A novel weak magnetic field measuring device

Abstract

This application discloses a novel weak magnetic field measuring device to solve the problems of high cost and limited accuracy in existing measurement methods. The novel weak magnetic field measuring device includes: a microcontroller, and a rotating device, a sensor array, and a host computer connected to the microcontroller; wherein the rotating device comprises: a two-dimensional rotating mechanism composed of two servo motors respectively mounted in the horizontal and vertical directions, and a gyroscope fixedly mounted at the end of the two-dimensional rotating mechanism; the sensor array includes a predetermined number of magnetometer sensors distributed on a sensor mounting platform; wherein the sensor mounting platform is fixed to the servo motors; the microcontroller communicates with the sensor array and the rotating device via an I2C interface, and is used to upload the measurement data of the rotating device and the sensor array to the host computer; the host computer is used to receive the uploaded data from the microcontroller to complete the measurement of the weak magnetic field.

Description

Technical Field

[0001] This application relates to the field of magnetic field measurement technology, and in particular to a novel weak magnetic field measuring device. Background Technology

[0002] In modern scientific research and industrial applications, the precise measurement of weak magnetic fields is of paramount importance, particularly in fields such as materials magnetic property analysis, biomedical research, and geological exploration. The need to measure weak magnetic fields typically stems from demands across multiple disciplines, all of which require extremely high precision in magnetic field measurements. In physics, researchers need to accurately measure weak magnetic fields to gain a deeper understanding of the intrinsic properties, structural composition, and time-varying processes of matter. In materials science, measuring weak magnetic fields allows researchers to investigate the internal magnetic distribution and performance characteristics of magnetic materials. In geology, measuring weak magnetic fields helps reveal the characteristics of geological structures, explore underground mineral resources, and assess earthquake risks. In geological exploration activities, high-precision magnetic field measuring instruments such as fluxgate magnetometers are widely used to detect subtle changes in the Earth's magnetic field; this data is crucial for understanding the Earth's internal structure, finding potential mineral resources, and assessing the risks posed by earthquakes.

[0003] Existing methods for measuring magnetic fields include those based on single-point fixed magnetometers (i.e., independent magnetometer sensor modules), which can only measure the magnetic field strength at a single point after the sensor is fixedly installed. Methods based on mechanical scanning magnetometers use a stepper motor to drive a single sensor for one-dimensional linear scanning, making it difficult to obtain three-dimensional magnetic field distribution information. Fixed array methods cannot actively scan for magnetic field measurement, and the high cost, limited sensitivity, and insufficient accuracy of magnetometer sensors impose many limitations on their practical applications. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a novel weak magnetic field measuring device.

[0005] The technical solution adopted in this embodiment of the utility model is as follows: On the one hand, this utility model embodiment provides a novel weak magnetic field measuring device, the device including: a microcontroller, and a rotating device, a sensor array and a host computer connected to the microcontroller; The rotating device comprises: a two-dimensional rotating mechanism consisting of two rudders respectively installed in the horizontal and vertical directions, and a gyroscope fixedly installed at the end of the two-dimensional rotating mechanism; The sensor array includes a predetermined number of magnetometer sensors distributed on a sensor mounting platform; wherein the sensor mounting platform is fixed to the servo motor. The microcontroller communicates with the sensor array and the rotating device via an I2C interface, and is used to upload the measurement data of the rotating device and the sensor array to the host computer. The host computer is used to receive the uploaded data from the microcontroller in order to complete the measurement of the weak magnetic field.

[0006] In one feasible implementation, the two-dimensional rotation mechanism includes: a first servo motor and a second servo motor; The rotation shaft of the first servo motor is fixedly connected to the base of the second servo motor, and the rotation shaft of the second servo motor is fixedly connected to the sensor mounting platform, forming a series rotation structure.

