Low-power soil moisture monitoring system and monitoring station thereof

Abstract

This invention belongs to the field of agricultural testing equipment, specifically relating to a low-power soil moisture monitoring system and its monitoring station. It is used to acquire the elemental content of nitrogen, phosphorus, and potassium in the soil at different sampling points within a testing area, as well as soil temperature, humidity, and pH value, according to a preset sampling frequency. The soil moisture monitoring system includes: multiple soil moisture monitoring stations, a wireless gateway, and a smart agriculture cloud platform. After each full data acquisition cycle, the smart agriculture cloud platform calculates the soil moisture change rate (ROCM) based on historical monitoring data. Then, it uses the ROCM to look up a preset ROCM-dormant time lookup table, generates the dormant time for the soil moisture sensors in the next sampling cycle, and distributes the updated dormant time to each soil moisture monitoring station. This achieves the goal of extending the dormant time of the soil moisture monitoring stations to reduce power consumption when soil moisture is stable. This invention solves the problems of high power consumption and poor stability in existing soil moisture monitoring stations.

Description

Technical Field

[0001] This invention belongs to the field of agricultural testing equipment, specifically relating to a low-power soil moisture monitoring system and its monitoring station. Background Technology

[0002] Soil moisture monitoring stations are a new type of monitoring equipment that collects parameters such as the content of macro-elements, temperature, humidity, pH, and EC value in the soil. This equipment is widely used in large-scale farms, and the monitoring results can serve as a basis for farmers to control crop growth and prevent and control pests and diseases, thereby improving crop yield.

[0003] Soil moisture monitoring stations are mainly installed in farmland in the field. Providing a separate power supply line for the equipment is very costly. Therefore, existing equipment usually uses distributed power sources. In addition, considering the application scenarios of soil moisture monitoring stations, it is usually not possible to set up independent communication lines for data transmission. Instead, they can only communicate with base stations using IoT wireless communication modules to upload data.

[0004] Because soil moisture monitoring stations rely on distributed power sources for self-powering, their power consumption significantly impacts battery life and operational stability. Existing equipment, particularly sensors and controllers, consumes considerable energy during extended operation and requires wireless communication with base stations, further contributing to its high power consumption. This means that during prolonged periods of severe weather that disrupt power generation, the equipment's batteries are easily depleted. Under such conditions, the batteries are prone to over-discharge damage, affecting battery life and potentially forcing the interruption of signal acquisition, thus increasing maintenance complexity. Summary of the Invention

[0005] To address the problems of high power consumption, poor stability, and susceptibility to failure under special weather conditions in existing soil moisture monitoring stations, this invention provides a low-power soil moisture monitoring system and its monitoring station.

[0006] This invention is achieved using the following technical solution:

[0007] A low-power soil moisture monitoring system is disclosed, which is used to acquire the elemental content of nitrogen, phosphorus, and potassium in the soil at different sampling points within a detection area, as well as the soil temperature, humidity, and pH value, according to a preset sampling frequency. The low-power soil moisture monitoring system includes: multiple soil moisture monitoring stations, at least one wireless gateway, and a smart agriculture cloud platform.

[0008] Each soil moisture monitoring station includes a support frame, a control box, a distributed power supply, and soil moisture sensors. The distributed power supply powers the soil moisture monitoring station. The probes of the soil moisture sensors are inserted into the soil at the sampling points and communicate with the control box via cables. The control box contains a LoRa-based communication module with wireless mesh self-organizing networking capabilities and a sampling controller. Each soil moisture monitoring station uses the communication module to form a wireless mesh network, thereby enabling the uploading of detection data and the receiving of data acquisition commands, including sleep time. The sampling controller is used to adjust the sampling time of the soil moisture sensors for the next cycle based on the received sleep time.

[0009] The wireless gateway communicates with each soil moisture monitoring station via a LoRa-based communication module and with a smart agriculture cloud platform via a 4G / 5G mobile communication network / mobile IoT network.

