JPH04313017A - Bearing display device - Google Patents

Abstract

PURPOSE:To reduce the influence of noise and detect weak geomagnetism by orienting Hall elements having the same characteristic in the same direction and synthesizing the outputs of the elements in the opposite phases by respectively applying voltages across the elements in the opposite directions. CONSTITUTION:Hall elements 9-12 which have the same size and characteristic and with which cores 13-16 which converge magnetic fluxes and have pointed tips are brought into contact or not brought into contact are mounted on a wiring board 8 in the same orientation. A geomagnetism sensor is constituted by respectively applying voltages across the elements in the opposite directions so that the conducting directions of the elements can alternately become opposite to each other, respectively amplifying the Hall output voltages of the elements by means of amplifiers, offsetting the external noise, synthesizing the Hall output voltages so that they can be added to each other, connecting a smoothing capacitor having an appropriate capacity between the output terminals of the amplifiers, and using a circuit which reduces internal noise. In addition, an electronic disk magnet type geomagnetism sensor is added to them. Therefore, geomagnetism detection which is hardly affected by noise can be realized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting and displaying geomagnetism using an electronic circuit or the like.

0002

2. Description of the Related Art A Hall element generates a Hall voltage due to the Hall effect, but a practical geomagnetic sensor using a Hall element has not yet been completed. The reason for this is that the S/N ratio of the circuit using the Hall element is poor. In the area around 35 degrees north latitude in the center of the Japanese archipelago, the horizontal component of the geomagnetism that is effective for detecting orientation is a small value of about 0.3 Gauss, and the Hall output voltage of the Hall element due to the geomagnetism is very small. Small, several 100 μV, depending on the device type
Due to the high degree of Internal noise is large, resulting in a poor S/N ratio.

[0003] The same applies to a Hall IC in which a Hall element and its amplifier are incorporated in one silicon substrate.

0004

SUMMARY OF THE INVENTION The main object of the present invention is to solve these problems and provide a practical orientation display device. Examples will be explained below.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view of an orientation display device using a Hall element embodying the present invention. FIG. 2 is an elevational view thereof. 1 is an aluminum outer box measuring approximately 3 x 5 x 10 cm in length, width, and height. 2 is a liquid crystal display attached to the top surface. 3 is a monitor using a magnetic needle. 4 is the speaker box attached to the rear (front side). 5 is the audio mode changeover switch. 6 is a relative direction setting switch. 7 is a light emitting/sounding switch.

[0006] If you put this device in your chest pocket or the like, and occasionally take it out of your pocket and look at the liquid crystal display 2, a compass-like dial will appear, allowing you to know your direction. At night, when the switch 7 is pressed, the backlight is turned on, making the display 2 easier to see, and the speaker 4 displays in audio language the direction in which the front of the outer box 1 is facing, such as "north" or "northeast."

[0007] When climbing a mountain at night or when a visually impaired person is walking, when the mode changeover switch 5 is pressed, the mode changes to a mode in which the direction is constantly displayed once every few seconds. If you press it again, it will only say when the heading has changed by 22.5 degrees. Furthermore, if you press it again, it will return to its original state and will only speak when switch 7 is pressed. If you put the outer box 1 in your pants pocket or a handbag and walk with the left side facing forward, while looking at the magnetic needle 3, turn the left side to the north and press the relative orientation setting switch 6 to make the left side face north. Time,"
The internal circuit operation is switched so that the audible message "North" is displayed.

FIG. 3 is an enlarged plan view of the printed wiring board of the main part of the electric circuit inside the outer box 1. Figure 4 is an elevation view. Figure 5
is an enlarged longitudinal sectional front view of the Hall element 9. FIG. 6 is a block diagram of the electric circuit. 8 is a Bakelite substrate. 9 and 10 are Hall elements facing front and back, with a main body measuring approximately 2 x 4 x 4 mm in length, width, and height, and four electrodes connected to conductive wires on the bottom surface of the substrate. 11 and 12 are similar Hall elements facing left and right. 13
16 is an iron core for magnetic flux convergence whose tip ends are in contact with these surfaces, and the tip of a 4 mm square prism is pointed at a 2 mm square. 17 to 20 are operational amplifiers (DC amplifiers) for amplifying the output voltage of each Hall element. 21 is an electronic circuit box containing an A-D converter, a microcomputer, and others.

