A sole metal detector

Abstract

The utility model relates to a kind of shoe sole metal detectors, including the bottom that two containing cavities are spaced apart and arranged side by side in inside, PCB coil board is horizontally arranged in each containing cavity, the bottom surface of each PCB coil board is provided with transmitting coil, the top surface of each PCB coil board is provided with receiving coil assembly, receiving coil assembly includes multiple receiving coils arranged in matrix and constitutes differential pair;Control mainboard electrically connected with transmitting coil and receiving coil is arranged in the bottom, the bottom is provided with sound alarm mechanism and light indicating mechanism electrically connected with control mainboard.The utility model improves the sensitivity of detection, can be suitable for the detection of smaller metal and can display its position.

Description

Technical Field

[0001] This utility model relates to metal detectors for security checks, and more particularly to a metal detector for shoe soles. Background Technology

[0002] A shoe sole metal detector is a security inspection device primarily used to detect prohibited metal items hidden in the soles of shoes. However, existing shoe sole metal detectors have limited detection sensitivity, only able to detect larger metal items hidden in the soles. They cannot detect smaller metal items, such as staples or paperclips, nor can they pinpoint the location of the hidden metal in the sole. Utility Model Content

[0003] To address the shortcomings of existing methods, this utility model provides a metal detector for shoe soles.

[0004] The technical solution adopted by this utility model to solve its technical problem is as follows: a shoe sole metal detector, comprising a base with two accommodating cavities arranged side by side at intervals inside, each accommodating cavity having a PCB coil board horizontally arranged inside, each PCB coil board having a transmitting coil on its bottom surface, and each PCB coil board having a receiving coil assembly on its top surface, the receiving coil assembly comprising multiple receiving coils arranged in a matrix and forming differential pairs; a control main board electrically connected to the transmitting and receiving coils is provided inside the base, and the base is provided with a sound alarm mechanism and a light indicator mechanism electrically connected to the control main board.

[0005] Preferably, a compensation coil is also provided on the PCB coil board.

[0006] Preferably, the compensation coil is a coil disposed inside the receiving coil and coaxial with the receiving coil, the outer diameter of the compensation coil is 1 / 5 to 1 / 3 of the outer diameter of the receiving coil, and the ratio of the number of turns of the compensation coil to the number of turns of the receiving coil is 1:15 to 1:20.

[0007] Preferably, the top surface of the base is provided with indicator marks for indicating the standing position at positions corresponding to the two receiving coil assemblies.

[0008] Preferably, each of the accommodating cavities has an electrically insulating support plate disposed on its inner bottom surface at a position located inside the ring of the transmitting coil and corresponding to the position between two adjacent receiving coils, and the PCB coil board is provided with a clearance through hole for avoiding the support plate.

[0009] Preferably, the base has an inverted T-shaped structure, and the light indicator mechanism is located at the top of the vertical part of the base.

[0010] Preferably, the light indicator mechanism includes an indicator light disposed within the base and a light-transmitting window disposed on the top surface of the base.

[0011] Preferably, the indicator light includes a first indicator light group for indicating the size of the metal and a second indicator light group for indicating the position of the metal; the light-transmitting window corresponding to the first indicator light group is in the shape of an inverted triangle, and the light-transmitting window corresponding to the second indicator light group is composed of multiple windows arranged in a back-to-forward interval.

[0012] Preferably, the control motherboard is also equipped with a communication module.

[0013] Preferably, the base is also equipped with a display screen.

[0014] The beneficial effects of this utility model are as follows: This utility model arranges the receiving coil matrix into differential pairs, dividing the sole into several independent detection areas not only longitudinally but also laterally. This makes it suitable for detecting smaller metals and can accurately detect the location of hidden metals on the sole, which is then indicated by a light indicator mechanism for ease of use. Furthermore, the structure and layout of the coils improve anti-interference capabilities, thereby further enhancing detection sensitivity. Attached Figure Description

[0015] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model;

[0016] Figure 2 This is a schematic diagram of the internal structure of the base in an embodiment of this utility model;

[0017] Figure 3 This is a schematic diagram of the top surface of the PCB coil board according to an embodiment of this utility model;

[0018] Figure 4 This is a schematic diagram of the bottom surface of the PCB coil board according to an embodiment of this utility model;

[0019] Figure 5 This is a schematic diagram of the bottom shell structure of an embodiment of this utility model;

[0020] Figure 6 This is a block diagram illustrating the principle of receiving coil signal processing in an embodiment of this utility model;

[0021] Component names and serial numbers in the diagram: 1-Base, 10-Accommodation cavity, 11-Indicator mark, 12-Support plate, 13-Bottom shell, 14-Top cover, 15-Partition plate, 2-PCB coil board, 20-Transmitting coil, 21-Receiving coil, 22-Compensation coil, 23-Avoidance through hole, 3-Control main board, 30-Communication module, 4-Sound alarm mechanism, 5-Light indicator mechanism, 50-First indicator light group, 51-Second indicator light group, 6-Display screen. Detailed Implementation

[0022] To more clearly illustrate the purpose, technical solution, and advantages of the embodiments of this utility model, the present utility model will be further described below in conjunction with the accompanying drawings and embodiments. A clear and complete description will be provided. Obviously, the described embodiments are some, but not all, embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.