[0010] The smart agriculture cloud platform acquires detection data from all sampling points within the detection area via a wireless gateway. After each full data collection cycle, it calculates the soil moisture change rate (ROCM) based on historical detection data. Then, it uses the ROCM to look up a preset ROCM-dormant time lookup table to generate the dormancy time of the soil moisture sensor in the next sampling cycle. The updated dormancy time is then sent to each soil moisture monitoring station, thereby extending the dormancy time of the soil moisture monitoring station to reduce power consumption when soil moisture is stable.

[0011] As a further improvement of the present invention, the formula for calculating the rate of change of soil moisture (ROCM) is as follows:

[0012]

[0013] In the above formula, These represent the rate of change of soil elements, the rate of change of temperature, the rate of change of soil moisture content, and the rate of change of pH, respectively. The percentages of change in soil moisture are respectively The weights; and These represent the nitrogen content of the i-th sampling point at the end and beginning of the current sampling period, respectively. and These represent the phosphorus content of the i-th sampling point at the end and start of the current sampling period, respectively; and These represent the soil potassium content at the i-th sampling point at the end and beginning of the current sampling period, respectively. and These are the maximum and minimum values ​​of the soil temperature detected at the i-th sampling point during the current sampling period, respectively. and These are the maximum and minimum values ​​of soil moisture content detected at the i-th sampling point within the current sampling period, respectively. and , i, and n represent the soil pH at the i-th sampling point at the end and start of the current sampling period, respectively; n represents the number of soil moisture monitoring stations deployed in the detection area.

[0014] As a further improvement to this invention, the mathematical expression for the soil moisture change rate-dormancy time comparison table is as follows:

[0015]

[0016] In the above formula, T represents the baseline sleep time vector. This represents the updated sleep time vector.

[0017] As a further improvement of the present invention, the soil moisture sensor adopts a six-in-one sensor that includes a nitrogen, phosphorus and potassium detection unit, a temperature and humidity detection unit and a pH detection unit.

[0018] The data format of the dormancy time vector T is T={T1, T2, T3}, where T1 represents the dormancy time of the nitrogen, phosphorus and potassium detection unit; T2 represents the dormancy time of the temperature and humidity detection unit; and T3 represents the dormancy time of the pH detection unit.

[0019] As a further improvement of the present invention, the nitrogen, phosphorus and potassium detection unit, temperature and humidity detection unit and pH detection unit in the soil moisture sensor adopt different signal sampling frequencies according to the preset data sampling standard, and T2 < T1, T3.

[0020] The wireless Mesh self-organizing network communication module in the control box adopts a low-power asynchronous sleep mode during operation.

[0021] As a further improvement of the present invention, the spatial layout between the various soil moisture monitoring stations should meet the following requirement: within a radius of the maximum communication distance of the wireless Mesh self-organizing network communication module of each monitoring station, there should be at least one other monitoring station or wireless gateway.

[0022] As a further improvement to the present invention, the networking method for each soil moisture monitoring station is as follows:

[0023] I. Initialization Phase

[0024] Select one or more monitoring stations that are close to the wireless gateway as primary monitoring stations and generate a route between them. Then, use the primary monitoring stations as relay nodes to determine secondary monitoring stations and generate a route between them. Continue in this manner until the wireless network of all monitoring stations is completed.

[0025] When each monitoring station generates a route with the previous level monitoring station, it first checks if there is a routing table. If so, it uses it as the subsequent data transmission path. Otherwise, it searches for a route by broadcasting. The monitoring station that receives the broadcast first within the communication range acts as a relay node to reply to the broadcast content, accept the route, and add it to the routing table.

[0026] II. Soil Moisture Monitoring Stage

[0027] Before each sleep time is reached and data sampling is triggered, the online status of each monitoring station is checked. When a monitoring station goes offline, the routing table is automatically updated, and the optimal route for transmitting data to the gateway is reselected for all monitoring stations that originally used the offline monitoring station as a relay node.

