Clothing humidity detection device and detection method

Abstract

The invention relates to the field of intelligent sensing, and particularly provides a clothes humidity detection device and method. The device comprises a PCB, a first electrode plate, a second electrode plate and a third electrode plate are arranged on the PCB, and planar capacitors are formed between the first electrode plate and the second electrode plate and between the first electrode plate and the third electrode plate. The method comprises the following steps: S1, signal excitation; s2, receiving a signal; s3, amplifying the signal; s4, carrying out signal differential processing; s5, humidity information is output; the method is realized by using the device. The three electrode plates are arranged on the PCB to form two planar capacitors, the electric field distribution is wide, the surface and internal humidity change can be sensed, and the clothes drying degree can be accurately reflected. By means of differential amplification processing of detection signals of the second electrode plate and the third electrode plate, initial capacitance and noise interference are eliminated, and high-accuracy humidity detection is achieved under the complex humidity distribution condition.

Description

Technical Field

[0001] The present application relates to the field of intelligent sensing, and more specifically, to a clothing humidity detection device and method. Background Art

[0002] Accurate detection of clothing humidity is crucial for clothing dryers and washing machines. Wrong humidity judgment will lead to the premature end or extension of the drying process, affecting the drying effect of the clothes. Therefore, accurate humidity detection can help washing machines and dryers accurately reflect the actual humidity of the clothes.

[0003] At present, many washing machines and dryers use resistance sensors to detect the humidity of clothes. The resistance sensor measures the resistance value by directly contacting the surface of the clothes, and then infers the humidity based on the resistance value. Humidity and resistance show a certain relationship. When the humidity of the clothes is high, its resistance value is low, and vice versa. According to this principle, the resistance sensor judges the humidity by sensing the resistance value on the surface of the clothes, and further infers the degree of dryness and wetness. However, this method has significant limitations, because the resistance sensor can only reflect the humidity state on the surface of the clothes, but cannot accurately measure the humidity inside the clothes. In practice, the surface of the clothes has been dried, but there is still high humidity inside. At this time, the resistance sensor cannot detect the internal humidity, resulting in misjudgment, terminating the drying process in advance, resulting in the inside of the clothes not being completely dry, and the drying cannot be completed effectively. Especially in the scene of down jackets, cotton-padded clothes, heavy clothes and mixed clothes, the situation of dry surface and wet inside is more common. In addition, when the amount of clothes is small, the contact between the clothes and the sensor electrodes is poor, resulting in a significant decrease in the accuracy of humidity measurement, a significant increase in the frequency of misjudgment, and ultimately affecting the user experience.

[0004] Therefore, the resistance sensor cannot accurately reflect the actual dryness and wetness of the clothes, especially it cannot detect the humidity inside the clothes, and cannot meet the needs of modern intelligent drying equipment for precise humidity detection. Summary of the invention

[0005] The object of the present invention is to provide a clothing humidity detection device and a detection method to solve the problem of inaccurate clothing humidity detection in the prior art in view of the above-mentioned deficiencies in the prior art.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: The present application provides a clothing humidity detection device, which includes a PCB board, on which a first electrode sheet, a second electrode sheet, and a third electrode sheet are arranged. The first electrode sheet, the second electrode sheet, and the third electrode sheet are close to the upper surface of the PCB board, and a planar capacitor is formed between the first electrode sheet and the second electrode sheet, and between the first electrode sheet and the third electrode sheet.