[0007] In one feasible embodiment, the microcontroller is an STM32 microcontroller; the control line PWM0 of the first servo is connected to the PA0 pin of the STM32 microcontroller, and the control line PWM1 of the second servo is connected to the PA1 pin of the STM32 microcontroller.

[0008] In one feasible implementation, the step angle between the first servo and the second servo is 5°.

[0009] In one feasible implementation, the device further includes: an optical encoder located at the shaft connection between the first servo and the second servo, and a laser ranging module located at the edge of the sensor mounting platform; The signal output terminals of the photoelectric encoder and laser ranging module are connected to the ADC interface of the STM32 microcontroller.

[0010] In one feasible implementation, the sensor array includes four HMC5883L magnetometer sensors, which are symmetrically distributed in a cross shape on the sensor mounting platform, and the spacing between each HMC5883L magnetometer sensor is equal.

[0011] In one feasible implementation, the sensor mounting platform is a three-layer composite structure; The three-layer composite structure includes: a base layer, an intermediate layer, and a surface layer; The base layer is an aluminum alloy heat sink plate, which is rigidly connected to the servo motor shaft. The intermediate layer is an electromagnetic shielding layer, covered with a permalloy thin film. The surface layer is an FR4 insulating substrate with cross-shaped sensor mounting positions etched on the surface. The four HMC5883L magnetometer sensors are fixed to the mounting positions with conductive silver paste. The sensor sensitive axis of the HMC5883L magnetometer sensors is arranged at a 45° angle to the axis of the sensor mounting platform.

[0012] In one feasible implementation, the microcontroller is an STM32 microcontroller and the gyroscope is an MPU6050 gyroscope; The SCL pin of the MPU6050 gyroscope is connected to the PF2 pin of the STM32 microcontroller, and the SDA pin is connected to the PF3 pin of the STM32 microcontroller. The SCL pin of each HMC5883L magnetometer sensor is connected to the PA5, PB6, PD11 and PE0 pins of the STM32 microcontroller, respectively, and the SDA pin of each HMC5883L magnetometer sensor is connected to the PA6, PB7, PD12 and PE1 pins of the STM32 microcontroller, respectively.

[0013] In one feasible implementation, the STM32 microcontroller communicates with the host computer via a USB-TTL module, wherein the TX pin of the USB-TTL module is connected to the PA9 pin of the STM32 microcontroller, and the RX pin is connected to the PA10 pin of the STM32 microcontroller.

[0014] In one feasible implementation, the device further includes a power supply for providing a stable voltage to the microcontroller, the rotating device, the sensor array, and the host computer.

[0015] The above-mentioned technical solutions adopted in the embodiments of this utility model can achieve the following beneficial effects: By using two servo motors mounted horizontally and vertically to drive the sensor array to rotate, combined with gyroscope angle feedback, automatic scanning of the magnetic field in three-dimensional space in all directions can be achieved, thus overcoming the limitations of single-point or one-dimensional strategies. Furthermore, this series structure provides the sensor array with two degrees of freedom of rotation, allowing for flexible attitude adjustment, covering any direction in space, eliminating measurement blind spots, and simplifying the mechanical structure by eliminating the need for additional transmission mechanisms, thus improving the device's lightweight design. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A schematic diagram of the architecture of a novel weak magnetic field measuring device provided for an embodiment of this utility model; Figure 2 A schematic diagram of the architecture of a sensor mounting platform provided for an embodiment of this utility model; Figure 3 A schematic diagram of an overall device provided for an embodiment of this utility model; Figure 4 A schematic diagram of a magnetoresistive bridge provided for an embodiment of this utility model; Figure 5 A schematic diagram illustrating the working principle of an HMC5883L magnetometer sensor provided in this specification embodiment; Figure 6 A three-dimensional magnetic field diagram provided for embodiments of this specification; Figure 7 A dot matrix effect diagram provided for an embodiment of this specification; Figure 8 is a schematic diagram of the minimum system and multiplexing function of a microcontroller provided in the embodiments of this specification. Figure 8(a) is the circuit diagram corresponding to the microcontroller, Figure 8(b) is the circuit diagram corresponding to the gyroscope, Figure 8(c) is the circuit diagram corresponding to the magnetometer sensor, Figure 8(d) is the circuit diagram corresponding to the servo motor, and Figure 8(e) is the circuit diagram corresponding to the host computer.

