Abstract:
A method of controlling music playback includes providing a sensor array comprising first sensors arranged adjacent to one another, receiving data output from first sensors of the sensor array, the data including activation times during which each of the first sensors was activated, comparing the activation times of each first sensor to determine if the first sensors were sequentially activated along a first direction or a second direction opposite to the first direction, controlling the music to be played in a forward direction if the first sensors were sequentially activated along the first direction, and controlling the music to be played in a backward direction if the first sensors were sequentially activated along the second direction.

Description:
BACKGROUND OF THE INVENTION  
   1. Field of the Invention 
   The present invention relates to a music playback device, and more specifically, to a touch sensor used for controlling direction, speed, and key of music playback on the music playback device. 
   2. Description of the Prior Art 
   Music is an important part of the lives of many. Recent technology advances have led to the introduction of numerous kinds of portable music players. People now have more control over what music they listen to, when and where they listen to it, and how they listen to it. With the variety of portable music players now on the market, new ways to control music playback are needed for offering users new ways to enjoy their music. 
   SUMMARY OF THE INVENTION  
   It is therefore an objective of the claimed invention to provide a music playing device and related method of controlling music playback. According to an embodiment of the claimed invention, a method of controlling music playback includes providing a sensor array comprising first sensors arranged adjacent to one another, receiving data output from first sensors of the sensor array, the data including activation times during which each of the first sensors was activated, comparing the activation times of each first sensor to determine if the first sensors were sequentially activated along a first direction or a second direction opposite to the first direction, controlling the music to be played in a forward direction if the first sensors were sequentially activated along the first direction, and controlling the music to be played in a backward direction if the first sensors were sequentially activated along the second direction. 
   According to another embodiment of the claimed invention, a method of controlling music playback includes providing a sensor array comprising first sensors arranged adjacent to one another, receiving data output from first sensors of the sensor array, the data including activation times during which each of the first sensors was activated, comparing the activation times of each first sensor to determine if the first sensors were sequentially activated along a first direction or a second direction opposite to the first direction, raising a key of the music if the first sensors were sequentially activated along the first direction, and lowering the key of the music if the first sensors were sequentially activated along the second direction. 
   According to yet another embodiment of the claimed invention, a music playing device includes a sensor array comprising first sensors arranged adjacent to one another, a sensor handling circuit for receiving data output from first sensors of the sensor array, the data including activation times during which each of the first sensors was activated, for comparing the activation times of each first sensor to determine if the first sensors were sequentially activated along a first direction or a second direction opposite to the first direction, and for outputting music control signals, and an audio output circuit for receiving the music control signals from the sensor handling circuit, for controlling the music to be played in a forward direction if the first sensors were sequentially activated along the first direction, and for controlling the music to be played in a backward direction if the first sensors were sequentially activated along the second direction. 
   According to still another embodiment of the claimed invention, a music playing device, includes a sensor array comprising first sensors arranged adjacent to one another, a sensor handling circuit for receiving data output from first sensors of the sensor array, the data including activation times during which each of the first sensors was activated, for comparing the activation times of each first sensor to determine if the first sensors were sequentially activated along a first direction or a second direction opposite to the first direction, and for outputting music control signals, and an audio output circuit for receiving the music control signals from the sensor handling unit, for raising a key of the music if the first sensors were sequentially activated along the first direction, and for lowering the key of the music if the first sensors were sequentially activated along the second direction. 
   These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram of a music playback device according to the present invention. 
       FIG. 2  is a detailed diagram of the sensor array. 
       FIG. 3  illustrates controlling the music direction and music speed with the first sensors. 
       FIG. 4  illustrates controlling the music key with the second sensors. 
       FIG. 5  is a timing illustrating sensor activation timing as sensors are sequentially activated. 
       FIG. 6  illustrates using timing information to determine if the first sensors are activated using positive acceleration or negative acceleration. 
       FIG. 7  is a detailed diagram of the temporary buffer. 
   

