting the scope of the embodiments but as merely providing illustrations of some of the presently preferred embodiments. For example, the above-described embodiments can be modified by one skilled in the art, especially in the combination of various described features, without departing from the spirit and the scope of the embodiments. 
     Thus the scope of the embodiments should be determined by the appended claims and their legal equivalents, rather than by the examples given.