Capacitive soil moisture detection device and system

Abstract

The present invention discloses a soil moisture detection device and system. A shell is provided, and a circuit board and a main control chip are provided inside the shell. One end of a substrate is plugged into the shell. At least two pole pieces are provided inside the substrate. The two pole pieces are provided face to face with a gap. The pole pieces are covered by the substrate material to form a capacitor structure. The capacitor structure can have a larger capacitance and can sensitively generate corresponding capacitance changes according to changes in soil humidity, thereby improving measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the field of soil moisture detection, and in particular to a capacitive soil moisture detection device and system. Background Art

[0002] Common soil moisture meters include resistive, capacitive and ionic types. The capacitive soil moisture meter detects soil moisture by detecting changes in the soil humidity, which causes changes in the capacitance of the capacitor in the substrate. The capacitance change is converted into a corresponding electrical signal.

[0003] The common structure of the substrate of the existing capacitive soil moisture meter is that a U-shaped electrode and a U-shaped electrode are arranged inside the substrate, and the U-shaped electrode surrounds the outside of the I-shaped electrode, forming a capacitor between the two, and the change in soil humidity causes the capacitance between the two to change. For example, a capacitive soil moisture sensor with patent publication number CN207516300U includes a thin sheet-shaped shell, a power conversion module, a moisture measurement circuit, a capacitance probe and a data interface, the lower end of the shell is a V-shaped tip, the data interface is located at the upper part of the shell, the capacitance probe is located in the middle of the shell, the capacitance probe is connected to the moisture measurement circuit, and the power conversion module is connected to the moisture measurement circuit and the data interface. Compared with the resistive soil moisture meter, this new type has the advantages of not easy to corrode and stable and reliable performance, but because the capacitance structure limits the size of the capacitance, which in turn affects its detection accuracy of soil moisture, it may not be able to detect a small change in soil moisture. Summary of the invention

[0004] Therefore, it is necessary to provide a capacitive soil moisture detection device and system to solve the problem that the capacitance structure of the existing soil moisture meter limits the size of the capacitance, thereby affecting its detection accuracy of soil moisture and may not be able to detect smaller soil moisture changes.

[0005] To achieve the above-mentioned purpose, the present invention provides a capacitive soil moisture detection device, comprising a substrate, a shell, a circuit board and a main control chip, wherein the main control chip is arranged on the circuit board, a moisture measuring circuit is provided on the circuit board and is arranged in the shell, the connecting end of the substrate is plugged into the shell, at least two pole pieces are provided inside the substrate, the pole pieces are face to face and arranged at intervals, and each of the pole pieces is covered by the substrate material; one of the pole piece lead pins is connected to the main control chip, and the other adjacent pole piece is provided with a ground terminal.

[0006] Furthermore, the substrate is a PCB board.

[0007] Furthermore, the substrate includes a front plate, a middle plate and a rear plate.

[0008] Furthermore, the substrate is provided with a series of via holes, and the via holes are arranged along the panel edge of the substrate; or the outer surface of the substrate is covered with a reinforcement layer.

[0009] Furthermore, the humidity measuring circuit also includes a first resistor, a pin of the electrode is respectively connected to the detection pin of the main control chip and one end of the first resistor, and the other end of the first resistor is connected to the signal output pin of the main control chip.

[0010] Furthermore, the humidity measuring circuit also includes:

[0011] A first capacitor, wherein the pin of the electrode piece is connected to the detection pin of the main control chip and one end of the first resistor through the first capacitor;

[0012] or a second capacitor, wherein two ends of the second capacitor are respectively connected to the pin of the electrode piece and the ground terminal of another electrode piece;

[0013] Or a second resistor, one end of the second resistor is connected to one end of the first resistor, and the other end of the second resistor is connected to another signal output pin of the main control chip.

[0014] Furthermore, the humidity measuring circuit also includes a frequency square wave chip and a third resistor, the first capacitor pin of the frequency square wave chip is connected to one of the pole pieces, the other adjacent pole piece is connected to one end of the third resistor, and the other end of the third resistor is connected to the second capacitor pin of the frequency square wave chip; the frequency output pin of the frequency square wave chip is connected to the frequency receiving pin of the main control chip.

[0015] Furthermore, the humidity measuring circuit also includes a selection chip, a first adjustment capacitor group and a second adjustment capacitor group, the access pin of the selection chip is connected to the first capacitor pin of the frequency square wave chip; one end of the first adjustment capacitor group is connected to the first output pin of the selection chip and one of the pole pieces, and the other end of the first adjustment capacitor group is connected to the second capacitor pin of the frequency square wave chip and another adjacent pole piece; one end of the second adjustment capacitor group is connected to the first output pin of the selection chip and one of the pole pieces, and the other end of the second adjustment capacitor group is connected to the second capacitor pin of the frequency square wave chip and another adjacent pole piece.

