Three-axis magnetometer based on TMR sensor

Abstract

The utility model discloses a three-axis magnetometer based on TMR sensors, which belongs to the technical field of magnetic field measurement and is characterized in that the output end of a first TMR sensor is connected with the input end of a first differential operational amplifier circuit; the output end of the first differential operational amplifier circuit is connected with the main control chip through a diode D3; the output end of the second TMR sensor is connected with the input end of the second differential operational amplifier circuit; the output end of the second differential operational amplifier circuit is connected with the main control chip through a diode D4; the output end of the third TMR sensor is connected with the input end of the third differential operational amplifier circuit; the output end of the third differential operational amplifier circuit is connected with the main control chip through a diode D5; the output end of the first differential operational amplifier circuit is connected with the main control chip through a first operational amplifier chip and a diode D1 in sequence; the output end of the second differential operational amplifier circuit is connected with the main control chip through the first operational amplifier chip and the diode D2 in sequence; and the display screen is connected with the main control chip. According to the utility model, a weak constant magnetic field and a weak alternating magnetic field can be measured; according to the utility model, the cost can be reduced, and the measurement accuracy can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of magnetic field measurement technology more particularly relates to a kind of three-axis magnetometer based on TMR sensor. BACKGROUND

[0002] Magnetic field is a basic physical field, it has or attractive or repulsive magnetic force on the magnet put into it, and its basic characteristics is able to exert force on moving charge. Magnetic field has important effect on human and earth ecological system, it is not only related to human health and quality of life, also affects the natural environment and ecological balance of earth. Weak magnetic field signal is important in cosmology, astrophysics. In the field of materials science, polymer structural material is usually generated many microdefects from preparation to application process. These microdefects are easy to evolve and develop, cause material damage, and in this process, the change of weak thermomagnetic field is of great significance to study and hinder material damage. The field of cosmic evolution, astrophysical phenomena, material science etc. have put forward very high requirements to the detection and analysis of weak magnetic field.

[0003] At present, there are many types of magnetometers applied in the field of weak magnetic field measurement, and the principles are different. According to the different principles, it can be roughly divided into resonance magnetometer, all-optical atomic magnetometer, superconducting quantum interference magnetometer, magneto-electric effect magnetometer, etc. The measurement objects of these magnetometers are mostly stable and weak magnetic field. In the field of alternating weak magnetic field, there are high-sensitivity optical fiber magnetic field sensing technology and weak magnetic field detection technology based on fluxgate sensor, but they all have the problems of high cost or low measurement accuracy.

[0004] Therefore, how to provide a three-axis magnetometer that can measure both weak constant magnetic field and weak alternating magnetic field, which can not only reduce cost but also help improve measurement accuracy is a problem that those skilled in the art need to solve. CONTENT OF THE UTILITY MODEL

[0005] Therefore, the purpose of the utility model is to provide a three-axis magnetometer based on TMR sensor.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A three-axis magnetometer based on TMR sensor, comprising a first TMR sensor, a second TMR sensor, a third TMR sensor, a first differential operational amplifier circuit, a second differential operational amplifier circuit, a third differential operational amplifier circuit, a first operational amplifier chip, a master control chip and a display screen.

[0008] The output end of the first TMR sensor is connected with the input end of the first differential operational amplifier circuit; the output end of the first differential operational amplifier circuit is connected with the master control chip through diode D3;

[0009] The output end of the second TMR sensor is connected with the input end of the second differential operational amplifier circuit; the output end of the second differential operational amplifier circuit is connected with the master control chip through diode D4;

[0010] The output end of the third TMR sensor is connected with the input end of the third differential operational amplifier circuit; the output end of the third differential operational amplifier circuit is connected with the master control chip through diode D5;

[0011] The output end of the first differential operational amplifier circuit is connected with the master control chip through the first operational amplifier chip and diode D1 in sequence;

[0012] The output end of the second differential operational amplifier circuit is connected with the master control chip through the first operational amplifier chip and diode D2 in sequence;

[0013] The display screen is connected with the master control chip.