[0028] After the network is established, the end nodes package their own detection data and device identification codes and send them to the next routing target; the relay nodes package their own detection data and device identification codes and send them together with the received data packets to the next routing target.

[0029] As a further improvement of the present invention, the distributed power supply in the soil moisture monitoring station adopts a solar panel with a battery; the solar panel generates electrical energy and stores it in the battery, thereby realizing self-powering for each soil moisture monitoring station.

[0030] As a further improvement of the present invention, the support frame of the soil moisture monitoring station includes a support rod and a base. The portion of the support rod located below the base includes a pointed end; the base is used to fix the station to the ground by means of ground nails or bolts. A control box is installed in the middle section of the support rod, a solar panel from a distributed power source is installed at the top of the support rod, and a battery and soil moisture sensor are pre-embedded below the base.

[0031] The present invention also includes a soil moisture monitoring station, which is the soil moisture monitoring station used in the aforementioned low-power soil moisture monitoring system; the soil moisture monitoring system has an automatic wireless networking function between monitoring stations, and an adaptive adjustment function for the data sampling frequency of each detection unit in the soil moisture sensor according to the received sleep time.

[0032] The technical solution provided by this invention has the following beneficial effects:

[0033] The soil moisture monitoring system provided by this invention has the function of automatic wireless networking between monitoring stations, and the function of analyzing soil moisture stability based on detection data, automatically updating the dormancy time, and then using the updated dormancy time to adaptively adjust the data sampling frequency of each detection unit in the soil moisture sensor.

[0034] Because the equipment in the soil moisture monitoring system of this invention can automatically form a network and automatically adjust its operating status, the operating power consumption of this soil moisture monitoring station is relatively low compared to existing equipment. It can maintain a longer operating time under the same power supply conditions, improve the service life and operating stability of the equipment, and the soil moisture monitoring effect is not easily affected by severe weather. Attached Figure Description

[0035] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0036] Figure 1 This is a system architecture diagram of a low-power soil moisture monitoring system provided in Embodiment 1 of the present invention.

[0037] Figure 2 This is a schematic diagram of the structure of a soil moisture monitoring station.

[0038] Figure 3 This is a product image of a soil moisture sensor, which is only found in soil moisture monitoring stations.

[0039] Figure 4 This is a system architecture diagram of a traditional soil moisture monitoring system.

[0040] Figure 5 This is a schematic diagram showing the spatial deployment of the wireless gateway and soil moisture monitoring station in a soil moisture monitoring system.

[0041] Figure 6 This is a schematic diagram of the network topology after the wireless gateways in the soil moisture monitoring system are networked.

[0042] Figure 7 A flowchart of the steps for establishing a network between soil moisture monitoring stations is provided for Embodiment 1 of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0044] Example 1

[0045] This embodiment provides a low-power soil moisture monitoring system, which is used to acquire the elemental content of nitrogen, phosphorus, and potassium in the soil at different sampling points within a detection area, as well as the soil temperature, humidity, and pH value, according to a preset sampling frequency. Figure 1As shown, the low-power soil moisture monitoring system includes: multiple soil moisture monitoring stations, at least one wireless gateway, and a smart agriculture cloud platform.

[0046] Among them, such as Figure 2 As shown, each soil moisture monitoring station includes a support frame, a control box, a distributed power supply, and a soil moisture sensor. Specifically, in this embodiment, the support frame of the soil moisture monitoring station includes a support rod and a base, with a pointed end on the part of the support rod located below the base. During installation, the pointed end of the support rod is first inserted into the soil to pre-align the soil moisture monitoring station, and then the base is fixed to the ground using ground nails or bolts. This ensures stable installation of the soil moisture monitoring station. In actual installation, the soil moisture monitoring station provided in this embodiment can be installed on hardened ground or directly on muddy ground. Depending on the soil environment, soil moisture monitoring stations with pointed ends of different lengths can be selected for the support frame.