[0007] By arranging the first electrode sheet, the second electrode sheet and the third electrode sheet on the PCB board and placing them close to the upper surface of the PCB board, two planar capacitor structures are formed, which can effectively improve the accuracy of humidity detection. Unlike traditional parallel plate capacitors, the electric field of the planar capacitor is distributed above the plane where the electrode sheet is located, and the electric field range is wider, which can cover the space within a certain range from the electrode sheet. This electric field distribution characteristic enables the planar capacitor to sense the changes in humidity on the surface and inside of the clothing, thereby reflecting the influence of humidity changes on the dielectric constant. Since humidity changes directly lead to changes in capacitance values, the planar capacitor structure can more sensitively capture signals of humidity changes. The two planar capacitors formed by the first electrode sheet and the second electrode sheet and the third electrode sheet can sense humidity changes at different positions when working, further improving the sensitivity and comprehensiveness of humidity measurement. Therefore, through this planar capacitor design, the device can more accurately detect humidity changes in clothing and achieve more reliable humidity measurement.

[0008] Furthermore, the distance between the first electrode sheet and the second electrode sheet is greater than the distance between the second electrode sheet and the third electrode sheet.

[0009] The distance between the first electrode sheet and the second electrode sheet is greater than the distance between the second electrode sheet and the third electrode sheet. This design improves the accuracy of humidity detection in the following two aspects. First, the distance between the electrodes formed by the first electrode sheet and the second electrode sheet is small, and the electric field distribution formed is mainly concentrated near the surface of the PCB board, which can more sensitively detect the humidity changes of clothes near the PCB board area. The compact electric field distribution enables the device to accurately sense the humidity changes on the surface of the clothes, especially when the amount of clothes is small or the distance between the clothes and the detection device is close, effectively avoiding the misjudgment of the surface humidity. Then, the distance between the electrodes formed by the first electrode sheet and the third electrode sheet is large, which makes the electric field range it generates wider and can cover the space area farther from the PCB board. For thicker clothes or when the internal humidity is high and the surface is dry, the wide-area electric field distribution can deeply sense the humidity changes inside the clothes, avoiding the detection error caused by the difference between the surface humidity and the internal humidity. Therefore, this difference design between the distances between the electrode sheets enables the device to take into account the detection of surface and deep humidity, improving the comprehensiveness and accuracy of the measurement.

[0010] In addition, the distance difference between the electrode sheets further improves the detection accuracy through the sensitivity of the capacitance value to humidity changes. The size of the capacitor is not only related to the humidity change, but also closely related to the distance between the two electrode sheets. When the distance difference between the first plane capacitor and the second plane capacitor is set, the basic capacitance values ​​of the two plane capacitors will vary due to different distances, and this difference may mask the effect of humidity changes on the capacitance value. If the distance between the second electrode sheet and the third electrode sheet is small, the difference in basic capacitance values ​​will be significantly reduced, making the effect of the dielectric constant change caused by humidity on the capacitance value more significant. The capacitance change more intuitively reflects the change in humidity, reduces the interference caused by the different distances between the electrode sheets, and thus improves the accuracy of the humidity detection results.

[0011] Furthermore, the distance between the first electrode sheet and the second electrode sheet is 20-80mm, and the distance between the second electrode sheet and the third electrode sheet is 5-30mm. The range of 20-80mm is selected to balance the detection depth and sensitivity. Too large a distance will result in an insignificant capacitance change, while too small a distance will not cover a deep enough area. The range of 20-80mm is an optimized value that takes both into account; the range of 5-30mm avoids the capacitance value being too large and difficult to detect changes when the spacing is too small, and also prevents the sensitivity to surface humidity changes from decreasing when the spacing is too large.

[0012] Furthermore, the first electrode sheet, the second electrode sheet, and the third electrode sheet are in the shape of a rectangle. The design of the rectangular electrode sheet can form an electric field region with a more uniform and larger extension range in the electric field distribution. The rectangular geometric structure allows the electric field to extend uniformly along the width and length of the electrode sheet, and the electric field coverage is wider and more uniform, which is conducive to detecting humidity changes in different parts of clothing. The rectangular electrode sheet has less edge effect and is not prone to excessive boundary electric field interference, which further improves the clarity of the humidity change signal and avoids unnecessary noise interference during the measurement process. In addition, the rectangular electrode sheet is easy to prepare on the PCB board through a standardized process. The rectangular design has lower complexity and higher precision in the preparation process such as photolithography and etching, and can ensure the consistency of the electrode sheet size and the clarity of the boundary, so that the electric field distribution and capacitance value have higher stability and repeatability, and this stability is directly related to the accuracy and reliability of humidity measurement.