[0017] In the diagram: 1. Microcontroller; 2. Rotating device; 3. Sensor array; 4. Host computer; 5. Servo motor; 6. Two-dimensional rotating mechanism; 7. Gyroscope; 8. Sensor mounting platform; 9. I2C interface; 10. Magnetometer sensor; 61. First servo motor; 62. Second servo motor; 11. Photoelectric encoder; 12. Laser ranging module; 13. ADC interface; 801. Base layer; 802. Middle layer; 803. Surface layer; 14. Cross-shaped sensor mounting position; 15. USB-TTL module; 16. Power supply. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] like Figure 1 The diagram illustrates a novel weak magnetic field measuring device. The device includes a microcontroller 1, a rotating mechanism 2 connected to the microcontroller 1, a sensor array 3, and a host computer 4. The rotating mechanism 2 comprises a two-dimensional rotating mechanism 6 consisting of two servo motors 5 mounted horizontally and vertically, and a gyroscope 7 fixedly mounted at the end of the two-dimensional rotating mechanism 6. The servo motors 5 drive the sensor array 3 to rotate two-dimensionally in a plane, enabling scanning of magnetic fields in different spatial orientations. The gyroscope 7 monitors the attitude of the rotating mechanism in real time, providing spatial coordinate references for the magnetic field data and ensuring the accuracy of the measurement direction. The sensor array 3 includes a predetermined number of sensors distributed in a... Figure 2The magnetometer sensor 10 is mounted on the sensor mounting platform 8 shown; the sensor mounting platform 8 is fixed to the rotating end of the servo motor. The magnetometer sensor 10 can detect weak magnetic field strength and direction changes in space, such as the Earth's magnetic field and the magnetic field generated by electric current. The multi-sensor array 3 layout enables multi-point synchronous acquisition of the magnetic field, improving measurement accuracy and reducing single-point errors through data fusion. The microcontroller 1 communicates with the sensor array 3 and the rotating device 2 via the I2C interface 9, and is used to upload the measurement data from the rotating device 2 and the sensor array 3 to the host computer 4. The host computer 4 receives the uploaded data from the microcontroller 1 to complete the measurement of the weak magnetic field. The host computer 4 can perform data fusion based on existing Kalman filtering and use MATLAB to plot a three-dimensional magnetic field graph. This process can be implemented by those skilled in the art based on existing common processing methods, so it will not be described in detail here.

[0020] Traditional fixed-point magnetic field measurements can only acquire local magnetic field data, failing to cover the magnetic field distribution in three-dimensional space and making them unsuitable for dynamic scenarios. This novel weak magnetic field measurement device utilizes two horizontally and vertically mounted servo motors 5 to drive the sensor array 3 to rotate. Combined with angle feedback from a gyroscope 7, it enables automatic scanning of the magnetic field in all three-dimensional spaces, overcoming the limitations of single-point or one-dimensional strategies. Furthermore, weak magnetic fields are susceptible to environmental noise, resulting in large measurement errors from single-point sensors and difficulty in distinguishing the true signal. This device, however, employs a multi-magneticmeter sensor array layout to achieve synchronous multi-point acquisition, canceling out random noise. Combined with real-time calibration of the rotation attitude by the gyroscope 7, it avoids measurement deviations caused by device shaking, improving the signal-to-noise ratio of weak signals.