[0016] Furthermore, the frequency square wave chip includes a plurality of different frequency division pins, and the detection pin of the main control chip is connected to one of the frequency division pins.

[0017] The present invention also provides a detection system, comprising any one of the soil moisture detection devices described above.

[0018] Different from the prior art, the above technical solution is to set a shell, and set a circuit board and a main control chip inside the shell, plug one end of the substrate into the shell, set at least two pole pieces inside the substrate, the two pole pieces are set face to face and a gap is set, and the pole pieces are covered by the substrate material to form a capacitor structure. The capacitor structure can have a larger capacitance and can sensitively generate corresponding capacitance changes according to changes in soil moisture, thereby improving measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an exploded structural diagram of the substrate;

[0020] Figure 2 is a stereoscopic diagram of the detection device;

[0021] Figure 3 It is a partial structural diagram of the humidity measuring circuit described in the specific implementation method;

[0022] Figure 4 This is a pin structure diagram of the main control chip described in the specific implementation method;

[0023] Figure 5 The circuit structure diagram of the humidity measuring circuit described in the specific implementation mode is provided with a frequency square wave chip;

[0024] Figure 6 The humidity measuring circuit described in the specific implementation manner is provided with a circuit structure diagram of a frequency square wave chip and a selection chip.

[0025] Description of reference numerals:

[0026] 10. Substrate; 20. Housing; 30. Pole piece. DETAILED DESCRIPTION

[0027] In order to explain the technical content, structural features, achieved objectives and effects of the technical solution in detail, the following is a detailed description in conjunction with specific embodiments and accompanying drawings.

[0028] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0029] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0030] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0031] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0032] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0033] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0034] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0035] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms such as "install", "connect", "connect", "fix", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For technicians in the technical field to which the present application belongs, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0036] See also Figures 1 to 6The present invention provides a capacitive soil moisture detection device, including a substrate 10, a housing 20, a circuit board and a main control chip. Preferably, the substrate 10 is a PCB board, which has high reliability and stability, and is equipped with mature processing technology and process system, which is convenient for processing and production, and has low cost. The main control chip is arranged on the circuit board, and the circuit board is provided with a moisture measurement circuit and is arranged in the housing 20. The circuit board is also provided with a corresponding button 201 circuit, a low point moisture measurement circuit, an LED circuit, a binding function circuit, an EEPROM circuit, a power supply circuit and a storage circuit to realize corresponding functions. The specific circuit structure can refer to the prior art. The connecting end of the substrate 10 is plugged into the housing 20, and the other end away from the connecting end of the substrate 10 can be set to a V-shaped sharp angle or a U-shaped arc, which is convenient for inserting into the soil. At least two pole pieces 30 are arranged inside the substrate 10. Generally speaking, two pole pieces 30 can form a capacitor structure. In particular, three pole pieces 30 or more can be arranged to form a capacitor structure. The pole piece 30 is preferably copper foil, which is an excellent conductive material with excellent conductivity. After being processed by the rolling process, it has high strength and toughness and can withstand certain stress and load. The pole pieces 30 are face to face and spaced apart. Each pole piece 30 is coated with the substrate 10 material, that is, the two pole pieces 30 are separated by the substrate 10 material, thereby forming a capacitor structure. Specifically, the substrate 10 includes a front plate, an intermediate plate and a rear plate. The two pole pieces 30 are respectively arranged on the two sides of the intermediate plate. The front plate and the rear plate are respectively covered on the two sides of the intermediate plate. The area of ​​the front plate and the rear plate is not less than the area of ​​the pole piece 30. For the convenience of production, the shape of the front plate and the rear plate is the same. One of the pole pieces 30 leads out a pin connected to the main control chip, and the other adjacent pole piece 30 is provided with a ground terminal. The working process of this embodiment is: turn on the power of the device, calibrate the device, insert the substrate 10 into the soil, adjust the capacitance between the two pole pieces 30 to a certain value through the main control chip, and detect the capacitance in real time. When the soil moisture changes, the charge carried in the soil changes accordingly, thereby affecting the capacitance of the capacitor structure formed by the combination of the pole pieces 30 in the substrate 10, causing its capacitance to change. The main control chip receives the electrical signal generated by the change in capacitance between the pole pieces 30, and converts and calculates it to obtain the corresponding humidity data, thereby realizing humidity detection. It should be noted that this embodiment can set a physical switch button, and can also set a wireless module to perform switch control and data reception and recording through a remote terminal.