[0013] Furthermore, an insulating layer is provided on the upper surface of the PCB board, and a copper clad layer is provided on the lower surface of the PCB board. The insulating layer on the upper surface of the PCB board is used to protect the circuit, isolate short circuits and enhance the stability of measurement; the copper clad layer on the lower surface is used to shield interference, enhance mechanical strength and heat dissipation performance. When in use, the copper clad layer is grounded, providing a low-impedance loop to ensure that the signal transmission process is not affected by potential fluctuations, reduce signal attenuation and distortion, and enhance the accurate transmission of humidity change signals; it can effectively reduce electromagnetic interference, reduce noise, and improve anti-static ability.

[0014] Furthermore, the device also includes a driving module, a measurement and control module, and a differential amplifier arranged on the PCB board, the driving module is connected to the first electrode sheet, the second electrode sheet and the third electrode sheet are connected to the two input ends of the differential amplifier, the output end of the differential amplifier is connected to the measurement and control module, and the other end of the measurement and control module is connected to the driving module.

[0015] In this way, on the one hand, the driving module is connected to the first electrode sheet to generate and apply an excitation signal, so that the first electrode sheet responds to the change in clothing humidity as an excitation electrode; the second electrode sheet and the third electrode sheet respectively receive the capacitance change signal caused by the clothing humidity, and transmit the signal to the two input ends of the differential amplifier. The differential amplifier differentially amplifies the signals from the second electrode sheet and the third electrode sheet, which can effectively eliminate the interference of the initial capacitance and background noise on the signal. The initial capacitance is determined by the basic structure and environmental conditions of the system, and its fixed value may mask the slight capacitance change caused by humidity change. The differential amplifier can eliminate the interference of the initial capacitance and environmental noise on the measurement result by comparing the difference between the two input signals, thereby ensuring that the output signal only reflects the capacitance change caused by humidity change. On the other hand, differential amplification can amplify the slight capacitance difference caused by clothing humidity change, making the influence of humidity change on signal output more obvious, and improving the accuracy of humidity measurement. The output signal of the differential amplifier is transmitted to the measurement and control module, which further processes and calculates the differentially amplified signal to obtain the humidity data of the clothing, and adjusts the timing and amplitude of the excitation signal through feedback control driving module to ensure that the system can dynamically adapt to the measurement requirements of humidity change. This closed-loop design enables the humidity detection device to adjust and optimize the measurement process in real time, thereby further improving the accuracy and stability of humidity detection.

[0016] Furthermore, the differential amplifier includes a first amplifier, a second amplifier, and a third amplifier. The input end of the first amplifier is connected to the third electrode sheet, the input end of the second amplifier is connected to the second electrode sheet, the output ends of the first amplifier and the second amplifier are connected to the two input ends of the third amplifier, and the output end of the third amplifier is connected to the measurement and control module.

[0017] The multi-stage amplifier structure can effectively enhance the signal processing capability while reducing interference and errors, ensuring that the weak capacitance signal caused by humidity changes is accurately measured and transmitted. The first amplifier and the second amplifier receive signals from the third electrode sheet and the second electrode sheet respectively, and preliminarily amplify the capacitance change signal caused by humidity changes, raising the weak signal to a range that is easy to process, thereby improving the signal resolution capability. The amplified signal is transmitted to the third amplifier for differential amplification. The differential amplifier eliminates common-mode components such as initial capacitance, background noise, and environmental interference, and only amplifies the signal difference caused by humidity changes, thereby significantly improving the signal-to-noise ratio and enhancing the accuracy of humidity measurement.

[0018] Furthermore, the measurement and control module is an MCU; its main functions are to generate excitation signals, collect and process humidity signals and control system operation.

