Abstract:
An electronic pedometer has a walk sensor that detects a walking movement of a user and outputs a walk signal corresponding to the walking movement. The walk sensor has a sensitivity axis along which a detection sensitivity of the walking movement by the walk sensor becomes a maximum. A calculation circuit calculates a number of walking steps of the user in accordance with the walk signal. A strap mounts the walk sensor on a part of the user&#39;s body so that the sensitivity axis of the walk sensor is located within a range of 30 degrees or less in either a clockwise or counterclockwise direction from an axis disposed at 90 degrees with respect to a longitudinal direction of the strap.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an electronic pedometer for measuring the number of steps by detecting a walk of a person or the like. 
   2. Description of the Prior Art 
   Heretofore, there has been developed an electronic pedometer for measuring the number of steps of a user by detecting a walk of the user using a walk sensor. 
   A watch type pedometer which is used by being worn on a wrist of a user like a watch has been developed as the electronic pedometer (refer to Patent Document 1 for example). 
   With the above conventional watch type electronic pedometer, since a pendulum sensor is used, the number of steps can be measured in a normal walk in which a user walks while he/she naturally swings his/her arms. However, there is encountered a problem that the number of steps cannot be measured in a case where a user walks with his/her arm being fixed to a predetermined position (e.g., at the ear) without swinging his/her arms, for example, in a case where the user walks while he/she communicates with someone using his/her mobile telephone. 
   In addition, while not being of a watch type, a product has also been developed with which the number of steps can be measured even in a state in which no arm is swung as in a state in which an electronic pedometer is held in a pocket or the like. In this case, two sensors are used and are disposed so as to perpendicularly intersect each other. As a result, the number of steps can be measured even in a state in which the electronic pedometer is held in a pocket or the like. However, there is encountered a problem in that a volume increases and circuits for amplifying signals from the sensors are required to be doubled in number because the two sensors are used, or when the electronic pedometer is driven in a time division manner in order to prevent such a situation, a time period required to drive the circuits increases, and hence the electronic pedometer of this type is unsuitable for the watch type pedometer. 
   &lt;Patent Document 1&gt; JP 2002-221434 A 
   It is an object of the present invention to provide an electronic pedometer, used at least by wearing a walk sensor on a wrist, which is capable of being miniaturized and of detecting a walk in a state in which no arm is swung. 
   SUMMARY OF THE INVENTION 
   According to the present invention, there is provided an electronic pedometer having: a walk sensor for detecting a walk of a user to output a walk signal corresponding to the walk; calculation means for calculating the number of steps of the user based on the walk signal; and a belt with which at least the walk sensor is worn on a wrist of the user, the walk sensor being used at least by being worn on the wrist of the user using the belt, wherein the walk sensor is disposed so that a sensitivity axis of the walk sensor is located in a range of 30Ω or smaller in a counterclockwise direction from 90Ω with respect to a longitudinal direction of the belt, or in a range of 30Ω or smaller in a clockwise direction from 90Ωwith respect to the longitudinal direction of the belt. 
   A walk sensor is disposed so that a sensitivity axis of the walk sensor is located in a range of 30Ω or smaller in a counterclockwise direction from 90Ω with respect to a longitudinal direction of a belt, or in a range of 30Ω or smaller in a clockwise direction from 90Ω with respect to the longitudinal direction of the belt. A user of the electronic pedometer uses the electronic pedometer at least by wearing the walk sensor on a wrist of the user using the belt. 
   Here, when the walk sensor is disposed so that the sensitivity axis of the walk sensor is located in the range of 30Ω or smaller in the counterclockwise direction from 90Ω with respect to the longitudinal direction of the belt, the walk sensor is preferably used by being worn on the left wrist of the user, and when the walk sensor is disposed so that the sensitivity axis of the walk sensor is located in the range of 30Ω or smaller in the clockwise direction from 90Ω with respect to the longitudinal direction of the belt, the walk sensor is preferably used by being worn on the right wrist of the user. 
   In addition, the walk sensor is preferably an acceleration sensor. 