Inside the Hall element 9 and other parts, as shown in FIG.
3 and 24, output electrodes 25 and 26 are attached on the left and right sides, and the periphery is surrounded by a plastic mold 27. In the electrical circuit diagram of FIG. 6, 28 and 29 are power batteries. 30 and 31 are smoothing capacitors for eliminating internal noise. 32 and 33 are A-
D converter. 34 is a division circuit with a built-in microcomputer. 35 is a direction determination circuit with a built-in microcomputer. 36 is a speech synthesis circuit.

Next, this operation will be explained. Now, when the outer box 1 is facing north, the iron cores 13 and 14 are facing north, and the lines of magnetic force (earth's magnetic field) from the earth's magnetic south pole to the magnetic north pole pass through the Hall elements 9 to 12 and the iron cores 13 to 16. , element 11,1
2 produces no output voltage. The horizontal component of the earth's magnetism magnetizes the front ends of the iron cores 13 and 14 as n-poles and the pointed rear ends as s-poles. At this time, since the front end of the iron core is thick and the rear end is thin, an effect occurs where the magnetic flux density increases in inverse proportion to the cross-sectional area at the rear end.

+6V is applied to the element 9 from the battery 28 to the electrode 23.
, a negative voltage, that is, a downward applied voltage is applied to the electrode 24, and as a result of the magnetic field lines penetrating from the rear to the front, a positive Hall output voltage is generated at the left electrode and a negative Hall output voltage is generated at the right electrode. Also,
An applied voltage directed upward from the bottom is applied to the element 10, and a negative output voltage is generated at the left output electrode and a positive output voltage is generated at the right output electrode.

[0012] The output voltage of both elements is
The output lines of both amplifiers are connected in parallel with opposite phases, and the outputs of elements 9 and 10 are also amplified by elements 9 and 10.
The right side of 9 is connected, and the right side of 9 and the left side of 10 are connected. As a result, the + voltages of 9 and 10 are combined, the - voltages are also combined, and the Hall output voltage becomes stronger. (Due to the parallel connection, it cannot be doubled.) External electromagnetic noise is added to the Hall elements 9 and 10, their conductors, operational amplifiers 17 and 18, etc., but they are all close together. Therefore, they are added with almost the same waveform, same phase, and same intensity, and the noise outputs amplified by the operational amplifiers 17 and 18 are combined with opposite phases and are almost canceled out.

Internal noise generated within the Hall element and operational amplifier is also amplified, combined, and added to the output voltage.
These noises are random white noises containing many high frequency components, and have a property that when averaged, the noise becomes approximately 0, and is approximately smoothed by the smoothing capacitor 30. In addition, if the capacitance of the capacitor 30 is too large,
Since the Hall output voltage is also averaged and the response speed becomes slower, the time constant expressed by the product of surrounding resistances is 0.1 to 1 s.
Set it so that the

The low-noise combined outputs of the operational amplifiers 17 and 18 are converted into a digital signal by an A-D converter 32 and input to a divider circuit 34. When the outer box 1 is facing north, the output from Hall elements 9 and 10 (the composite value of the output of the left output terminal of element 9 and the output of the right terminal of element 10) is maximum, and then rotated to the right. If you go, it changes in proportion to the cosine of the rotation angle from north. (Proportional to the sine of the inclination angle of the magnetic field lines with respect to the plane of the element.) Hall element 11,
12, the attached iron cores 15, 16, and other parts operate almost in the same way as the Hall elements 9, 10 and their attached parts.

That is, the voltage of the battery 29 is applied downward to the element 11 and applied upward to the element 12, and the outputs of both elements are amplified by the operational amplifiers 19 and 20, respectively, and are combined in opposite phases, so that the Hall output is strengthened and the external noise is canceled out,
Internal noise is attenuated by a smoothing capacitor 31, digitized by an A-D converter 33, and then input to a dividing circuit 34.