[0014] Preferably, the first differential operational amplifier circuit comprises a first AD620AN chip and a resistor R1; the second differential operational amplifier circuit comprises a second AD620AN chip and a resistor R2; and the third differential operational amplifier circuit comprises a third AD620AN chip and a resistor R3;

[0015] The V- pin of the first TMR sensor is connected with the No. 2 pin of the first AD620AN chip;

[0016] The V+ pin of the first TMR sensor is connected with the No. 3 pin of the first AD620AN chip;

[0017] One end of the resistor R1 is connected with the No. 1 pin of the first AD620AN chip; and the other end is connected with the No. 8 pin of the first AD620AN chip;

[0018] The No. 7 pin of the first AD620AN chip is connected with +5V voltage;

[0019] The No. 4 pin of the first AD620AN chip is connected with -5V voltage;

[0020] The No. 5 pin of the first AD620AN chip is connected with ground;

[0021] The V- pin of the second TMR sensor is connected with the No. 2 pin of the second AD620AN chip;

[0022] The V+ pin of the second TMR sensor is connected with the No. 3 pin of the second AD620AN chip;

[0023] One end of the resistor R2 is connected with the No.1 pin of the second AD620AN chip; the other end is connected with the No.8 pin of the second AD620AN chip;

[0024] The No.7 pin of the second AD620AN chip is connected with +5V voltage;

[0025] The No.4 pin of the second AD620AN chip is connected with -5V voltage;

[0026] The No.5 pin of the second AD620AN chip is connected with ground;

[0027] The V- pin of the third TMR sensor is connected with the No.2 pin of the third AD620AN chip;

[0028] The V+ pin of the third TMR sensor is connected with the No.3 pin of the third AD620AN chip;

[0029] One end of the resistor R3 is connected with the No.1 pin of the third AD620AN chip; the other end is connected with the No.8 pin of the third AD620AN chip;

[0030] The No.7 pin of the third AD620AN chip is connected with +5V voltage;

[0031] The No.4 pin of the third AD620AN chip is connected with -5V voltage;

[0032] The No.5 pin of the third AD620AN chip is connected with ground.

[0033] Preferably, the main control chip is STC8G1K08-20 chip;

[0034] The No.6 pin of the first AD620AN chip is connected with the anode of diode D3; the cathode of the diode D3 is connected with the P1.2 pin of the STC8G1K08-20 chip;

[0035] The No.6 pin of the second AD620AN chip is connected with the anode of diode D4; the cathode of the diode D4 is connected with the P1.1 pin of the STC8G1K08-20 chip;

[0036] The No.6 pin of the third AD620AN chip is connected with the anode of diode D5; the cathode of the diode D5 is connected with the P1.3 pin of the STC8G1K08-20 chip.

[0037] Preferably, the first operational amplifier chip is LM358 chip;

[0038] The No. 6 pin of the first AD620AN chip is connected with the No. 3 pin of the LM358 chip through the resistor R4;

[0039] The No. 6 pin of the second AD620AN chip is connected with the No. 5 pin of the LM358 chip through the resistor R5;

[0040] The No. 8 pin of the LM358 chip is connected with +5V voltage;

[0041] The No. 4 pin of the LM358 chip is connected with -5V voltage;

[0042] The No. 6 pin of the LM358 chip is grounded;

[0043] The No. 2 pin of the LM358 chip is grounded;

[0044] The No. 1 pin of the LM358 chip is connected with the anode of the diode D1; the cathode of the diode D1 is connected with the P3.2 pin of the STC8G1K08-20 chip;

[0045] The No. 7 pin of the LM358 chip is connected with the anode of the diode D2; the cathode of the diode D2 is connected with the P3.3 pin of the STC8G1K08-20 chip.

[0046] Preferably, the display screen is an OLED display screen;

[0047] The P1.4 pin of the STC8G1K08-20 chip is connected with the SDA pin of the OLED display screen;

[0048] The P1.5 pin of the STC8G1K08-20 chip is connected with the SCL pin of the OLED display screen.