   In addition, the electronic pedometer may include timing means for timing time. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred form of the present invention is illustrated in the accompanying drawings in which: 
       FIG. 1  is a front view showing an external appearance of an electronic pedometer according to an embodiment mode of the present invention; 
       FIG. 2  is a partially enlarged front view showing the external appearance of the electronic pedometer according to the embodiment mode of the present invention; 
       FIG. 3  is a diagram showing a maximum value of an arm swing angle range in a normal walk of a general walker; 
       FIG. 4  is a diagram showing an arm swing angle range of 80% of persons; 
       FIG. 5  is a graph showing a situation in which sensitivity changes depending on mounting angles of an acceleration sensor; 
       FIG. 6  is a graph showing a change in sensitivity when an arm swing angle is maximum; 
       FIG. 7  is a graph showing a change in sensitivity caused by arm swing in 80% of persons; 
       FIG. 8  is a waveform chart showing a waveform of a walk signal from a person for whom a large output is obtained from an acceleration sensor when a sensitivity axis of the acceleration sensor is set at 90Ω; 
       FIG. 9  is a waveform chart showing a waveform of a walk signal from a person for whom a large output is obtained from an acceleration sensor when a sensitivity axis of the acceleration sensor is set at 75Ω; 
       FIG. 10  is a waveform chart showing a waveform of a walk signal from a person for whom a large output is obtained from an acceleration sensor when a sensitivity axis of the acceleration sensor is set at 60Ω; 
       FIG. 11  is a waveform chart showing a waveform of a walk signal from a person for whom a large output is obtained from an acceleration sensor when a sensitivity axis of the acceleration sensor is set at 45Ω; 
       FIG. 12  is a waveform chart showing a waveform of a walk signal from a person for whom a small output is obtained from an acceleration sensor when a sensitivity axis of the acceleration sensor is set at 90Ω; 
       FIG. 13  is a waveform chart showing a waveform of a walk signal from a person for whom a small output is obtained from an acceleration sensor when a sensitivity axis of the acceleration sensor is set at 75Ω; 
       FIG. 14  is a waveform chart showing a waveform of a walk signal from a person for whom a small output is obtained from an acceleration sensor when a sensitivity axis of the acceleration sensor is set at 60Ω; 
       FIG. 15  is a waveform chart showing a waveform of a walk signal from a person for whom a small output is obtained from an acceleration sensor when a sensitivity axis of the acceleration sensor is set at 45Ω; and 
       FIG. 16  is a graph showing an angle range of the sensitivity axis of the acceleration sensor in which a walk level can be measured. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   An electronic pedometer according to an embodiment mode of the present invention is a watch type electronic pedometer which is used by being worn on a wrist of a user. The watch type electronic pedometer has: an acceleration sensor as a walk sensor for detecting a walk of a user to output a walk signal corresponding to the walk; calculation means for calculating the number of steps of the user based on the walk signal; and a belt with which at least the acceleration sensor is worn on a wrist of the user, and is used at least by wearing the acceleration sensor on the wrist of the user using the belt. The electronic pedometer according to this embodiment mode will hereinafter be described with reference to the drawings. 
     FIG. 1  is a front view showing an external appearance of an electronic pedometer according to an embodiment mode of the present invention, and shows an electronic pedometer for a left wrist which is used by being worn on a left wrist of a user. In addition,  FIG. 2  is a partially enlarged view of  FIG. 1 . In  FIGS. 1 and 2 , an electronic pedometer  100  includes an electronic pedometer main body  101  having a display portion  102  and a manipulation portion  103  which can be manipulated from the outside, a belt, strap or band  105  which is constituted by a main portion and a buttons and with which the electronic pedometer main body  101  is worn on a wrist of a user, and a buckle  104  provided at an end portion of the belt  105 . 
   The display portion  102  has a step number display portion  201  for displaying thereon the number of steps which a user has taken, and a time display portion  202  for displaying thereon data on a time, a walk time period, and the like. 
   A plurality of small holes  106  are formed in the belt  105 . The electronic pedometer main body  101  is worn on the arm of a user by engaging suitable one of the small holes  106  with the buckle  104 . 
   An acceleration sensor  203  as a walk sensor for detecting a walk level of a user is provided inside the electronic pedometer main body  110 . The acceleration sensor  203  used herein is an element able to detect an acceleration, and is called a shock sensor, an impact sensor, a vibration sensor or the like. Various kinds of acceleration sensors which are of a bimorph type, of unimorph type, of a piezo type, and the like can be used. 
   In addition, the electronic pedometer main body  101  includes in its inside calculation means for calculating the number of steps of a user based on a walk signal which corresponds to a walk and which is outputted from the acceleration sensor  203 , timing means for timing, display driving means for displaying data on the accumulated number of steps of a user calculated by the calculation means, data on a time measured by the timing means, and the like on the display portion  102 , and the like. 