[0019] The present application also proposes a method for detecting clothing humidity, which comprises the following steps: S1, signal excitation: generating an excitation signal with a specific timing and pulse width through the measurement and control module, the excitation signal is amplified by the driving module, and the driving module applies the excitation signal to the first electrode sheet; S2, signal reception: the second electrode sheet and the third electrode sheet receive a detection signal generated by a capacitance change, and the capacitance change is related to the humidity of the clothes; S3, signal amplification: the second amplifier amplifies the detection signal of the second electrode sheet, and the first amplifier amplifies the detection signal of the third electrode sheet; S4, signal differential processing: the third amplifier performs differential amplification on the signals from the first amplifier and the second amplifier; S5. Output humidity information: The output signal of the differential amplifier is transmitted to the measurement and control module, and the measurement and control module calculates the humidity value of the clothes according to the received signal change; The method is implemented using the above-mentioned device.

[0020] Furthermore, the excitation signal in S1 is an AC signal, and the frequency of the signal is 1kHz-100kHz.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) A first electrode sheet, a second electrode sheet, and a third electrode sheet are arranged on the PCB board to form two planar capacitor structures. The electric field of the planar capacitor is distributed above the electrode sheets and has a wide range. It can sense the humidity changes on the surface and inside of the clothing, reflect the influence of humidity on the dielectric constant, and then capture the capacitance change signal caused by humidity. It can accurately reflect the drying degree of the clothing, and the humidity detection accuracy is relatively high.

[0022] (2) The detection signals detected by the second electrode sheet and the third electrode sheet are differentially amplified, which can accurately capture the humidity changes of the clothes under complex humidity distribution conditions, avoid the misjudgment problem caused by initial capacitance, environmental noise and small signal loss in traditional detection methods, and achieve high-accuracy detection of humidity.

[0023] (3) The distance between the first electrode sheet and the second electrode sheet is small, and the electric field formed is concentrated near the surface of the PCB board, which can accurately detect the surface humidity of the clothes. It is suitable for the situation where the amount of clothes is small or close to the detection device; the distance between the first electrode sheet and the third electrode sheet is large, and the electric field distribution is wider, which can cover the internal area of ​​the clothes, detect thicker clothes or high internal humidity, and avoid misjudgment. The distance difference design reduces the influence of the basic capacitance value and makes the influence of humidity changes on the capacitance value more significant, which enhances the sensitivity and accuracy of humidity measurement and realizes more comprehensive humidity detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a clothing humidity detection device provided by the present invention; Figure 2 A schematic diagram of another clothing humidity detection device provided by the present invention; Figure 3 A schematic cross-sectional view of a clothing humidity detection device provided by the present invention; Figure 4 A schematic diagram of the clothing humidity detection device and circuit connection relationship provided by the present invention; Figure 5 This is a physical picture of the clothing humidity detection device provided by the present invention.

[0025] Icon: 1-PCB board; 2-first electrode sheet; 3-second electrode sheet; 4-third electrode sheet; 5-insulating layer; 6-copper cladding layer. DETAILED DESCRIPTION

[0026] In order to make the implementation process of the present invention clearer, it will be described in detail below with reference to the accompanying drawings.