The Hall outputs of the elements 11 and 12 change in proportion to -sine when the outer box 1 rotates clockwise from north. (If the magnetic lines of force penetrate from the right side of the element 11, the output becomes -.) The division circuit 34 calculates the ratio of the output of the element 11 etc. and the output of the element 9 etc., that is, the -tangent. This value is input to the direction determination circuit 35, and the circuit 35 uses this value and whether the left output terminal voltage of the element 9 is + or - as a parameter to determine the direction in which the outer box 1 is facing, and displays the entire display 2. A dial indicating the direction is displayed, and the speech synthesis circuit 36
Information only on the direction in which the outer box 1 is facing is sent, converted into audio language, and displayed on the speaker 4.

The output of element 9 increases or decreases as the latitude changes and the horizontal component of the earth's magnetism changes, and although the direction cannot be determined from that value alone, it was obtained by using the value of element 11 as the dividend.
If you calculate the tangent, this value is not affected by latitude and is correlated only with direction. However, when facing north and south, the -tangent is both 0, and when facing northeast and southwest, it is both -1. are equal.

However, when facing north and northeast, the cosine (
The value of the output of element 9) is +, and the cosine is - in the south and southwest directions, and if the -tangent and cosine millionaire are used as parameters, all directions can be specified. The determination circuit 35 performs such calculations and determines the direction. In addition, when the application electrodes of the Hall elements are on the left and right sides, an applied voltage is applied to one element in a row to the left and to the other element to the right, and the upper and lower output electrodes are turned upside down for synthesis.

The entire surface of the element 10 may be attached to the rear surface of the element 9. In that case, the tip of the iron core 14 may be attached so as to be in contact with the rear surface of the core 10, and the four conductors of each of the elements 9 and 10 may be inserted alternately between them, or they may be layered vertically with an insulator interposed between them. good. Iron cores 13 to 16 may be omitted. Attach a larger number of Hall elements beside or after elements 9 and 10, alternately reverse the direction of the applied voltage, and combine the amplified outputs alternately in opposite directions, or combine them in series or parallel without amplification. However, it may be added to one low-noise operational amplifier. Design of running direction and layout of printed wiring,
If the noise can be reduced by covering the entire circuit with aluminum foil to shield external electrical noise, the circuit is configured with the Hall element 9, operational amplifier 17, and capacitor 30, and element 10 and operational amplifier 18 are omitted. It's okay.

The outputs of the operational amplifiers 17 and 18 may be combined in series. Two Hall elements are formed in one silicon substrate, a downward voltage is applied to one, and an upward voltage is applied to the other, and the output voltages of both are amplified by operational amplifiers installed in the same silicon substrate. After that, an LSI may be used in which the external noise is reduced by synthesis, and the internal noise is reduced by an internally built-in capacitor or an external capacitor.

The battery 28 may be replaced by a power source that generates a sine wave or other waveform pulsating current, and a downward pulsating current may flow through the element 9 and an upward pulsating current may flow through the element 10. In this case, the frequency of the pulsating flow may be low frequency or high frequency, but a pulsating flow output with the same waveform is generated in the operational amplifier. This pulsating flow may be passed through narrow-band filters that allow the pulsating flow to pass through to cut noise components, and may be further synthesized so that the noise components cancel each other out, and may be smoothed by a capacitor 30.

[0022] When alternating current is applied instead of pulsating current,
Using a triac or the like, the alternating current that has passed through the bandpass filter is connected to the capacitor 30 only when the voltage applied to the element 9 is downward.
must be sent to. Hall elements 9, 10
A high resistance may be placed between each application electrode and the power source to reduce external noise that enters through the conductive wires connected to the power source.

There are a large number of printed wiring conductors on the bottom surface of the substrate 8, but if there are any intersections, external noise with opposite phases will occur in the system of elements 9 and 10, and the above-mentioned problem will occur. In some cases, the noise may become stronger due to wiring connections. Therefore, in such a case, apply voltages in the same direction to elements 9 and 10, and combine the outputs of operational amplifiers 17 and 18 in the same phase, so that the external noise is attenuated and the Hall output is strengthened. .

Even if the direction is determined while suppressing noise using the Hall elements 9 to 12 as described above, if a source of strong external noise is nearby, the division circuit 34
The input input to the system fluctuates greatly, making it impossible for the determination circuit to determine the direction. In such a case, the determination circuit temporarily stops determination based on the data from the division circuit, and switches to direction determination using the next system provided inside the outer box 1, although the accuracy is slightly lower.

