Soil humidity measuring sensor and humidity measuring method

Abstract

The invention relates to a soil humidity measuring sensor and a humidity measuring method, and belongs to the technical field of sensors.The sensor comprises a high-frequency signal generator, a probe, a storage and an MCU unit, and the MCU unit controls the high-frequency signal generator to generate high-frequency signals; the high-frequency signal is transmitted into soil through the probe to be reflected, then an analog-to-digital converter is called through the MCU unit to collect a return signal, and then the return signal is converted into a soil humidity value and stored in a register. The humidity measurement method comprises the following steps: supplying power to the humidity acquisition circuit, generating a high-frequency signal by the high-frequency signal generator, transmitting the high-frequency signal into soil through the probe, and judging whether pulse return time is reached; if the pulse return time is reached, an analog-to-digital converter is called through the MCU unit to collect return signals, data are processed after signal collection is completed, and the processed data are stored in a register; and if the pulse return time is not reached, repeating the above judgment whether the pulse return time is reached.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a soil humidity measuring sensor and a humidity measuring method. BACKGROUND

[0002] In agricultural production, ecological environment monitoring and adjustment, soil moisture and temperature are basic and important data, and with the continuous development of Internet of Things, big data and other technologies, agricultural intelligence has become a trend. Soil temperature and humidity sensor as an important part of intelligent agriculture, can realize remote monitoring and intelligent control, and provide more suitable growth environment for crops.

[0003] Among the common measurement methods, the drying method can accurately measure the humidity of the soil, but the method has high labor intensity, long time consumption, and cannot realize rapid and convenient measurement demand. Other methods such as resistance method, TDR (time domain reflectometry), and capacitance method have the disadvantages of low precision and high cost. SUMMARY

[0004] In order to overcome the above-mentioned defects of the prior art, the present application provides a soil humidity measuring sensor to solve the problems raised in the background art.

[0005] In order to achieve the above-mentioned application purposes, the present application provides a soil humidity measuring sensor, which comprises a high-frequency signal generator, a probe, a memory and an MCU unit. The MCU unit controls the high-frequency signal generator to generate a high-frequency signal. The high-frequency signal is transmitted into the soil through the probe and reflected. The returned signal is collected by the MCU unit calling an analog-to-digital converter, and then the returned signal is converted into a soil humidity value and stored in the register.

[0006] Further, the low-power mode of the sensor is realized by the following method. The MCU unit realizes the purpose of reducing power consumption by closing the power supply of soil humidity collection.

[0007] Further, the stable algorithm of the sensor is realized by the following method. The collected data is processed, and abnormal data is filtered out and the threshold is increased to ensure the smoothness and stability of the data.

[0008] Further, the probe is a stainless steel probe.

[0009] The present application also discloses a method for measuring humidity using the above-mentioned soil humidity measuring sensor, comprising the following steps: S1: power supply for the sensor, prepare for humidity collection; S2: power supply for the humidity collection circuit, the high-frequency signal generator generates a high-frequency signal, which is transmitted into the soil through the probe, and whether the pulse return time is reached is judged; S3: if the pulse return time is reached, the analog-to-digital converter is called by the MCU unit to collect the return signal, and after the signal collection is completed, the data is processed and stored in the register; if the pulse return time is not reached, the high-frequency signal generator continues to generate a high-frequency signal through the probe into the soil, and after the reflected signal is returned, step S2 is repeated to determine whether the pulse return time is reached.

[0010] Compared with the prior art, the beneficial effects of the present application are: The applicant designs a soil temperature and humidity sensor with shorter measurement time, lower cost and higher measurement accuracy based on FDR; The sensor of the present application increases a low-power mode compared with the common FDR type soil temperature and humidity sensor on the market, which ensures that the device can realize longer soil environment monitoring when powered by a battery; data processing is increased to improve the stability and reliability of the data. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 The circuit diagram of the embodiment of the present application; Figure 2 The workflow diagram of the embodiment of the present application. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. The embodiments of the present application will be described below in conjunction with the drawings.

[0013] The soil moisture sensor uses electromagnetic induction principle, measures the water content of the soil by sending high-frequency electromagnetic waves to the soil and receiving reflected signals. The existing soil humidity sensor mainly consists of an oscillator, a transmitting probe, a receiving probe and a signal processing unit.

[0014] The oscillator inside the sensor generates electromagnetic waves of a specific frequency band, which are sent to the soil through a stainless steel probe. When the electromagnetic waves propagate in the soil, they will be reflected when encountering soil layers with different water content. The sensor receives the reflected signal and analyzes the frequency change of the signal through advanced algorithm, thereby calculating the dielectric constant of the soil. According to the relationship between the dielectric constant of the soil and the water content, the sensor can calculate the water content of the soil.

