Evaporation wireless transmission method and system based on soil moisture content

Abstract

The invention relates to the technical field of soil moisture content monitoring, in particular to a wireless transmission method and system based on soil moisture content evaporation. The system comprises a data acquisition unit, an MCU control unit, a data transmission unit and a data analysis unit, the MCU control unit adopts a hardware module with an STM32L series single-chip microcomputer as a core. The data transmission unit is realized by adopting an NB-IoT wireless communication module, and the data analysis unit is used for acquiring soil moisture information, soil temperature information and soil humidity information and compensating the soil moisture information based on soil temperature data and humidity data. According to the invention, a frequency domain reflection method measurement technology and a low-power-consumption wide-area Internet of Things technology are combined, so that remote accurate monitoring is realized. The binary regression analysis method is adopted to effectively reduce the influence of the temperature on the sensor precision and reduce the sensitivity temperature coefficient. Ultra-low power consumption is realized through STM32L series MCU and a PSM mode of NB-IoT, and the system is suitable for long-term field monitoring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil moisture monitoring, and in particular to a soil moisture evaporation wireless transmission method and system. BACKGROUND

[0002] Soil moisture, also known as soil humidity, refers to the water content of soil, which is the most important and most commonly used soil information. Soil moisture prediction is the basis for developing a reasonable irrigation system and improving water use efficiency. Soil moisture monitoring and prediction is based on monitoring point layout, monitoring method, soil moisture monitoring technology precision, and soil moisture data analysis and monitoring model. In order to more accurately grasp the soil moisture, it is necessary to detect the soil moisture at different depths, and at the same time, it is necessary to use data transmission to return the information to the total control station by using the sensors randomly distributed at different positions in the field.

[0003] With the development and gradual improvement of wireless communication technology, the application field of the technology gradually expands to the agricultural field and gradually penetrates into the whole process of agricultural production and management. In the field of field information collection and acquisition, wireless communication technology is introduced to realize remote field data acquisition and improve the efficiency of field data acquisition. SUMMARY

[0004] The purpose of the present application is to provide a soil moisture evaporation wireless transmission method and system, which realizes remote acquisition and wireless transmission of soil moisture information.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A soil moisture evaporation wireless transmission system, comprising a data acquisition unit, an MCU control unit, a data transmission unit and a data analysis unit;

[0007] The data acquisition unit adopts frequency domain reflection method to acquire soil moisture evaporation information, which includes a humidity sensor for acquiring soil moisture information and a temperature and humidity sensor for acquiring soil temperature and humidity;

[0008] The MCU control unit is connected with the humidity sensor and the temperature and humidity sensor, and the MCU control unit adopts a hardware module with an STM32L051C8T6 single-chip microcomputer as the core;

[0009] The data transmission unit is realized by adopting an NB-IoT wireless communication module, and the NB-IoT wireless communication module comprises an NB wireless transmission module and an M5311 SIM card module;

[0010] The data analysis unit is used for acquiring soil moisture information, soil temperature information and soil humidity information, and compensating the soil moisture information based on soil temperature data and humidity data.

[0011] Further, the temperature and humidity sensor adopts an SHT10 temperature and humidity sensor.

[0012] Further, the humidity sensor is composed of a sensor probe, a main body and a power supply, the sensing probe is composed of two feedback probes and one output probe; the two feedback probes are composed of metal rods and are parallel to each other, forming a positive and negative pole of a capacitor.

[0013] Further, the MCU control unit is connected with a reset circuit, a crystal oscillator circuit and a power supply circuit.

[0014] Further, the reset circuit comprises a capacitor and a resistor connected to the NRST pin of the single-chip microcomputer, the resistor is connected to the power supply circuit, and the capacitor is grounded.

[0015] Further, the crystal oscillator circuit is used for providing a clock signal for the single-chip microcomputer, and comprises a high-speed crystal oscillator and a low-speed crystal oscillator; the high-speed clock selects an 8MHz crystal oscillator, and the load capacitor is 20pf; the low-speed clock selects a 32.768KHz crystal oscillator.

[0016] Further, the power supply circuit adopts a lithium battery for power supply, and is connected with a voltage conversion circuit.

[0017] Further, a binary regression analysis method is adopted for temperature compensation of the FDR soil humidity sensor.