[0023] Examples of embodiments of this utility model Figures 1 to 6As shown, a shoe sole metal detector has a base 1 with two accommodating cavities 10 arranged side-by-side at intervals inside. The base 1 is composed of a non-metallic bottom shell 13 and a top cover 14. The bottom shell 13 is composed of an integrally formed bottom plate and an annular side plate on the top surface of the bottom plate. The bottom shell 13 is divided into a left accommodating cavity and a right accommodating cavity by a partition 15 located in the middle of the bottom shell 13. After the top cover 14 is installed on the bottom shell 13, it closes the accommodating cavity 10. An anti-slip pad can also be provided at the bottom of the base 1. Each accommodating cavity 10 is horizontally arranged. A PCB coil board 2 is provided. If a step or groove is provided on the upper part of the inner sidewall of each accommodating cavity 10, the PCB coil board 2 can be installed on the step or in the groove. Each PCB coil board 2 has a transmitting coil 20 on its bottom surface and a receiving coil assembly on its top surface. The receiving coil assembly includes multiple receiving coils 21 arranged in a matrix and forming differential pairs. The transmitting coils 20 are arranged along the circumference of the PCB coil board 2 at the edge of its bottom surface, and the receiving coils 21... The receiving coils 21 are arranged in a matrix structure with intervals. For example, three rows of receiving coils 21 are arranged at intervals along the front-to-back direction, and two columns are arranged at intervals along the left-to-right direction. In this way, six receiving coils 21 are set on the top surface of the PCB coil board 2, forming six detection areas. The two receiving coils 21 in each row form a differential pair. By analyzing the difference in signal strength of each receiving coil 21, the position of the metal object on the XY plane can be accurately located. The signal strength reflects the size of the metal object. Even small metal objects can be detected, and the location and size of the metal hidden in the sole of the shoe can be determined based on the detection results. A differential pair means that one receiving coil A is wound in a clockwise direction, and the other receiving coil B is wound in a counterclockwise direction. The two receiving coils 21 are connected in series in reverse order, that is, the end point of one receiving coil A is connected to the starting point of another receiving coil B. This forms a differential pair coil layout, which further enhances the signal-to-noise ratio and anti-interference ability, and improves sensitivity.The base 1 houses a control board 3 electrically connected to the transmitting coil 20 and the receiving coil 21. The control board 3 can be located within any one of the accommodating cavities 10, or a third accommodating cavity can be located in front of, behind, or between two accommodating cavities 10. The control board 3 is then installed in this third accommodating cavity, where a rechargeable battery electrically connected to the control board 3 is also installed. Alternatively, an electrical connection interface can be provided on the base 1, through which the control board 3 can be electrically connected to an external power source. The control board 3 includes a transmitting drive unit, a signal processing unit, and a processor. The transmitting drive unit regulates the current driving the transmitting coil, generating a high-frequency alternating current with a specific frequency and controllable amplitude to drive the transmitting coil 20 to generate an alternating magnetic field. The signal processing unit processes the signal detected by the receiving coil 21 and transmits the processed signal to the processor. The processor (MCU) is used to control the operation of the transmission drive unit, process the signals transmitted by the signal processing unit, and output the detection results. The transmission drive unit includes a DC-DC converter, a digital signal generator, and a power drive module. The DC-DC converter is used to change the transmission current of the transmission coil 20. The processor adjusts the output voltage of the DC-DC converter by controlling the duty cycle of the DC-DC converter, thereby indirectly changing the transmission current of the transmission coil 20 and thus changing the detection sensitivity of the detector to meet different usage requirements. The digital signal generator receives the DC voltage output from the DC-DC converter and outputs a corresponding high-frequency signal to the power drive module. The power drive module amplifies the received signal and converts it into a high-frequency AC current to drive the transmission coil 20. The DC-DC converter, digital signal generator, and power drive module are all existing technologies and will not be described in detail here. The signal processing unit processes the signal detected by the receiving coil 21 sequentially through a differential amplifier, a filter, an analog multiplexer, a digital-to-analog converter, and a digital lock-in amplifier.Each differential pair is equipped with a corresponding differential amplifier. The receiving coil 21 senses a change in the magnetic field, generating a small voltage signal. The differential amplifier receives these signals and amplifies the difference between them, thus highlighting the difference between the target metal and pure environmental interference, effectively suppressing these common-mode interferences. A filter is installed after each differential amplifier. The filter receives the signal after preliminary amplification by the differential amplifier, filters out noise and interference, ensuring that only signals related to the frequency of the transmitting magnetic field enter the subsequent processing stage. Bandpass filters are selected for this purpose. An analog multiplexer sends multiple parallel, conditioned analog signals in an orderly and sequential manner. The signal is digitized by an ADC; the analog-to-digital converter (ADC) receives the analog signal and converts it into a digital signal; the digital lock-in amplifier receives the digital signal from the ADC and a digital reference signal of the same frequency and phase from the digital signal generator, performs phase and amplitude detection, extracts the target signal buried in noise, and transmits it to the processor; at the same time, a communication module 30 is also set on the control motherboard 3. The communication module 30 adopts a wired or wireless communication module and connects to the control terminal through the communication module 30 for convenient management; the base 1 is equipped with a sound alarm mechanism 4 and a light indicator mechanism 5 electrically connected to the control motherboard 3. When metal is detected, the sound alarm mechanism 4 will sound an alarm, such as by using a speaker; the light indicator mechanism 5 is used to indicate the operating status and detection results of the detector. The light indicator mechanism 5 uses LED lights to indicate the operating status or detection structure of the detector.

