A soil moisture detection device and system

Abstract

The application discloses a soil humidity detection device, which is characterized in that a first electrode and a second electrode are arranged in soil where humidity needs to be detected, a power supply switch circuit is closed by a main control chip, an external voltage is added to a signal oscillation source, the signal oscillation source converts the voltage into an oscillation signal, the oscillation signal reaches the first electrode through a first capacitor and a first electrode, when the soil between the first electrode and the second electrode is completely dry, the soil between the first electrode and the second electrode is equivalent to an open circuit, at this time, a detection unit can collect a stronger oscillation signal of a corresponding frequency, when the soil between the first electrode and the second electrode is humid, the oscillation signal is transmitted from the first electrode to the second electrode through the humid soil, at this time, the strength of the oscillation signal of the corresponding frequency collected by the detection unit changes, the change amount data is transmitted to the main control chip, and soil humidity data can be obtained by calculation of the main control chip. Through the above detection mode, the detection accuracy of soil humidity can be improved, and the practicality of the soil humidity detection device is improved.

Description

Technical Field

[0001] This invention relates to the field of soil moisture detection, and more particularly to a soil moisture detection device and system. Background Technology

[0002] Existing soil moisture meters are commonly resistance type, which involves inserting two metal needles into the soil and measuring soil moisture by creating a voltage difference between the two electrodes. Alternatively, a small current can be controlled to flow between the electrodes, and the change in resistance value can be calculated and correlated with soil moisture. The principle is that as soil moisture increases, the number of ions in the water increases accordingly, meaning the ion carrying capacity increases. Soil moisture is determined by detecting the relative number of these ions. However, in practice, even soils with the same moisture content may have different ion counts, resulting in varying current carrying capacity. This can lead to different moisture readings for the same soil type, thus causing resistance-type soil moisture meters to have relatively poor measurement accuracy.

[0003] For example, a soil moisture, conductivity, and temperature monitoring device (patent publication number CN216350474U) includes: a power module for supplying power; contact electrodes for contacting the soil and detecting soil moisture and conductivity; and a moisture detection module for detecting soil moisture, which is composed of three stainless steel rods connected to the internal circuitry. When collecting soil conductivity data, the microcontroller sends an I2C bus command through the EC-SCL and EC-SDA pins of the AD5933 to initiate impedance conversion. After conversion, the impedance value of the equivalent impedance RX is read, and the soil conductivity is calculated. This achieves soil moisture measurement. However, this measurement method suffers from the aforementioned problems. Summary of the Invention

[0004] Therefore, there is a need to provide a soil moisture detection device to improve the accuracy of soil moisture detection.

[0005] To achieve the above objectives, the present invention provides a soil moisture detection device, comprising a probe for setting electrodes and contacting the soil, including a first capacitor, a first inductor, a first resistor, a detection unit, a main control chip, and an oscillation signal source. The electrodes include a first pole and a second pole. The output terminal of the oscillation signal source is electrically connected to the first capacitor, one end of the first inductor and the first resistor, the input terminal of the detection unit, and the first pole. The second pole is grounded. The output terminal of the detection unit is connected to the voltage detection terminal of the main control chip.

[0006] Furthermore, there are at least two probes, with the first electrode and the second electrode located on two different probes.

[0007] Furthermore, there are at least three probes, and each probe also includes a functional unit. The functional unit is disposed on a probe different from the first and second electrodes, and the signal output terminal of the functional unit is connected to the functional detection terminal of the main control chip. The functional unit is a temperature sensing unit or a pH detection unit.

[0008] Furthermore, the first electrode and the second electrode are disposed on the same probe.

[0009] Furthermore, it also includes a temperature sensing unit, the output of which is connected to the temperature detection terminal of the main control chip; or

[0010] It also includes a pH detection unit, which is disposed between the two electrodes, and the output terminal of the pH detection unit is connected to the pH detection terminal of the main control chip.

[0011] Furthermore, it also includes a switching unit, one input terminal of which is connected to the output terminal of the detection unit, and the other input terminal is connected to one end of the temperature sensing unit or the pH detection unit. The output terminal of the switching unit is connected to the voltage detection terminal of the main control chip, and the control terminal of the switching unit is connected to the control terminal of the main control chip.

[0012] Furthermore, it also includes a display unit and a wireless transmission unit, the wireless transmission unit being connected to the main control chip, through which humidity parameters are transmitted to the display unit.

[0013] Furthermore, the output terminal of the detection unit is connected to the voltage detection terminal of the main control chip through a second resistor or a follower unit; or the oscillation signal source is a crystal oscillator or an MCU.