[0037] The present invention sets a shell 20, sets a circuit board and a main control chip inside the shell 20, plugs one end of the substrate 10 into the shell 20, sets at least two pole pieces 30 inside the substrate 10, and the two pole pieces 30 are set face to face with a gap, and the pole pieces 30 are coated by the material of the substrate 10, so as to form a capacitor structure. The capacitor structure can have a larger capacitance and can sensitively generate corresponding capacitance changes according to the changes in soil humidity, thereby improving the measurement accuracy and facilitating more precise control of the humidity of the environmental soil.

[0038] Since the substrate 10 needs to be inserted into the soil for a long time, and the substrate 10 is mounted with a multi-layer structure, it may be intruded by water vapor or cracked due to thermal expansion and contraction. In order to make the substrate 10 more stable and the layers tightly fitted, in some embodiments, the substrate 10 is provided with a series of vias, and the vias are arranged along the panel edge of the substrate 10. The via process is a conventional PCB circuit board processing process, which is relatively mature and has a low processing cost, and can well improve the stability of the interlayer bonding of the substrate 10. In other embodiments, the outer surface of the substrate 10 is coated with a reinforcement layer, which can be a protective film, such as a polytetrafluoroethylene film or a polyimide film, which can achieve waterproof, dustproof and corrosion-resistant effects; or a protective agent, such as epoxy resin, polyurethane, etc., is coated on the outer surface of the substrate 10 by spraying or dipping to achieve comprehensive protection.

[0039] In certain embodiments, see Figure 3-4 The humidity measuring circuit also includes a first resistor ( Figure 3 , R1), one of the pins of the pole piece 30 is respectively connected to the detection pin of the main control chip ( Figure 4 , U1-PA5), one end of the first resistor is connected, and the other end of the first resistor is connected to the signal output pin ( Figure 4 , U1-PA2). The signal output pin of the main control chip sends a square wave signal of a certain frequency through the first resistor to the electrode 30 to charge the capacitor. When the capacitance of the capacitor is affected by soil moisture, the main control chip detects the voltage change through the detection pin and obtains the corresponding humidity data by calculating the voltage change. Further, the humidity measurement circuit also includes a first capacitor ( Figure 3 , C1), the pin of the electrode 30 is connected to the detection pin of the main control chip and one end of the first resistor through the first capacitor, that is, the first capacitor is connected in series, and the total capacitance can be adjusted by the first capacitor to achieve the effect of adjusting the current size to avoid excessive instantaneous current and damage to electronic components. Further, the humidity measurement circuit also includes a second capacitor ( Figure 3, C2), the two ends of the second capacitor are respectively connected to the pin of the electrode 30 and the ground terminal of the other electrode 30, that is, the second capacitor is connected in parallel, and its function is the same as that of the first capacitor, which will not be described here. Further, the humidity measurement circuit also includes a second resistor ( Figure 3 , R2), one end of the second resistor is connected to one end of the first resistor, and the other end of the second resistor is connected to another signal output pin of the main control chip. The current value is adjusted by the second resistor so that the circuit runs stably.

[0040] In some embodiments, the humidity measuring circuit further comprises a frequency square wave chip ( Figure 5 , U3) and the third resistor ( Figure 5 , R3), the frequency square wave chip's first capacitor pin ( Figure 5 , U3-COUT) is connected to one of the pole pieces 30, another adjacent pole piece 30 is connected to one end of the third resistor, and the other end of the third resistor is connected to the second capacitor pin ( Figure 5 , U3-ROUT) connection; the frequency square wave chip frequency output pin ( Figure 5 , U3-RH) and the frequency receiving pin of the main control chip ( Figure 5 , U1-PA0) connection. In this embodiment, the frequency square wave chip receives the change of the capacitance between the pole pieces 30 and sends the corresponding frequency square wave signal to the main control chip. After receiving the frequency signal, the main control chip calculates and obtains the corresponding humidity data. Further, the humidity measurement circuit also includes a selection chip ( Figure 6 , U5), the first regulating capacitor group ( Figure 6 , C13, C14) and the second regulating capacitor group ( Figure 6 , C15, C16), the first regulating capacitor group and the second regulating capacitor group are both composed of multiple capacitors connected in parallel, and the access pin of the selection chip ( Figure 6 , U5-B) with the first capacitor pin of the frequency square wave chip ( Figure 6 , U3-COUT), one end of the first regulating capacitor group is connected to the first output pin ( Figure 6 , U5-A1), one of the pole pieces 30 is connected, the other end of the first regulating capacitor group is connected to the second capacitor pin ( Figure 6 , U3-ROUT), and another adjacent electrode 30, one end of the second regulating capacitor group is connected to the first output pin ( Figure 6 , U5-A2), one of the pole pieces 30 is connected, the other end of the second regulating capacitor group is connected to the second capacitor pin ( Figure 6, U3-ROUT), and the other adjacent pole piece 30. The capacitance of the first regulating capacitor group and the capacitance of the second regulating capacitor group can be set to different capacitances according to different actual usage scenarios. The specific capacitance value should be determined according to the measured soil moisture value and range. Different connection circuits can be switched through the selection chip to change the capacitance, achieve fast switching, be compatible with multiple different usage scenarios, and improve practicality. Furthermore, the frequency square wave chip includes multiple different frequency division pins ( Figure 6 , Q4-Q14), the detection pin of the main control chip is connected to one of the frequency division pins. Specifically, the multiple frequency division pins of the frequency square wave chip can correspond to different frequency divisions, and different frequency divisions can be used to transmit square wave signals of different frequencies by switching the frequency divisions, and the main control chip receives square wave signals of different frequencies to achieve more accurate humidity detection.