[0047] Distributed power supply is used to power soil moisture monitoring stations. In this embodiment, the distributed power supply uses solar panels with built-in batteries; the solar panels generate electricity and store it in the batteries, thereby enabling each soil moisture monitoring station to be self-powered. The solar panels in the distributed power supply are installed on the top of the support rod, while the batteries and soil moisture sensors are pre-embedded below the base.

[0048] In this embodiment, the soil moisture sensor adopts the following method: Figure 3 The sensor shown is a six-in-one unit comprising nitrogen, phosphorus, and potassium (NPK) detection units, temperature and humidity detection units, and pH detection units. In this soil moisture sensor, the NPK detection unit detects the content of these three nutrients in the soil, while the humidity sensor detects the soil moisture content and temperature. The pH detection unit detects the soil's acidity or alkalinity. During use, the soil moisture sensor's probe should be inserted into the soil at the sampling point and connected to the control box via a cable; in this embodiment, the soil moisture sensor is directly embedded in the soil.

[0049] In this embodiment, the control box is installed in the middle section of the support rod. The control box includes a central control module, a communication module based on LoRa and equipped with a wireless mesh self-organizing network, and a sampling controller. Each soil moisture monitoring station uses the communication module to form a wireless mesh network, thereby enabling the uploading of detection data and the receiving of data acquisition commands, including sleep time. The sampling controller is used to adjust the sampling time of the soil moisture sensor for the next cycle based on the received sleep time.

[0050] The wireless gateway serves as the communication medium and data fusion terminal between various soil moisture monitoring stations and the smart agriculture cloud platform. On one side, it wirelessly connects to each soil moisture monitoring station via a LoRa-based communication module. On the other side, it connects to the smart agriculture cloud platform via a 4G / 5G mobile communication network / mobile IoT network. During operation, the wireless gateway acquires monitoring data from all soil moisture monitoring stations within the detection area during each data sampling cycle. It then unpacks and parses the acquired data packets, classifies and encodes the data according to preset rules, and finally uploads it to the smart agriculture cloud platform.

[0051] The smart agriculture cloud platform acquires detection data from all sampling points within the detection area via a wireless gateway. This data can be analyzed and processed by various applications within the smart agriculture cloud platform, enabling dynamic monitoring of soil moisture at the equipment site and generating corresponding guidance for agricultural production based on the monitoring results.

[0052] Specifically, in this embodiment, the power consumption of the device is optimized through two strategies: dynamically adjusting the device's sleep state and redesigning the data transmission method for communication between devices. The following will describe the solution of this embodiment in detail;

[0053] I. Dormant State

[0054] After each full data acquisition cycle, the low-power soil moisture monitoring system calculates the soil moisture change rate (ROCM) based on historical monitoring data. It then uses this ROCM to look up a pre-defined "ROCM-Sleep Time" lookup table to generate the sleep time for the soil moisture sensors in the next sampling cycle. The updated sleep time is then distributed to each soil moisture monitoring station, thereby extending the sleep time of the monitoring stations to reduce power consumption when soil moisture is stable.

[0055] The Rate of Change in Soil Moisture (ROCM) is a newly proposed state parameter in this embodiment. ROCM can be used to assess fluctuations in soil moisture within the detection range. In the practical application of this embodiment, ROCM is used to dynamically adjust the signal sampling frequency and equipment operation mode of each soil moisture monitoring station within the monitoring area. When the soil moisture in the detection area is stable, the sleep time of the soil moisture monitoring station is appropriately extended. During the operation of the soil moisture monitoring station in this embodiment, if signal sampling is not required, both the central control module and the gas function module operate in a single-listening sleep mode, simply waiting to receive instructions from the smart agriculture cloud platform without performing any tasks, until they are awakened from sleep mode. Therefore, the soil moisture monitoring system provided in this embodiment can significantly reduce the operating power consumption of the equipment.

