Abstract:
To provide an electric pedometer of low cost which is not erroneously operated by an external force exerted to a pedometer case thereof without using an acceleration sensor of a special structure and without executing a signal processing for removing a disturbance by a software, a circuit board contained in a module containing portion of a pedometer case of an electronic pedometer is constituted by two sheets of a main board mounted with an electronic circuit element for executing a signal processing and a sub board mounted with an acceleration sensor. The sub board is formed by a flexible circuit board and is fixed to the main board by a fixing member having flexibility. Further, an electric connection between the sub board and the main board is carried out by soldering terminal region in a projected shape formed by partially extending the sub board of the flexible circuit board.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an electronic pedometer including a circuit board mounted with an acceleration sensor. 
         [0003]    2. Description of the Related Art 
         [0004]    A general electronic pedometer is constituted by a control portion such as CPU for carrying out various operations and controls in accordance with a program, a time counting portion including a reference clock signal generator and a dividing/timing circuit, a program storing portion such as ROM stored with the program, a data storing portion such as RAM stored with various data of a step number and the like, inputting means for setting time or switching a mode, LCD for displaying time, a step number or the like, a display driver for driving LCD, and a step number sensor as disclosed in, for example, Japanese Patent Publication No. 3493550 (Patent Reference 1). As the step number sensor of the electronic pedometer, a semiconductor acceleration sensor is representative. 
         [0005]    As described above, the general electronic pedometer is a portable electronic apparatus constituted by adding a step number counting function to a portable electronic timepiece, and therefore, the electronic pedometer is provided with various functions other than the step counting function. Representing the functions by display modes, there are a time display mode, a stopwatch mode, a step number mode, a distance mode and the like. The modes are switched by operating an external operating member of a change over switch or the like provided to a pedometer case of an exterior or the like by a user. In the respective modes, the external operating member is operated. For example, in the step number mode, a pitch is changed or the like by operating the external operating member. 
         [0006]    Owing to such a structure, the semiconductor acceleration sensor constituting the step number sensor of the electronic pedometer not only detects acceleration by walking of the user but detects an acceleration of the electronic pedometer by operating the external operating member. When, the acceleration sensor detects the acceleration of the electronic pedometer by operating the external operating member by the user, the semiconductor acceleration sensor generates an accelerating signal similar to that in a case of detecting the acceleration by walking of the user. The acceleration signal is counted as the step number by being operated to process by the control portion, and therefore, the acceleration of the electronic pedometer by operating the external operating member is counted erroneously as the step number. 
         [0007]    Hence, according to the electronic pedometer of a background art disclosed in Patent Reference 1 mentioned above, when the user operates the external operating member, counting of the step number is stopped by a constant time period from when the external operating member is operated, a predicted step number is added to a step number value until stopping to count the step number after the predetermined time period has elapsed, thereby, the step number is made to be proximate to an actual step number. The predicted step number is a step number by which the user is predicted to walk during the predetermined time period and is calculated by, for example, by multiplying an average step number per unit time immediately before stopping to count the step number by the predetermined time period. 
         [0008]    In this way, the electronic pedometer of the background art is on a premise that the step number which differs from the actual step number is counted by operating the external operating member, counting of the actual step number is stopped by the constant time period from when the external operating member is operated, and the predicted step number during the stop period calculated by the predetermined operation processing is added to the step number until stopping to count the step number. Therefore, when the external operating member is operated in walking, the electronic pedometer of the background art can display certainly a value proximate to the actual step number. However, the electronic pedometer of the background art adds to process the predicted step number even when the external operating number is operated in stopping to walk, and therefore, there poses a problem that the displayed step number differs from the actual step number. Further, when the external operating member is operated, there is a case in which a walk pitch which differs from the walk pitch until when the pedometer is operated is constituted, however, the predicted step number is not calculated in correspondence with a change in the walk pitch, and therefore, there poses a problem that the displayed step number differs from the actual step number. The problems are caused because the electronic pedometer of the background art is constituted by a structure which cannot count only the actual step number. 