[0014] Furthermore, it also includes a second capacitor, with one end of the first capacitor, the first inductor, and the first resistor connected to one end of the second capacitor, and the other end of the second capacitor connected to one of the two poles.

[0015] A soil testing system is also provided, including the soil moisture detection device described in any of the above embodiments.

[0016] Unlike existing technologies, the above-described technical solution places the first and second electrodes within the soil where moisture needs to be detected. The main control chip controls the power supply switch circuit to close, applying an external voltage to the signal oscillation source. The signal oscillation source converts this voltage into an oscillation signal, which travels through a first capacitor and a first inductor to the first electrode. When the soil between the first and second electrodes is completely dry, it acts as an open circuit, allowing the detection unit to collect a strong oscillation signal at the corresponding frequency. When the soil between the first and second electrodes is moist, the oscillation signal is transmitted from the first electrode to the second electrode through the moist soil. This causes a change in the intensity of the oscillation signal at the corresponding frequency collected by the detection unit. This change is transmitted to the main control chip, which then calculates the soil moisture data. This detection method improves the accuracy of soil moisture detection and enhances the practicality of the soil moisture detection device. Attached Figure Description

[0017] Figure 1 This is a partial circuit structure diagram of the oscillation signal source and the detection unit described in the specific implementation embodiment;

[0018] Figure 2 This is a schematic diagram of the connection pin structure of the main control chip described in a specific implementation method;

[0019] Figure 3 This is a schematic diagram of the device structure with multiple probes described in a specific embodiment;

[0020] Figure 4 This is a schematic diagram of the device structure for a single probe as described in a specific embodiment;

[0021] Figure 5 A cross-sectional view of a single probe as described in the specific embodiment;

[0022] Figure 6 This is a schematic diagram of the circuit structure of the follower unit described in a specific embodiment;

[0023] Figure 7 This is a schematic diagram of the circuit structure of the functional unit described in a specific implementation method;

[0024] Figure 8 This is a schematic diagram of the circuit structure of the switching unit described in a specific implementation.

[0025] Explanation of reference numerals in the attached figures:

[0026] 10. Soil moisture detection device; 11. First electrode; 12. Second electrode; 20. Functional unit; 21. Temperature sensing unit; 22. pH detection unit. Detailed Implementation

[0027] To explain in detail the technical content, structural features, objectives, and effects of the technical solution, the following description is provided in conjunction with specific embodiments and accompanying drawings.

[0028] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0029] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0030] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0031] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0032] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0033] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0034] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0035] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0036] Please see Figures 1 to 8 A soil moisture detection device 10 includes a probe for setting two electrodes and contacting the soil. Its basic structure can refer to existing soil moisture detectors, such as having a housing, a circuit board and a main control chip inside the housing, and the main control chip connected to the two electrodes through a transmission line. The electrodes can be fixedly connected to the housing or extended through the transmission line. Common electrodes include resistive and capacitive types. This invention improves the resistive soil moisture detection device. Specifically, the soil moisture detection device includes a first electrode 11, a second electrode 12, a first capacitor (C7), a first inductor (L1), a first resistor (R10), a detection unit, a main control chip (U5), and an oscillation signal source (Y1). The first electrode 11 and the second electrode 12 are metal electrodes, preferably stainless steel, which is not easy to rust and has a long service life. The oscillation signal source can be a crystal oscillator or an MCU. In this embodiment, a crystal oscillator, such as a quartz crystal oscillator, is used. The output terminal (Y1, 3) of the oscillation signal source is electrically connected to the first capacitor, one end of the first inductor and the first resistor, the input terminal of the detection unit, and the first electrode 11. The second electrode 12 is grounded. The output terminal of the detection unit is connected to the voltage detection terminal of the main control chip. The first capacitor and the first inductor are connected in series, and the order of their series connection is not limited. For details, please refer to [reference needed]. Figure 1The output terminal of the oscillation signal source is connected to one end of the first capacitor, the other end of the first capacitor is connected to one end of the first inductor, the other end of the first inductor is connected to one end of the first resistor, the other end of the first resistor is grounded, and the other end of the first inductor is connected to the first pole 11. The detection unit includes a detector (U3) and a detection circuit structure. Specifically, the input terminal (U3,3) of the detector is connected to the other end of the first inductor, the output terminal (U3,4) of the detector is connected to the voltage detection terminal of the main control chip, and the detection circuit structure is connected in parallel between the detector and the main control chip. The detection circuit structure specifically includes a third capacitor (C9), a fourth capacitor (C10), a third resistor (R12), and a diode (D2). Preferably, the other end of the first inductor is also connected to one end of a load resistor (R11), and the other end of the load resistor is connected to the first pole 11 and the input terminal of the detection unit. By adjusting the resistance value of the load resistor (R11), the current value can be adjusted to facilitate testing the stability of the device.