[0024] Further improvements, such as Figure 3 As shown, a compensation coil 22 is also provided on the PCB coil board 2. Each receiving coil 22 has a concentric compensation coil 22. The compensation coil 22 actively cancels the crosstalk generated by the transmitting coil 20 to its corresponding receiving coil 21. That is, the compensation coil 22 is a coil set inside the receiving coil 21 and coaxial with the receiving coil 21. The outer diameter of the compensation coil 22 is 1 / 5 to 1 / 3 of the outer diameter of the receiving coil 21, and the ratio of the number of turns of the compensation coil 22 to the number of turns of the receiving coil 21 is 1:15 to 1:20. The number of turns of the compensation coil 22 is much less than the number of turns of the receiving coil 21, and the amplitude of the interference signal voltage induced by it is also much less than the interference signal voltage induced by the receiving coil 21. Then, by differential amplification, the total output signal of the receiving coil 21, including the target signal and the interference signal, is subtracted by the proportionally amplified output signal of the compensation coil 22, which can effectively cancel most of the direct coupling interference from the transmitting coil 20 and greatly suppress the background noise.

[0025] Further improvements, such as Figure 1As shown, the top surface of the base 1 is provided with indicator marks 11 for indicating the standing position at the positions corresponding to the two receiving coil assemblies. That is, indicator marks 11 are provided on the left and right sides of the top surface of the base 1. The left indicator mark 11 is set to correspond to the position of the receiving coil assembly in the left accommodating cavity, and the right indicator mark 11 is set to correspond to the position of the receiving coil assembly in the right accommodating cavity. If the indicator mark 11 is set to the shape of a shoe sole, the indicator mark 11 can remind you of the correct standing position on the base, and can also better detect.

[0026] Further improvements, such as Figures 2 to 5 As shown, an electrically insulating support plate 12 is provided on the inner bottom surface of each accommodating cavity 10, located within the ring of the transmitting coil 20 and corresponding to the position between two adjacent receiving coils 21. The PCB coil board 2 is provided with a clearance through hole 23 to avoid the support plate 12. That is, the support plate 12 is provided on the inner bottom surface of the bottom shell 13 constituting the base 1. After the PCB coil board 2 is installed inside the bottom shell 13, the support plate 12 is positioned within the space corresponding to the ring of the transmitting coil 20, and its top end protrudes through the clearance through hole 23, abutting against the upper cover 14. On the bottom surface, the upper cover 14 is supported when the detector is used to detect the sole of the shoe. At the same time, the support plate 12 is used to separate the receiving coils 21 to reduce the mutual interference between adjacent receiving coils 21. When there are six receiving coils 21 arranged in three rows and two columns, the support plate 12 is arranged in the front and back direction. Two left arms in the left direction are extended in the front and back direction on the left side wall of the support plate 12, and two right arms in the left and back direction are extended in the right direction on the right side wall of the support plate, thus separating the six receiving coils 21.

[0027] Further improvements, such as Figure 1 As shown, the base has an inverted T-shaped structure, which divides the top surface of the base 1 into two parts, corresponding to the left and right feet, making it convenient to use. The light indicator mechanism 5 is located at the top of the vertical part of the base 1, which makes it convenient to view the detection results and also avoids damage to the base when stepping on it during detection.