[0056] Specifically, the formula for calculating the soil moisture change rate (ROCM) provided in this embodiment is as follows:

[0057]

[0058] In the above formula, These represent the rate of change of soil elements, the rate of change of temperature, the rate of change of soil moisture content, and the rate of change of pH, respectively. The percentages of change in soil moisture are respectively The weights; and These represent the nitrogen content of the i-th sampling point at the end and beginning of the current sampling period, respectively. and These represent the phosphorus content of the i-th sampling point at the end and start of the current sampling period, respectively; and These represent the soil potassium content at the i-th sampling point at the end and beginning of the current sampling period, respectively. and These are the maximum and minimum values ​​of the soil temperature detected at the i-th sampling point during the current sampling period, respectively. and These are the maximum and minimum values ​​of soil moisture content detected at the i-th sampling point within the current sampling period, respectively. and , i, and n represent the soil pH at the i-th sampling point at the end and start of the current sampling period, respectively; n represents the number of soil moisture monitoring stations deployed in the detection area.

[0059] To achieve quantitative adjustment of dormancy time based on monitored soil moisture change rates, this embodiment creates a soil moisture change rate-dormancy time lookup table, establishing a one-to-one mapping between soil moisture change rate values ​​and dormancy time values. Specifically, the mathematical expression for the soil moisture change rate-dormancy time lookup table in this embodiment is as follows:

[0060]

[0061] In the above formula, T represents the baseline sleep time vector. This represents the updated sleep time vector.

[0062] In the low-power soil moisture monitoring system provided in this embodiment, when the soil moisture change rate is less than 5%, it indicates that the soil moisture is relatively stable and frequent monitoring is unnecessary. In this case, the next data sampling cycle will begin after the baseline sleep time, which is a relatively long sleep period. When the soil moisture change rate is in the range of [5%, 10%), it indicates significant fluctuations in soil moisture. In this case, the data sampling frequency should be increased; in this embodiment, the sleep time is shortened to half its original value. Furthermore, when the soil moisture change rate is greater than 10%, it indicates relatively drastic fluctuations in soil moisture. In this case, the data sampling frequency should be further increased; in this embodiment, the sleep time is shortened to one-third of its original value.

[0063] It should be noted that although the soil moisture sensor provided in this embodiment is a six-in-one sensor module, it is essentially a combination of multiple sensors. In this embodiment, the frequencies of soil element monitoring, temperature and humidity monitoring, and pH monitoring differ. Generally, the nitrogen, phosphorus, and potassium detection units, temperature and humidity detection units, and pH detection units in the soil moisture sensor use different signal sampling frequencies according to preset data sampling standards, satisfying T2 < T1 and T3. For example, within a daily data sampling period, the minimum detection frequency for nitrogen, phosphorus, and potassium content and pH value is only once a day, while the detection frequency for soil temperature and soil moisture content may be once per hour or even less. Therefore, the updated dormancy time vector obtained by querying the soil moisture change rate-dormancy time lookup table in this embodiment is actually a one-dimensional array. Specifically, the data format of the dormancy time vector T is T={T1, T2, T3}, where T1 represents the dormancy time of the nitrogen, phosphorus, and potassium detection unit; T2 represents the dormancy time of the temperature and humidity detection unit; and T3 represents the dormancy time of the pH detection unit. Therefore, when the soil moisture monitoring system in this embodiment updates the dormancy time of the sensors, it actually adjusts the nitrogen, phosphorus, and potassium detection units, temperature and humidity detection units, and pH detection units proportionally.

