CN102100168A

CN102100168A - Monopolar plate type automatic soil humidity controller

Info

Publication number: CN102100168A
Application number: CN2009102611969A
Authority: CN
Inventors: 卓学
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-12-19
Filing date: 2009-12-19
Publication date: 2011-06-22

Abstract

The invention provides a monopolar plate type automatic soil humidity controller which comprises a fixed polar plate, an insulation film, a carbon rod, a main circuit, a power supply and an electromagnetic water outlet switch. By using the electrical conductivity of soil and a high dielectric constant characteristic of water simultaneously and enabling the main circuit to be connected with soil to be tested through the carbon rod, the monopolar plate type automatic soil humidity controller ensures that a virtual capacitor is formed between the fixed polar plate and the soil; and the main circuit is used for comparing the frequency through an oscillating circuit, and the on or off of the electromagnetic water outlet switch is controlled through comparing judgment, therefore, the soil is kept in a certain humidity range. The monopolar plate type automatic soil humidity controller has a simple process and low cost, can be massively produced, and can be widely applied to the fields of agriculture automatic irrigation, flower planting and the like.

Description

The board-like soil moisture automatic controller of one pole

Technical field:

The present invention relates to agriculture automatic irrigation, soil moisture field of detecting, be specifically related to a kind of system that realizes automatic irrigation by the humidity that detects soil

Background technology:

The soil of growth such as crops, flowers need possess the certain humidity environment, and the automatic control of implementing this humidity environment not only helps reducing the labour intensity when irrigating but also can saving irrigation water.In the method for measuring soil moisture, the most direct oven drying method, though this method is measured accurately, sampling, oven dry are time-consuming bothersome, are not suitable in the automation control the in good time measurement to soil moisture.The in good time measuring method of soil moisture mainly contains: conductance method, radiant heat method, microwave method, depressimeter method, neutron determination method, time domain reflectometry, capacitance method etc.The depressimeter method only can be measured the moisture of soil capillary section; Conductance method is the electrical conductivity by measured soil, draws the soil moisture value indirectly, and is also relevant with ionic species and concentration in the soil because soil conductivity is not only relevant with soil moisture, so water quality and fertilising that measurement is irrigated influence bigger; Electrothermal way, microwave method etc. also have certain limitation in method of operating, reappearance and use aspect flexible; The NEUTRON METHOD measurement category is wide, the precision height, but cost is higher relatively, has certain nuclear radiation danger, is not suitable for common agricultural and uses; Time domain reflectometry measures accurately but complex technical process is with high costs; Common capacitance method has been utilized the high-k characteristic of water, tested soil as dielectric, is arranged two pole plates between tested soil, the regional soil humidity between like this can only measuring pad, and all need on the induction pole plate, arrange moisture absorption medium, complex technical process.

Summary of the invention:

At prior technical characteristics, the invention provides the board-like soil moisture automatic controller of a kind of one pole, the board-like soil moisture automatic controller of one pole has utilized the soil of different humidity to have the characteristic of different conductances and the high-k characteristic of water simultaneously, uses simple material just can finish the mensuration of soil moisture.The present invention is made up of fixed polar plate, insulation film, carbon-point, main circuit, power supply, electromagnetism effluent switch.Fixed polar plate is by surface treatment, makes its surface with one deck insulation film plastic packaging, and when pole plate was embedded in the tested soil, the pole plate both sides can form an air gap band, because soil has certain electric conductivity, so air gap band and soil form another virtual pole plate; This virtual pole plate links to each other with the control main circuit by carbon-point, constitutes the electric capacity that can measure; When soil moisture was low, the conductance of soil was less, the virtual pole plate that air gap band and soil constitute and extremely by the fixed polar plate of edge material plastic packaging from far away, the capacitance that reflects is just little; Adopt timer and peripheral resistance capacitance to form multivibrator in the main circuit, the electric capacity that fixed polar plate and virtual pole plate are formed is as the capacity cell of this oscillator, calculate the output signal frequency value of oscillator with the timer of single-chip microcomputer, and with two limiting values that configure in advance relatively, stop water supply thereby when control electromagnetism effluent switch is opened to soil water supply and when closed, the soil that keeps being detected is in the humidity environment of suitable crop or flower growth.