[0027] The present invention provides a clothing humidity detection device, such as Figure 1As shown, the device includes a PCB board 1, a first electrode sheet 2, a second electrode sheet 3, and a third electrode sheet 4. The material of the electrode sheet is metal, which can be copper. The first electrode sheet 2, the second electrode sheet 3, and the third electrode sheet 4 are arranged on the PCB board 1. The first electrode sheet 2, the second electrode sheet 3, and the third electrode sheet 4 are close to the upper surface of the PCB board 1. The upper surface of the PCB board 1 is a humidity detection area. The first electrode sheet 2 is a driving electrode, and the second electrode sheet 3 and the third electrode sheet 4 are detection electrodes; a first plane capacitor is formed between the first electrode sheet 2 and the second electrode sheet 3, and a second plane capacitor is formed between the first electrode sheet 2 and the third electrode sheet 4. Humidity will change the dielectric environment between the electrodes, thereby changing the capacitance between the electrodes. The change in the capacitance between the electrodes can detect the change in humidity. Compared with the parallel plate capacitor, the electric field of the plane capacitor is distributed above the plane where the electrode sheet is located, and can reach a space far away from the electrode sheet, that is, the humidity change inside the clothes will affect the capacitance value of the first plane capacitor and the second plane capacitor, so that the degree of dryness and wetness inside the clothes can be detected, so that the humidity detection result is closer to the actual humidity, and the humidity detection result of the clothes is more accurate.

[0028] Furthermore, the distance between the first electrode sheet 2 and the second electrode sheet 3 is greater than the distance between the second electrode sheet 3 and the third electrode sheet 4; the distance between the first electrode sheet 2 and the second electrode sheet 3 is 20-80mm, and the distance between the second electrode sheet 3 and the third electrode sheet 4 is 5-30mm. The two electrode sheets of the first planar capacitor are close to each other, and the electric field generated is close to the surface of the PCB board 1. The two electrode sheets of the second planar capacitor are far away from each other, and the electric field generated is far away from the surface of the PCB board 1. In this way, on the one hand, compared with the second electrode sheet 3, the electric field generated by the second planar capacitor formed by the third electrode sheet 4 far away from the first electrode sheet 2 is more widely distributed in space, and can be distributed in an area farther from the PCB board 1, which enables the humidity of clothes in farther areas to be detected, avoiding the problem of inaccurate humidity detection caused by thick clothes or uneven drying. On the other hand, the distance between the second electrode sheet 3 and the third electrode sheet 4 is small, and the capacitance value between the electrode sheets is related to the distance between the two electrode sheets, that is, the difference between the first plane capacitance and the second plane capacitance is not only related to the humidity of the clothes but also to the difference in distance. Setting a smaller spacing is beneficial to reducing the difference in capacitance value caused by the difference in distance, so that changes in humidity have a greater impact on changes in capacitance, thereby improving the accuracy of humidity detection.

[0029] Furthermore, the first electrode sheet 2, the second electrode sheet 3, and the third electrode sheet 4 are rectangular in shape; the sizes of the first electrode sheet 2, the second electrode sheet 3, and the third electrode sheet 4 can be the same or different. The same size has the advantage of easy preparation; when the sizes are different, preferably, the length is the same, that is, the length in the direction perpendicular to the long side of the PCB board 1 is the same, and the width is different, that is, the length along the long side of the PCB board 1 is different. The rectangular electrode can change the area by changing the width, and the length remains unchanged. Other shapes are not convenient for preparing electrodes with the same length and different areas. When the length is the same, the electric field lines will evenly expand from the surface of one electrode and converge to another electrode, avoiding excessive concentration or uneven expansion of the electric field, making the distribution of the electric field uniform, thereby avoiding the influence of changes in the electric field strength on the dielectric constant, and ultimately avoiding its influence on the capacitance, thereby improving the accuracy of humidity detection. Specifically, the length of the electrode is 1-5cm, which is specifically related to the size of the PCB board 1. The width of the second electrode sheet 3 and the third electrode sheet 4 is smaller than their length, and the length of the first electrode sheet 2 is 1.2-1.5 times the length of the second electrode sheet 3 or the third electrode sheet 4. If the length is too large, the electric field will be excessively localized at the edge of the electrode, and the edge effect will be strong, which is not conducive to the uniform distribution of the electric field. That is, the area of ​​the second electrode sheet 3 and the third electrode sheet 4 is equal, and the area of ​​the first electrode sheet 2 is larger than the area of ​​the second electrode sheet 3. The larger driving electrode can generate a stronger electric field, ensuring that the excitation signal can cover a wider area, improving the stability and uniformity of the electric field, so that the capacitance change is easier to detect; the detection electrode with a smaller area can reduce the parasitic capacitance effect between the driving electrode and the driving electrode, which is more conducive to sensing the dielectric constant change caused by humidity changes, and reducing the interference of other factors in the environment.