   While the details of a mounting angle of the acceleration sensor  203  to the belt  105  will be described later, since the electronic pedometer  100  shown in  FIGS. 1 and 2  is an electronic pedometer for a left wrist, the acceleration sensor  203  is disposed in a position where when the electronic pedometer main body  101  is viewed from the display portion  102  side, a sensitivity axis K of the acceleration sensor  203  is located in a range S of 30Ω or smaller in a counterclockwise direction from a direction Y making 90Ω with respect to a longitudinal direction X of the belt  105 . Note that when a movement direction of the acceleration sensor  203  or a direction along which a mechanical shock is applied to the acceleration sensor  203  is aligned with the sensitivity axis K, the detection sensitivity becomes maximum. 
   When the electronic pedometer  100  is worn on a left wrist, a palm is on a B side and an elbow is on an A side. 
   It should be noted that in a case of a watch type electronic pedometer for a right arm which is used in a state of being worn on a right wrist, the acceleration sensor  203  is disposed in a position where when the electronic pedometer main body  101  is viewed from the display portion  102  side, the sensitivity axis K of the acceleration sensor  203  is located in a range of 30Ω or smaller in a clockwise direction from the direction Y making 90Ω with respect to the longitudinal direction X of the belt  105 . When the electronic pedometer  100  is worn on a right wrist, a palm is on the A side and an elbow is on the B side. 
   In this embodiment mode, a watch type electronic pedometer needs to be constructed so that in order to make countable the number of steps in a walk in a state in which a user&#39;s hand is put into a pocket or such a walk that a user communicates with someone using his/her mobile telephone on a walk other than a normal walk (a walk in which a user normally walks while he/she swings his/her arms), any of signals generated through arm swing is not detected, and only a signal representing vertical movement of the body is detected as much as possible. While an arm swinging form during a normal walk depends on persons, generally, arms are largely swung forward and are less swung backward. 
   In addition, the vertical movement of the body is caused when a foot is landed on the earth. Thus, in a state in which a person normally walks, when a hand&#39;s position is in the foremost portion and in the rearmost portion in accordance with back and forth swing of an arm, a foot is landed on the earth to cause the vertical movement of the body. 
     FIG. 3  is a diagram showing a maximum value in an arm swing angle range in a normal walk of a general walker, and  FIG. 4  is a diagram showing an arm swing angle range of 80% of persons. As shown in  FIGS. 3 and 4 , while the arm swing angle range of a person is generally equal to or smaller than 45Ω in a traveling direction, the arm swing angle range of 80% of persons is equal to or smaller than 35Ω. While the arm swing angle range of a person is generally equal to or smaller than 25Ω in the opposite (backward) direction, similarly, 80% of persons show the angle range of 15Ω or smaller. 
     FIG. 5  is a graph showing a situation in which the sensitivity changes depending on mounting angles of the acceleration sensor  203 .  FIG. 5  shows a situation in which the detection sensitivity of the acceleration sensor  203  changes depending on an angle between the sensitivity axis K of the acceleration sensor  203  and the shaking direction (movement direction) of the acceleration sensor  203 . In  FIG. 5 , when the arm is swung in the direction of the sensitivity axis K of the acceleration sensor  203 , the sensitivity of the acceleration sensor  203  becomes maximum. It reveals that when the direction of the sensitivity axis K of the acceleration sensor  203  is set at 45Ω with respect to the movement direction of the acceleration sensor  203 , the sensitivity of the acceleration sensor  203  attenuates by 25% from a maximum value. 
     FIG. 6  is a graph showing a sensitivity change in a case where the sensitivity axis K of the acceleration sensor  203  is changed when the arm swing angle of a user has the maximum value (at 45Ω in the traveling direction and at 25Ω in the backward direction). In  FIG. 6 , an axis of abscissa represents an angle of the sensitivity axis K with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side, and an axis of ordinate represents a rate of change in sensitivity with a maximum value of the sensitivity of the acceleration sensor  203  defined as 100%. 
   In  FIG. 6 , a solid line represents a rate of change in sensitivity when the vertical movement is carried out in a state in which a left arm having the acceleration sensor  203  worn therein is held upright, or lowered just downwardly (vertical state), a short broken line represents a rate of change in sensitivity when the vertical movement is carried out in a state in which the right and left arms are held up in the traveling direction by 45Ω from the downward direction (refer to  FIG. 3 ), and a long broken line represents a rate of change in sensitivity when the vertical movement is carried out in a state in which the left arm is held up backward from the downward direction by 25Ω (−25Ω) (refer to  FIG. 3 ). 
