Device for detecting soil humidity

Abstract

The utility model provides a device for detecting soil humidity. The device comprises a water bin, a soil bin, a sampling circuit, a water bin probe and a soil bin soil probe. Wherein the bottom of the water bin is provided with a first inward-convex groove, the bottom of the soil bin is provided with a second inward-convex groove, and the water bin probe is located in the first inward-convex groove. And the soil bin soil probe is connected with the second end of the water bin probe to form a new cylindrical electrode of the single-electrode capacitor, the upper half part of the new cylindrical electrode is in close contact with the soil, and the lower part of the new cylindrical electrode is arranged in the center of the water bin. The first end of the water sump probe is connected with the sampling circuit, and the sampling circuit collects the capacitance value of the single-electrode capacitor and judges the soil humidity according to the capacitance value, so that detection of the soil humidity is completed. The first inward-protruding groove and the second inward-protruding groove are arranged, the water bin probe is not in direct contact with water, the soil bin soil probe is also not in direct contact with soil, the soil bin soil probe is not in direct contact with the soil, and it is guaranteed that the single-electrode probe is not polluted and rusted by the soil.

Description

Technical Field

[0001] This utility model relates to the field of soil moisture detection, and more specifically, to a device for detecting soil moisture. Background Technology

[0002] Currently, in existing technologies, it is often inconvenient to measure the moisture content of small, localized soil areas, and the sensors used to measure soil moisture are usually in direct contact with the soil, making the probes susceptible to soil contamination and corrosion. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0004] Therefore, the first aspect of this utility model proposes a device for detecting soil moisture.

[0005] In view of the above, the first aspect of this utility model provides a device for detecting soil moisture, comprising: a water tank, wherein a first cavity is provided inside the water tank, a first convex groove is provided at the bottom of the water tank, and a first through hole is provided at the top of the first convex groove; a soil tank, wherein the soil tank is partially located inside the first cavity, and a second convex groove is provided at the bottom of the soil tank; a sampling circuit, wherein the sampling circuit is connected to the bottom of the water tank and is located outside the water tank; a water tank probe, wherein the first end of the water tank probe is connected to the sampling circuit and is located in the first convex groove; and a soil tank probe, wherein the soil tank probe is connected to the soil tank and is located in the second convex groove, and the second end of the water tank probe passes through the first through hole and is connected to the soil tank probe; wherein the sampling circuit, the water tank probe, and the soil tank probe cooperate to measure soil moisture.

[0006] In addition, the device for detecting soil moisture in the above-mentioned technical solution provided by this utility model may also have the following additional technical features:

[0007] In some technical solutions of this utility model, optionally, the second end of the water tank probe is a spring-loaded contact pin, and the soil tank probe is a rivet type.

[0008] In some technical solutions of this utility model, optionally, the shielding layer structure is located at the first inner convex groove and is placed on the outside of the water tank probe.

[0009] In some technical solutions of this utility model, optionally, the sampling board structure and the sampling circuit are connected to the water tank through the sampling board structure. The sampling board structure is provided with a crescent-shaped groove, and the shielding layer structure is connected to the sampling board structure and is located at the crescent-shaped groove.

[0010] In some technical solutions of this utility model, optionally, a support foot is provided at the bottom of the soil chamber; a water inlet is provided at the bottom of the soil chamber; and absorbent cotton is provided, with the absorbent cotton part located inside the water inlet, the first end of the absorbent cotton located inside the soil chamber, and the other end of the absorbent cotton located inside the water chamber.

[0011] Optionally, in some technical solutions of this utility model, the sampling circuit includes: a first operational amplifier, the positive input terminal of which is electrically connected to the controller; a first resistor, the first end of which is connected to the negative input terminal of the first operational amplifier, and the second end of which is electrically connected to the output terminal of the first operational amplifier; a first capacitor, the first end of which is electrically connected to the output terminal of the first operational amplifier, and the second end of which is electrically connected to the first end of the water tank probe; an inductor, the first end of which is electrically connected to the second end of the first capacitor, and the second end of which is connected to ground; a second operational amplifier, the positive input terminal of which is electrically connected to the second end of the first capacitor; and a diode, the anode of which is electrically connected to the output terminal of the second operational amplifier. The cathode of the diode is electrically connected to the negative input terminal of the second operational amplifier; the first terminal of the second resistor is connected to the cathode of the diode, and the second terminal of the second resistor is connected to ground; the first terminal of the second capacitor is electrically connected to the cathode of the diode, and the second terminal of the second capacitor is connected to ground; the positive input terminal of the third operational amplifier is connected to the cathode of the diode, and the negative input terminal of the third operational amplifier is electrically connected to the output terminal of the third operational amplifier; the first terminal of the third resistor is connected to the negative input terminal of the third operational amplifier, and the second terminal of the third resistor is electrically connected to the output terminal of the third operational amplifier; the ADC sampling circuit is electrically connected to the output terminal of the third operational amplifier; the shielding layer structure is connected to ground.

