Abstract:
An electronic timepiece has an oscillating circuit for producing a clock signal. A dividing circuit divides the clock signal and produces a divided output signal used to count elapsed time. A calculating circuit calculates time information in accordance with the divided output signal produced by the dividing circuit. A detecting circuit detects a horizontal state of the electronic timepiece relative to a ground reference. A bearing measurement device measures bearing information when a horizontal state of the electronic timepiece relative to the ground reference is detected by the detecting circuit. A display circuit displays time information calculated by the calculating circuit and displays bearing information measured by the bearing measurement circuit.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electronic timepiece, such as a wrist watch, with a bearing detector and, more particularly, to an electronic watch with a bearing detector for performing of starting and ending operations bearing measurement. 
     2. Description of the Prior Art 
     A conventional electronic wrist watch with a bearing detector, as shown, for example comprise by a block diagram in FIG. 7, comprise a microprocessor (CPU)  10 , a memory (ROM)  11  for storing a system program, processing program and the like for the CPU  10 , a memory (RAM)  12  for storing processing data and the like, an oscillation circuit  13  for providing a clock signal to the CPU  10 , a display circuit  14  driven by the CPU  10  for performing time display, bearing measurement value display and the like, a bearing detection circuit  15  controlled by the CPU  10  for performing bearing measurement, a frequency-dividing circuit  16  for frequency-dividing an oscillation frequency of the oscillation circuit  13  and generating a 1-Hz timing signal, a push button  17  for starting bearing measurement and an interrupt circuit  18 . 
     Although the electronic wrist watch with a bearing detector is usually utilized by wearing on the arm, a wearer has been required to press a measurement push button  17  when starting bearing measurement. The wearer fully understands that measurement with the electronic wrist watch with a bearing detector positioned in a horizontal state is suited for bearing measurement. However, there are often cases that the push button  17  is pressed in a state that the electronic wrist watch with an bearing detector is not horizontal but inclined. If bearing measurement is made by the electronic wrist watch with a bearing detector in such an inclined state, there is a problem that the measurement accuracy is decreased. 
     The problem that the present invention is to solve is to improve bearing measurement accuracy by automatically starting bearing measurement when an electronic wrist watch with a bearing detector becomes is positioned a horizontal state. 
     SUMMARY OF THE INVENTION 
     In order to solve the above problem in the conventional art, an electronic watch with a bearing detector comprises a microprocessor, a memory for storing a processing program, processing data and the like for the microprocessor, an oscillation circuit for providing a clock signal to the microprocessor, a display circuit driven by the microprocessor to perform time display, bearing measurement value display and the like, and a bearing detection circuit controlled by the microprocessor to perform bearing measurement, wherein when a horizontal detection circuit detects a horizontal state of the electronic wrist watch with a bearing detector, bearing measurement and bearing measurement value display are performed. 
     According to the present invention, bearing measurement is started by detecting a horizontal state of the electronic wrist watch with a bearing detector relative to a ground reference by the horizontal detection circuit and is continued until a measurement stop signal is inputted. Further, the measurement stop signal can be inputted manually by pressing a push button or automatically after counted a predetermined time period counted by a timer has elapsed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred form of the present invention is illustrated in the accompanying drawings in which: 
     FIG. 1 is a block diagram showing a structure of one embodiment of the present invention; 
     FIG. 2 is a basic flowchart of bearing measurement in the invention; 
     FIG. 3 is a flow chart of bearing measurement from a start to an end due to elapsing a predetermined time period in the present invention; 
     FIG. 4 is a flow chart of bearing measurement from a start to an end by pressing push button in the present invention; 
     FIGS. 5A-5D are figures showing one example of a horizontal sensor used in the horizontal detection circuit, wherein FIG. 5A is a perspective view, FIG. 5B is a longitudinal sectional view in a horizontal state, FIG. 5C is a longitudinal sectional view in an inclined state, and FIG. 5D is a plan view in an inclined state shown with a lid removed; 
     FIG. 6 is a figure showing one example of a display panel of the electronic wrist watch with a bearing detector; and 
     FIG. 7 is a block diagram showing a structure of a conventional electronic wrist watch with a bearing detector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     One embodiment of a electronic wrist watch with an bearing detector of the present invention is basically structured by adding to a conventional apparatus shown in FIG. 7 means for obtaining a bearing measurement (i.e., detecting a predetermined azimuth on the earth, and for displaying a bearing measurement value when a horizontal state of the electronic wrist watch with a bearing detector. 
