CN2575668Y

CN2575668Y - Multiside biological chip

Info

Publication number: CN2575668Y
Application number: CN 02282748
Authority: CN
Inventors: 赵春江; 王纪华; 乔晓军; 魏超; 杨月英
Original assignee: Beijing Research Center for Information Technology in Agriculture
Current assignee: Beijing Research Center for Information Technology in Agriculture
Priority date: 2002-11-01
Filing date: 2002-11-01
Publication date: 2003-09-24
Anticipated expiration: 2012-11-01

Abstract

The utility model relates to a resistance type sensor of a water content of soil, which is composed of a mesh-shaped plastic protective cover, a porous ceramic filtering layer, a humidity-sensitive plaster body, metal electrodes and a transmitter, wherein the transmitter is connected with the metal electrodes by connecting conducting wires and is composed of an Ad mu C812 SCM and a peripheral circuit thereof. The utility model can be used in occasions, such as agricultural field irrigation, greenhouse nutrient solution fertilization, irrigation and maintenance of field lawn and trees, etc. The utility model realizes real-time on-line measurement of the water content of the soil.

Description

The resistance-type Soil Moisture Sensor

Technical field

The utility model is a kind of resistance-type Soil Moisture Sensor of the 0-5V of having general-purpose simulation signaling interface, be mainly used in occasions such as the irrigation of agriculture land for growing field crops, the fertilising of warmhouse booth nutrient solution, the irrigation of open-air lawn trees and maintenance, can carry out online in real time to soil moisture content and measure.

Background technology

The method of the real-time measured soil water cut of conventional online comprises negative pressure method, capacitance method, time domain reflectometry (TDR) gypsum electric-resistivity method etc.Need carry out preliminary works such as water filling before wherein the negative pressure method is used, more loaded down with trivial details; The capacitance method less stable; Time domain reflectometry (TDR) though good stability and measuring accuracy height, price is very expensive; Price is low, easy to use though the gypsum electric-resistivity method has, ratio of performance to price advantages of higher, and present product exists shortcomings such as long-time stability are relatively poor, is difficult to popularize.

Summary of the invention

The purpose of this utility model, be release a kind of easy to use, measurement is accurate, cheap and long-time stability are good, the novel resistance-type Soil Moisture Sensor that is easy to promote.

The utility model is made up of sensing probe and transmitter two parts, and is middle by 5 connections of two core flexible cords.Wherein to be divided into be three layers to sensing probe, and outermost one deck is a netted plastic protective cover 1, and middle one deck is that porous ceramics filtering layer 2, interior one deck are placed in the wet gypsum body of sense for the wet gypsum body 3 of sense, metal electrode 4.The transmitter portion of external is characterized as a rectangular build ABS plastic shell (6), the circuit module (7) that Ad μ C812 single-chip microcomputer and peripheral circuit thereof constitute directly is welded on the printed circuit board (PCB) (9), printed circuit board (PCB) by be positioned at 4 screw retention of four jiaos on the internal backplane of rectangular parallelepiped ABS plastic shell (6), signal input socket (10) signal accessory power outlet (8) two ends that lay respectively at rectangular parallelepiped ABS plastic shell (6) are respectively applied for sensor probe and link to each other with measurement instrument.It is output as analog 0-5V voltage signal.

Wrapped up the filtering layer 2 that one deck is made up of special porous ceramics specially outside the main sensing unit in the sensing probe assembly " the wet gypsum body of sense " 3.

By AD μ C812 single-chip microcomputer, LM324 four high guaily unit integrated circuit U ₁With cmos analog switch CD4051 integrated circuit U ₂, resistance R ₁Common positive negative pulse stuffing generator of forming and measurement become send output circuit.The utility model has the advantages that:

1. sensor and transmitter split-type design are middlely linked by thin and soft wire, and be very easy to use.

2. general 0-5V signal output can directly link to each other with most of test instrumentations and TT﹠C system.

3. measuring the resolution height, is 1%, measuring accuracy can reach ± and 3%.

4. reliable operation, long-time stability are good.