[0012] Optionally, in some technical solutions of this utility model, the top of the shielding layer structure is provided with a limiting groove, the bottom of the shielding layer structure is provided with a heat-insulating hole, and the bottom of the shielding layer structure is provided with a welding point.

[0013] The proposed solution ensures that the soil probe does not directly contact the soil, thus preventing soil contamination and corrosion of the single electrode probe and extending its service life.

[0014] The mechanical restraint between the water tank and the soil container ensures a reliable and effective elastic connection between the single-electrode probe and the probe inside the soil. Installation is precise, convenient, simple, and highly consistent.

[0015] A sleeve-type shielding layer is used to wrap the single electrode probe to ensure that the overall sensor is less affected by the water level in the water tank and has high anti-interference ability.

[0016] The capacitance value is calculated by measuring the resonant frequency of the LC resonant circuit, which has high precision and accuracy.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 A cross-sectional view of an apparatus for detecting soil moisture according to an embodiment of the present invention is shown;

[0020] Figure 2 A schematic diagram of a sampling circuit according to an embodiment of the present invention is shown;

[0021] Figure 3 Three views of a shielding layer according to an embodiment of the present invention are shown;

[0022] in, Figures 1 to 3 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0023] 1. Water tank; 2. Soil tank; 3. Water tank probe; 4. Soil tank probe; 5. Shielding layer structure; 11. Support foot; 12. Water intake port; 51. Limiting groove; 52. Heat insulation hole; 53. Welding point. Detailed Implementation

[0024] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0026] The following reference Figures 1 to 3 This invention describes an apparatus for detecting soil moisture according to some embodiments of the present invention.

[0027] In one embodiment of this utility model, such as Figure 1As shown, a device for detecting soil moisture is proposed, comprising: a water tank 1, which has a first cavity, a first convex groove at the bottom, and a first through hole at the top; a soil tank 2, which is partially located within the first cavity, and has a second convex groove at the bottom; a sampling circuit connected to the bottom of the water tank 1 and located outside the water tank 1; a water tank probe 3, whose first end is connected to the sampling circuit and is located within the first convex groove; and a soil tank probe 4, which is connected to the soil tank 2 and is located within the second convex groove, with the second end of the water tank probe 3 passing through the first through hole and connected to the soil tank probe 4; wherein the sampling circuit, the water tank probe 3, and the soil tank probe 4 cooperate to measure soil moisture.

[0028] This invention proposes a device for detecting soil moisture, comprising a water tank 1, a soil tank 2, a sampling circuit, a water tank probe 3, and a soil tank probe 4. The bottom of the water tank 1 has a first convex groove, the bottom of the soil tank 2 has a second convex groove, and the water tank probe 3 is located within the first convex groove.

[0029] In this system, the second ends of the soil probe 4 and the water probe 3 are connected to form a new cylindrical electrode for a single-electrode capacitor. The upper half of the new cylindrical electrode is in close contact with the soil, while the lower half is placed in the center of the water reservoir 1. Based on this, the first end of the water probe 3 is connected to the sampling circuit. The sampling circuit collects the capacitance value of the single-electrode capacitor and determines the soil moisture based on the capacitance value, thereby completing the detection of soil moisture.

[0030] Furthermore, because of the first and second convex grooves, the water tank probe 3 will not come into direct contact with water, and the soil tank probe 4 will also not come into direct contact with soil. This ensures that the single electrode probe is not contaminated or corroded by soil, thus extending its service life.

