CN210953898U

CN210953898U - Multivibrator soil humidity monitoring and early warning device

Info

Publication number: CN210953898U
Application number: CN201921382229.0U
Authority: CN
Inventors: 鲁晓丽; 严小农; 李纪明; 姜欣
Original assignee: Mudanjiang university
Current assignee: Mudanjiang university
Priority date: 2019-08-23
Filing date: 2019-08-23
Publication date: 2020-07-07
Anticipated expiration: 2029-08-23

Abstract

The utility model provides a multivibrator soil moisture monitoring and early warning device, includes: the soil detection device comprises a multivibrator circuit, a soil probe, an LED indicating device and a measurement display device; the two soil probes are respectively connected into the multivibrator circuit through the pins of the charging and discharging resistor circuit, and the LED indicating device is connected with the output end of the multivibrator circuit. This multivibration soil moisture monitoring early warning device regards as charge and discharge resistance with soil resistance, through acquireing a series of rectangular waves of output, come direct detection soil moisture and judge its change law with the help of this rectangular wave oscillation frequency and change, to soil moisture real-time supervision, in good time make irrigation early warning, owing to need not carry out the secondary conversion to data parameter, information response speed is fast, data transmission is efficient, it is reliable and stable to have the performance, measurement accuracy is higher, the cost of manufacture is lower, use the convenient characteristics of maintenance, but wide application in fields such as agricultural production, monitoring and scientific research experiment.

Description

Multivibrator soil humidity monitoring and early warning device

Technical Field

The utility model relates to a soil moisture monitoring early warning device, in particular to multivibrator soil moisture monitoring early warning device.

Background

Soil moisture is the physical quantity that expresses the soil moisture degree of certain degree of depth soil layer, also known as soil moisture content, and soil moisture sensor then is the instrument or the device that detects soil moisture, mainly is applied to soil moisture content and detects and production scientific research fields such as agricultural irrigation and forestry protection. Through the continuous development of many years, the soil humidity sensor forms a product series with various types and forms, according to the measurement principle, the measurement method is generally divided into a capacitance type, a resistance type, an ion sensitive type, a light intensity type, a surface acoustic wave type and the like, the main techniques used by these sensors can be classified into time domain reflectometry, standing wave rate method, frequency domain reflectometry, capacitance method, etc., the working principle is that the volume water content value of the soil is indirectly deduced by measuring the change of the dielectric parameter of the soil, because the dielectric parameters of the soil are greatly influenced by various external condition factors such as the property, the temperature, the air pressure and the like of the soil, the conversion process from the dielectric parameters to the measurement parameters is very complicated, the technical requirement is also high, the realization of accurate measurement has higher difficulty and longer period, therefore, the existing humidity sensors have the problems of complicated use, high cost and inconvenience for large-scale popularization and application. In the agricultural actual production, it is very important to know and master the change rule and the change condition of the soil humidity in time, but the technical principle and the product form of the soil sensor in the prior art are difficult to meet the use requirements of the agricultural industrial actual production, so the detection technical scheme of the soil humidity sensor is simplified, the development cost is low, the performance is stable, the use is convenient, the real-time visual monitoring can be realized, the soil humidity dynamic state can be timely mastered, the soil irrigation early warning can be timely made, the soil humidity monitoring device which is beneficial to the industrial popularization and use is beneficial, and the soil humidity monitoring device becomes a realistic subject for promoting the agricultural modern development at present.

SUMMERY OF THE UTILITY MODEL

The utility model aims at: the multivibrator soil humidity monitoring and early warning device is low in cost, stable in performance and convenient to use.

The utility model provides a multivibrator soil moisture monitoring and early warning device, includes: the soil detection device comprises a multivibrator circuit 1, a soil probe 2 and an LED indicating device 3; the soil probes 2 are made of conductor metal materials, a fixed distance W is kept between the two soil probes, the two soil probes 2 are respectively connected into the multivibrator circuit 1 through charging and discharging resistance circuit pins A and B, when the soil probes 2 are inserted into soil, soil resistance between the two soil probes 2 is the charging and discharging resistance of the multivibrator circuit 1, and the LED indicating device 3 is connected with an output end Uout of the multivibrator circuit 1.