[0049] Preferably, the above-mentioned three-axis magnetometer further comprises a three-terminal voltage stabilizing integrated circuit and a three-terminal negative voltage stabilizing integrated circuit;

[0050] The input end IN of the three-terminal voltage stabilizing integrated circuit is connected with 12V voltage, and the output end OUT outputs +5V voltage;

[0051] The input end IN of the three-terminal negative voltage stabilizing integrated circuit is connected with -12V voltage, and the output end OUT outputs -5V voltage.

[0052] Preferably, the above-mentioned three-axis magnetometer further comprises a capacitor C1, a capacitor C2, a polarity capacitor C3, a polarity capacitor C4, a polarity capacitor C5, a capacitor C6, a capacitor C7 and a polarity capacitor C8;

[0053] One end of the capacitor C1 is connected with the input end IN of the three-terminal voltage stabilizing integrated circuit, and the other end is grounded;

[0054] One end of the capacitor C2 is connected with the input end IN of the three-terminal negative voltage stabilization integrated circuit, and the other end is grounded.

[0055] The positive pole of the polar capacitor C3 is connected with the input end IN of the three-terminal voltage stabilization integrated circuit, and the negative pole is grounded.

[0056] The negative pole of the polar capacitor C4 is connected with the input end IN of the three-terminal negative voltage stabilization integrated circuit, and the positive pole is grounded.

[0057] One end of the capacitor C6 is connected with the output end OUT of the three-terminal voltage stabilization integrated circuit, and the other end is grounded.

[0058] One end of the capacitor C7 is connected with the output end OUT of the three-terminal negative voltage stabilization integrated circuit, and the other end is grounded.

[0059] The positive pole of the polar capacitor C5 is connected with the output end OUT of the three-terminal voltage stabilization integrated circuit, and the negative pole is grounded.

[0060] The negative pole of the polar capacitor C8 is connected with the output end OUT of the three-terminal negative voltage stabilization integrated circuit, and the positive pole is grounded.

[0061] Preferably, the first TMR sensor, the second TMR sensor and the third TMR sensor all adopt TMR2013.

[0062] Preferably, the three-terminal voltage stabilization integrated circuit adopts 7805, and the three-terminal negative voltage stabilization integrated circuit adopts 7905.

[0063] Preferably, the diode D1 and the diode D2 all adopt IN4148, and the diode D3, the diode D4 and the diode D5 all adopt 2AP9.

[0064] According to the technical scheme, compared with the prior art, the utility model discloses a kind of design and manufacturing scheme of three-axis magnetometer based on TMR sensor, which can obtain the following beneficial technical effects:

[0065] 1) the utility model can measure weak constant magnetic field and weak alternating magnetic field.

[0066] 2) the utility model can not only reduce cost but also help to improve measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0067] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only a part of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0068] Fig. 1 The three-axis magnetometer circuit connection diagram provided by the present application is provided.

[0069] Fig. 2 The circuit connection diagram of 7805 and 7905 provided by the present application is provided. DETAILED DESCRIPTION

[0070] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0071] As shown in the drawings, Figs. 1-2 The present application discloses a design and manufacturing scheme of a three-axis magnetometer based on a TMR sensor, comprising a first TMR sensor, a second TMR sensor, a third TMR sensor, a first differential operational amplifier circuit, a second differential operational amplifier circuit, a third differential operational amplifier circuit, a first operational amplifier chip, a master control chip and a display screen.

[0072] The output end of the first TMR sensor is connected with the input end of the first differential operational amplifier circuit; the output end of the first differential operational amplifier circuit is connected with the master control chip through a diode D3.

[0073] The output end of the second TMR sensor is connected with the input end of the second differential operational amplifier circuit; the output end of the second differential operational amplifier circuit is connected with the master control chip through a diode D4.

[0074] The output end of the third TMR sensor is connected with the input end of the third differential operational amplifier circuit; the output end of the third differential operational amplifier circuit is connected with the master control chip through a diode D5.

[0075] The output end of the first differential operational amplifier circuit is connected with the master control chip through the first operational amplifier chip and a diode D1 in sequence.

[0076] The output end of the second differential operational amplifier circuit is connected with the master control chip through the first operational amplifier chip and a diode D2 in sequence.

[0077] The display screen is connected with the master control chip.