[0021] Furthermore, in one feasible embodiment of this application, the two-dimensional rotation mechanism 6 includes a first servo motor 61 and a second servo motor 62; wherein the rotation axis of the first servo motor 61 is fixedly connected to the base of the second servo motor 62, and the rotation axis of the second servo motor 62 is fixedly connected to the sensor mounting platform 8, forming a series rotation structure. It is understood that traditional single-axis rotation mechanisms can only achieve one-dimensional linear scanning. In this application, by setting the first servo motor 61 and the second servo motor 62, coverage of the horizontal and vertical planes is achieved, effectively improving the spatial coverage of magnetic field measurement. That is, the rotation axis of the first servo motor 61 in the horizontal direction is fixedly connected to the base of the second servo motor 62, responsible for driving the entire structure to rotate in the horizontal direction to achieve azimuth adjustment. The rotation axis of the second servo motor 62 in the vertical direction is directly connected to the sensor mounting platform 8, responsible for driving the sensor array 3 to rotate in the vertical direction to achieve pitch angle adjustment. Through this series structure, the sensor array 3 gains two degrees of freedom of rotation, allowing it to flexibly adjust its attitude and cover any direction in space, eliminating measurement blind spots. Furthermore, this structure eliminates the need for additional transmission mechanisms, simplifying the mechanical structure and improving the device's lightweight design. In addition, the servo motor 5 can be driven using only PWM pulse width modulation signals, which can be directly output by the microcontroller without complex drive circuitry. Compared to a solution combining a servo motor and a reducer, this effectively reduces production and maintenance costs.

[0022] Furthermore, in one feasible embodiment of this application, such as Figure 3 The microcontroller 1 shown is an STM32 microcontroller 1. Referring to Figures 8(a) and 8(d), it can be seen that the control line PWM0 of the first servo 61 is connected to the PA0 pin of the STM32 microcontroller 1, and the control line PWM0 of the second servo 62 is connected to the PA1 pin of the STM32 microcontroller 1. In this embodiment, the STM32 microcontroller 1 is connected to the servo 5 through specific pins, forming a control link based on PWM pulse width modulation. That is, the PA0 pin of the STM32 microcontroller 1, connected to the control line of the first servo 61, is responsible for horizontal angle adjustment. The PA1 pin of the STM32 microcontroller 1, connected to the control line of the second servo 62, is responsible for vertical angle adjustment. By using specific pins, the driving of the servo 5 can be achieved simply by those skilled in the art setting and controlling the PWM pulse width modulation signal according to actual needs. The microcontroller 1 can output directly without complex driving circuitry, minimizing resource consumption while improving the stability of magnetic field measurement.

[0023] Furthermore, in a feasible embodiment of this application, the step angle between the first servo motor 61 and the second servo motor 62 is 5°, meaning that each time the angle is adjusted, the servo motor 5 will rotate in 5° increments. For example, during horizontal scanning, the servo motor 5 starts from 0° and rotates sequentially to 5°, 10°, 15°... up to 180°. If the step angle is too small, it will result in too many scanning points, increasing measurement time; if the angle is too large, it may miss key magnetic field change features. A 5° step provides sufficient spatial resolution in most application scenarios, reducing redundancy while ensuring data quality.

[0024] In one feasible embodiment of this application, the device further includes: an optical encoder 11 located at the shaft connection between the first servo motor 61 and the second servo motor 62, and a laser ranging module 12 located at the edge of the sensor mounting platform 8. The signal output terminals of the optical encoder 11 and the laser ranging module 12 are connected to the ADC interface 13 of the STM32 microcontroller 1. By installing the optical encoder 11 at the shaft connection between the first servo motor 61 and the second servo motor 62, the actual rotation angle of the two servo motors 5 is measured in real time. Simultaneously, based on the laser ranging module 12 deployed at the edge of the sensor mounting platform 8, the distance to the target object is measured as the platform rotates, enabling real-time feedback of the actual angle of the servo motors 5. Through the coordinated work of the optical encoder 11 and the laser ranging module 12, not only is the angle control accuracy improved, but also a precise mapping between magnetic field data and real three-dimensional space is achieved. For example... Figure 6 and Figure 7 The image shows a three-dimensional magnetic field graphic and dot matrix effect diagram formed by data points obtained after the operation ends, based on the rotation angle range of each servo from 0 to 180°, with each rotation being 5°. The data is obtained in a spatial rectangular coordinate system with the connection point of the two servos as the origin.