     That is, as shown in a block diagram of FIG. 1, the one embodiment of an electronic wrist watch with a bearing detector is structured by a microprocessor (CPU)  10 , a memory (ROM)  11  for storing a system program, processing program and the like for the CPU  10 , a memory (RAM)  12  for storing processing data and the like, an oscillation circuit  13  for providing a clock signal to the CPU  10 , a display circuit  14  driven by the CPU  10  and performing time display, bearing measurement value display and the like, a bearing detection circuit  15  controlled by the CPU  10  for performing bearing measurement, a frequency-dividing circuit  16  for frequency-dividing an oscillation frequency and generating a 1-Hz timing signal, a push button  17 , an interrupt circuit  18  and a horizontal detection circuit  19  for generating a horizontal detection signal. The interrupt circuit  18  inputs a timing signal from the frequency-dividing circuit  16 , a bearing measurement stop signal from the push button  17  and a horizontal detection signal from the horizontal detection circuit  19 , respectively, to the CPU  10 . The bearing measurement stop signal can be generated by a timer, as hereinafter described. 
     The horizontal detection circuit  19  is arranged within a case of the electronic wrist watch with a bearing detector or attached to the case. Consequently, the horizontal detection circuit  19  generates a horizontal detection signal when the electronic wrist watch with a bearing detector is positioned in a horizontal state, and provides it to the interrupt circuit  18 . The interrupt circuit  18  allows this horizontal detection signal to input to the CPU  10 . The horizontal detection circuit  19  is provided with a horizontal sensor  20  as described below. 
     The horizontal sensor  20  is comprised, for example as shown in a perspective view  5 A, longitudinal sectional views  5 B and  5 C and a plan view with a lid removed  5 D of FIGS. 5, a circular container  21  of an insulation material having a generally-cylindrical interior chamber  21   a,  two conductive strip members  24   a  and  24   b  arranged within the circular container  21  to function as a pair of fixed contacts, and a conductive spherical member  25  enclosed in the circular container  21  to function as a movable contact. 
     The circular container  21  is formed by a cup-formed lid member  22  and a dish-formed bottom member  23 . The dish-formed bottom member  23  is formed by a conical surface  23   a  opened at a center with a small hole  23   c  and a horizontal surface  23   b  provided on an outer side thereof. The two conductive strip members  24   a  and  24   b  have respective outer ends projecting outside the container  21  to function as a pair of terminals, and respective inner ends thereof extend to ends of small hole  23   c  of the bottom member  23  to function as a pair of fixed contacts. The two conductive strip members  24   a  and  24   b  at surfaces are exposed in the generally-cylindrical interior chamber  21   a  and buried in the bottom member  23 . The conductive spherical member  25  functioning as a movable contact is enclosed within the generally-cylindrical interior chamber  21   a  of the container  21  so that it can freely rotate and move according to gravity. 
     When the horizontal sensor  20  is positioned in a horizontal state relative to the ground, as shown in FIG. 5B, the conductive spherical member  25  moves to and seats on the small hole  23   c  in the center of the bottom member  23 , and electrically connects between the paired inner ends of the two conductive strip members  24   a  and  24   b.  When the horizontal sensor  20  is inclined from a horizontal state and if inclined left for example, then as shown in FIGS. 5C and 5D the conductive spherical member  25  leaves from the center small hole  23   c  of the bottom member  23  and moves to an end of the generally-cylindrical interior chamber  21   a  of the container  21 , thus electrically disconnecting the paired inner ends of the two conductive strip members  24   a  and  24   b.  In this manner, the horizontal sensor  20  electrically detects a horizontal state. 
     In the one embodiment apparatus of the invention structured as explained above, the operation from start to end of bearing measurement will be explained with reference to FIG. 2 to FIG.  4 . FIG. 2 is a basic flowchart of a bearing measurement operation from start to end, FIG. 3 is a flowchart of a bearing measurement operation which ends automatically after lapse of a predetermined time and, FIG. 4 is a flowchart of a bearing measurement operation which ends when a push button is manually pressed. 
     In FIG. 2, if the electronic wrist watch with a bearing detector is rendered in a bearing measurement mode, the horizontal detection circuit  19  starts operation ( 101 ). When the horizontal detection circuit  19  detects a horizontal state, it provides a horizontal detection signal to the interrupt circuit  18 . The interrupt circuit  18  inputs the horizontal detection signal to the CPU  10 . Thereupon, the CPU  10  determines that the electronic wrist watch with a bearing detector has been positioned in a horizontal state ( 102 ) relative to the ground and drives the display circuit  14  to perform horizontal state display ( 103 ). Next, the CPU  10  drives the bearing detection circuit  15  to perform bearing measurement ( 104 ) and further drives the display circuit  14  to make a bearing measurement value display ( 105 ). Completing the bearing measurement value display, the CPU  10  ends the horizontal detection, bearing measurement and measurement value display ( 106 ). The series of operations are executed according to a content of a program stored in the ROM  11 . In this manner, the electronic wrist watch with a bearing detector in a bearing measurement mode automatically starts bearing measurement if positioned in a horizontal state. 