[0041] The present invention also provides a soil detection system, which is an upper integrated system, including a data acquisition module, a display module, an information transmission module and an information storage module. The soil moisture detection devices described in the above embodiments can be set in the soil at different positions to collect humidity data and transmit it back to the system for calculation and integration. In addition, the system can add corresponding sensors according to detection requirements, such as soil conductivity, groundwater level, groundwater quality, air humidity, air temperature, light intensity and other parameters.

[0042] It should be noted that, although the above embodiments have been described in this article, the patent protection scope of the present invention is not limited thereby. Therefore, based on the innovative concept of the present invention, changes and modifications made to the embodiments described herein, or equivalent structures or equivalent process changes made using the contents of the present invention specification and drawings, directly or indirectly applying the above technical solutions to other related technical fields, are all included in the patent protection scope of the present invention.

Claims

1. A capacitive soil moisture detection device, comprising a substrate, a housing, a circuit board and a main control chip, wherein the main control chip is arranged on the circuit board, a moisture detection circuit is arranged on the circuit board and is arranged in the housing, and a connecting end of the substrate is plugged into the housing, characterized in that: At least two pole pieces are arranged inside the substrate, the pole pieces are face to face and spaced apart, and each pole piece is covered by the substrate material; a lead pin of one pole piece is connected to the main control chip, and another adjacent pole piece is provided with a ground terminal; The humidity measuring circuit further comprises a frequency square wave chip and a third resistor, wherein a first capacitor pin of the frequency square wave chip is connected to one of the pole pieces, another pole piece is connected to one end of the third resistor, and the other end of the third resistor is connected to a second capacitor pin of the frequency square wave chip; a frequency output pin of the frequency square wave chip is connected to a frequency receiving pin of the main control chip; The humidity measuring circuit also includes a selection chip, a first adjustment capacitor group and a second adjustment capacitor group, and the access pin of the selection chip is connected to the first capacitor pin of the frequency square wave chip; One end of the first regulating capacitor group is connected to the first output pin of the selection chip and one of the pole pieces, and the other end of the first regulating capacitor group is connected to the second capacitor pin of the frequency square wave chip and another of the pole pieces; One end of the second regulating capacitor group is connected to the first output pin of the selection chip and one of the pole pieces, and the other end of the second regulating capacitor group is connected to the second capacitor pin of the frequency square wave chip and another of the pole pieces; The main control chip detects voltage changes through the detection pin, and obtains corresponding humidity data by calculating the voltage changes; The capacitance of the first regulating capacitor group and the capacitance of the second regulating capacitor group are set to different capacitances according to different actual usage scenarios. The specific capacitance value is determined according to the measured soil moisture value and range. By switching different connection circuits through the selection chip, the capacitance is changed, and fast switching is achieved, which is compatible with multiple different usage scenarios; The humidity measuring circuit further includes a first resistor, a pin of the electrode piece is respectively connected to a detection pin of the main control chip and one end of the first resistor, and the other end of the first resistor is connected to a signal output pin of the main control chip; The humidity measuring circuit also includes: A first capacitor, wherein the pin of the electrode piece is connected to the detection pin of the main control chip and one end of the first resistor through the first capacitor; A second resistor, one end of the second resistor is connected to one end of the first resistor, and the other end of the second resistor is connected to another signal output pin of the main control chip.

2. A capacitive soil moisture detection device according to claim 1, characterized in that: The substrate is a PCB board.

3. A capacitive soil moisture detection device according to claim 2, characterized in that: The substrate includes a front plate, a middle plate and a rear plate.

4. A capacitive soil moisture detection device according to claim 1, characterized in that: The substrate is provided with a series of via holes, and the via holes are arranged along the panel edge of the substrate.

5. A capacitive soil moisture detection device according to claim 1, characterized in that: The outer surface of the substrate is covered with a reinforcement layer.

6. A capacitive soil moisture detection device according to claim 1, characterized in that: The frequency square wave chip includes a plurality of different frequency division pins, and the detection pin of the main control chip is connected to one of the frequency division pins.

7. A detection system, characterized in that: A capacitive soil moisture detection device comprising any one of claims 1-6.

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