         [0009]    Meanwhile, expressing structurally, according to the electronic pedometer of the background art, as shown by  FIG. 9  through  FIG. 10 , a circuit board  10  mounted with an electronic circuit element for executing a signal processing and an acceleration sensor  4  is arranged at inside of a pedometer case  1 , and an outer peripheral edge thereof is fixed to the pedometer case  1  by a board fixing portion  6  at two portions through four portions. When an external force is exerted to the pedometer case  1  of such an electronic pedometer, a strain generated the pedometer case  1  is transmitted to the circuit board  10 . The strain is propagated to the acceleration sensor, thereby, the acceleration sensor  4  generates a strain detecting signal in response to the strain. The strain detecting signal is processed as a step number signal by the electronic circuit element for signal processing mounted to the circuit board  10  and an erroneous step number which is not the actual step number is counted. The external force is generated also when an unanticipated impact or an excessively large pressure is applied in mounting or detaching the electronic pedometer, or when the electronic pedometer is impacted to something carelessly other than when exerted by operating the external operating member. However, there poses a problem that a method of preventing an erroneous operation of the electronic pedometer by a software as described in Patent Reference 1 is not applicable to such an unanticipated external force. 
         [0010]    JP-A-1-287417 (Patent Reference 2) describes an electronic pedometer constituted by attaching a damping member comprising an elastic member to one face of a printed board, attaching one end of an acceleration detecting type sensor comprising a piezoelectric element to the damping member to form the acceleration detecting type sensor as a cantilever, and attaching to a free end of the sensor. According to the electronic pedometer including the step number sensor attached with the acceleration detecting type sensor at the cantilever, up and down rocking of the cantilever generated in accordance with an acceleration of an up and down movement is detected by the acceleration detecting type sensor, thereby, the step number is counted. According to the electronic pedometer having such a unique structure, the acceleration detecting type sensor does not respond to a movement having a high frequency and constituting noise by interposing the damping member. Therefore, the electronic pedometer can prevent an erroneous operation by an external force exerted to the pedometer case and the external force for generating a movement having a high frequency and constituting noise. 
         [0011]    However, the electronic pedometer described in Patent Reference 2 needs to use the acceleration detecting type sensor of a special structure, and therefore, there poses a problem that cost is increased by that amount and a size or a shape of the pedometer case is restricted. Further, only a movement having a high frequency and constituting noise can be absorbed by the damping member constituting an indispensable constituent element of the acceleration detecting type sensor of the special structure, and therefore, there poses a problem that the electronic pedometer is erroneously operated when an external force generating the other movement is exerted to the pedometer case. 
       SUMMARY OF THE INVENTION 
       [0012]    A problem to be resolved by the invention is to provide an electronic pedometer of low cost which is not erroneously operated even when an external force is exerted to a pedometer case without using an acceleration sensor of a special structure and without executing a signal processing for removing a disturbance by a software. 
         [0013]    In order to resolve the problem, in an electronic pedometer for detecting a step number by an acceleration sensor, a circuit board is constituted by two sheets of a main board mounted with an electronic circuit element for executing a signal processing and a sub board mounted with the acceleration sensor, and the sub board is arranged at inside of the pedometer case so as not to receive a strain from the main board and the pedometer case. 
         [0014]    That is, a first electronic pedometer for resolving the problem is an electronic pedometer for detecting a step number by an acceleration sensor, wherein a circuit board is constituted by two sheets of a main board mounted with an electronic circuit element for executing a signal processing and a sub board mounted with the acceleration sensor, the sub board is fixed to a pedometer case at one portion and an interval between the sub board and the main board is connected by a flexible conductive member. 
         [0015]    Further, a second electronic pedometer for resolving the problem is an electronic pedometer for detecting a step number by an acceleration sensor, wherein a circuit board is constituted by two sheets of a main board mounted with an electronic circuit element for executing a signal processing and a sub board mounted with the acceleration sensor, the sub board is fixed to the main board by way of a fixing member having a flexibility and an interval between the sub board and the main board is connected by a flexible conductive member. 