[0037] The working principle of this embodiment is as follows: First, the first electrode 11 and the second electrode 12 are placed in the soil where the moisture needs to be detected. The main control chip controls the power supply switch circuit to close, applying an external voltage to the signal oscillation source. The signal oscillation source converts the voltage into an oscillation signal (frequency signal, such as 12 / 24 / 50MHz). The oscillation signal reaches the first electrode 11 through the first capacitor and the first inductor. When the soil between the first electrode 11 and the second electrode 12 is completely dry, it is equivalent to an open circuit between them. At this time, the detection unit can collect a strong oscillation signal of the corresponding frequency. When the soil between the first electrode 11 and the second electrode 12 is moist, the oscillation signal is transmitted from the first electrode 11 to the second electrode 12 through the moist soil. At this time, the intensity of the oscillation signal of the corresponding frequency collected by the detection unit changes. By transmitting the change data to the main control chip, the soil moisture data can be obtained by the main control chip. Through the above detection method, the accuracy of soil moisture detection can be improved, and the practicality of the soil moisture detection device can be improved.

[0038] Common resistive probe detection devices are single-needle or multi-needle. The mechanical structure of this invention can be directly applied to existing structures, using existing mature mechanical structures and processing technology, thus maintaining a low-cost advantage.

[0039] See Figure 3 and 7Taking a multi-needle design as an example, in some embodiments, there are at least two probes, with the first electrode 11 and the second electrode 12 located on two different probes. By placing the first electrode 11 and the second electrode 12 on separate probes, electrical contact between them can be completely avoided, and the distance between them can be easily adjusted to ensure stable detection of soil moisture. However, correspondingly, the production cost of this embodiment is higher than that of a single-needle design. Further, there are at least three probes, including a functional unit 20. The functional unit 20 is located on probes different from the first electrode 11 and the second electrode 12, and the signal output terminal (A2) of the functional unit 20 is connected to the functional detection terminal (TE) of the main control chip. The functional unit 20 is a temperature sensing unit 21 or a pH detection unit 22. The temperature sensing unit 21 is a common temperature sensor, such as the soil temperature sensor model HA2002, and the pH detection unit 22 can refer to existing probe-type soil acidity meters.

[0040] See Figure 4-5 To reduce costs, in some embodiments, the number of probes is one, i.e., a single probe. Specifically, the first electrode 11 and the second electrode 12 are disposed on the same needle. Referring to Figure x, the body of the probe is a hollow cylindrical shape, which can serve as the first electrode 11 or the second electrode 12, while the tip of the probe can serve as the second electrode 12 or the first electrode 11. The part of the tip that fits into the body is insulated by injection molding. Depending on the function of the device, two wires are led out from the inside of the body. When the device is equipped with a temperature sensing unit 21 or a pH detection unit 22, four wires can be led out. Two wires are used to connect the two electrodes, i.e., the body and the tip, respectively, and the other two wires are connected to the temperature sensing unit 21 (thermocouple) or the pH detection unit 22. The temperature sensing unit 21 is disposed inside the probe, and its output is connected to the temperature detection terminal of the main control chip. It also includes a pH detection unit 22, which is disposed between the two electrodes (see Figure x). A metal absorption section is provided at the probe tip for pH detection; its principle is similar to existing probe-type soil pH meters and will not be elaborated here. The output of the pH detection unit 22 is connected to the pH detection terminal of the main control chip. (See Figure x for details.) Figure 8 Furthermore, it also includes a switching unit (U2), one input terminal of which ( Figure 8 A1) and the output terminal of the detector unit ( Figure 1 A1) connected, the other input terminal ( Figure 8 A2) and one end of the temperature sensing unit 21 or the pH detection unit 22 ( Figure 7 A2) is connected, and the output terminal of the switching unit ( Figure 8 A) and the voltage detection terminal of the main control chip ( Figure 1 A) is connected, and the control terminal (A4) of the switching unit is connected to the control terminal (A5) of the main control chip. Figure 1 (A4) Connection. Since the detection of multiple parameters such as humidity, temperature or pH in a single-needle structure may cause mutual interference, the switching unit can automatically switch the detection function to avoid interference and improve detection accuracy and stability.

[0041] In some embodiments, a display unit and a wireless transmission unit are also included. The wireless transmission unit is connected to the main control chip and transmits humidity parameters to the display unit. The display unit can be a display screen or a projection device. By placing the display unit at a high location or in a control room, the humidity data received by the wireless transmission unit and displayed on the display unit is easy to observe. At the same time, placing the display unit in a location away from the soil can also avoid water vapor or salt spray corrosion, which could cause display screen failure and extend its service life.