Description of drawings:

Fig. 1 is a theory diagram of the present invention

Fig. 2 is the structure chart of fixed polar plate

Fig. 3 is the structure chart of main circuit

Among the figure: 1 fixed polar plate, 2 insulation films, 3 carbon-points, 4 main circuits, 5 power supplys, 6 electromagnetism effluent switch, 7 AT89S51 single-chip microcomputers, 8 555 timers

Specific embodiments:

Narrate specific embodiments of the present invention below by accompanying drawing, select for use a slice 35 * 25 chamferings for R2 thickness be the stalloy of 0.5mm as fixed polar plate (1), the roughness Ra0.8 on steel disc surface, flatness is 0.08 (as Fig. 2).Fixed polar plate (1) is gone up with insulation film (2) plastic packaging, and fixed polar plate (1) is inserted in the soil, with a lead fixed polar plate (1) and main circuit (4) is joined; Carbon-point (3) is linked to each other with main circuit (4) with lead, and during carbon-point (3) other end was placed into the soil, constituted a virtual electric capacity between fixed polar plate (1) and the tested soil this moment.

Main circuit (4) (as Fig. 3) utilizes 555 timers (8) as critical piece, and simulated capacitance is as the capacity cell of oscillating circuit, and external suitable electric capacity and resistance can constitute multivibrator, and the frequency of oscillating impulse and pulsewidth can be subjected to the adjusting of electric capacity.Thereby circuit has produced vibration, exports rectangular pulse signal, calculates the frequency of input signal with AT89S51 single-chip microcomputer (7).

First soil for growth humidity environment according to crop provides two limiting value (c1 of simulated capacitance when needs are irrigated and needs are irrigated, c2), two frequency of oscillation (f1 that configure of these corresponding main circuits of two limiting values (3), f2), when the main circuit (3) of the board-like soil moisture automatic controller of one pole is connected power supply (5), main circuit will be measured the simulated capacitance value in real time, in circuit, form real-time frequency of oscillation, real-time frequency of oscillation and the f1 that measures, f2 relatively, real-time measuring frequency is during less than f1, then electromagnetism effluent switch (6) is opened, and soil is irrigated; Otherwise if real-time measuring frequency during greater than f2, then electromagnetism effluent switch (6) is closed, and soil is stopped to pour water, and the humidity of control soil is in the scope that is fit to plant growing.

The present invention has simple in structure, utilize the electric conductivity of soil and the high-k characteristic of water dexterously simultaneously, make between fixed polar plate and the soil and form simulated capacitance, the fixed polar plate manufacture craft is simple, material is easy to obtain, do not need A/D converter in the main circuit, circuit structure is simple, and is with low cost.

Claims

1. the board-like soil moisture automatic controller of one pole is made up of fixed polar plate (1), insulation film (2), carbon-point (3), main circuit (4), power supply (5), electromagnetism effluent switch (7).It is characterized in that: fixed polar plate (1) insulation film (2) plastic packaging, and link to each other by lead with main circuit (4), carbon-point (3) one ends bury with soil in, the other end links to each other with main circuit (4) with lead, and the high-k characteristic of utilizing the electric conductivity of soil and water simultaneously is virtual electric capacity of formation between fixed polar plate (1) and the tested soil at this moment.

2. the board-like soil moisture automatic controller of one pole according to claim 1 is characterized in that: fixed polar plate (1) is that a slice 35 * 25, chamfering are the stalloy of 0.5mm for R2 thickness, the roughness Ra0.8 on steel disc surface, and flatness is 0.08.

3. the board-like soil moisture automatic controller of one pole according to claim 1, it is characterized in that: main circuit (4) is the frequency of oscillation measuring circuit that 555 timers (8) and AT89S51 single-chip microcomputer (7) are formed, and relatively controls the switching of electromagnetism effluent switch (7) with the frequency of oscillation of measuring in real time in the circuit and two limiting frequencies that configure in advance.