[0064] II. Network Connection Method

[0065] like Figure 4 As shown, traditional soil moisture monitoring stations communicate with base stations via their respective communication modules, and then upload their monitoring data to the smart agriculture cloud platform through the base station. Unlike this approach, the soil moisture monitoring system in this embodiment uses…

[0066] The control box contains a LoRa-based communication module with wireless mesh self-organizing network functionality, and a gateway to enable networking between soil moisture monitoring stations. When data transmission is required, the networked wireless communication network is used to send data from each soil moisture monitoring station to the wireless gateway, which then uploads the data to the smart agriculture cloud platform.

[0067] In the new networking scheme provided in this embodiment, the communication modules in each soil moisture monitoring station adopt an asynchronous sleep low-power mode during operation, resulting in extremely low power consumption. Furthermore, because the wireless gateway in this invention needs to "preprocess" the data collected by each soil moisture monitoring station, it can more promptly detect potential offline faults at any soil moisture monitoring station and ensure that the smart agriculture cloud platform always receives the most comprehensive monitoring data, preventing data loss from sample points.

[0068] Since this embodiment adopts a LoRa-based terminal self-organizing network communication method, the spatial layout between the various soil moisture monitoring stations should meet the following requirement: within a radius equal to the maximum communication distance of the wireless mesh self-organizing network communication module of each monitoring station, there should be at least one other monitoring station or wireless gateway. In this embodiment, the maximum communication distance of the LoRa-based communication module is approximately 3-5 km. When the physical distance between any two monitoring stations or gateways is less than the communication distance, a communication link can always be formed between the monitoring stations in the network. The entire communication network is as follows: Figure 5 and Figure 6 This is a typical graph structure. Each node is a terminal, and the edges between nodes are communication links. Different monitoring stations can be directly connected to the gateway or indirectly connected to the gateway by using other monitoring stations as relay nodes.

[0069] Specifically, in the soil moisture monitoring system provided in this embodiment, the networking method for each soil moisture monitoring station is as follows:

[0070] I. Initialization Phase

[0071] Select one or more monitoring stations close to the wireless gateway as primary monitoring stations and generate routes between them. Then, use the primary monitoring stations as relay nodes to determine secondary monitoring stations and generate routes between them, and so on, until the wireless network of all monitoring stations is completed. For example, in Figure 6 In the system, monitoring stations 1 and 2 are level 1 monitoring stations, which can be directly connected to the gateway, while monitoring stations 3 and 4 are level 2 monitoring stations, which can use monitoring station 1 or 2 as relay nodes to indirectly communicate with the gateway.

[0072] like Figure 7As shown, during the networking process, when each monitoring station generates a route with the previous level monitoring station, it first checks if there is a routing table. If so, it uses it as the subsequent data transmission path; otherwise, it searches for a route through broadcast. The monitoring station that receives the broadcast first within the communication range acts as a relay node to reply to the broadcast content, accept the route, and add it to the routing table.

[0073] II. Soil Moisture Monitoring Stage

[0074] Before each sleep time is reached and data sampling is triggered, the online status of each monitoring station is checked. When a monitoring station goes offline, the routing table is automatically updated, and the optimal route for transmitting data to the gateway is reselected for all monitoring stations that originally used the offline monitoring station as a relay node.

[0075] After the network is established, the end nodes package their own detection data and device identification codes and send them to the next routing target; the relay nodes package their own detection data and device identification codes and send them together with the received data packets to the next routing target.

[0076] Example 2

[0077] This embodiment provides a soil moisture monitoring station, which is the same soil moisture monitoring station used in the low-power soil moisture monitoring system of Embodiment 1. Specifically, the soil moisture monitoring system of this embodiment has an automatic wireless networking function between monitoring stations, and an adaptive adjustment function for the data sampling frequency of each detection unit in the soil moisture sensor based on the received sleep time. Therefore, the operating power consumption of this soil moisture monitoring station is relatively low compared to existing equipment, allowing it to maintain a longer operating time under the same power supply conditions, improving the equipment's lifespan and operational stability, and making the soil moisture monitoring effect less susceptible to the impact of severe weather.