[0015] For example, Figure 1As shown, the soil humidity measurement sensor includes a high-frequency signal generator, a probe, a memory and an MCU unit, the MCU unit controls the high-frequency signal generator to generate a high-frequency signal, the high-frequency signal is transmitted into the soil through the probe and reflected, and then the returned signal is collected by the MCU unit calling an analog-to-digital converter, and the returned signal is converted into a soil humidity value and stored in a register; The soil humidity measurement sensor of the present application can not only collect soil humidity but also collect temperature information. The temperature and humidity collection of the soil humidity measurement sensor is performed by collecting the temperature and humidity of the soil through a high-performance steel probe and transmitting the data to the MCU unit for data processing by an IO port. Figure 1 The soil humidity signal is transmitted to the MCU unit by calculating the phase change of the 50Mhz frequency electromagnetic wave emitted by the C701 capacitor and the X701 through the U702, so as to calculate the soil moisture content. The temperature is detected by the MCU unit signal through the voltage division of the thermistor and the R709 resistor. The soil humidity measurement sensor of the present application is designed based on FDR (frequency domain reflectance) and has shorter measurement time, lower cost and higher measurement accuracy. The sensor of the present application increases a low-power mode compared with the common FDR soil temperature and humidity sensor on the market, which ensures that the device can realize longer soil environment monitoring when powered by a battery. The low-power mode is realized by closing the power supply of the soil humidity collection circuit. At the same time, data processing is added to improve the stability and reliability of the data.

[0016] Further, the low-power mode of the sensor is realized by the following method: the MCU unit realizes the purpose of reducing power consumption by closing the power supply of the soil humidity collection.

[0017] Further, the stable algorithm of the sensor is realized by: processing the collected data, removing abnormal data and increasing threshold jump to ensure the smoothness and stability of the data, and ensuring the accuracy of the data by setting the calibration algorithm by software.

[0018] Further, the probe is a stainless steel probe to ensure stable operation in harsh environments.

[0019] Reference Figure 2 A method for measuring humidity using the above soil humidity measurement sensor, comprising the following steps: S1: power supply for the sensor, prepare for humidity collection; S2: power supply for the humidity collection circuit, the high-frequency signal generator generates a high-frequency signal, which is transmitted into the soil through the probe, and judges whether the pulse return time is reached; S3: if the pulse return time is reached, the MCU unit calls the analog-to-digital converter to collect the return signal, after the signal collection is completed, the data is processed, and after the processing is completed, the data is stored in the register; if the pulse return time is not reached, the high-frequency signal generator continues to generate a high-frequency signal through the probe into the soil, and after the reflected signal returns, step S2 is repeated to determine whether the pulse return time is reached.

[0020] The technical solutions of the present application are described above in combination with specific embodiments, but it should be noted that the above description is only for the purpose of explaining the solutions of the present application, and cannot be interpreted as a specific limitation on the scope of protection of the invention in any way. Based on the explanation here, those skilled in the art can think of other specific embodiments or equivalent replacements of the present application without creative labor, which will fall within the scope of protection of the present application.

Claims

1. A soil moisture measuring sensor, characterized in that, It comprises a high-frequency signal generator, a probe, a memory and an MCU unit, the MCU unit controls the high-frequency signal generator to generate high-frequency signals, the high-frequency signals are transmitted into the soil through the probe, and after being reflected, the MCU unit calls an analog-digital converter to collect the returned signals, then the returned signals are converted into soil humidity values and stored in the register.

2. The soil moisture measuring sensor according to claim 1, characterized in that The low-power mode of the sensor is realized by the following way: the MCU unit realizes the purpose of reducing power consumption by closing the power supply of soil humidity collection.

3. The soil moisture measuring sensor according to claim 1, characterized in that, The stable algorithm of the sensor is realized by the following way: the collected data are processed, the abnormal data are filtered out and the threshold jump is increased, so as to ensure the smoothness and stability of the data.

4. The soil moisture measuring sensor according to claim 1, characterized in that, The probe is a stainless steel probe.

5. A method of measuring the moisture content of soil using a sensor according to any one of claims 1 to 4, wherein, The method comprises the following steps: S1: power supply for the sensor is provided to prepare for humidity collection; S2: power supply for the humidity collection circuit is provided, the high-frequency signal generator generates high-frequency signals, the high-frequency signals are transmitted into the soil through the probe, and whether the pulse return time is reached is judged; S3: if the pulse return time is reached, the MCU unit calls the analog-digital converter to collect the returned signals, after the signal collection is completed, the data are processed, and after the processing is completed, the data are stored in the register; if the pulse return time is not reached, the high-frequency signal generator continues to generate high-frequency signals which are transmitted into the soil through the probe, after the reflected signals are returned, step S2 is repeated to judge whether the pulse return time is reached.

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