FIG. 7 is an enlarged plan view of the electronic disk magnet type geomagnetic sensor provided in the outer box 1. FIG. 8 is a cross-sectional view thereof. FIG. 9 is a vertical right side view. 37 is a spherical transparent plastic container with a diameter of about 2 cm, the bottom of which is fixed to the bottom of the outer box 1. 38 has its front pole at 0 degrees upper latitude (lower latitude),
A light-emitting element that emits red light is attached to the outer surface of the container at a position of 45 degrees upper latitude and 0 degrees left longitude when the left longitude (right longitude) is 0 degrees.
diode). 39 is a light emitting element that emits slightly higher green light. (Power consumption is lower than when using an incandescent light bulb.) 40 is a light receiving element with a red filter attached near 20 degrees upper latitude and 0 degrees left longitude. 41 is a light receiving element with a green filter attached slightly above it. 42 is water stored in the lower half of the container. 43 is a durable disk magnet which has been given buoyancy by pasting a foamed resin plate on its lower surface, and has an n-pole at the front end. 44 is the part where the front 45° area of the upper surface was painted with paint containing a mixture of red pigment and green pigment at a ratio of 7:0. 45-51 is 6:1, 5
These are the areas painted with paint containing a mixture of red and green pigments in the ratio: 2:2, 4:3, 3:4, 2:5, 1:6, 0:7.

The computer in the determination circuit 35 applies a pulse voltage of 1 ms pulse width and 30 Hz to the light emitting elements 38 and 39.
In order to send the light to the disk, a beam of red and green light with a solid angle of about 30 degrees is irradiated from them to the disk magnet below. Of the diffusely reflected light, the red component enters the light-receiving element 40, the green component enters the light-receiving element 41, and their outputs are amplified by an amplifier (not shown) in the determination circuit 35, digitized by an A-D converter, and then converted to a computer. The ratio of red and green light intensities is calculated.

If the ratio is 7:0, the direction the outer box 1 faces is judged to be north, 3:4 to the south, 0:7 to the northwest, 6.5:0.5 to the north-northeast, etc. It is determined that If the outer box 1 is tilted in the direction that the front surface is up and down, there is no problem, but if the right side is lowered in the state shown in the figure, the reflected light from the green pigment 51 will also enter the light-receiving element 41, and the light will actually be in the north direction. Even though the direction is correct, it is determined to be northeast.

As a countermeasure, the light beam is made narrower, the surface of the disc magnet 43 is subdivided into 16 or more parts, and pigments such as red, green, or blue are added, and the mixture ratios are changed for each color. In addition to green light receiving elements, blue light receiving elements may also be used. Alternatively, the following may be used. FIG. 10 is a plan view when the states of the light-emitting element and light-receiving element are changed in the above case.
Reference numerals 52 and 53 denote red and green light emitting elements that are attached near the upper pole of the container 37 and emit light almost evenly onto the upper surface of the disc magnet 43. 54 to 57 are 0 degrees and 90 degrees to the right longitude on 20 degrees upper latitude,
Red attached at 180 degrees and 90 degrees left longitude, respectively.
These are green, red, and green light receiving elements.

Red and green pulsed lights are emitted from the light emitting elements 52 and 53, and the red light enters the light receiving element 54 at an intensity of 7, the intensity of the green light enters the light receiving element 56 at an intensity of 3, the green light enters the light receiving element 55 at an intensity of 2, and the intensity at 57 at an intensity of 6. If the direction is entered at such a rate, the determination circuit 35 determines that the direction is northward. Outer box 1
If it faces northeast, red will be 6 at 54, 2 at 56, and green will be 5.
5 with a strength of 3 and 57 with a strength of 7.

In such a case, the determination circuit 35 determines that the direction is northeast. Hereinafter, determination is made in this manner in any direction. If the front of the outer box is lowered when facing north, element 5
4 approaches the disk magnet 43, and 56 moves away, so red light enters 54 with an intensity of 10, 56 with an intensity of 1, green light with an intensity of 2 into 55, and 6 into 57. From the combination, it was determined that it was facing north.

[0031] In any other direction, the direction can be determined in this manner even if the vehicle is tilted in any direction. This can be done by determining the output value of each light-receiving element in all cases through actual measurement and storing it in a comparison table of the judgment circuit, or by incorporating an experimental formula obtained from the actual measurement results into the computer program. Calculate by calculation.