[0028] Further improvements, such as Figure 1 and Figure 2As shown, the light indicator mechanism 5 includes an indicator light disposed within the base 1 and a light-transmitting window disposed on the top surface of the base 1, such as the indicator light being positioned between two accommodating cavities 10. The indicator light includes a first indicator light group 50 for indicating the size of the metal and a second indicator light group 51 for indicating the position of the metal. The light-transmitting window corresponding to the first indicator light group 50 is inverted triangular in shape, and the light-transmitting window corresponding to the second indicator light group 51 is composed of multiple windows arranged in a back-to-foreground pattern. Both the first indicator light group 50 and the second indicator light group 51 consist of multiple indicator lights, which are arranged along the front-to-back direction of the base 1. They are respectively connected to the GPIO pins of the processor. The processor uses a mapping table disposed within the processor to control the GPIO port to light up the corresponding LEDs based on the received results. For the left and right feet, one first indicator light group 50 can be shared, or separate first indicator light groups 50 can be set. When sharing one first indicator light group 50, if metal is detected in both the left and right feet, the first indicator light group 50 will light up. 0 indicates only larger metals, and the second indicator light group 51 is set independently. At this time, the first indicator light group 50 uses a single-color LED light, and its corresponding light-transmitting window is an inverted triangular shape. That is, the apex of its light-transmitting window is on the back side of the top surface of the base 1, and the bottom edge of the light-transmitting window is on the front side of the top surface of the base 1. It does not light up when there is no hidden metal on the sole, and lights up when there is hidden metal. The size of the hidden metal is determined by the position of the light-transmitting window from the top to the bottom. The second indicator light group 51 uses LEDs that can emit different colors and displays the detection results through the color change of the LED light. Its corresponding light-transmitting window is set to be circular or waist-shaped. If there is no hidden metal on the sole, all LEDs of the second indicator light group 51 are green. If there is hidden metal on the sole, the second indicator light 51 at the position corresponding to the hidden metal is red.

[0029] Further improvements, such as Figure 1 and Figure 2 As shown, a display screen 6 is also provided on the base 1 to display the detection results of the detector, as well as the charging and discharging status and the amount of power of the battery.

[0030] Although the present invention has been described in detail above with general description and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A metal detector for shoe soles, characterized in that, The device includes a base with two accommodating cavities arranged side-by-side at intervals. Each cavity contains a horizontally arranged PCB coil board. The bottom surface of each PCB coil board has a transmitting coil, and the top surface of each PCB coil board has a receiving coil assembly. The receiving coil assembly includes multiple receiving coils arranged in a matrix and forming differential pairs. The base contains a control main board electrically connected to the transmitting and receiving coils. The base also contains a sound alarm mechanism and a light indicator mechanism electrically connected to the control main board.

2. The metal detector for shoe soles according to claim 1, characterized in that, The PCB coil board is also equipped with a compensation coil.

3. The metal detector for shoe soles according to claim 2, characterized in that, The compensation coil is a coil disposed inside the receiving coil and coaxial with the receiving coil. The outer diameter of the compensation coil is 1 / 5 to 1 / 3 of the outer diameter of the receiving coil, and the ratio of the number of turns of the compensation coil to the number of turns of the receiving coil is 1:15 to 1:

20.

4. The metal detector for shoe soles according to claim 1, characterized in that, The top surface of the base is provided with indicator marks for indicating the standing position at positions corresponding to the two receiving coil assemblies.

5. The metal detector for shoe soles according to claim 1, characterized in that, On the inner bottom surface of each of the accommodating cavities, an electrically insulating support plate is provided at a position located inside the ring of the transmitting coil and corresponding to the position between two adjacent receiving coils. The PCB coil board is provided with a clearance through hole for avoiding the support plate.

6. The metal detector for shoe soles according to claim 1, characterized in that, The base has an inverted T-shaped structure, and the light indicator mechanism is located at the top of the vertical part of the base.

7. The metal detector for shoe soles according to claim 1, characterized in that, The light indicator mechanism includes an indicator light installed inside the base and a light-transmitting window on the top surface of the base corresponding to the position of the indicator light.

8. The metal detector for shoe soles according to claim 7, characterized in that, The indicator lights include a first indicator light group for indicating the size of the metal and a second indicator light group for indicating the position of the metal; the light-transmitting window corresponding to the first indicator light group is in the shape of an inverted triangle, and the light-transmitting window corresponding to the second indicator light group is composed of multiple windows arranged in a back-to-forward interval.

9. The metal detector for shoe soles according to claim 1, characterized in that, The control motherboard is also equipped with a communication module.

10. The metal detector for shoe soles according to claim 1, characterized in that, The base is also equipped with a display screen.

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