The operating principle of the multivibrator soil humidity monitoring and early warning device is as follows: when the soil probe 2 is inserted into the monitored soil and the multivibrator circuit 1 is powered on, the multivibrator circuit 1 generates oscillation, a series of pulse signals in a rectangular waveform can be obtained at an output end Uout, and the soil resistance between the soil probes 2 is used as a charging and discharging resistance of the multivibrator circuit 1 to output a pulse width to the output end Uout, namely: the pulse frequency, which produces a direct effect, when the soil moisture content is high, the soil resistance is small, the output pulse width is smaller, the pulse frequency is larger, the flashing frequency of the LED indicating device is faster, on the contrary, when the soil moisture content is lower, the soil resistance is larger, the output pulse width is larger, the pulse frequency is smaller, the flashing frequency of the LED indicating device is slower, through adjusting two distance W between the soil probe 2 and the relevant parameter of access component in the multivibrator circuit 1 will frequency control is in the scope that people's eye can clearly observe, and preferred scope is 0.1 ~ 10 Hz, and the user can directly pass through the change law of the direct visual monitoring soil humidity of LED indicating device's flicker frequency still can carry out the opportunity and the intensity of soil irrigation according to the qualitative judgement of use experience simultaneously.

Further, the multivibration soil humidity monitoring and early warning device further comprises a measurement display device 4, wherein the measurement display device 4 and the LED indicating device 3 are connected in parallel at the output end Uout of the multivibration circuit 1, record and/or read the pulse signal, and display the monitoring value of the soil humidity.

In order to ensure the working stability of the multivibrator circuit 1, a 555 timer multivibrator circuit which has a simple circuit structure, stronger power output capability and higher oscillation frequency precision is preferably selected.

The utility model has the advantages that: the utility model provides a multivibration soil moisture monitoring and early warning device, with the charge-discharge resistance of soil resistance as multivibration circuit, through the series of rectangular wave that acquires output, come direct detection soil moisture and judge its change law with the help of this rectangular wave oscillation frequency and change, to soil moisture real-time supervision, in good time make irrigation early warning, owing to need not carry out secondary conversion to data parameter, information response speed is fast, data transmission efficiency is high, it is reliable and stable to have the performance, measurement accuracy is higher, the cost of manufacture is lower, use and maintenance are convenient, but wide application in agricultural water conservation, warmhouse booth, flowers and vegetables, meadow pasture soil short-term test, plant cultivation and scientific research such as scientific experiment produce the scientific research field.

Drawings

FIG. 1 is a schematic structural diagram of a multivibrator soil humidity monitoring and early warning device.

Fig. 2, 555 timer multivibrator circuit diagram.

Fig. 3, 555 timer multivibrator oscillating waveform and output waveform diagram.

Detailed Description

The claimed technical solution of the present invention is further described below by the specific embodiments with reference to the attached drawings.

A multivibrator soil humidity monitoring and early warning device is shown in figure 1 and comprises a multivibrator circuit 1, a soil probe 2, an LED indicating device 3 and a pulse width measurement display device 4; the multi-harmonic oscillation circuit 1 is a 555 timer multi-harmonic oscillation circuit, the soil probes 2 are made of stainless steel materials, the distance W between the two soil probes 2 is 7 cm, the two soil probes 2 are respectively connected into the multi-harmonic oscillation circuit 1 through charging and discharging resistance circuit pins A and B, when the soil probes 2 are inserted into soil, the soil resistance between the two soil probes 2 is the charging and discharging resistance of the multi-harmonic oscillation circuit 1, and the LED indicating device 3 and the pulse width measurement display device 4 are connected in parallel with the output end Uout of the multi-harmonic oscillation circuit 1.