In this case, the light receiving element 57 is omitted and the light receiving element 54 to
Although such a determination can be made even if 56 is arranged in an equilateral triangle, one or two light receiving elements may be added. The number of colored areas on the disc magnet may be reduced to 2 to 4 areas, and each element may be arranged on the side of the upper latitude of 45 degrees so that the intruding light from areas other than directly below can enter well. As shown in the plan view of the container 37 in FIG. 11, a red light emitting element 58 is attached to the upper pole, and light receiving elements 59 to 62 without a filter are arranged around it,
As shown in the plan view of the disk 43 in FIG. 12, almost the entire surface 63 is painted black, a white dot 64 is added at one place, and the front surface of the disk magnet is irradiated with pulsed light emitted from the light emitting element 58. The reflected light from 64 may be received by the light receiving elements 59 to 62, and the determination circuit 35 may detect the position of the white point from the output distribution to determine the direction.

Note that the upper and lower surfaces are made of glass, and light emitting elements are attached to eight places around the upper surface of the compass that rotates the magnetic needle inside, and eight light receiving elements are attached to the lower surface of the glass directly below each light emitting element. detects the light-receiving element that is blocked by
Compared to the method of determining the orientation, the above method allows the orientation to be determined using a smaller number of light emitting elements and light receiving elements.

FIG. 13 is a plan view of the container 37. FIG. 14 is a plan view of the disk 43. 65 is a semiconductor laser installed at 45 degrees upper latitude and 0 degrees left longitude, and has a polarization device using a piezoelectric element at its lower end. 66 is a light receiving element. 67 is a large number of radial lines drawn with black lines on the white surface of the disc magnet 43;
The angle between the lines varies depending on location. The light emitted from the laser 65 is deflected left and right by a polarizer at the bottom end, and is reflected in the radial line 6 directly below.
7 is scanned left and right, the reflected light causes a change in intensity, and the output voltage of the light receiving element 66 contains pulses, and the judgment circuit 3
5, the number of pulses within a unit time (0.1 s, etc.) is counted, and where on the disc magnet 43 the light hits is detected, and the direction is determined.

In FIGS. 7 to 9, the thickness of the disc magnet 43 is increased, the periphery is made into a spherical surface, the portions partitioned by meridian lines are colored in different colors, and a color sensor is attached to the equatorial outer surface of the spherical container 37, and the area near the sensor is Alternatively, the direction may be detected by determining the color that is coming. A bar code indicating the orientation may be recorded on the peripheral surface of the disk magnet, and the code may be read by a laser beam scanning device provided on the outer equatorial surface of the container 37 to determine the orientation. (Instead of a barcode, the light and dark pattern of the talkie recording may be recorded, and the output of the photoelectric element may be converted into sound.) A real image of the disk magnet is created with a convex lens, and a photoelectric element or CCD is placed in the imaging section, and the color and You can also read barcodes.

Note that the circuits shown in FIGS. 1 to 6 produce errors when the outer box 1 is tilted from horizontal. For example, if the outer box 1 is placed horizontally on the equator where the geomagnetic direction is horizontal and the front face is directed to the northeast, the output ratio between the Hall elements 11 and 9 will be -0.7.
V: Suppose that it is 0.7V. Therefore, the front and back axis of the outer box (y
rotate 90 degrees around the axis).

The angle of incidence of the lines of magnetic force on element 9 does not change due to rotation, and the output also does not change, but the surface of element 11 becomes horizontal, the output becomes 0, and the output ratio of elements 11 and 9 becomes 0. Even though outer box 1 is facing northeast,
The determination circuit 35 determines that the vehicle is facing north. (If you lift the left edge of the outer box by 45 degrees, it will be determined to be north-northeast.) Similarly, if you rotate around the left-right axis (x-axis), it will be determined to be facing east even though it is facing northeast. .

When the outer box 1 is facing north in a zone with an angle of inclination of 45 degrees, if the outer box is rotated 90 degrees around the y-axis in the direction of lowering the left edge, the outer box is facing north. It is determined to be facing northeast. Thus, except in exceptional cases (when it is tilted around the east-west axis), if the outer box 1 is tilted, an error will occur.