[0025] In one feasible embodiment of this application, the sensor array 3 includes four HMC5883L magnetometer sensors 10. The HMC5883L magnetometer sensors 10 are symmetrically distributed in a cross shape on the sensor mounting platform 8, with equal spacing between each sensor. It should be noted that the HMC5883L magnetometer sensors 10 are high-precision triaxial magnetoresistive sensors, capable of measuring the strength and direction of weak magnetic fields. They are highly sensitive and suitable for geomagnetic measurements, weak magnetic field detection, and other similar scenarios. The four sensors are symmetrically distributed in a cross shape on the sensor mounting platform 8, meaning they are arranged symmetrically in pairs along the horizontal and vertical directions, with equal spacing between each sensor. This solves the problem that a single magnetometer sensor is easily affected by environmental interference, leading to large deviations in measurement data and an inability to accurately reflect the true distribution of the magnetic field. Since interfering magnetic fields are usually uniformly distributed in space, while the target magnetic field exhibits gradient changes, the symmetrical layout allows for the use of magnetic field gradient characteristics to distinguish between environmentally interfering target magnetic fields. Furthermore, the symmetrically distributed sensors facilitate the use of existing algorithms by those skilled in the art to offset the measurement errors of a single sensor. Furthermore, if one sensor fails, the remaining three sensors can still maintain basic measurement functions through layout symmetry, which helps improve the reliability of the device. In addition, as... Figure 4 and Figure 5 As shown, the HMC5883L magnetometer sensor used in this application contains an H-bridge circuit with a set / reset band drive. The ASIC includes large switching FETs that can transmit large, short pulses to the sensor's set / reset band. This set / reset band is largely a resistive load. No external set / reset circuit is needed. The ASIC automatically performs the set / reset operation for each measurement. A measurement is performed after a set pulse is generated, followed by a measurement after a reset pulse is generated. Half of the difference between the two measurements is placed in the data output register of each of the three axes. In this way, the sensor's internal bias and temperature drift differences are canceled out in all measurements.

[0026] Furthermore, in a feasible embodiment of this application, the sensor mounting platform 8 is a three-layer composite structure. Wherein, as... Figure 2 The three-layer composite structure shown includes: a base layer 801, an intermediate layer 802, and a surface layer 803. The base layer 801 is an aluminum alloy heat sink, rigidly connected to the servo motor 5's rotating shaft. The intermediate layer 802 is an electromagnetic shielding layer, covered with a permalloy film. The surface layer 803 is an FR4 insulating substrate with cross-shaped sensor mounting positions 14 etched on its surface. Four HMC5883L magnetometer sensors 10 are fixed to the mounting positions using conductive silver paste. The sensor sensing axes of the HMC5883L magnetometer sensors 10 are arranged at a 45° angle to the axis of the sensor mounting platform 8.