[0018] The application also provides a soil moisture content evaporation wireless transmission method, comprising the following steps:

[0019] Step 1: data acquisition;

[0020] The sensor is powered on and initialized, the MCU control unit sends a start transmission timing, the data acquisition unit acquires soil moisture, temperature and humidity data, the data is transmitted to the MCU control unit, and the MCU control unit receives and processes the data and stores them;

[0021] Step 2: data transmission;

[0022] The SIM card in the NB-IoT wireless communication module is identified and registered with a network, and an MQTT server is configured; an MQTT connection is established; data is uploaded to a data analysis unit; and the NB-IoT wireless communication module enters a low-power mode;

[0023] Step 3: compensation of soil moisture data based on temperature and humidity;

[0024] Collect sensor output under different temperature and humidity; establish binary regression equation, calculate coefficient through Matlab; and then realize obtaining real soil moisture information

[0025] The application has the advantages that the frequency domain reflection method measurement technology is combined with the low-power wide-area Internet of Things technology to realize remote and accurate monitoring. The binary regression analysis method is used to effectively reduce the influence of temperature on the accuracy of the sensor and reduce the sensitivity temperature coefficient. The STM32L series MCU and the PSM mode of the NB-IoT are used to realize ultra-low power consumption and are suitable for long-term outdoor monitoring. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of the system structure of the application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application.

[0028] Embodiment 1

[0029] The application discloses a soil moisture evaporation wireless transmission system based on soil moisture content, which comprises a data acquisition unit, an MCU control unit, a data transmission unit and a data analysis unit.

[0030] The data acquisition unit adopts the frequency domain reflection method to collect soil moisture evaporation information, and comprises a humidity sensor for collecting soil moisture information and a temperature and humidity sensor for collecting soil temperature and humidity. The temperature and humidity sensor adopts an SHT10 temperature and humidity sensor, which not only has the functions of collecting soil temperature and soil humidity data, but also can transmit data to the MCU control unit. Meanwhile, the humidity sensor is composed of a sensor probe, a main body and a power supply, and the sensing probe is composed of two feedback probes and an output probe. The two feedback probes are composed of metal rods and are parallel to each other, forming a positive and negative electrode of a capacitor. When the sensor is inserted into the soil, the soil between the two metal rods is the soil to be measured, i.e., the dielectric medium. The crystal oscillator of the FDR sensor emits an oscillation signal with a frequency of 100 MHz, which is transmitted to the probe after being amplified by the driving unit.

[0031] The MCU control unit is connected with the humidity sensor and the temperature and humidity sensor, respectively. The MCU control unit adopts a hardware module with an STM32L051C8T6 single-chip microcomputer as the core, has low power consumption, and has a working temperature of-40℃ to 85℃, which is perfectly suitable for outdoor environments. The MCU control unit is connected with a reset circuit, a crystal oscillator circuit and a power supply circuit,

[0032] The reset circuit includes a capacitor and a resistor connected to the NRST pin of the single-chip microcomputer, the resistor is connected to the power supply circuit, and the capacitor is grounded. The single-chip microcomputer needs to be reset before starting, and after starting, each module is reset to the initial state. When the reset circuit receives a voltage of 3.3V, the capacitor is charged, at this time the voltage value between the two ends of the resistor is 0, the NRST pin is high, and the normal operation is performed. Press the reset key, the capacitor releases all the electricity, after a few milliseconds, the voltage value between the two ends of the capacitor becomes small, the voltage value between the two ends of the resistor reaches the maximum, the NRST pin is low, and the reset is successful.

[0033] The crystal oscillator circuit is used to provide a clock signal for the single-chip microcomputer, and the single-chip microcomputer in the embodiment is selected as STM32L051C8T6. The crystal oscillator circuit includes a high-speed crystal oscillator and a low-speed crystal oscillator. The high-speed clock selects an 8MHz crystal oscillator, and the load capacitor is 20pf. The low-speed clock selects a 32.768KHz crystal oscillator.

[0034] The power supply circuit adopts a lithium battery for power supply, the working voltage of the single-chip microcomputer is 3.3V, the output voltage of the lithium battery is 5V, and the voltage difference between the input and the output is 1.7V. In order to guarantee the power supply conditions required for the normal operation of each device, the power supply circuit in the embodiment further includes a voltage conversion circuit. The voltage conversion circuit is realized by using an SPX3819 module. After the output voltage of the lithium battery passes through the SPX3819 module, the upper end output voltage is 5V, and the lower end output voltage is 3.3V. All the working voltages required by the hardware modules are realized.

[0035] The data transmission unit is realized by using an NB-IoT wireless communication module. The NB-IoT wireless communication module includes an NB wireless transmission module and an M5311 SIM card module. The NB-IOT wireless communication module is the key to realize remote transmission, and is responsible for the forwarding of sensor and control signal data in the whole system. Through it, the data is transmitted to the data analysis unit.