In order to prevent such errors, elements 9 and 11
etc. may be floated on the oil surface or suspended in a pendulum shape, but it is also possible to add a Hall element for magnetic detection in the z-axis direction and a tilt sensor of the outer box 1 for determination. . Two Hall elements Z similar to element 9 are mounted on substrate 8.
It is attached to the top surface of the board 8 so that the output is maximized when the lines of magnetic force perpendicularly penetrate from below, and each output is amplified by an operational amplifier to obtain a low-noise output voltage. The output of elements 11, 9, and Z in the earth's magnetic field is proportional to the strength of the magnetic field, and the output is proportional to the sine of the angle of incidence with respect to the surface of each element, but the strength of the earth's magnetic field is the same for all three. Therefore, the value is proportional to the sine of the incident angle.

[0040] With the center of the display 4 as the starting point, the outer box 1
In a three-dimensional spatial coordinate system in which the upper surface of the Corresponds to coordinates, y-coordinates, and z-coordinates. For example, outer box 1
is horizontal and the Y axis (front and back axis of the outer box) points north, and if the earth's magnetic field enters horizontally from the south, it becomes 0V:1V:0V,
If the y-axis points northeast and the geomagnetism enters from 45 degrees south (45 degrees inclination), -0.5V: 0.5V: -0.7V
The output ratio of each element is proportional to the proportion of each coordinate of the geomagnetic vector.

Therefore, from the output ratio of elements 11 and 9, x・y
The inclination of the geomagnetic vector on the coordinate plane is found, and the inclination of the geomagnetic vector on the y/z coordinate plane is found from the output ratio of elements Z and 9. If the x/y coordinate plane is horizontal, from the former value, The direction in which the y-axis (the front-rear axis of the outer box 1) is facing can be immediately specified. However, in this case as well, since the direction in which the outer box 1 and its coordinate system are inclined from the horizontal plane cannot be specified, the following inclination sensor is provided inside the outer box 1.

10 mm with a surface parallel to the peripheral surface of the outer box 1
Piezo elements made of pressure-sensitive rubber or the like having a thickness of 1 mm are pasted on six sides of a cubic lead weight, and the piezo elements are placed in a 12 mm cubic cavity in an outer box 1. The piezo elements on the right, front, and bottom surfaces of the weight are designated as piezo elements X, Y, and Z, and a positive voltage is applied to them so that when the full weight of the weight is applied to each, an output voltage of +1V is generated. Piezo element X-, Y-,
A negative voltage is applied to Z- such that when the full weight of the weight is applied to each, an output voltage of -1V is produced.

If the outer box 1 is horizontal, an output of +1V is generated from the piezo element Z system, and an output of 1V is generated from the other systems. If you tilt 30 degrees to the right (the angle with the horizontal plane is 60 degrees) and 20 degrees backward (the angle with the horizontal plane is 110 degrees), the X system will be 0.5 V, and the Y system will be 0.5 V.
The system produces an output, such as -0.34 V, which is proportional to the sine of the angle of inclination with respect to the vertical plane and the cosine of the angle of inclination with respect to the horizontal plane.

[0044] With respect to the horizontal plane obtained in this way, the x plane (x, z coordinate plane perpendicular to the x,y coordinate plane)
Three types of data consisting of the sine of each inclination angle are obtained and used for subsequent correction. In addition, if the Hall element Z is omitted and the tilt sensor is provided, the outer box 1 is turned north, the left edge is raised, and the left edge is tilted so that it is rotated 45 degrees around the y-axis.If the earth's magnetic field is applied, the inclination angle becomes 0 degrees. When , the output ratio of elements 11 and 9 is 0:0.7
= 0, and the correct judgment result is that it is facing north, but when the inclination angle is 45 degrees, the output ratio is -0.5:0.7 = 0.7...
‥, and an incorrect judgment result that the direction is northwest is obtained.
If is omitted, an erroneous determination result may occur even if the inclination of the coordinate plane is known.

Furthermore, since the inclination angle of the z-plane can be calculated from the data of the x-plane and the y-plane, the sensor for the z-plane may be omitted. For example, attach the center of the top surface of the aforementioned lead weight to the bottom end of the piano wire whose top end is fixed inside the outer box 1, and suspend it, allowing light to pass from above into the gap between the four sides of the weight and the surrounding container. The transmitted light may be converted into a voltage using four photoelectric elements, and the inclination angles of the x-plane and y-plane may be determined by utilizing the fact that the magnitude of the voltage is correlated with the inclination angle of the outer box.