[0030] More preferably, if Figure 2As shown, the shape of the first electrode sheet 2 is circular, and the shape of the second electrode sheet 3 and the third electrode sheet 4 is a part of a circular ring. The radius of curvature of the corresponding circular ring of the second electrode sheet 3 and the third electrode sheet 4 is equal to the radius of curvature of the circular shape of the first electrode sheet 2. The line connecting the center of the circle of the first electrode sheet 2, the geometric center of the second electrode sheet 3, and the geometric center of the third electrode sheet 4 is parallel to the direction of the long side of the PCB board 1. The electric field emitted by the circular electrode is evenly distributed at all angles in space, avoiding the electric field concentration or unevenness caused by the rectangular electrode. The uniform electric field distribution can effectively cover the surrounding space, ensuring that the capacitance change signal caused by humidity changes is evenly sensed, especially for complex clothing or environments with uneven humidity, it can provide more stable and accurate signals. For the detection electrode, taking the second electrode sheet 3 as an example, along different positions of the arc, each point on the second electrode sheet 3 is the same distance from the first electrode sheet 2, which makes the electric field induction evenly distributed on the second electrode sheet 3, thereby effectively avoiding the signal error caused by the asymmetric shape of the electrode sheet. It ensures that the sensing ability of humidity changes at different positions on the second electrode sheet 3 is consistent and is not affected by distance changes, minimizing the measurement error caused by uneven electric field distribution. The effect of humidity changes on capacitance values ​​is more significant because the uniformity of the electric field increases, making the effect of humidity changes on capacitance changes more direct and obvious. In contrast, the electric field strength and distribution of the rectangular electrode sheet at different positions will be different, which may cause inconsistency in capacitance measurement, thereby affecting the accuracy of humidity detection. The lengths of the second electrode sheet 3 and the third electrode sheet 4 along the arc direction can be the same or different; preferably, the length of the third electrode sheet 4 is greater than the length of the second electrode sheet 3, and the larger area can sense the electric field in a larger range, compensate for the signal attenuation caused by the long distance, and keep the sensing ability consistent with the second electrode sheet 3. In this way, the detection signals on the second electrode sheet 3 and the third electrode sheet 4 are less affected by factors such as distance, reduce interference from factors other than humidity signals, and ensure that the change in dielectric constant caused by humidity becomes the main factor in capacitance change, thereby improving the accuracy of humidity detection.

[0031] Furthermore, if Figure 3As shown, an insulating layer 5 is provided on the upper surface of the PCB board 1, and a copper-clad layer 6 is provided on the lower surface of the PCB board 1. The material of the insulating layer 5 can be glass fiber reinforced epoxy resin, polytetrafluoroethylene, polyimide, polyamide, etc., with a thickness of 50-200μm. The thickness of the copper-clad layer 6 is 35μm, 70μm, or 105μm. The distance between the first electrode sheet 2, the second electrode sheet 3, and the third electrode sheet 4 and the surface of the PCB board 1 is 50-500μm, and the distance between the first electrode sheet 2, the second electrode sheet 3, and the third electrode sheet 4 and the surface of the PCB board 1 can be the same or different. Preferably, the distance between the first electrode sheet 2 and the surface of the PCB board 1 is greater than the distance between the second electrode sheet 3 and the third electrode sheet 4 and the surface of the PCB board 1, and the distance between the first electrode sheet 2 and the surface of the PCB board 1 is 450-500μm. The distance between the first electrode sheet 2 and the PCB board 1 is slightly larger, which increases the divergence of the electric field, reduces the concentration of the electric field, and makes the electric field strength cover the humidity detection area more evenly; it also reduces the parasitic capacitance effect between the electrodes, making the influence of humidity changes on capacitance more prominent, avoiding the error caused by the local effect of the strong electric field in the measurement, and improving the signal and stability. The detection electrode is closer to the surface of the PCB board 1, effectively sensing the change of the surface dielectric constant, ensuring that the detection electrode can fully sense the humidity change without being affected by the distortion of the electric field strength.