[0078] It can be understood that the TMR sensor is a tunneling magnetoresistance sensor.

[0079] The first TMR sensor, the second TMR sensor and the third TMR sensor are vertically arranged in pairs, and are respectively used for measuring the magnetic field intensity in the X-axis, Y-axis and Z-axis directions and converting the magnetic field intensity into an electrical signal output;

[0080] The first differential operational amplifier circuit, the second differential operational amplifier circuit and the third differential operational amplifier circuit are respectively used for amplifying the electrical signal output by the first TMR sensor, the second TMR sensor and the third TMR sensor;

[0081] The diode D3, the diode D4 and the diode D5 are respectively used for rectifying the electrical signal output by the first differential operational amplifier circuit, the second differential operational amplifier circuit and the third differential operational amplifier circuit;

[0082] The first operational amplifier chip is used for converting the electrical signal output by the first differential operational amplifier circuit and the second differential operational amplifier circuit into a square wave signal;

[0083] The diode D4 and the diode D5 are respectively used for rectifying the square wave signal output by the first operational amplifier chip.

[0084] In an embodiment, the first differential operational amplifier circuit comprises a first AD620AN chip and a resistor R1; the second differential operational amplifier circuit comprises a second AD620AN chip and a resistor R2; and the third differential operational amplifier circuit comprises a third AD620AN chip and a resistor R3.

[0085] The V- pin of the first TMR sensor is connected with the No. 2 pin of the first AD620AN chip;

[0086] The V+ pin of the first TMR sensor is connected with the No. 3 pin of the first AD620AN chip;

[0087] One end of the resistor R1 is connected with the No. 1 pin of the first AD620AN chip, and the other end is connected with the No. 8 pin of the first AD620AN chip;

[0088] The No. 7 pin of the first AD620AN chip is connected with +5V voltage;

[0089] The No. 4 pin of the first AD620AN chip is connected with -5V voltage;

[0090] The No. 5 pin of the first AD620AN chip is connected with ground.

[0091] The V- pin of the second TMR sensor is connected with the No. 2 pin of the second AD620AN chip;

[0092] The V+ pin of the second TMR sensor is connected with the No. 3 pin of the second AD620AN chip;

[0093] One end of the resistor R2 is connected with the No. 1 pin of the second AD620AN chip; the other end is connected with the No. 8 pin of the second AD620AN chip;

[0094] The No. 7 pin of the second AD620AN chip is connected with +5V voltage;

[0095] The No. 4 pin of the second AD620AN chip is connected with -5V voltage;

[0096] The No. 5 pin of the second AD620AN chip is connected with ground;

[0097] The V- pin of the third TMR sensor is connected with the No. 2 pin of the third AD620AN chip;

[0098] The V+ pin of the third TMR sensor is connected with the No. 3 pin of the third AD620AN chip;

[0099] One end of the resistor R3 is connected with the No. 1 pin of the third AD620AN chip; the other end is connected with the No. 8 pin of the third AD620AN chip;

[0100] The No. 7 pin of the third AD620AN chip is connected with +5V voltage;

[0101] The No. 4 pin of the third AD620AN chip is connected with -5V voltage;

[0102] The No. 5 pin of the third AD620AN chip is connected with ground.

[0103] It can be understood that the resistor R1, the resistor R2 and the resistor R3 are used for adjusting the amplification multiple of the AD620AN chip. Specifically: Wherein, R represents the resistor R1, the resistor R2 or the resistor R3; G represents the amplification multiple.

[0104] In an embodiment, the master control chip is an STC8G1K08-20 chip;

[0105] The No. 6 pin of the first AD620AN chip is connected with the anode of the diode D3; the cathode of the diode D3 is connected with the P1.2 pin of the STC8G1K08-20 chip;

[0106] The No. 6 pin of the second AD620AN chip is connected with the anode of diode D4; the cathode of the diode D4 is connected with the P1.1 pin of the STC8G1K08-20 chip;

[0107] The No. 6 pin of the third AD620AN chip is connected with the anode of diode D5; the cathode of the diode D5 is connected with the P1.3 pin of the STC8G1K08-20 chip.