   DETAILED DESCRIPTION  
   Please refer to  FIG. 1 .  FIG. 1  is a block diagram of a music playback device  10  according to the present invention. A music decoder  12  receives music data, decodes the music data, and stores the decoded music data in a temporary buffer  14 . An audio output circuit  16  reads the decoded music data from the temporary buffer  14  and produces audio output. To control music playback, a sensory array  20  is provided having a plurality of sensors S 1 -S 9 . A sensor handling circuit  18  receives input from the sensor array  20 , converts the input from analog format to digital format, and produces corresponding control signals to be sent to the audio output circuit  16 . The control signals control the key in which music is played, the direction in which music played (i.e. either forward or backward), and the playing speed. 
   Please refer to  FIG. 2 .  FIG. 2  is a detailed diagram of the sensor array  20 . The sensor array  20  comprises first sensors  22  shown having a horizontal arrangement and second sensors  24  having a vertical arrangement. The first sensors  22  contain sensors S 1 -S 5 , and the second sensors contain sensors S 3  and S 6 -S 9 . Each of the sensors is activated when the user pushes down on them. Music playback is controlled by analyzing when each sensor S 1 -S 9  is turned on and off. That is, the duration and the sequence in which the sensors S 1 -S 9  are activated determines how music playback will be controlled. Music playback is controlled by activating the first sensors  22  from left to right or from right to left in sequence, or by activating the second sensors  24  from top to bottom or from bottom to top in sequence. 
   Please refer to  FIG. 3 .  FIG. 3  illustrates controlling the music direction and music speed with the first sensors  22 . If the first sensors  22  are activated from left to right, music is controlled to play back in the forward direction, which is the normal direction. If the first sensors  22  are activated from right to left, music is controlled to play back in the backward direction. In addition, playback speed can be controlled for either the forward direction or the backward direction by changing the acceleration used when the user sequentially activates the first sensors  22 . A positive acceleration will increase the music speed in either the forward direction or the backward direction, depending on the sequence in which the first sensors  22  are activated. On the other hand, a negative acceleration in either direction will decrease the music speed in that corresponding playback direction. 
   Please refer to  FIG. 4 .  FIG. 4  illustrates controlling the music key with the second sensors  24 . Often times, a user wishes to change the key of a song being played so that the key better matches the user&#39;s vocal range. For instance, the key can be changed from C to C# if the key is raised by a half step. If the second sensors  24  are activated from bottom to top, the music key is raised by a predetermined amount. If the second sensors  24  are activated from top to bottom, the music key is lowered by the predetermined amount. 
   Please refer to  FIG. 5 .  FIG. 5  is a timing illustrating sensor activation timing as sensors are sequentially activated. In  FIG. 5 , the first sensors  22  are activated from left to right, which controls music to be played in the forward direction. Analyzing the timing not only allows the sensor handling circuit  18  to determine which direction the sensors are being sequentially activated in, but it also allows the sensor handling circuit  18  to determine if there is positive or negative acceleration involved. As shown in  FIG. 5 , sensor S 1  is turned on at time t 1  and is turned off approximately at the same time that sensor S 2  is turned on, which is at time t 2 . Sensors S 3 , S 4 , and S 5  are sequentially activated and deactivated at times t 3 , t 4 , and t 5 , respectively. 
   Please refer to  FIG. 6 .  FIG. 6  illustrates using timing information to determine if the first sensors  22  are activated using positive acceleration or negative acceleration. In Case  1  shown in  FIG. 6 , sensor S 1  was active between times t 1  and t 2 , and the duration is written as t 12  for shorthand. In Case  1 , sensor S 1  was active for the longest amount of time, and sensors to the right of sensor S 1  were active for increasingly shorter periods of time. Therefore, it can be concluded that the user&#39;s finger is positively accelerating as it moves across the sensors S 1 -S 5  from left to right. This positive acceleration from left to right is used to increase the music speed in the forward direction. 
   In contrast, Case  2  shows a situation in which the user&#39;s finger is negatively accelerating as it moves across the sensors S 1 -S 5  from left to right. This is because the time period t 12  during which sensor S 1  is active is shorter than all other time periods, and the time periods get increasingly longer from left to right. This negative acceleration from left to right is used to decrease the music speed in the forward direction. 
   As an example, Equation 1 below can be used for approximately calculating the acceleration used when activating the first sensors  22  if the first sensors  22  are activated from left to right. 
   
     
       
         
           
             
               
                 
                   
                     
                       t 
                       23 
                     
                     - 
                     
                       t 
                       12 
                     
                   
                   
                     
                       t 
                       45 
                     
                     - 
                     
                       t 
                       34 
                     
                   
                 
                 = 
                 γ 
               
             
             
               
                 ( 
                 1 
                 ) 
               
             
           
         
       
     
   
   where γ represents an acceleration value. If γ is greater than 1, the acceleration is positive, if γ is less than 1, the acceleration is negative, and if γ is equal to 1, there is zero acceleration. The playback speed can be calculated by multiplying γ by a constant value. For convenience, the playback speed can also be rounded off to the nearest integer, such as 1×, 2×, and so on. 
   Please refer to  FIG. 7 .  FIG. 7  is a detailed diagram of the temporary buffer  14 . Seven frames are shown in the temporary buffer  14 , i−3, i−2, i−1, i, i+1, i+2, and i+3. The frame i represents the frame currently being played. The frame i−1 represents the frame immediately preceding the current frame i and the frame i+1 represents the frame immediately following the current frame i. As shown in  FIG. 7 , when playing music in the forward direction, the frames are played from the current frame i downward. On the other hand, the frames are played from the current frame i upward when playing music in the backward direction. The music speed also determines how many frames are played per unit time. That is, twice as many frames will be played when the speed is 2× as at a normal playing speed. The temporary buffer  14  should be large enough to handle whatever playing speed and whatever playing direction the user selects using the first sensors  22 . 
   In summary, the sensor array  20  is a tool that allows the user to quickly and intuitively control music playback. The user can easily control the playback direction, the playback speed, and the key of the music being played. 
   Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.