[0031] It's important to understand that a single-electrode capacitor is a special type of capacitor, distinct from traditional two-electrode capacitors. A single-electrode capacitor typically relies on an external environment as its second electrode, interacting with its single electrode to create a capacitive effect. One electrode of this type of capacitor is an actual metallic conductor, while the other electrode is the ground (or grounding system), which can be considered a giant conductor. The capacitance value of this capacitor depends primarily on the shape and size of the actual metallic conductor, its distance from the ground, and the environmental medium, such as air or soil. Due to the greater distance from the ground, the overall capacitance of a single-electrode capacitor is usually smaller; the surrounding environmental medium significantly affects the capacitance value, and the single-electrode design also leads to an uneven electric field distribution.

[0032] Understandably, single-electrode capacitors generally come in three shapes: parallel-plate capacitors, spherical capacitors, and cylindrical capacitors. A capacitor consisting of a cylindrical electrode and ground is a typical single-electrode grounded capacitor. In this structure, the cylindrical electrode acts as a conductor, forming a capacitance with the ground (the other conductor) through air or other media. The charges on the surface of the cylindrical electrode interact with the opposite charges on the ground under the influence of the electric field, creating an electric field. This electric field emanates from the metal electrode and diffuses towards the ground; the electric field strength in the medium is primarily determined by the dielectric constant of the dielectric material distributed near the metal electrode.

[0033] It is important to understand that the first convex groove (second convex groove) refers to the groove formed by the inward indentation of the bottom of the water tank 1 (or soil tank 2). In other words, the convex groove is located on the outside of the water tank 1 (or soil tank 2). Therefore, when placing an item into the groove, the bottom of the outer side must be placed into the first convex groove (second convex groove).

[0034] Specifically, after detecting soil moisture, the capacitance values ​​of dry and fully moist soil are mapped to 0% and 100% moisture using a "two-point calibration" method. First, ensuring the soil is dry, the soil chamber is placed in water chamber 1, ensuring a reliable connection between the water chamber probe 3 and the soil chamber probe. The average value of the recorded frequencies is stored as 0% moisture. Second, ensuring the soil is fully moist, the soil chamber is placed in again, and the average value of the recorded frequencies is stored as 100% moisture. Finally, by calculating the normalized data corresponding to the real-time frequency values ​​between zero and full moisture, the change in soil moisture is determined. The frequency normalization value SF, combined with the preset level to confirm the current liquid level information, is calculated using the following formula: .in, This is the frequency value measured under no-load conditions; It is the frequency value measured at full scale liquid level; This is the real-time value of the currently measured frequency; This represents the soil moisture value.

[0035] Furthermore, in some embodiments of this utility model, the second end of the water tank probe 3 is a spring-loaded contact pin, and the soil tank probe 4 is a rivet type.

[0036] In this embodiment, the second end of the water tank probe 3 is a spring contact pin. The second end of the water tank probe 3 can abut against the contact surface of the soil tank probe. Through the structure of the telescopic spring, it is ensured that when the soil tank is vertically placed into the water tank 1, the soil tank rivet probe and the water tank 1 spring probe are reliably connected together due to gravity and elasticity, which increases the reliability and stability of the cylindrical electrode of the single electrode capacitor.

[0037] Meanwhile, the soil chamber probe is rivet-shaped, with an overall length of 12mm and a diameter of 5mm. This size of rivet-shaped probe can confine most of the electric field inside the soil chamber, thereby reducing interference from the external environment. The rivet-shaped surface can also provide a larger contact area for the water chamber probe 3, ensuring good connection between the two probes.

[0038] Specifically, the first section of the water tank probe 3 is a fixed head.

[0039] Furthermore, in some embodiments of this utility model, the shielding layer structure 5 is located at the first inner convex groove and is placed outside the water tank probe 3.

[0040] In this embodiment, although the water tank probe 3 is located at the center of the entire water tank 1 and is not in contact with the liquid, the penetrating power of the electric field means that water in the water tank 1 can significantly affect this single-electrode probe. Therefore, a shielding layer structure 5 is placed outside the water tank probe 3 to completely enclose the central probe, ensuring that even at the highest liquid level, the liquid can still shield the electric field around the central probe from interference. This maximizes the accuracy and consistency of soil moisture measurement.

[0041] Preferably, the shielding layer structure 5 is 32mm away from the water tank probe.

[0042] Specifically, the outer sides of both the soil probe 4 and the water probe 3 are encased in injection molding.