[0108] In an embodiment, the first operational amplifier chip is an LM358 chip;

[0109] The No. 6 pin of the first AD620AN chip is connected with the No. 3 pin of the LM358 chip through the resistance R4;

[0110] The No. 6 pin of the second AD620AN chip is connected with the No. 5 pin of the LM358 chip through the resistance R5;

[0111] The No. 8 pin of the LM358 chip is connected with +5V voltage;

[0112] The No. 4 pin of the LM358 chip is connected with -5V voltage;

[0113] The No. 6 pin of the LM358 chip is connected with ground;

[0114] The No. 2 pin of the LM358 chip is connected with ground;

[0115] The No. 1 pin of the LM358 chip is connected with the anode of diode D1; the cathode of the diode D1 is connected with the P3.2 pin of the STC8G1K08-20 chip;

[0116] The No. 7 pin of the LM358 chip is connected with the anode of diode D2; the cathode of the diode D2 is connected with the P3.3 pin of the STC8G1K08-20 chip.

[0117] It can be understood that:

[0118] When the measured magnetic field is a constant weak magnetic field (the methods for solving the magnetic field intensity involved below are prior art):

[0119] The STC8G1K08-20 chip converts the electrical signal input by the P1.2 pin into the magnetic field intensity B X X of the X axis; specifically: dividing the input of the P1.2 pin by the amplification of the first AD620AN chip, and then dividing by the sensitivity (unit: V / GS) of the first TMR sensor, the magnetic field intensity B X X of the X axis can be obtained;

[0120] The STC8G1K08-20 chip converts the electrical signal input by the P1.1 pin into the magnetic field intensity B of the Y axis Y ; Specifically, the input of the P1.1 pin is divided by the amplification multiple of the second AD620AN chip, and then divided by the sensitivity (unit: V / GS) of the second TMR sensor, so that the magnetic field intensity B of the Y axis is obtained Y ;

[0121] The STC8G1K08-20 chip converts the electrical signal input by the P1.3 pin into the magnetic field intensity B of the Z axis Z ; Specifically, the input of the P1.3 pin is divided by the amplification multiple of the third AD620AN chip, and then divided by the sensitivity (unit: V / GS) of the third TMR sensor, so that the magnetic field intensity B of the Z axis is obtained Z ;

[0122] The total magnetic field intensity of the constant weak magnetic field is

[0123] 2) When the measured magnetic field is an alternating weak magnetic field (the following methods for solving the magnetic field intensity are prior art):

[0124] The STC8G1K08-20 chip calculates the period T of the alternating weak magnetic field according to the input of the P3.2 pin and the P3.3 pin (the input is a rectified square wave signal); the period of the alternating weak magnetic field can be obtained by detecting the time interval of two rising edges of the rectified square wave signal);

[0125] When the second rising edge is delayed by T / 4 (at this time, it corresponds to the peak-to-peak value of the alternating weak magnetic field), the inputs of the P1.2 pin, the P1.1 pin and the P1.3 pin are collected, and the STC8G1K08-20 chip converts the electrical signals input by the P1.2 pin, the P1.1 pin and the P1.3 pin into the magnetic field intensity B of the X axis X , the magnetic field intensity B of the Y axis Y and the magnetic field intensity B of the Z axis Z (Conversion method is consistent with constant magnetic field);

[0126] The total magnetic field intensity of the alternating weak magnetic field is

[0127] Therefore, the magnetic field intensity of the constant weak magnetic field and the magnetic field intensity of the alternating magnetic field can be measured by the utility model.

[0128] In an embodiment, the display screen is an OLED display screen;

[0129] The P1.4 pin of the STC8G1K08-20 chip is connected with the SDA pin of the OLED display screen;

[0130] The P1.5 pin of the STC8G1K08-20 chip is connected with the SCL pin of the OLED display screen.

[0131] The VCC pin of the OLED display screen is connected with +5V voltage.

[0132] The GND pin of the OLED display screen is grounded.

[0133] The GND pin of the OLED display screen is connected with the VCC pin of the OLED display screen through the filtering capacitor C14.