         [0016]    By the invention, an electronic pedometer of low cost which is not erroneously operated even when an external force is exerted to the pedometer case can be provided without using an acceleration sensor of a special structure. Although according to the electronic pedometer of the invention, a strain by the external force exerted to the pedometer case is generated only at the main board and is not generated at the sub board. Further, the external force includes a pressure by an unanticipated impact applied to the pedometer case, a pressure when a user operates an external operating member of a change over switch or the like provided to the pedometer case and the like. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a block circuit diagram of an electronic pedometer of Embodiment 1 of the invention; 
           [0018]      FIG. 2  is a plane view of the electronic pedometer of Embodiment 1 of the invention shown by removing a display panel and removing an electronic circuit element of IC or the like from a circuit unit; 
           [0019]      FIG. 3  is a sectional view of the electronic pedometer of Embodiment 1 of the invention; 
           [0020]      FIG. 4  is a plane view of the electronic pedometer of Embodiment 1 of the invention; 
           [0021]      FIG. 5  is a sectional view of an electronic pedometer of Embodiment 2 of the invention; 
           [0022]      FIG. 6  is a sectional view of a modified example of the electronic pedometer of Embodiment 2 of the invention; 
           [0023]      FIG. 7  is a partial plane view of an electronic pedometer of Embodiment 3 of the invention constituted by a plane view of a sub board mounted with an electronic circuit element of a semiconductor acceleration sensor or the like and a partial plane view of a main board mounted with a sub board; 
           [0024]      FIG. 8  is a sectional view of the electronic pedometer of Embodiment 3 of the invention; 
           [0025]      FIG. 9  is a plane view of an electronic pedometer of a background art; and 
           [0026]      FIG. 10  is a sectional view of the electronic pedometer of the background art. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    An electronic pedometer according to the invention is characterized in that a circuit board is constituted by two sheets of a main board mounted with an electronic circuit element for executing a signal processing and a sub board mounted with the acceleration sensor, the main board is fixed to a pedometer case at a plurality of portions, and the sub board is formed by a flexible circuit board and fixed to the main board by a fixing member having a flexibility.] 
       Embodiment 1 
       [0028]    An electronic pedometer of Embodiment 1 of the invention is characterized in an electronic pedometer including an acceleration sensor, a main board mounted with an electronic circuit element for executing a signal processing, and a sub board mounted with the acceleration sensor, wherein the main board is fixed to a pedometer case at a plurality of portions, and the sub board is fixed to the pedometer case at one portion and connects an interval between the main board and the sub board by a flexible conductive member. 
         [0029]    That is, as shown by a block circuit diagram of  FIG. 1 , an electronic pedometer  1  of Embodiment 1 is constituted by including two sheets of separate circuit boards, that is, a main board  2  mounted with an electronic circuit element for executing a signal processing and a sub board  3  mounted with an acceleration sensor. The main board  2  is mounted with CPU  11  for executing various operations and controls in accordance with a program, an oscillating circuit  15 , a dividing circuit  14 , ROM  12  mounted with the program, and RAM  13  stored with various data of a step number and the like. Next, the sub board  3  is mounted with an electronic circuit element constituting a semiconductor acceleration sensor  4  and an amplifying circuit  16 . A pedometer module contained in a module containing portion of the pedometer case  1  is constituted by including the main board  2 , the sub board  3  and a liquid crystal display portion  9 . 
         [0030]    The main board  2  is a glass epoxy board of a shape and a dimension in correspondence with a rectangular module containing portion of the pedometer case  1 , a surface thereof is formed with a printed circuit, and mounted with an electronic circuit element for executing the above-described signal processing. The main board  2  is fixed to a peripheral edge portion of the pedometer case  1  at four portions of board fixing portions  6  as shown by  FIG. 2  through  FIG. 4 . 
         [0031]    The pedometer case  1  is constituted by a plastic case main body  1 A having a rectangular module containing portion opened to a back side and a case back  1 B. A surface of the case main body  1 A is formed with a rectangular display window at a center portion thereof, and four corners of the case are respectively formed with external operating member guide holes respectively opened to a case surface and the module containing portion. Four corners of the main board  2  are formed with switch patterns of switch portions  5 B at positions in correspondence with the external member guide holes. The switch pattern is electrically connected to the printed circuit. 
         [0032]    The sub board  3  is a glass epoxy board of a predetermined shape and a predetermined dimension, and a surface thereof is formed with a printed circuit, and mounted with the electronic circuit element constituting the semiconductor acceleration sensor  4  and the amplifying circuit  16  as described above. As shown by  FIG. 2  and,  FIG. 3 , the sub board  3  is fixed to the pedometer case  1  at one portion of a board fixing portion  7  by fixing means of a screw or the like and an interval between the sub board  3  and the main board  2  are electrically connected by a flexible conductive member  8 . 
         [0033]    That is, the sub board  3  mounted with the semiconductor acceleration sensor  4  is fixed by screwing a fixing screw  7 A to a boss  7 B integrally formed with a center portion of the case back  1 B of the pedometer case  1  by way of an attaching hole of the sub board  3 . Further, the printed circuit of the sub board  3  and the printed circuit of the main board  2  are electrically connected by a heat seal connector constituting the flexible conductive member  8 . In sum, the acceleration sensor  4  is provided with a sensitivity axis in a plane direction of the sub board  3  and the sub board  3  is arranged in parallel with a bottom face of the pedometer case  1  and is fixed thereto at one portion. 