[0032] Furthermore, if Figure 4 As shown, the device also includes a driving module, a measurement and control module, and a differential amplifier arranged on a PCB board 1. The measurement and control module is an MCU. The driving module is connected to the first electrode sheet 2. The second electrode sheet 3 and the third electrode sheet 4 are connected to two input ends of the differential amplifier (differential amplifier circuit in the figure). The output end of the differential amplifier is connected to the measurement and control module, and the other end of the measurement and control module is connected to the driving module. The actual picture is as shown in FIG. Figure 5 The detection signals received by the second electrode sheet 3 and the third electrode sheet 4 are differentially amplified, and the influence of the initial capacitance is effectively eliminated through the differential circuit form, and the capacitance change caused by the medium change is amplified, thereby greatly improving the accuracy of humidity detection.

[0033] Furthermore, the differential amplifier includes a first amplifier A1, a second amplifier A2, and a third amplifier A3. The input end of the first amplifier A1 is connected to the third electrode sheet 4, the input end of the second amplifier A2 is connected to the second electrode sheet 3, the output ends of the first amplifier A1 and the second amplifier A2 are connected to two input ends of the third amplifier A3, and the output end of the third amplifier A3 is connected to the measurement and control module.

[0034] The present application also proposes a method for detecting clothing humidity, which is implemented using the above device, and the specific steps are as follows: S1, signal excitation; The measurement and control module generates an excitation signal with a specific timing and pulse width. The signal is an AC signal with a frequency range of 1kHz-100kHz. The signal is amplified by the driving module and applied to the first electrode sheet 2. The AC signal is used to excite the capacitive field, causing the capacitance between the first plane capacitor and the second plane capacitor to change when the humidity of the clothing changes. The expression of the AC excitation signal is: Among them, V e (t) is the voltage of the excitation signal, V0 is the signal amplitude, f is the signal frequency, and t is time.

[0035] S2, signal reception; The second electrode sheet 3 and the third electrode sheet 4 are used as detection electrodes to receive the capacitance signal caused by humidity changes. Humidity changes will change the dielectric constant ε of the clothing, thereby affecting the capacitance value between the electrodes. The expression of the capacitance value is: Where A is the effective area of ​​the electrode sheet, d is the distance between the electrode sheets, and ε is the dielectric constant affected by the change in clothing humidity. The signals detected by the second electrode sheet 3 and the third electrode sheet 4 are: Wherein, C2 is the capacitance value of a first planar capacitor formed by the first electrode sheet 2 and the second electrode sheet 3 , and C3 is the capacitance value of a second planar capacitor formed by the first electrode sheet 2 and the third electrode sheet 4 .

[0036] S3, signal amplification; The signals received by the second electrode sheet 3 and the third electrode sheet 4 are preliminarily amplified by the second amplifier A2 and the first amplifier A1 respectively. The amplified signals are: Wherein, G1 and G2 are gain coefficients of the first amplifier A1 and the second amplifier A2.

[0037] S4, signal differential processing; The amplified signal is transmitted to the two input terminals of the third amplifier A3 for differential amplification. The function of the differential amplifier is to eliminate the influence of common-mode signals such as initial capacitance and environmental noise, and only amplify the signal difference caused by humidity changes. The output signal is: After entering the amplified signal expression, we can get: Where G3 is the gain factor of the third amplifier A3, the output of the differential amplifier is only related to the capacitance changes C2 and C3 caused by humidity.

[0038] S5. Output humidity information.