[0043] Furthermore, in some embodiments of this utility model, the sampling plate structure and the sampling circuit are connected to the water tank 1 through the sampling plate structure. The sampling plate structure is provided with a crescent-shaped groove, and the shielding layer structure 5 is connected to the sampling plate structure. The shielding layer structure 5 is located at the crescent-shaped groove.

[0044] In this embodiment, the sampling plate structure is provided with a crescent-shaped groove, and the shielding layer structure 5 is connected to the sampling plate structure. The shielding layer structure 5 is located at the crescent-shaped groove. The crescent-shaped groove enables better welding of the shielding layer structure 5, thereby improving the stability and reliability of the connection.

[0045] Specifically, the first end of the water tank probe 3 is connected to the sampling plate by welding.

[0046] Furthermore, in some embodiments of this utility model, a support foot 11 is provided at the bottom of the soil chamber 2; a water inlet 12 is provided at the bottom of the soil chamber 2; and absorbent cotton is partially located inside the water inlet 12, with one end of the absorbent cotton located inside the soil chamber 2 and the other end of the absorbent cotton located inside the water chamber 1.

[0047] In this embodiment, the bottom of the soil chamber 2 is provided with a water inlet 12, and absorbent cotton is provided inside the water inlet 12. Both ends of the absorbent cotton extend out of the water inlet 12, with the first end of the absorbent cotton located inside the soil chamber 2 and the other end located inside the water chamber 1. Thus, when water is added to the water chamber 1, the absorbent cotton absorbs the water from the water chamber 1, thereby retaining the moisture. When the soil in the soil chamber 2 is dry, it absorbs the moisture from the absorbent cotton, thus changing the soil moisture more efficiently.

[0048] Specifically, the other end of the absorbent cotton is flush with the support foot 11, which improves the stability of the soil chamber 2.

[0049] Furthermore, in some embodiments of this utility model, such as Figure 2 As shown, the sampling circuit includes: a first operational amplifier, the positive input terminal of which is electrically connected to the controller; a first resistor, the first end of which is connected to the negative input terminal of the first operational amplifier, and the second end of which is electrically connected to the output terminal of the first operational amplifier; a first capacitor, the first end of which is electrically connected to the output terminal of the first operational amplifier, and the second end of which is electrically connected to the first end of the water tank probe 3; an inductor, the first end of which is electrically connected to the second end of the first capacitor, and the second end of which is connected to ground; a second operational amplifier, the positive input terminal of which is electrically connected to the second end of the first capacitor; and a diode, the anode of which is electrically connected to the output terminal of the second operational amplifier, and the cathode of which is electrically connected to the first... The negative input terminal of the second operational amplifier is electrically connected; the first terminal of the second resistor is connected to the cathode of the diode, and the second terminal of the second resistor is connected to ground; the first terminal of the second capacitor is electrically connected to the cathode of the diode, and the second terminal of the second capacitor is connected to ground; the positive input terminal of the third operational amplifier is connected to the cathode of the diode, and the negative input terminal of the third operational amplifier is electrically connected to the output terminal of the third operational amplifier; the first terminal of the third resistor is connected to the negative input terminal of the third operational amplifier, and the second terminal of the third resistor is electrically connected to the output terminal of the third operational amplifier; the ADC sampling circuit is electrically connected to the output terminal of the third operational amplifier; the shielding layer structure 5 is connected to ground.

[0050] In this embodiment, the sampling circuit includes a first operational amplifier, a first resistor, a first capacitor, an inductor, a second operational amplifier, a diode, a second resistor, a second capacitor, a third operational amplifier, a third resistor, and an ADC sampling circuit.

[0051] First, the positive input terminal of the first operational amplifier is electrically connected to the controller, and the controller inputs a signal source frequency within a certain frequency range to the positive input terminal of the first operational amplifier.

[0052] Secondly, the first terminal of the first capacitor is electrically connected to the output terminal of the first operational amplifier, the second terminal of the first capacitor is electrically connected to the first terminal of the water tank probe 3, the first terminal of the inductor is electrically connected to the second terminal of the first capacitor, the second terminal of the inductor is connected to ground, and the shielding layer structure 5 is connected to ground. Essentially, the first capacitor, inductor, shielding layer structure 5, and water tank probe 3 form an LC resonant circuit. It should be noted that the second terminal of the first capacitor is connected to both the water tank probe 3 and the inductor, while the second terminal of the inductor and the shielding layer structure 5 are both connected to ground. This is essentially equivalent to the shielding layer and water tank probe 3 forming a capacitor and inductor connected in parallel, thus effectively becoming an LC resonant circuit. Then, the LC resonant circuit samples via a "frequency sweep".