[0036] The data analysis unit is used to obtain soil moisture information, soil temperature information and soil humidity information, and compensate the soil moisture information based on the soil temperature data and humidity data. In the embodiment, a binary regression analysis method is used to compensate the temperature of the FDR soil humidity sensor.

[0037] Embodiment 2

[0038] The embodiment provides a soil moisture evaporation wireless transmission method based on the soil moisture evaporation wireless transmission system in the embodiment.

[0039] Step 1: data acquisition;

[0040] The sensor is powered on and initialized, the MCU control unit sends a start transmission timing, the data acquisition unit acquires soil moisture, temperature and humidity data, the data is transmitted to the MCU control unit through an I2C interface, and the MCU control unit receives and processes the data and stores them.

[0041] Step 2: Data transmission

[0042] The SIM card in the NB-IoT wireless communication module is identified and registered with the network, and the MQTT server is configured; an MQTT connection is established; data is uploaded to the data analysis unit; and the NB-IoT wireless communication module enters a low-power mode.

[0043] Step 3: Compensation of soil moisture data based on temperature and humidity

[0044] Sensor output under different temperatures and humidities is acquired, a binary regression equation is established, coefficients are calculated through Matlab, and real soil moisture information is obtained.

[0045] The embodiment can be linked with a drip irrigation system to achieve precise control of water and thus improve yield; and soil moisture data can be uploaded to build a reliable authentication system for agricultural product quality. Through precise acquisition and scientific utilization of soil moisture information, not only can crop yield and quality be significantly improved, but also data support can be provided for agricultural industrial production to achieve the dual goals of efficient use of water resources and sustainable development of agriculture.

[0046] The above merely describes a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, within the technical scope disclosed by the present application, can make equivalent replacements or changes to the technical scheme and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A soil moisture evaporation wireless transmission system, characterized in that, It comprises a data acquisition unit, an MCU control unit, a data transmission unit and a data analysis unit. The data acquisition unit adopts a frequency domain reflection method to collect soil moisture information, and comprises a humidity sensor for collecting soil moisture information and a temperature and humidity sensor for collecting soil temperature and humidity. The MCU control unit is connected with the humidity sensor and the temperature and humidity sensor, and adopts an STM32L051C8T6 single-chip microcomputer as a core hardware module. The data transmission unit is realized by using an NB-IoT wireless communication module, which comprises an NB wireless transmission module and an M5311 SIM card connection module. The data analysis unit is used to acquire soil moisture information, soil temperature information and soil humidity information, and compensate soil moisture information based on soil temperature data and humidity data.

2. The soil moisture evaporation wireless transmission system according to claim 1, wherein, The temperature and humidity sensor adopts an SHT10 temperature and humidity sensor.

3. The wireless transmission system for soil moisture evaporation according to claim 1, wherein, The humidity sensor is composed of a sensor probe, a main body and a power supply, and the sensing probe is composed of two feedback probes and an output probe.

4. The wireless transmission system for soil moisture evaporation according to claim 1, wherein, The MCU control unit is connected with a reset circuit, a crystal oscillator circuit and a power supply circuit.

5. The soil moisture evaporation wireless transmission system according to claim 4, wherein, The reset circuit comprises a capacitor and a resistor connected to the NRST pin of the single-chip microcomputer, the resistor is connected to the power supply circuit, and the capacitor is grounded.

6. The soil moisture evaporation wireless transmission system according to claim 4, wherein, The crystal oscillator circuit is used to provide a clock signal for the single-chip microcomputer, and comprises a high-speed crystal oscillator and a low-speed crystal oscillator.

7. The wireless transmission system based on soil moisture evaporation according to claim 4, characterized in that: The power supply circuit adopts a lithium battery, and is connected with a voltage conversion circuit.

8. The soil moisture evaporation wireless transmission system according to claim 1, wherein, The binary regression analysis method is used to compensate the temperature of the FDR soil humidity sensor.

9. A method based on the soil moisture evaporation wireless transmission system according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: Step 1: data acquisition; The sensor is powered on and initialized, the MCU control unit sends a start transmission timing, the data acquisition unit collects soil moisture, temperature and humidity data, the data is transmitted to the MCU control unit, and the MCU control unit receives and processes the data and stores them; Step 2: data transmission; The SIM card in the NB-IoT wireless communication module is identified and registered with the network, the MQTT server is configured, the MQTT connection is established, the data is uploaded to the data analysis unit, and the NB-IoT wireless communication module enters a low-power mode; Step 3: compensation of soil moisture data based on temperature and humidity; The sensor output under different temperatures and humidities is collected; A binary regression equation is established, the coefficients are calculated by Matlab, and the real soil moisture information is obtained.

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