[0042] In some embodiments, see Figure 1 and 6 The output of the detection unit is connected to the voltage detection terminal of the main control chip via a second resistor (R18) or a follower unit. The second resistor is used to regulate the current and prevent excessive current from damaging the circuit. The follower unit serves to buffer, isolate, and improve the load-carrying capacity. To a certain extent, it can avoid signal loss caused by high output impedance and low input impedance of the next stage, ensuring that the oscillation signal collected by the detection unit can be stably transmitted to the main control chip, thus ensuring the stability of humidity detection. The follower unit consists of a follower (U6) and a follower circuit structure. The follower, also known as a buffer amplifier, unity-gain amplifier, or isolation amplifier, is an operational amplifier circuit whose output voltage is equal to the input voltage. It only provides buffering and does not amplify the input signal, and its voltage gain is 1.

[0043] In some embodiments, a second capacitor (C8) is also included. One end of the first capacitor, the first inductor, and the first resistor, and one end of the second capacitor are connected together. The other end of the second capacitor is connected to one of the two terminals. The second capacitor is used to regulate the oscillation signal emitted by the oscillation signal source. At the same time, it can effectively isolate static electricity from the human body, preventing accidental short circuits caused by hand contact during manual operation, which could lead to excessive instantaneous current and damage to the circuit.

[0044] The present invention also provides a soil testing system, which is a super-integrated system including a data acquisition module, a display module, an information transmission module and an information storage module. It can collect humidity data by setting multiple testing devices in soil at different locations or depths, and transmit the data back to the system for calculation and integration. In addition, the system can add corresponding sensors according to the testing requirements, such as parameters for soil conductivity, groundwater level, groundwater quality, air humidity, air temperature and light intensity.

[0045] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of the present invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of the present invention, or equivalent structural or procedural transformations made using the content of the present invention's specification and drawings, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of patent protection of the present invention.

Claims

1. A soil moisture detection device, comprising a probe for setting electrodes and contacting the soil, characterized in that: It includes a first capacitor, a first inductor, a first resistor, a detector unit, a main control chip, and an oscillation signal source. The electrodes include a first pole and a second pole. The output terminal of the oscillation signal source is electrically connected to the first capacitor, one end of the first inductor and the first resistor, the input terminal of the detector unit, and the first pole. The second pole is grounded. The output terminal of the detector unit is connected to the voltage detection terminal of the main control chip. The oscillation signal source converts voltage into frequency signal. When the soil between the first and second poles is completely dry, the detector unit collects a strong oscillation signal of the corresponding frequency. When the soil between the first and second poles is wet, the intensity of the oscillation signal of the corresponding frequency collected by the detector unit changes. It also includes a second capacitor, with one end of the first capacitor, the first inductor, and the first resistor connected to one end of the second capacitor, and the other end of the second capacitor connected to one of the two poles.

2. The soil moisture detection device according to claim 1, characterized in that: The probe has at least two parts, with the first pole and the second pole located on two different probes.

3. The soil moisture detection device according to claim 2, characterized in that: The probe has at least three parts and also includes a functional unit. The functional unit is disposed on a probe that is different from the first pole and the second pole, and the signal output terminal of the functional unit is connected to the functional detection terminal of the main control chip. The functional unit is a temperature sensing unit or a pH detection unit.

4. The soil moisture detection device according to claim 1, characterized in that: The first electrode and the second electrode are disposed on the same probe.

5. A soil moisture detection device according to claim 4, characterized in that: It also includes a temperature sensing unit, the output of which is connected to the temperature detection terminal of the main control chip; or It also includes a pH detection unit, which is disposed between the two electrodes, and the output terminal of the pH detection unit is connected to the pH detection terminal of the main control chip.

6. A soil moisture detection device according to claim 5, characterized in that: It also includes a switching unit, one input terminal of which is connected to the output terminal of the detection unit, and the other input terminal is connected to one end of the temperature sensing unit or the pH detection unit. The output terminal of the switching unit is connected to the voltage detection terminal of the main control chip, and the control terminal of the switching unit is connected to the control terminal of the main control chip.

7. The soil moisture detection device according to claim 1, characterized in that: It also includes a display unit and a wireless transmission unit. The wireless transmission unit is connected to the main control chip and transmits humidity parameters to the display unit through the wireless transmission unit.

8. A soil moisture detection device according to claim 1, characterized in that: The output of the detection unit is connected to the voltage detection terminal of the main control chip via a second resistor or a follower unit; or The oscillation signal source is a crystal oscillator or an MCU.

9. A soil testing system, characterized in that: Includes the soil moisture detection device according to any one of claims 1-8.

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