[0134] It can be understood that the STC8G1K08-20 chip sends the calculated B X , B Y , B Z , B through the P1.4 pin to the SDA pin of the OLED display screen, and the OLED display screen can display the specific values of B X , B Y , B Z .

[0135] The P1.5 pin of the STC8G1K08-20 chip is connected with the SCL pin of the OLED display screen, which is used for synchronizing the clock of the STC8G1K08-20 chip and the OLED display screen.

[0136] In an embodiment, the three-axis magnetometer further comprises a three-terminal voltage stabilizing integrated circuit and a three-terminal negative voltage stabilizing integrated circuit.

[0137] The input end IN of the three-terminal voltage stabilizing integrated circuit is connected with 12V voltage, and the output end OUT outputs +5V voltage.

[0138] The input end IN of the three-terminal negative voltage stabilizing integrated circuit is connected with -12V voltage, and the output end OUT outputs -5V voltage.

[0139] In an embodiment, the three-axis magnetometer further comprises a capacitor C1, a capacitor C2, a polar capacitor C3, a polar capacitor C4, a polar capacitor C5, a capacitor C6, a capacitor C7, and a polar capacitor C8.

[0140] One end of the capacitor C1 is connected with the input end IN of the three-terminal voltage stabilizing integrated circuit, and the other end is grounded.

[0141] One end of the capacitor C2 is connected with the input end IN of the three-terminal negative voltage stabilizing integrated circuit, and the other end is grounded.

[0142] The positive pole of the polar capacitor C3 is connected with the input end IN of the three-terminal voltage stabilizing integrated circuit, and the negative pole is grounded.

[0143] The negative pole of the polar capacitor C4 is connected with the input end IN of the three-terminal negative voltage stabilization integrated circuit, and the positive pole is grounded.

[0144] One end of the capacitor C6 is connected with the output end OUT of the three-terminal voltage stabilization integrated circuit, and the other end is grounded.

[0145] One end of the capacitor C7 is connected with the output end OUT of the three-terminal negative voltage stabilization integrated circuit, and the other end is grounded.

[0146] The positive pole of the polar capacitor C5 is connected with the output end OUT of the three-terminal voltage stabilization integrated circuit, and the negative pole is grounded.

[0147] The negative pole of the polar capacitor C8 is connected with the output end OUT of the three-terminal negative voltage stabilization integrated circuit, and the positive pole is grounded.

[0148] It can be understood that the capacitor C1, the capacitor C2, the polar capacitor C3, the polar capacitor C4, the polar capacitor C5, the capacitor C6, the capacitor C7 and the polar capacitor C8 are used for filtering.

[0149] In an embodiment, the first TMR sensor, the second TMR sensor and the third TMR sensor all adopt TMR2013.

[0150] In an embodiment, the three-terminal voltage stabilization integrated circuit adopts 7805, and the three-terminal negative voltage stabilization integrated circuit adopts 7905.

[0151] In an embodiment, the diode D1 and the diode D2 all adopt IN4148, and the diode D3, the diode D4 and the diode D5 all adopt 2AP9.

[0152] It can be understood that, in the utility model, the diode D1, the diode D2, the diode D3, the diode D4 and the diode D5 are all used for rectification.

[0153] In an embodiment, further comprising a capacitor C9, a capacitor C10, a capacitor C11, a capacitor C12 and a capacitor C13, one end of the capacitor C9 is connected with the No.7 pin of three AD620AN chips respectively, and the other end is grounded.

[0154] The capacitor C10, the capacitor C11, the capacitor C12 and the capacitor C13 are all connected in parallel with the capacitor C9.

[0155] In an embodiment, further comprising a capacitor C15, a capacitor C16, a capacitor C17 and a capacitor C18, one end of the capacitor C15 is connected with the No.4 pin of three AD620AN chips respectively, and the other end is grounded.

[0156] Capacitor C16, capacitor C17, capacitor C18 are connected in parallel with capacitor C15.

[0157] It can be understood that: capacitor C9, capacitor C10, capacitor C11, capacitor C12, capacitor C13, capacitor C15, capacitor C16, capacitor C17, capacitor C18 are used for filtering.