Knowing the orientation of the outer box 1 means knowing the orientation of its y-axis (front-back axis). (Although the elevation and inclination angles of the y-axis, that is, the rotation around the x-axis, have an effect on the output of each Hall element, they are unrelated to the direction determination.) Therefore, based on the information from the tilt sensor, coordinate transformation is performed. By calculation, find the direction of the geomagnetic vector in a coordinate system in which the x, y coordinate plane is returned to horizontal, or the x axis is rotated around the y axis and made horizontal, and the y, z coordinate plane and the geomagnetic Find the angle formed by the vector, set the direction of the geomagnetic vector to north, and find the direction of the y-axis, then outer box 1
The direction in which the object faces will be known.

[0047] These calculations were performed by recording the relationship between the output ratio of each Hall element and the orientation corresponding to the output ratio of the tilt sensor, which was calculated using formulas based on three-dimensional analysis geometry, or determined experimentally. Various methods can be used, such as calculation methods using tables as seeds. Various other design changes are possible.

[0048]

[Effects of the Invention] If the present invention is carried out, the structure is relatively simple, is not affected by noise, can detect weak geomagnetism, and can display the direction on a liquid crystal display or synthesized voice.
The advantage arises that an orientation display device is obtained that can be produced inexpensively.

[Brief explanation of drawings]

FIG. 1 is a plan view of an orientation display device embodying the present invention.

[Figure 2] Its elevation view.

FIG. 3 is an enlarged plan view of the internal wiring board.

[Figure 4] Its elevation view.

FIG. 5 is an enlarged longitudinal sectional front view of the Hall element 9.

[Fig. 6] Block diagram of the electric circuit.

FIG. 7 is an enlarged plan view of the electronic disk magnet type geomagnetic sensor inside the outer box 1.

[Fig. 8] Its cross-sectional view.

[Fig. 9] Its vertical right side view.

FIG. 10 is a plan view of a slightly deformed container 37.

FIG. 11 is a plan view of the container 37.

FIG. 12 is a plan view of the disc magnet in that case.

FIG. 13 is a plan view of the container 37.

FIG. 14 is a plan view of the disk 43.

[Explanation of symbols]

1 Outer box. 2 LCD display. 4 Speaker box. 8 Bakelite substrate. 9 Hall element. 10 Hall element. 11 Hall element. 12 Hall element. 13 Iron core for magnetic flux convergence. 17 Operational amplifier. 21 Electronic circuit box. 22 Semiconductor board in Hall element. 23 Application electrode in Hall element. 28 Power battery. 30 Smoothing capacitor for internal noise cancellation. 32 AD converter. 34 Division circuit. 35 Direction determination circuit. 36 Speech synthesis circuit. 37 A spherical container for an electronic disk magnet type geomagnetic sensor inside the outer box 1. 38 Red light emitting element. 39 Green light emitting element. 40 Red light receiving element. 41 Green light receiving element. 42 Water in a container. 43 A disc magnet floating on water. 44 Red colored surface of a disk magnet. 45 A colored surface with a little green added to red. 51 Green colored surface. 63 Black side of disk magnet. 64 White spot. 65 Semiconductor laser. 67 Radial lines drawn on a disc magnet.

Claims (1)

[Claims] Claim 1: On one wiring board, a set of magnetic flux convergence cores of the same size and characteristics with sharp tips are in contact with each other, or a single Hall element is attached facing the same direction, and adjacent An applied voltage is applied so that the current direction of each Hall element is alternately reversed, and the Hall output voltage of each element is amplified through an amplifier, and the output voltage of each amplifier is
The external noise cancels each other out, the Hall output voltages are combined so that they are added, and a smoothing capacitor of an appropriate capacity is inserted between the output terminals of the amplifier to attenuate the internal noise. A large number of line patterns with different colors or distances between the lines are applied to the surface of the disk magnet floating in water, and an optical device is installed to detect the relative position of the container and the disk magnet based on the color, distance between the lines, etc. A direction display device consisting of a geomagnetic sensor and a geomagnetic sensor.