   As shown in  FIG. 6 , it is understood that in a case where the acceleration sensor  203  is worn on the arm so that the sensitivity axis K of the acceleration sensor  203  becomes vertical to the longitudinal direction X of the belt  105 , the sensitivity attenuates by 25% from a maximum value when the arm is swung in the traveling direction by 45Ω, and the sensitivity attenuates by about 7% when the arm is swung backward by 25Ω. In addition, in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K makes 45Ω with respect to the longitudinal direction X of the belt  105 , the sensitivity becomes maximum when the arm is swung in the traveling direction by 45Ω. Also, the sensitivity attenuates by about 60% when the arm is swung backward by 25Ω. 
     FIG. 7  is a graph showing a rate of change in sensitivity when the sensitivity axis K of the acceleration sensor  203  is changed in a case where about 80% of persons swing their arms (in the traveling direction by 35Ω and backward by 15Ω. Similar to the example of  FIG. 6 , an axis of abscissa represents an angle of the sensitivity axis K with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side, and an axis of ordinate represents a rate of change in sensitivity with a maximum value of the sensitivity of the acceleration sensor  203  defined as 100%. 
   In  FIG. 7 , a solid line represents a rate of change in sensitivity when the vertical movement is carried out in a state in which a left arm having the acceleration sensor  203  worn therein is held upright, or lowered just downwardly (vertical state), a short broken line represents a rate of change in sensitivity when the vertical movement is carried out in a state in which the left arm is held up in the traveling direction by 35Ω from the downward direction (refer to  FIG. 4 ), and a long broken line represents a rate of change in sensitivity when the vertical movement is carried out in a state in which the left arm is held up backward from the downward direction by 15Ω (−15Ω) (refer to  FIG. 4 ). 
   An angle of the arm of a person communicating with someone using his/her mobile telephone or the like generally becomes 125Ω. Here, this state shows the same rate of change in sensitivity as that in a state in which the arm is swung in the traveling direction by 35Ω. 
     FIG. 8  is a waveform chart showing a waveform of a walking signal from a person for whom a large output is obtained from the acceleration sensor  203  in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  makes 90Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side;  FIG. 9  is a waveform chart showing a waveform of a walking signal from a person for whom a large output is obtained from the acceleration sensor  203  in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  makes 75Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side;  FIG. 10  is a waveform chart showing a waveform of a walking signal from a person for whom a large output is obtained from the acceleration sensor  203  in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  makes 60Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side; and  FIG. 11  is a waveform chart showing a waveform of a walking signal from a person for whom a large output is obtained from the acceleration sensor  203  in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  makes 45Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side. 
   In  FIGS. 8 to 11 , each peak of the walking signal represents one step. When an angle between the sensitivity axis K and the longitudinal direction X of the belt  105  is in a range of 90Ω to 60Ω, satisfactory signal waveforms are obtained ( FIGS. 8 to 10 ). However, as shown in  FIG. 11 , when the angle between the sensitivity axis K and the longitudinal direction X of the belt  105  is 45Ω, each peak of the walk signal corresponding to a walk detected when the arm (the left arm in this embodiment mode) having the electronic pedometer  100  worn therein is swung in the traveling direction is large, but each peak of the walk signal detected when the arm is swung backward is small. Thus, there is a possibility that the walk measurement becomes unsuitable to cause a measurement error. 
     FIG. 12  shows a waveform of a walk signal from a person for whom a small output is obtained from the acceleration sensor  203  in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  makes 90Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side.  FIG. 13  shows a waveform of a walk signal from a person for whom a small output is obtained from the acceleration sensor  203  in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  makes 75Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side.  FIG. 14  shows a waveform of a walk signal from a person for whom a small output is obtained from the acceleration sensor  203  in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  makes 60Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side.  FIG. 15  shows a waveform of a walk signal from a person for whom a small output is obtained from the acceleration sensor  203  in a case where the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  makes 45Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side. 
   In  FIGS. 12 to 15 , each peak of the signal represents one step similarly to  FIGS. 8 to 11 . Regarding a person for whom a small output is obtained from the acceleration sensor  203 , the satisfactory walk detection signal becomes hard to obtain as the angle between the sensitivity axis K and the longitudinal direction X of the belt  105  becomes smaller. As a result, the walk measurement becomes unstable. Hence, there is a possibility that a large measurement error is caused. 
     FIG. 16  is a characteristic diagram showing a range in which a walk can be measured using the acceleration sensor  203 . An axis of abscissa represents an angle between the sensitivity axis K of the acceleration sensor  203  and the longitudinal direction X of the belt  105  when viewed from the display portion  102  side, and an axis of ordinate represents normalized sensitivity of the acceleration sensor  203 . As shown in  FIG. 16 , the acceleration sensor  203  has the satisfactory sensitivity in a region in which the angle of sensitivity axis K is equal to or larger than 60Ω. In this embodiment mode, the range of the angle between the sensitivity axis K of the acceleration sensor  203  and the longitudinal direction X of the belt  105  when viewed from the display portion  102  side is determined as follows with reference to the characteristic diagram of  FIG. 16 . 