[0053] Then, the positive input terminal of the second operational amplifier is electrically connected to the second terminal of the first capacitor, the anode of the diode is electrically connected to the output terminal of the second operational amplifier, the cathode of the diode is electrically connected to the negative input terminal of the second operational amplifier, the first terminal of the second resistor is connected to the cathode of the diode, and the second terminal of the second resistor is connected to ground. Essentially, the second operational amplifier, diode, second resistor, and second capacitor form a peak detection circuit, and the LC resonant circuit sends the sampling result to the peak detection circuit.

[0054] Next, the peak detection circuit transmits its output to the ADC sampling circuit. The ADC sampling circuit determines the specific value of the current resonant frequency based on the different amplitudes received, and then converts the resonant frequency into the current capacitance value according to the formula.

[0055] Building upon this foundation, to isolate the signal while ensuring the circuit's power remains unaffected, this invention uses the first and third operational amplifiers as non-inverting voltage followers to isolate the signal placement circuit from interference. Furthermore, because leakage current and parasitic capacitance exist in most practical non-inverting voltage follower circuits, the design further incorporates a first resistor connected to the negative input terminal of the first operational amplifier, and a second resistor electrically connected to the output terminal of the first operational amplifier. Similarly, the first terminal of the third resistor is connected to the negative input terminal of the third operational amplifier, and the second terminal is electrically connected to the output terminal of the third operational amplifier. This reduces the impact of leakage current and improves stability.

[0056] Understandably, for ease of understanding, the water tank probe 3 is located at... Figure 2 At point P+, the shielding layer structure 5 is located Figure 2 P-point.

[0057] Preferably, the sampling circuit is placed on the side of the sampling board structure away from the water tank 1. An LC resonant circuit and the sampling circuit are placed there. A 1% precision C0G or NPO capacitor and a 2% precision wire-wound inductor are used to achieve maximum consistency. Simultaneously, the connection line between the inductor and the center probe is kept as short and thick as possible to reduce parasitic capacitance. Furthermore, wide traces are used on the circuit board to wrap the connection line of the water tank probe 3, reducing the influence of the circuit board itself on the capacitance value of the water tank probe 3.

[0058] Furthermore, in some embodiments of this utility model, such as Figure 3 As shown, the shielding layer structure 5 has a limiting groove 51 at the top, a heat-insulating hole 52 at the bottom, and a welding point 53 at the bottom.

[0059] In this embodiment, the top of the shielding layer structure 5 is provided with a limiting groove 51 for limiting, and the bottom of the shielding layer structure 5 is provided with a heat-insulating hole 52, thereby avoiding excessive heat dissipation during welding and enhancing convenience.

[0060] In one specific embodiment, the workflow of this utility model is as follows:

[0061] First, place the soil chamber 2 inside the first cavity, aligning it with the positions of the soil chamber probe 4 and the water chamber probe 3. Through the action of the spring contact pin at the second end of the water chamber probe 3 and the gravity of the soil chamber probe 4, the water chamber probe 3 and the soil chamber probe 4 are connected to form a single-electrode grounded capacitor.

[0062] Then, an appropriate amount of soil is placed in the soil chamber 2 and an appropriate amount of water is placed in the water chamber 1. A single-electrode grounded capacitor, consisting of a water chamber probe 3 and a soil chamber probe 4, measures the soil moisture. The water in the water chamber 1 is absorbed by the absorbent cotton, thereby changing the soil moisture.

[0063] Because changes in soil moisture will cause changes in the capacitance value of a single-electrode grounded capacitor, the LC resonant circuit, composed of a first capacitor, an inductor, a shielding layer structure 5, and a water tank probe 3, samples by "frequency sweep".

[0064] Next, the LC resonant circuit sends the sampling result to the peak detection circuit, which consists of a second operational amplifier, a diode, a second resistor, and a second capacitor. The peak detection circuit then sends its output to the ADC sampling circuit. The ADC sampling circuit determines the specific value of the current resonant frequency based on the different amplitudes received, and then converts the resonant frequency into the current capacitance value according to the formula.