[0078] Example 3

[0079] Based on Examples 1 and 2, this embodiment also provides a new low-power soil moisture monitoring system, which achieves the same low-power performance as in Example 1 in another way.

[0080] Specifically, this embodiment integrates an embedded computer system in the gateway. This computer system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it performs the process described in Embodiment 1, which is completed by the smart agriculture cloud platform: first, it calculates the soil moisture change rate (ROCM) based on historical monitoring data; then, it queries a preset "soil moisture change rate - dormancy time" lookup table based on the ROCM; and finally, it generates the dormancy time of the soil moisture sensor for the next sampling cycle.

[0081] Specifically, in this embodiment, the memory (i.e., the readable storage medium) includes flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disk, optical disk, etc. In some embodiments, the memory can be an internal storage unit of a computer device, such as the hard disk or RAM of the computer device. In other embodiments, the memory can also be an external storage device of the computer device, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., equipped on the computer device. Of course, the memory can also include both internal storage units and external storage devices of the computer device. In this embodiment, the memory is typically used to store the operating system and various application software installed on the computer device. In addition, the memory can also be used to temporarily store various types of data that have been output or will be output.

[0082] In some embodiments, the processor may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor is typically used to control the overall operation of a computer device. In this embodiment, the processor is used to run program code stored in memory or process data.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low power consumption soil moisture monitoring system, characterized by, It is used to acquire the elemental content of nitrogen, phosphorus, and potassium in the soil at different sampling points within the detection area, as well as the soil temperature, humidity, and pH value, according to a preset sampling frequency. The low-power soil moisture monitoring system includes: Multiple soil moisture monitoring stations are provided. Each station includes a support frame, a control box, a distributed power supply, and a soil moisture sensor. The distributed power supply powers the soil moisture monitoring station. The probes of the soil moisture sensors are inserted into the soil at sampling points and communicate with the control box via cables. The control box contains a LoRa-based communication module with wireless mesh self-organizing networking capabilities and a sampling controller. Each soil moisture monitoring station uses the communication module to form a wireless mesh network, thereby enabling the uploading of detection data and the receiving of data acquisition commands, including sleep time. The sampling controller is used to adjust the sampling time of the soil moisture sensor for the next cycle based on the received sleep time. At least one wireless gateway communicates with each soil moisture monitoring station via a LoRa-based communication module and communicates with a smart agriculture cloud platform via a 4G / 5G mobile communication network / mobile IoT network. The smart agriculture cloud platform acquires detection data from all sampling points within the detection area via a wireless gateway. After each full data collection cycle, it calculates the soil moisture change rate (ROCM) based on historical detection data. Then, it uses the ROCM to look up a preset ROCM-dormant time reference table to generate the dormancy time of the soil moisture sensor in the next sampling cycle. The updated dormancy time is then sent to each soil moisture monitoring station, thereby extending the dormancy time of the soil moisture monitoring station to reduce power consumption when soil moisture is stable. When the soil moisture change rate is less than 5%, the next data sampling period will arrive after the baseline dormancy time; when the soil moisture change rate is in the range of [5%, 10%), the dormancy time will be shortened to half of the original value; when the soil moisture change rate is greater than 10%, the dormancy time will be shortened to one-third of the original value. The formula for calculating the rate of change of soil moisture (ROCM) is as follows: In the above formula, These represent the rate of change of soil elements, the rate of change of temperature, the rate of change of soil moisture content, and the rate of change of pH, respectively. The percentages of change in soil moisture are respectively The weights; and These represent the nitrogen content of the i-th sampling point at the end and beginning of the current sampling period, respectively. and These represent the phosphorus content of the i-th sampling point at the end and start of the current sampling period, respectively; and These represent the soil potassium content at the i-th sampling point at the end and beginning of the current sampling period, respectively. and These are the maximum and minimum values ​​of the soil temperature detected at the i-th sampling point during the current sampling period, respectively. and These are the maximum and minimum values ​​of soil moisture content detected at the i-th sampling point within the current sampling period, respectively. and , i, and n represent the soil pH at the i-th sampling point at the end and start of the current sampling period, respectively; n represents the number of soil moisture monitoring stations deployed in the detection area.