         [0034]    In integrating the electronic pedometer of Embodiment  1 , switch operating members  5 A of 4 pieces of operating buttons or the like are inserted to be arranged at guide holes formed at four corners of the case main body  1 A movably in axial directions such that head portions thereof are exposed to the surface of the case main body  1 A. Next, a pedometer module is contained in the module containing portion from a back side opening of the case main body  1 A. Then, an upper side of a peripheral edge of the main board  2  is brought into contact with a board attaching stepped portion formed at an inner side face of the module containing portion of the case main body  1 A, and a liquid crystal display unit  9 B of the liquid crystal display portion  9  is disposed at a display window formed at a case surface. 
         [0035]    Next, the peripheral edge of the main board  2  is screwed to the main board attaching stepped portion at 4 portions of the board fixing portions  6  by fixing screws from the back side of the case main body  1 A, thereby, the pedometer module is fixed to the case main body  1 A. The main board attaching stepped portion is formed at a position of forming a space in which the sub board  3  mounted with the semiconductor acceleration sensor  4  is contained downward from the main board  2 . Finally, a back side opening of the case main body  1 A is enclosed by the case back  1 B. In this case, the case back  1 B is already fixed with the sub board  3  at one portion of the fixing portion  7 . Further, although not illustrated in  FIG. 1  and  FIG. 2 , key inputting means  17  shown in  FIG. 4  is arranged at a side face of the case main body  1 A, and a battery  18  is contained at inside of the module containing portion of the pedometer case  1 . 
         [0036]    Meanwhile, the display window on the surface side of the case main body  1 A is enclosed by a display window glass  9 A before integrating the pedometer module to the case main body  1 A. Further, a rubber switch is arranged above the switch pattern of the switch portion  5 B formed at the main board  2  before integrating the pedometer module to the case main body  1 A. The rubber switch is a switch which is electrically conducted by being pressed by a front end of the switch operating member  5 A to make the switch portion  5 B electrically conducted and make the switch portion  5 B not conducted by being brought into an electrically insulated state when not pressed by the front end of the switch operating member  5 A. The rubber switch is an elastic member, and therefore, normally, that is, when not operated, the rubber switch functions as a spring member for pushing up the switch operating member  5 A in a direction of the surface of the case main body  1 A. 
         [0037]    According to the electronic pedometer of Embodiment 1 of the invention constituted as descried above, when a pressure by an unanticipated impact is applied to the pedometer case  1 , a strain by the pressure is generated at the pedometer case  1 . Then, the strain is propagated in the main board  2 . According to the main board  2  mounted with the electronic circuit element for executing the signal processing, the peripheral edge is fixed to the pedometer case  1  at four portions, at least at two portions thereof. However, the strain is not propagated to the sub board  3  mounted with the acceleration sensor  4 . The acceleration sensor  4  is provided with the sensitivity axis in the plane direction of the sub board  3 , and the sub board  3  is arranged in parallel with the bottom face of the pedometer case  1  and fixed thereto at one portion. Further, because the heat seal connector constituting the flexible conductive member  8  is adopted for electrically connecting the sub board  3  and the main board  2 , and therefore, the strain propagating in the main board  2  is hampered by the flexible conductive member  8  and is not propagated in the sub board  3 . 
         [0038]    When a stress is applied to the switch portion  5 B by operating the switch operating portion  5 A of the external operating portion  5  by the user, a strain by the stress is generated at the switch portion  5 B of the main board  2  and propagates in the main board  2 . However, the strain is not propagated to the sub board  3  mounted with the acceleration sensor  4 . Because the sub board  3  is fixed to the pedometer case  1  at one portion and the heat seal connector constituting the flexible conductive member  8  is adopted for electrically connecting the sub board  3  to the main board  2 . That is, the strain propagating in the main board  2  is hampered by the flexible conductive member  8  and is not propagated to the sub board  3 . 
         [0039]    Although the electronic pedometer of Embodiment 1 has been explained in details as described above, the sub board  3  is not limited to be arranged at inside of the pedometer case  1  to constitute two layers along with the main board  2 , but may naturally be arranged at inside of the pedometer case  1  to constitute the same plane. Further, the method of fixing the sub board  3  to the pedometer case  1  is not naturally limited to the method of fixing the sub board  3  to the pedometer case  1  by screwing the fixing screw  7 A to a single piece of the fixing boss  7 B formed at the bottom face of the pedometer case  1 . 