[0065] In the claims, description, and accompanying drawings of this utility model, the term "plural" refers to two or more objects. Unless otherwise explicitly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description process, and are not intended to indicate or imply that the device or element referred to must have the described specific orientation, or be constructed and operated in a specific orientation. Therefore, these descriptions should not be construed as limitations on this utility model. The terms "connect," "install," "fix," etc., should be interpreted broadly. For example, "connect" can be a fixed connection between multiple objects, a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects or an indirect connection between multiple objects through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood based on the specific circumstances described above.

[0066] In the claims, description, and drawings of this utility model, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In the claims, description, and drawings of this utility model, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A device for detecting soil moisture, characterized in that, include: Water tank (1), the water tank (1) is provided with a first cavity, the bottom of the water tank (1) is provided with a first convex groove, and the top of the first convex groove is provided with a first through hole; Soil chamber (2), the soil chamber (2) is partially located in the first cavity, and the bottom of the soil chamber (2) is provided with a second inner convex groove; A sampling circuit is connected to the bottom of the water tank (1) and is located outside the water tank (1); Water tank probe (3), the first end of the water tank probe (3) is connected to the sampling circuit, and the water tank probe (3) is located in the first convex groove; Soil probe (4), the soil probe (4) is connected to the soil chamber (2), the soil probe (4) is located in the second inner convex groove, and the second end of the water chamber probe (3) passes through the first through hole and is connected to the soil probe (4). The sampling circuit, the water reservoir probe (3), and the soil reservoir probe (4) work together to measure soil moisture.

2. The device for detecting soil moisture according to claim 1, characterized in that, The second end of the water reservoir probe (3) is a spring-loaded contact pin, and the soil reservoir probe (4) is a rivet type.

3. The device for detecting soil moisture according to claim 1, characterized in that, The shielding layer structure (5) is located at the first convex groove and is placed on the outside of the water tank probe (3).

4. The device for detecting soil moisture according to claim 3, characterized in that, The sampling board structure is provided with a crescent-shaped groove. The sampling circuit is connected to the water tank (1) through the sampling board structure. The sampling board structure is connected to the sampling board structure and the shielding layer structure (5) is located at the crescent-shaped groove.

5. The device for detecting soil moisture according to claim 1, characterized in that, Support foot (11), the support foot (11) is located at the bottom of the soil chamber (2); A water intake (12) is located at the bottom of the soil chamber (2); The absorbent cotton is located inside the water inlet (12), with one end of the absorbent cotton located inside the soil chamber (2) and the other end of the absorbent cotton located inside the water chamber (1).

6. The device for detecting soil moisture according to claim 3, characterized in that, The sampling circuit includes: The first operational amplifier, the positive input terminal of which is electrically connected to the controller; A first resistor, the first end of which is connected to the negative input terminal of the first operational amplifier, and the second end of which is electrically connected to the output terminal of the first operational amplifier; The first capacitor has its first end electrically connected to the output terminal of the first operational amplifier, and its second end electrically connected to the first end of the water tank probe (3). An inductor, wherein a first end of the inductor is electrically connected to a second end of the first capacitor, and the second end of the inductor is connected to ground; The second operational amplifier has its positive input terminal electrically connected to the second terminal of the first capacitor. A diode, wherein the anode of the diode is electrically connected to the output terminal of the second operational amplifier, and the cathode of the diode is electrically connected to the negative input terminal of the second operational amplifier; The second resistor has a first end connected to the cathode of the diode and a second end connected to ground. The second capacitor has a first terminal electrically connected to the cathode of the diode and a second terminal connected to ground. A third operational amplifier, wherein the positive input terminal of the third operational amplifier is connected to the cathode of the diode, and the negative input terminal of the third operational amplifier is electrically connected to the output terminal of the third operational amplifier; The third resistor has its first end connected to the negative input terminal of the third operational amplifier, and its second end electrically connected to the output terminal of the third operational amplifier. An ADC sampling circuit, wherein the ADC sampling circuit is electrically connected to the output terminal of the third operational amplifier; The shielding layer structure (5) is connected to the ground electrode.

7. The device for detecting soil moisture according to claim 3, characterized in that, The shielding layer structure (5) has a limiting groove (51) at the top, a heat-insulating hole (52) at the bottom, and a welding point (53) at the bottom.

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