     In FIG. 3, if the electronic wrist watch with a bearing detector is rendered in a bearing measurement mode, the horizontal detection circuit  19  starts operation ( 201 ). The horizontal detection circuit  19  if detecting a horizontal state, provides a horizontal detection signal to the interrupt circuit  18 . The interrupt circuit  18  inputs the horizontal detection signal to the CPU  10 . Thereupon, the CPU  10  determines that the electronic wrist watch with a bearing detector has been positioned in a horizontal state ( 202 ) and drives the display circuit  14  to make horizontal state display ( 203 ). Next, the CPU  10  drives the bearing detection circuit  15  to perform bearing measurement ( 204 ) and further drives the display circuit  14  to perform bearing measurement value display ( 205 ). Subsequently, the CPU  10  determines whether or not 30 seconds has passed from a start of bearing measurement ( 206 ) and, if not elapsed by 30 seconds, continues the bearing measurement and measurement value display. In the case that 30 seconds has elapsed is determined, the CPU  10  ends the horizontal detection, bearing measurement and measurement value display ( 207 ). The series of CPU  10  operations are executed according to a content of a program stored in the ROM  11 . 
     In this manner, the electronic wrist watch with a bearing detector in a bearing measurement mode can automatically start bearing measurement merely by being positioned in a horizontal state and, after lapse of a predetermined period of time, automatically ends the bearing measurement. This predetermined time was 30 seconds in the flowchart of FIG. 3, but can be arbitrary set and changed. Also, measurement of the predetermined time is performed using, for example, a built-in timer. That is, the predetermined time is set on this timer, and a count is started at a time point that a horizontal detection signal from the horizontal detection circuit  19  is inputted through the interrupt circuit  18  to the CPU  10 . When the count value reaches the set predetermined value, a coincidence signal is generated to end the count. The coincidence signal is utilized as a measurement end signal. 
     In FIG. 4, if the electronic wrist watch with a bearing detector is rendered in a bearing measurement mode, the horizontal detection circuit  19  starts operation ( 301 ). The horizontal detection circuit  19 , if when it detects a horizontal state, provides a horizontal detection signal to the interrupt circuit  18 . The interrupt circuit  18  inputs the horizontal detection signal to the CPU  10 . Thereupon, the CPU  10  determines that the electronic wrist watch with a bearing detector has been positioned in a horizontal state ( 302 ) and drives the display circuit  14  to perform horizontal state display ( 303 ). Next, the CPU  10  drives the bearing detection circuit  15  to perform bearing measurement ( 304 ) and further drives the display circuit  14  to perform bearing measurement value display ( 305 ). Subsequently, the CPU  10  determines whether measurement stop input has been made by the push button  17  or not ( 306 ). If there is no measurement stop input, the bearing measurement and measurement value display are continued. In the case that measurement stop input has been made by the push button  17 , the CPU  10  ends the horizontal detection, bearing measurement and measurement value display ( 307 ). The series of CPU  10  operations are executed according to a content of a program stored in the ROM  11 . 
     In this manner, the electronic wrist watch with a bearing detector according to the invention, in the bearing measurement mode, automatically starts a bearing measurement by merely being positioned in a horizontal state, and the bearing measurement can be ended also by pressing manually the push button  17  to generate a measurement stop signal. 
     FIG. 6 is a figure showing one example of a display panel used for the display circuit  14  of the electronic wrist watch with a bearing detector according to the present invention. The display panel is, for example, an LCD panel. The display panel of FIG. 6 has inner and outer display areas divided by larger and smaller two circles. The inner display area has time display in a center and horizontal state display thereunder. In FIG. 6, the time display exhibits 10:8:59 and the horizontal state display is indicated by characters of BEARING within a box. The horizontal state display may be other display instead of BEARING. In the outer display region, i.e. in a doughnut-formed area surrounded by the larger and smaller two circles, four bearing marks of a triangular mark indicative of north and three square marks indicative of west, east and south are displayed with an equal interval on a circumference. It is understood that the bearing marks can be other than the marks shown in FIG.  6 . 
     By the present invention, bearing measurement could be automatically started by merely positioning the electronic wrist watch with an bearing detector in a horizontal state relative to the ground. Accordingly, because bearing measurement is made in a horizontal state, i.e. in a state parallel with the ground, the accuracy of a bearing measurement using an electronic wrist watch with a bearing detector. Also, because a bearing measurement push button is not required to be manually pressed to start a bearing measurement, the electronic wrist watch is easy for a wearer to utilize.