   Since in the normal life, a human being does nothing with his/her arms being held backward, a maximum value of the angle between the sensitivity axis K of the acceleration sensor  203  and the longitudinal direction X of the belt  105  when viewed from the display portion  102  side is set as 90Ω. In addition, in order to allow the walk signal to be detected every step even for a person whose walk signal is at a low level, a minimum value of the angle between the sensitivity axis K of the acceleration sensor  203  and the longitudinal direction X of the belt  105  when viewed from the display portion  102  side is set as 60Ω (30Ω in a counterclockwise direction from the direction of 90Ω with respect to the longitudinal direction X of the belt  105 ). That is, the sensitivity axis K of the acceleration sensor  203  is set in a range S of 30Ω or smaller in a counterclockwise direction from the direction of 90Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side, thereby allowing the number of steps to be satisfactorily counted. 
   Note that in a case of the watch type electronic pedometer for a right hand as well described above, the sensitivity axis of the acceleration sensor can be set similarly to the foregoing. In the case of the watch type electronic pedometer for a right hand, the sensitivity axis K is set in a range of 30Ω or smaller in a clockwise direction from the direction of 90Ω with respect to the longitudinal direction X of the belt  105 , thereby making it possible to count the number of steps in a satisfactory manner. 
   When the number of steps is counted using the watch type electronic pedometer  100  for a left hand constructed as described above, a user of the electronic pedometer  100  wears the electronic pedometer  100  in his/her left wrist using the belt  105 , and starts the processing for counting the number of steps by manipulating the manipulation portion  103 , and also starts to walk, thereby counting the number of steps. The user checks data on the number of steps and data on a walk time period which are displayed on the step number display portion  201  and the time display portion  202  of the display portion  102 , respectively. 
   When the number of steps is counted using the watch type electronic pedometer for a right hand described above, the number of steps is counted with the electronic pedometer being worn on a right wrist of a user. 
   As described above, the electronic pedometer according to this embodiment mode includes: an acceleration sensor for detecting a walk of a user to output a walk signal corresponding to the walk; calculation means for calculating the number of steps of the user based on the walk signal; a belt with which the acceleration sensor is worn on a wrist of the user; and a display portion for displaying thereon data on the number of steps calculated by the calculation means, in which the walk sensor being used at least by being worn on the wrist of the user using the belt, the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  is located in the range S of 30Ω or smaller in a counterclockwise direction from the direction of 90Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side, or in the range of 30Ω or smaller in a clockwise direction from the direction of 90Ω with respect to the longitudinal direction X of the belt  105  when viewed from the display portion  102  side. 
   Here, when the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  is located in the range S of 30Ω or smaller in the counterclockwise direction from the direction of 90Ω with respect to the longitudinal direction X of the belt  105 , the electronic pedometer is used in a state of being worn on a left wrist of the user, while when the acceleration sensor  203  is disposed so that the sensitivity axis K of the acceleration sensor  203  is located in the range S of 30Ω or smaller in the clockwise direction from the direction of 90Ω with respect to the longitudinal direction X of the belt  105 , the electronic pedometer is used in a state of being worn on a right wrist of the user. 
   As a result, in the watch type electronic pedometer in which at least the walk sensor is used in a state of being worn on a wrist, the miniaturization becomes possible, and even in walking with no arm being swung, the satisfactory walk detection becomes possible. 
   Note that while in the above embodiment mode, the construction is adopted in which the electronic pedometer main body  101  is used in a state of being worn on a wrist of a user, a construction may be adopted in which at least the acceleration sensor  203  is worn on a wrist of a user. 
   The present invention can also be applied to an electronic pedometer which is constructed such that all constituent elements of the pedometer are worn on the user&#39;s body when in use, or an electronic pedometer which is constructed such that some (including at least sensors) of constituent elements are worn on the user&#39;s body, and other constituent elements wirelessly transmit/receive signals to/from the constituent elements, and the other constituent elements are provided away from the user. 
   According to the present invention, effects are offered in which miniaturization becomes possible since a walk can be detected using a single walk sensor, and a walk in a state in which no arm is swung can be detected since the sensitivity axis of the walk sensor is constructed so as to have a predetermined angle when the electronic pedometer is used. 
   In addition, it becomes possible to construct the electronic pedometer having a function as a watch, and to measure almost the numbers of steps in normal life.