[0039] The output signal of the differential amplifier is transmitted to the measurement and control module, which samples and processes the amplitude, frequency and phase changes of the signal to calculate the capacitance change caused by humidity. : According to the relationship between capacitance change and humidity, the humidity value H is calculated through a calibration model (such as a linear or nonlinear function): in, It is a calibration function of humidity and capacitance change.

[0040] The MCU eventually outputs the calculated humidity value to the system to control the operating status of the drying equipment and realize real-time humidity monitoring and control.

[0041] The device and method of the present application are also applicable to the detection of carpet humidity. By placing the electrode of the device close to the carpet surface and utilizing the sensitive response of the capacitor to the change of dielectric constant caused by humidity, the humidity on the carpet surface and inside can be accurately detected. The method is also applicable to carpet humidity monitoring in homes, commercial places or industrial environments, providing real-time data support for carpet cleaning, maintenance and drying processes.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A clothing humidity detection device, comprising a PCB board, characterized in that: The PCB board is provided with a first electrode sheet, a second electrode sheet, and a third electrode sheet. The first electrode sheet, the second electrode sheet, and the third electrode sheet are close to the upper surface of the PCB board, and a planar capacitor is formed between the first electrode sheet and the second electrode sheet, and between the first electrode sheet and the third electrode sheet.

2. The clothing humidity detection device according to claim 1, characterized in that: The distance between the first electrode sheet and the second electrode sheet is greater than the distance between the second electrode sheet and the third electrode sheet.

3. The clothing humidity detection device according to claim 2, characterized in that: The distance between the first electrode sheet and the second electrode sheet is 20-80 mm, and the distance between the second electrode sheet and the third electrode sheet is 5-30 mm.

4. The clothing humidity detection device according to claim 3, characterized in that: The first electrode sheet, the second electrode sheet and the third electrode sheet are in a rectangular shape.

5. The clothing humidity detection device according to claim 4, characterized in that: An insulating layer is disposed on the upper surface of the PCB board, and a copper cladding layer is disposed on the lower surface of the PCB board.

6. The clothing humidity detection device according to claim 5, characterized in that: The device also includes a driving module, a measurement and control module, and a differential amplifier arranged on the PCB board, the driving module is connected to the first electrode sheet, the second electrode sheet and the third electrode sheet are connected to two input ends of the differential amplifier, the output end of the differential amplifier is connected to the measurement and control module, and the other end of the measurement and control module is connected to the driving module.

7. The clothing humidity detection device according to claim 6, characterized in that: The differential amplifier includes a first amplifier, a second amplifier, and a third amplifier. The input end of the first amplifier is connected to the third electrode sheet, the input end of the second amplifier is connected to the second electrode sheet, the output ends of the first amplifier and the second amplifier are connected to the two input ends of the third amplifier, and the output end of the third amplifier is connected to the measurement and control module.

8. The clothing humidity detection device according to claim 7, characterized in that: The measurement and control module is MCU.

9. A method for detecting clothing humidity, characterized in that: The method comprises the following steps: S1, signal excitation: generating an excitation signal with a specific timing and pulse width through the measurement and control module, the excitation signal is amplified by the driving module, and the driving module applies the excitation signal to the first electrode sheet; S2, signal reception: the second electrode sheet and the third electrode sheet receive a detection signal generated by a capacitance change, and the capacitance change is related to the humidity of the clothes; S3, signal amplification: the second amplifier amplifies the detection signal of the second electrode sheet, and the first amplifier amplifies the detection signal of the third electrode sheet; S4, signal differential processing: the third amplifier performs differential amplification on the signals from the first amplifier and the second amplifier; S5, output humidity information: the output signal of the differential amplifier is transmitted to the measurement and control module, and the measurement and control module calculates the humidity value of the clothes according to the change of the received signal; The method is implemented using the device described in any one of claims 1-8.

10. The method for detecting clothing humidity according to claim 9, characterized in that: The excitation signal in S1 is an AC signal, and the frequency of the signal is 1kHz-100kHz.

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