[0027] In this device, an aluminum alloy heat sink serves as the base layer (801) rigidly connected to the servo motor 5's shaft. This provides mechanical support while utilizing the high thermal conductivity of aluminum alloy to conduct heat generated by the sensor to the servo motor 5. Furthermore, due to the low density, high strength, and thermal conductivity of aluminum alloy (approximately 200 W / (m·K), zero-point drift caused by sensor temperature rise is effectively reduced. A high-permeability permalloy electromagnetic shielding layer (802) is used as the intermediate layer. Its high magnetic permeability guides external magnetic fields into its interior, forming a magnetic bypass and reducing the intensity of the magnetic field penetrating to the surface, thus shielding against external electromagnetic interference. An FR4 insulating substrate (803) serves as the surface layer. FR4's low dielectric constant reduces signal crosstalk during magnetic field measurement, provides electrical insulation and a sensor mounting surface, and the etched cross-shaped mounting position (14) ensures sensor layout accuracy. The thermal expansion coefficient of FR4 matches the HMC5883L packaging material, effectively reducing stress deformation caused by temperature changes. Conductive silver paste provides fixation, ensuring reliable electrical connections while offering some elasticity to buffer mechanical vibrations. Furthermore, the 45° cross arrangement allows the sensor array to form multiple detection directions of 0°, 45°, 90°, and 135° in the horizontal plane, which can reduce the difference in response sensitivity to magnetic fields in any direction.

[0028] In one feasible embodiment of this application, the microcontroller 1 is an STM32 microcontroller 1, and the gyroscope 7 is an MPU6050 gyroscope 7. As shown in Figures 8(a) and 8(b), the SCL pin of the MPU6050 gyroscope 7 is connected to the PF2 pin of the STM32 microcontroller 1, and the SDA pin is connected to the PF3 pin of the STM32 microcontroller 1. As shown in Figures 8(a) and 8(c), the SCL pin of the HMC5883L magnetometer sensor 10 is connected to the PA5, PB6, PD11, and PE0 pins of the STM32 microcontroller 1, respectively, and the SDA pin of the HMC5883L magnetometer sensor 10 is connected to the PA6, PB7, PD12, and PE1 pins of the STM32 microcontroller 1, respectively. That is, each HMC5883L magnetometer sensor 10 is connected in parallel with the STM32 microcontroller 1. As can be seen from the above embodiments, the microcontroller 1, based on multi-bus connectivity, can simultaneously access the gyroscope 7 and the magnetometer sensor 10, resulting in a higher data update rate compared to the single-bus polling method. While maintaining system compactness, it significantly improves the communication reliability, signal quality, and real-time performance of the multi-sensor system, providing crucial hardware support for high-precision magnetic field measurement.

[0029] Furthermore, in a feasible embodiment of this application, the STM32 microcontroller 1 communicates with the host computer 4 via a USB-TTL module 15. As shown in Figures 8(a) and 8(e), the TX pin of the USB-TTL module 15 is connected to the PA9 pin of the STM32 microcontroller 1, and the RX pin is connected to the PA10 pin of the STM32 microcontroller 1. The USB-TTL module 15 acts as a level conversion bridge, converting the USB interface signal from the host computer 4 into a TTL level recognizable by the STM32 microcontroller 1. The TX pin of the USB-TTL module 15, connected to the PA9 pin of the STM32 microcontroller 1, is used to transmit instructions from the host computer 4 to the STM32 microcontroller 1. The RX pin of the USB-TTL module 15, connected to the PA10 pin of the STM32 microcontroller 1, is used for the STM32 microcontroller 1 to feed data back to the host computer 4. This level conversion solves the problem of level incompatibility between different devices. Furthermore, the USB-TTL module 15 incorporates built-in filtering and voltage regulation circuits, which reduce interference during signal transmission, ensure data stability during long-distance transmission, and prevent data errors caused by noise. In addition, the USB-TTL module 15 is a mature, standardized device, inexpensive, and requires no custom circuitry, effectively reducing device costs.

[0030] In one feasible embodiment of this application, the device further includes a power supply 16 for providing a stable voltage to the microcontroller 1, the rotating device 2, the sensor array 3, and the host computer 4.