       Embodiment 2 
       [0040]    An electronic pedometer of Embodiment 2 of the invention is characterized in an electronic pedometer for detecting a step number by an acceleration sensor, wherein a circuit board is constituted by two sheets of a main board mounted with an electronic circuit element for executing a signal processing and a sub board mounted with the acceleration sensor, the sub board is fixed to the main board by way of a fixing member having a flexibility and an interval between the main board and the sub board is connected by a flexible conductive member. Therefore, the electronic pedometer of Embodiment 2 differs in a constitution of arranging the sub board at inside of the pedometer case so as not to receive a strain from the main board and the pedometer case and other constitution is the same as that of Embodiment 1. 
         [0041]    That is, as shown by  FIG. 5 , the electronic pedometer of Embodiment 2 includes the main board  2  mounted with an electronic circuit element for executing a signal processing and the sub board  3  mounted with the acceleration sensor  4 . The sub board  3  is fixed to the main board  2  by way of the fixing member  20  having the flexibility. Further, an interval between the printed circuit of the sub board  3  and the printed circuit of the main board  2  is electrically connected by a heat seal connector constituting the flexible conductive member  8 . 
         [0042]    Further, as shown by  FIG. 6 , the electronic pedometer of Embodiment 2 includes the main board  2  mounted with an electronic circuit element for executing a signal processing, and the sub board  3  mounted with the acceleration sensor  4 . The sub board  3  is fixed to the main board  2  by way of the fixing member  20  having the flexibility. Further, the interval between the printed circuit of the sub board  3  and the printed circuit of the main board  2  is electrically connected by a flat cable constituting the flexible conductive member  8 . 
         [0043]    The fixing member  20  having the flexibility is a double coated adhering tape coated with an acrylic species adhering agent, an acrylic species adhering agent or a silicone species adhering agent. 
         [0044]    Further, similar to Embodiment 1, the sub board  3  is a glass epoxy board having a predetermined shape and a predetermined dimension, the acceleration sensor  4  is provided with the sensitivity axis in the plane direction of the sub board  3 , and the main board  2  is arranged in parallel with the bottom face of the pedometer case and fixed thereto at the plurality of portions. 
         [0045]    According to the electronic pedometer of Embodiment 2 of the invention constituted as described above, when a pressure by an unanticipated impact is applied to the pedometer case  1 , a strain by the pressure is generated at the pedometer case  1 . Then, the strain is propagated in the main board  2 . Because the main body  2  mounted with the electronic circuit element for executing the signal processing is fixed to the pedometer case  1 . However, the strain is not propagated to the sub board  3  mounted with the acceleration sensor  4 . Because the acceleration sensor  4  is provided with the sensitivity axis in the plane direction of the sub board  3  and the sub board  3  is fixed to the main board  2  by way of the fixing member  20  having the flexibility. Further, the heat seal connector or the flat cable constituting the flexible conductive member  8  is adopted for electrically connecting the sub board  3  and the main board  2 , thereby, the strain propagating in the main board  2  is hampered by the flexible conductive member  8  and is not propagated to the sub board  3 . 
       Embodiment 3 
       [0046]    An electronic pedometer of Embodiment 3 of the invention is characterized in an electronic pedometer for detecting a step number by an acceleration sensor, wherein a circuit board is constituted by two sheets of a main board mounted with an electronic circuit element for executing a signal processing and a sub board mounted with the acceleration sensor, the sub board is formed by a flexible circuit board and fixed to the main board by way of a fixing member having a flexibility, and an interval between the sub board and the main board is connected by a flexible conductive member utilizing a portion of the flexible circuit board. 
         [0047]    That is, according to the electronic pedometer of Embodiment 3 of the invention, different from Embodiment 1 and Embodiment 2 in which the sub board  3  is formed by the glass epoxy board, the sub board  3  is formed by the flexible circuit board. Further, the sub board  3  of the flexible circuit board mounted with the acceleration sensor is fixed to the main board mounted with the electronic circuit element for executing the signal processing by way of the fixing member having the flexibility similar to Embodiment 2. However, electric connecting means between the printed circuit of the sub board and the printed circuit of the main board realizes the function of the flexible conductive member of Embodiment 2 by utilizing a portion of the flexible circuit board forming the sub board. 