[0158] In an embodiment, further comprising light emitting diode LED1 and light emitting diode LED2;

[0159] The anode of the light emitting diode LED1 is connected to +5V voltage, and the cathode is connected to the P3.5 pin of the STC8G1K08-20 chip through the resistor R6;

[0160] The anode of the light emitting diode LED2 is connected to +5V voltage, and the cathode is connected to the P3.4 pin of the STC8G1K08-20 chip through the resistor R6;

[0161] Wherein, the resistor R6, resistor R7 is a current limiting resistor, to prevent the light emitting diode LED1, light emitting diode LED2 from being destroyed;

[0162] The light emitting diode LED1 and the light emitting diode LED2 are respectively used for detecting whether the STC8G1K08-20 chip is electrified, and whether five diodes (diode D1, diode D2, diode D3, diode D4 and diode D5) have data input into the STC8G1K08-20 chip (this part is prior art).

[0163] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same and similar parts between the embodiments can be referred to each other. For the device disclosed by the embodiment, since it corresponds to the method disclosed by the embodiment, the description is relatively simple, and the related parts can be referred to the method part.

[0164] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A triaxial magnetometer based on a TMR sensor, characterized in that, It includes a first TMR sensor, a second TMR sensor, a third TMR sensor, a first differential operational amplifier circuit, a second differential operational amplifier circuit, a third differential operational amplifier circuit, a first operational amplifier chip, a main control chip, and a display screen; The output terminal of the first TMR sensor is connected to the input terminal of the first differential operational amplifier circuit; the output terminal of the first differential operational amplifier circuit is connected to the main control chip through diode D3. The output terminal of the second TMR sensor is connected to the input terminal of the second differential operational amplifier circuit; the output terminal of the second differential operational amplifier circuit is connected to the main control chip through diode D4. The output terminal of the third TMR sensor is connected to the input terminal of the third differential operational amplifier circuit; the output terminal of the third differential operational amplifier circuit is connected to the main control chip through diode D5. The output of the first differential operational amplifier circuit is connected to the main control chip in sequence through the first operational amplifier chip and diode D1; The output of the second differential operational amplifier circuit is connected to the main control chip in sequence through the first operational amplifier chip and diode D2; The display screen is connected to the main control chip.

2. A triaxial magnetometer based on a TMR sensor according to claim 1, characterized in that, The first differential operational amplifier circuit includes a first AD620AN chip and a resistor R1; the second differential operational amplifier circuit includes a second AD620AN chip and a resistor R2; the third differential operational amplifier circuit includes a third AD620AN chip and a resistor R3. The V-pin of the first TMR sensor is connected to pin 2 of the first AD620AN chip; The V+ pin of the first TMR sensor is connected to pin 3 of the first AD620AN chip. One end of the resistor R1 is connected to pin 1 of the first AD620AN chip; the other end is connected to pin 8 of the first AD620AN chip. Pin 7 of the first AD620AN chip is connected to a +5V voltage; Pin 4 of the first AD620AN chip is connected to a -5V voltage; Pin 5 of the first AD620AN chip is grounded; The V-pin of the second TMR sensor is connected to pin 2 of the second AD620AN chip; The V+ pin of the second TMR sensor is connected to pin 3 of the second AD620AN chip; One end of the resistor R2 is connected to pin 1 of the second AD620AN chip; the other end is connected to pin 8 of the second AD620AN chip. Pin 7 of the second AD620AN chip is connected to a +5V voltage; Pin 4 of the second AD620AN chip is connected to a -5V voltage; Pin 5 of the second AD620AN chip is grounded; The V-pin of the third TMR sensor is connected to pin 2 of the third AD620AN chip; The V+ pin of the third TMR sensor is connected to pin 3 of the third AD620AN chip. One end of the resistor R3 is connected to pin 1 of the third AD620AN chip; the other end is connected to pin 8 of the third AD620AN chip. Pin 7 of the third AD620AN chip is connected to a +5V voltage; Pin 4 of the third AD620AN chip is connected to a -5V voltage; Pin 5 of the third AD620AN chip is grounded.