[0031] The various embodiments in this application are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0032] It should be noted that in the description of this disclosure, terms such as "center," "upper," "lower," "top," "bottom," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this disclosure. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] Furthermore, it should be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances. It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0034] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A novel weak magnetic field measuring device, characterized in that, The device includes: a microcontroller, and a rotating device, a sensor array, and a host computer connected to the microcontroller; The rotating device comprises: a two-dimensional rotating mechanism consisting of two rudders respectively installed in the horizontal and vertical directions, and a gyroscope fixedly installed at the end of the two-dimensional rotating mechanism; The sensor array includes a predetermined number of magnetometer sensors distributed on a sensor mounting platform; wherein the sensor mounting platform is fixed to the servo motor. The microcontroller communicates with the sensor array and the rotating device via an I2C interface, and is used to upload the measurement data of the rotating device and the sensor array to the host computer. The host computer is used to receive the uploaded data from the microcontroller in order to complete the measurement of the weak magnetic field.

2. The novel weak magnetic field measuring device according to claim 1, characterized in that, The two-dimensional rotation mechanism includes: a first servo motor and a second servo motor; The rotation shaft of the first servo motor is fixedly connected to the base of the second servo motor, and the rotation shaft of the second servo motor is fixedly connected to the sensor mounting platform, forming a series rotation structure.

3. The novel weak magnetic field measuring device according to claim 2, characterized in that, The microcontroller is an STM32 microcontroller; the control line PWM0 of the first servo is connected to the PA0 pin of the STM32 microcontroller, and the control line PWM1 of the second servo is connected to the PA1 pin of the STM32 microcontroller.

4. A novel weak magnetic field measuring device according to claim 2, characterized in that, The step angle between the first servo and the second servo is 5°.

5. A novel weak magnetic field measuring device according to claim 3, characterized in that, The device further includes: an optical encoder located at the shaft connection between the first servo and the second servo, and a laser ranging module located at the edge of the sensor mounting platform; The signal output terminals of the photoelectric encoder and laser ranging module are connected to the ADC interface of the STM32 microcontroller.

6. A novel weak magnetic field measuring device according to claim 3, characterized in that, The sensor array includes four HMC5883L magnetometer sensors, which are symmetrically distributed in a cross shape on the sensor mounting platform, and the spacing between each HMC5883L magnetometer sensor is equal.

7. A novel weak magnetic field measuring device according to claim 6, characterized in that, The sensor mounting platform is a three-layer composite structure; The three-layer composite structure includes: a base layer, an intermediate layer, and a surface layer; The base layer is an aluminum alloy heat sink plate, which is rigidly connected to the servo motor shaft. The intermediate layer is an electromagnetic shielding layer, covered with a permalloy thin film. The surface layer is an FR4 insulating substrate with cross-shaped sensor mounting positions etched on the surface. The four HMC5883L magnetometer sensors are fixed to the mounting positions with conductive silver paste. The sensor sensitive axis of the HMC5883L magnetometer sensors is arranged at a 45° angle to the axis of the sensor mounting platform.

8. A novel weak magnetic field measuring device according to claim 6, characterized in that, The microcontroller is an STM32 microcontroller, and the gyroscope is an MPU6050 gyroscope; The SCL pin of the MPU6050 gyroscope is connected to the PF2 pin of the STM32 microcontroller, and the SDA pin is connected to the PF3 pin of the STM32 microcontroller. The SCL pin of each HMC5883L magnetometer sensor is connected to the PA5, PB6, PD11 and PE0 pins of the STM32 microcontroller, respectively, and the SDA pin of each HMC5883L magnetometer sensor is connected to the PA6, PB7, PD12 and PE1 pins of the STM32 microcontroller, respectively.

9. A novel weak magnetic field measuring device according to claim 3, characterized in that, The STM32 microcontroller communicates with the host computer via a USB-TTL module, wherein the TX pin of the USB-TTL module is connected to the PA9 pin of the STM32 microcontroller, and the RX pin is connected to the PA10 pin of the STM32 microcontroller.

10. A novel weak magnetic field measuring device according to claim 1, characterized in that, The device also includes a power supply for providing a stable voltage to the microcontroller, rotating device, sensor array, and host computer.

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