Wherein: the 555 timer multivibrator circuit is composed of a 555 timer IC, a charging resistor R1, a charging and discharging capacitor C and a filter capacitor C, as shown in FIG. 2₀The filter comprises the following components, the charging resistor R1 is 1000-3000 ohms, the charging and discharging capacitor C is 22-47 microfarads, and the filter capacitor C₀0.1 microfarads; the 555 timer multivibrator circuit has no stable state, only has two temporary stable states, does not need an external trigger signal, can use an alternating current power supply, and charges the charge and discharge capacitor C through the charging resistor R1 and the soil resistor during working, and simultaneously moves at intervals, and the charge and discharge capacitor C also discharges to the discharge end B through the soil resistor; when the voltage of the input end Uin is V_ccWhen the voltage is high, the charging and discharging capacitor C is 2/3V_ccAnd 1/3V_ccIs charged and discharged, thereby obtaining a voltage V at the discharge end B and the output end Uout respectively_cDischarge and voltage of V₀As shown in fig. 3, with an oscillation period T, the output end Uout outputs an oscillation wave V₀The peak period is t_w1Trough period of t_w2At t, of a series of rectangular waves_w1The LED indicator 3 lights up during a period t_w2And in the period, the LED indicating device 3 is turned off, and the flashing frequency is 1/T.

When the multivibrator soil humidity monitoring and early warning device is applied to soil humidity monitoring, a worker can judge the humidity condition of soil in real time by observing the flicker frequency of the LED indicating device 3 in a monitoring area, timely provides irrigation early warning of the monitoring area according to the empirical relationship between the soil humidity in the monitoring area and the flicker frequency of the LED indicating device 3, and timely implements irrigation of the monitoring area, so that the soil humidity is improved, and the agricultural production needs are met; meanwhile, for the purposes of scientific experiments and production tests, the pulse width output by the output end Uout can be measured and read through the pulse width measurement and display device 4, the measured analog quantity is converted into a digital quantity through necessary data correction and calculation, and a specific numerical value of the soil humidity of the monitored area is obtained and displayed.

This embodiment a multivibrator soil moisture monitoring and early warning device, stable performance is reliable, measurement accuracy is higher, wherein: the measuring range is 0-100% RH, the measuring precision is +/-3% RH, the resolution ratio is 1% RH, the design structure is reasonable, the manufacturing cost is low, the use and the maintenance are convenient, the device is widely applicable to the fields of agricultural industrial production, production science tests and the like, the real-time monitoring of the soil humidity is realized, and the early warning of soil irrigation is timely made.

Claims

1. The utility model provides a multivibrator soil moisture monitoring and early warning device which characterized in that includes: the soil detection device comprises a multivibrator circuit (1), a soil probe (2) and an LED indicating device (3);

the soil probes (2) are two and keep a fixed distance W, the two soil probes (2) are respectively connected into the multi-resonant circuit (1) through charging and discharging resistance line pins A and B, and the LED indicating device (3) is connected with the output end Uout of the multi-resonant circuit (1).

2. The multivibrator soil humidity monitoring and early warning device according to claim 1, further comprising: also comprises a measurement display device (4);

the measurement display device (4) and the LED indicating device (3) are connected in parallel at the output end Uout of the multi-resonant circuit.

3. The multivibrator soil humidity monitoring and early warning device as claimed in claim 1 or 2, wherein: the multivibrator circuit (1) is a 555 timer multivibrator circuit.

4. The multivibrator soil humidity monitoring and early warning device as claimed in claim 3, wherein: the 555 timer is provided with a plurality of timersIn the harmonic oscillation circuit, the charging resistor R1 is 1000-3000 ohm, the charging and discharging capacitor C is 22-47 microfarads, and the filter capacitor C₀Is 0.1 microfarads.

5. The multivibrator soil humidity monitoring and early warning device as claimed in claim 3, wherein: the distance W between the two soil probes (2) is 7 cm.