5. simple in structure, cost is low, be fit to agricultural and use.

Description of drawings:

Fig. 1 is the object construction synoptic diagram of the present utility model accompanying drawing that can make an abstract.

Fig. 2 is a composition structural representation of the present utility model.

Embodiment

It is three layers that the soil moisture sensing probe partly is divided into: outermost one deck is a netted plastic protective cover 1, and whole probe is shielded; Middle one deck is the filtering layer 2 that porous ceramics is formed, this layer effect is to have the different kinds of ions of considerable influence to filter out to measuring accuracy and stability in the soil, guarantee measuring accuracy so on the one hand, also greatly prolonged the serviceable life of probe on the other hand; Innermost layer has been the gypsum body 3 of the wet effect of sense, the difference of the moisture that is absorbed along with the gypsum body, and corresponding variation also can take place in the resistance that gypsum body interior metal electrode is 4, like this, has just known the moisture in the current soil by the measurement to this resistance.

Transmitter part as shown in Figure 2, the built-in 2.5V high-precision voltage reference of AD μ C812 single-chip microcomputer is by operation amplifier circuit U ₁After-2 bufferings drive again through resistance R ₁Link with an end of sensing probe; The other end of sensing probe is set up 2 with+5V and ground wire respectively through cmos analog switch and is selected 1 interface channel; Earlier analog switch is pushed ground wire one end during use, at this moment sensing probe resistance and R ₁Formation is to the bleeder circuit of 2.5V, and this voltage is through U ₁Enter 12 built-in bit A/D converters of AD μ C812 single-chip microcomputer after-1 driving and become digital measured value, this value is proportional with the sensing probe resistance value.After this process is finished, again analog switch is pushed+5V one end, produce at the two ends of sensing probe this moment and the antipodal voltage signal of state just now, the purpose that produces this signal produces AC signal to eliminate direct current signal to the polarization that sensing probe produces to sensing probe, prolongs its job stability and serviceable life.

AD μ C812 single-chip microcomputer is exported by built-in 12 A/D conversion circuits (DA) port through the linearization of internal processes and compensation back, greenhouse, through operational amplifier U after having obtained the signal voltage measurement result of sensing probe ₁Directly export corresponding 0-5V digital signal after-3 driver drives of forming.This sensor is characterized as two parts split-type design outward, is linked to each other by two core flexible cords between sensing probe and transmitter, and transmitter partly is trifocal 9-30V power supply, and output signal is the 0-5V DC voltage, and resolution is 1%.

Claims

1. the resistance-type Soil Moisture Sensor is characterized in that being made up of sensing probe and transmitter two parts, and sensing probe is connected by two core flexible cords (5) with transmitter is middle; It is three layers that sensing probe is divided into, and outermost one deck is netted plastic protective cover (1), and middle one deck is that porous ceramics filtering layer (2), interior one deck are placed in the wet gypsum body of sense for the wet gypsum body (3) of sense, metal electrode (4); The transmitter portion of external is characterized as a rectangular build ABS plastic shell (6), the circuit module (7) that Ad μ C812 single-chip microcomputer and peripheral circuit thereof constitute directly is welded on the printed circuit board (PCB) (9), printed circuit board (PCB) by be positioned at 4 screw retention of four jiaos on the internal backplane of rectangular parallelepiped ABS plastic shell (6), signal input socket (10) signal accessory power outlet (8) lays respectively at the two ends of rectangular parallelepiped ABS plastic shell (6).It is output as analog 0-5V voltage signal.

2. resistance-type Soil Moisture Sensor as claimed in claim 1 is characterized in that the wet gypsum of sense in the soil moisture content sensing probe is external to have wrapped up the filtering layer that one deck is made up of porous ceramics.

3. resistance-type Soil Moisture Sensor as claimed in claim 1 is characterized in that by AD μ C812 single-chip microcomputer, LM324 four high guaily unit integrated circuit U ₁With cmos analog switch CD4051 integrated circuit U ₂, resistance R ₁Common positive negative pulse stuffing generator and the metering circuit of forming.