2. The low-power soil moisture monitoring system as described in claim 1, characterized in that: The mathematical expression for the soil moisture change rate-dormancy time comparison table is as follows: In the above formula, T represents the baseline sleep time vector. This represents the updated sleep time vector.

3. The low-power soil moisture monitoring system as described in claim 2, characterized in that: The soil moisture sensor is a six-in-one sensor that includes nitrogen, phosphorus, and potassium detection units, temperature and humidity detection units, and pH detection units. The data format of the sleep time vector T is T={T1, T2, T3}, where T1 represents the sleep time of the nitrogen, phosphorus and potassium detection unit; T2 represents the sleep time of the temperature and humidity detection unit; and T3 represents the sleep time of the pH detection unit.

4. The low power consumption soil moisture monitoring system of claim 3, wherein: The nitrogen, phosphorus, and potassium detection unit, temperature and humidity detection unit, and pH detection unit in the soil moisture sensor adopt different signal sampling frequencies according to the preset data sampling standard, and T2 < T1, T3; The wireless mesh self-organizing network communication module in the control box adopts a low-power asynchronous sleep mode during operation.

5. The low-power soil moisture monitoring system as described in claim 1, characterized in that: The spatial layout between each soil moisture monitoring station should meet the following requirement: within a radius of the maximum communication distance of the wireless Mesh self-organizing network communication module of each monitoring station, there should be at least one other monitoring station or wireless gateway.

6. The low power consumption soil moisture monitoring system of claim 5, wherein: The networking method for each soil moisture monitoring station is as follows: I. Initialization Phase Select one or more monitoring stations that are close to the wireless gateway as primary monitoring stations to generate routes between them, and use the primary monitoring stations as relay nodes to determine secondary monitoring stations and generate routes between them, and so on, until the wireless networking of all monitoring stations is completed. When each monitoring station generates a route with the previous level monitoring station, it first checks if there is a routing table. If so, it uses it as the subsequent data transmission path. Otherwise, it searches for a route by broadcasting. The monitoring station that receives the broadcast first within the communication range acts as a relay node to reply to the broadcast content, accept the route, and add it to the routing table. II. Soil Moisture Monitoring Stage Before each sleep time is reached and data sampling is triggered, the online status of each monitoring station is checked. When a monitoring station goes offline, the routing table is automatically updated, and the optimal route for transmitting data to the gateway is reselected for all monitoring stations that used the offline monitoring station as a relay node in the original routing table. After the network is established, the end nodes package their own detection data and device identification codes and send them to the next routing target; the relay nodes package their own detection data and device identification codes and send them together with the received data packets to the next routing target.

7. The low power consumption soil moisture monitoring system of claim 1, wherein: The distributed power supply in the soil moisture monitoring station uses solar panels with batteries; the solar panels generate electricity and store it in the batteries, thereby enabling each soil moisture monitoring station to be self-powered.

8. The low power consumption soil moisture monitoring system of claim 6, wherein: The support frame of the soil moisture monitoring station includes a support rod and a base. The portion of the support rod located below the base includes a pointed end. The base is used to fix the station to the ground by means of ground nails or bolts. The control box is installed in the middle section of the support rod, the solar panel of the distributed power supply is installed at the top of the support rod, and the battery and soil moisture sensor are pre-embedded below the base.

9. A soil moisture monitoring station, characterized in that, It is a soil moisture monitoring station used in the low-power soil moisture monitoring system as described in any one of claims 1-8; the soil moisture monitoring system has an automatic wireless networking function between monitoring stations, and an adaptive adjustment function for the data sampling frequency of each detection unit in the soil moisture sensor according to the received sleep time.

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