3. A triaxial magnetometer based on a TMR sensor according to claim 2, characterized in that, The main control chip is an STC8G1K08-20 chip; Pin 6 of the first AD620AN chip is connected to the anode of diode D3; the cathode of diode D3 is connected to pin P1.2 of the STC8G1K08-20 chip. Pin 6 of the second AD620AN chip is connected to the anode of diode D4; the cathode of diode D4 is connected to pin P1.1 of the STC8G1K08-20 chip. Pin 6 of the third AD620AN chip is connected to the anode of diode D5; the cathode of diode D5 is connected to pin P1.3 of the STC8G1K08-20 chip.

4. A triaxial magnetometer based on a TMR sensor according to claim 3, characterized in that, The first operational amplifier chip is an LM358 chip; Pin 6 of the first AD620AN chip is connected to pin 3 of the LM358 chip via resistor R4. Pin 6 of the second AD620AN chip is connected to pin 5 of the LM358 chip via resistor R5. Pin 8 of the LM358 chip is connected to a +5V voltage; Pin 4 of the LM358 chip is connected to a voltage of -5V; Pin 6 of the LM358 chip is grounded; Pin 2 of the LM358 chip is grounded; Pin 1 of the LM358 chip is connected to the anode of diode D1; the cathode of diode D1 is connected to pin P3.2 of the STC8G1K08-20 chip. Pin 7 of the LM358 chip is connected to the anode of diode D2; the cathode of diode D2 is connected to pin P3.3 of the STC8G1K08-20 chip.

5. A triaxial magnetometer based on a TMR sensor according to claim 3, characterized in that, The display screen is an OLED display screen; The P1.4 pin of the STC8G1K08-20 chip is connected to the SDA pin of the OLED display. The P1.5 pin of the STC8G1K08-20 chip is connected to the SCL pin of the OLED display.

6. A triaxial magnetometer based on a TMR sensor according to claim 1, characterized in that, It also includes three-terminal voltage regulator integrated circuits and three-terminal negative voltage regulator integrated circuits; The input terminal IN of the three-terminal voltage regulator integrated circuit is connected to a 12V voltage, and the output terminal OUT outputs a +5V voltage. The input terminal IN of the three-terminal negative voltage regulator integrated circuit is connected to a -12V voltage, and the output terminal OUT outputs a -5V voltage.

7. A triaxial magnetometer based on a TMR sensor according to claim 6, characterized in that, It also includes capacitors C1, C2, C3, C4, C5, C6, C7, and C8. One end of the capacitor C1 is connected to the input terminal IN of the three-terminal voltage regulator integrated circuit, and the other end is grounded; One end of the capacitor C2 is connected to the input terminal IN of the three-terminal negative voltage regulator integrated circuit, and the other end is grounded; The positive terminal of the polarized capacitor C3 is connected to the input terminal IN of the three-terminal voltage regulator integrated circuit, and the negative terminal is grounded. The negative terminal of the polarized capacitor C4 is connected to the input terminal IN of the three-terminal negative voltage regulator integrated circuit, and the positive terminal is grounded. One end of the capacitor C6 is connected to the output terminal OUT of the three-terminal voltage regulator integrated circuit, and the other end is grounded; One end of the capacitor C7 is connected to the output terminal OUT of the three-terminal negative voltage regulator integrated circuit, and the other end is grounded; The positive terminal of the polarized capacitor C5 is connected to the output terminal OUT of the three-terminal voltage regulator integrated circuit, and the negative terminal is grounded. The negative terminal of the polarized capacitor C8 is connected to the output terminal OUT of the three-terminal negative voltage regulator integrated circuit, and the positive terminal is grounded.

8. A triaxial magnetometer based on a TMR sensor according to claim 1, characterized in that, The first TMR sensor, the second TMR sensor, and the third TMR sensor all use TMR2013.

9. A triaxial magnetometer based on a TMR sensor according to claim 6, characterized in that, The three-terminal voltage regulator integrated circuit uses 7805; the three-terminal negative voltage regulator integrated circuit uses 7905.

10. A triaxial magnetometer based on a TMR sensor according to claim 7, characterized in that, Diodes D1 and D2 are both IN4148; diodes D3, D4 and D5 are all 2AP9.

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