         [0048]    Explaining further in details, as shown by  FIG. 8 , the sub board  3  mounted with an electronic circuit element of the acceleration sensor  4  or the like is fixed to the main board  2  mounted with the electronic circuit element for executing the signal processing by way of the fixing member  20  having the flexibility. The sub board  3  is formed by the flexible circuit board, as shown in  FIG. 7  and constituted by an electronic circuit element mounting region  3 A, four of terminal regions  3 B, two of locking regions  3 C, a narrow portion  3 D formed between the electronic circuit element mounting region  3 A and the locking region  3 C, and a printed circuit  3 E formed on the sub board  3 . The electronic circuit element mounting region  3 A is mounted with electronic circuit elements of the acceleration sensor  4 , a resistor  22 , a capacitor  23  and the like. Five of the terminal regions  3 B are formed by being extended from the electronic circuit element mounting region  3 A in a left direction of  FIG. 7 , and therefore, in a direction of a center portion of the main board  2  in a projected shape. The locking regions  3 C are formed by being respectively extended from the electronic circuit element mounting region  3 A to upper and lower sides in a right direction of  FIG. 7 , and therefore, in upper and lower directions of one end portion  2 A of the main board  2 . Five of terminal portions  3 F of the printed circuit pattern  3 E are formed in a projected shape in correspondence with five of the terminal region  3 B in a projected shape of the sub board  3 . 
         [0049]    The pedometer case  1  is constituted by an upper case  1 A of a plastic having the rectangular module containing portion opened to the back side, a lower case  1 B, a glass  1 C for closing an opening portion of the upper case  1 A, and a holding plate  1 D of the glass  1 C. The locking region  3 C of the sub board  3  is formed with a through hole  3 E for receiving a coupling projected portion  1 E formed at the upper case  1 A for coupling the upper case  1 A and the lower case  1 B of the pedometer case  1 . 
         [0050]    The fixing member  20  having the flexibility is a double coated adhering tape coated with an acrylic species adhering agent, an acrylic species adhering agent or a silicone species adhering agent. 
         [0051]    Further, electric connecting means between the printed circuit  3 E of the sub board  3  and the printed circuit of the main board  2  is realized by utilizing a portion of the flexible circuit board forming the sub board  3 . That is, the electric connecting means is realized by five of the terminal regions  3 B formed by being extended from the electronic circuit element mounting region  3 A of the sub board  3  in the direction of the center portion of the main board  2  in the projected shape and five of the terminal portions  3 F in the projected shape of the printed circuit  3 E extended to the terminal regions. Further, the five projected shape terminal portions  3 F of the sub board  3  are soldered ( 21 ) to corresponding terminal portions of the printed circuit of the main board  2 . 
         [0052]    Further, the acceleration sensor  4  is provided with the sensitivity in the plane direction of the sub board  3 , the main board  2  is interposed by the upper case and the lower case of the pedometer case  1 , arranged in parallel with the bottom face and fixed thereto by the plurality of portions. 
         [0053]    According to the electronic pedometer of Embodiment 3 of the invention constituted as described above, when a pressure by an unanticipated impact is applied to the pedometer case  1 , a strain by the pressure is generated at the pedometer case  1 . Then, the strain is propagated in the main board  2 . Because the main board  2  mounted with the electronic circuit element for executing the signal processing is fixed to the pedometer case  1 . However, the strain is not propagated to the sub board  3  mounted with the acceleration sensor  4 . Because the acceleration sensor  4  is provided with the sensitivity axis in the plane direction of the sub board  3 , and the sub board  3  is fixed to the main board  2  by way of the fixing member  20  having the flexibility. Further, the electric connection of the sub board  3  and the main board  2  is realized by the flexible conductive member formed by utilizing a portion of the sub board  3  constituting the flexible circuit board, that is, the five terminal regions  3 B formed by being extended in the projected shape from the electronic element mounting region  3 A of the sub board  3 , and therefore, the strain propagating in the main board  2  is hampered by the flexible conductive member and is not propagated in the sub board  3 . 
         [0054]    Further, as shown by the plane view of  FIG. 7 , in Embodiment 3, the sub board  3  includes the two locking regions  3 C and the locking regions  3 C are pinched by the upper case  1 A and the lower case  1 B. Therefore, also the sub board  3  includes a region fixed to the pedometer case  1 . However, the strain generated at the case is not transmitted to the electronic element mounting region  3 A of the sub board  3  by way of the locking region  3 C. Because the flexible narrow portion  3 D is formed between the electronic circuit element mounting region  3 A and the locking region  3 C of the sub board  3 . Further, the locking region  3 C is not necessarily needed in view of the function of Embodiment 3.