CN105181765A

CN105181765A - Soil humidity sensor

Info

Publication number: CN105181765A
Application number: CN201510686731.0A
Authority: CN
Inventors: 王文拓
Original assignee: Hangzhou Chuan Hui Agricultural Science And Technology Co Ltd
Current assignee: Hangzhou Chuan Hui Agricultural Science And Technology Co Ltd
Priority date: 2015-10-22
Filing date: 2015-10-22
Publication date: 2015-12-23

Abstract

The invention provides a soil humidity sensor. The soil humidity sensor comprises a crystal oscillator excitation signal, a loading network, a phase discriminator, a low pass filter and an AD (Analogue-Digital) acquisition unit, wherein the output end of the crystal oscillator excitation signal is connected with the loading network and the phase discriminator respectively; the loading network is connected with the phase discriminator; the phase discriminator is connected with the low pass filter and the AD acquisition unit sequentially. The novel soil humidity sensor provided by the invention has the advantages of low price, convenience and safety, rapidness and accuracy, fixed point and continuousness, automation, wide measuring range, few calibration and high precision, has an application range, is suitable for the fields of water-saving agricultural irrigation, greenhouses, flowers and vegetables, grass farms, soil rapid detection, plant cultivation, scientific experiments and the like, and is especially suitable for common products including intelligent flowerpots and the like.

Description

A kind of soil humidity sensor

Technical field

The invention belongs to soil moisture measurement technical field, particularly relate to a kind of soil humidity sensor.

Background technology

Soil humidity sensor is the checkout equipment the most often applied in soil moisture detection.Traditional soil humidity sensor, primarily of two large classes:

One class is resistor-type, carrys out indirect reaction soil moisture by measuring resistance, can not be used for measuring humidity value, its low price, being applicable to sizing and measuring, can only being used for judging that soil is the need of watering.

Another kind of is FDR type, its utilize electromagnetic pulse principle, according to electromagnetic wave in media as well frequencies of propagation measure the apparent dielectric constant of soil, thus obtain volumetric water content of soil.FDR type soil humidity sensor have handy and safe, quick and precisely, fixed point continuously, robotization, wide-range, the advantage such as few demarcation, be a kind of good soil water measurement sensor, but expensive, be unsuitable for the product that intelligent flowerpot etc. is common.

Summary of the invention

For the deficiencies in the prior art, the invention provides a kind of novel soil humidity sensor, it has low price, handy and safe, quick and precisely, fixed point continuously, robotization, wide-range, to demarcate less, advantage that precision is high, applied range, be applicable to water-saving agriculture irrigation, warmhouse booth, flowers or vegetables, grass farm, field such as soil speed survey, plant cultivation, scientific experimentation etc., be particularly suitable for the product that intelligent flowerpot etc. is common.

For achieving the above object, the technical scheme that the present invention takes is:

A kind of soil humidity sensor, comprise crystal oscillator pumping signal, laod network, phase detector, low-pass filter and AD collector, the output terminal of described crystal oscillator pumping signal connects laod network and phase detector respectively, and described laod network connects described phase detector, and described phase detector connects low-pass filter and AD collector more successively.

As preferably, described crystal oscillator pumping signal comprises Enable Pin, earth terminal, output terminal and power end, and this crystal oscillator pumping signal can produce pumping signal, for encouraging soil load.

As preferably, described laod network is RC network, is made up of a resistance and a capacitor, and capacitor connects two and visits sheets, visits the electric capacity that sheet inserts soil test soil.

As preferably, described phase detector comprises earth terminal, output terminal, power end and two input ends, and two input ends respectively connect crystal oscillator pumping signal and laod network, carries out phase demodulation respectively to pumping signal with through the signal of laod network phase shift.

As preferably, described low-pass filter comprises: input end, for feed-in duty cycle signals; Export termination AD collector, for feed-in direct current signal; Resistance and capacity cell, one end of described resistance connects input end, and the other end of resistance connects output terminal and capacity cell respectively, described capacity cell ground connection, and described AD collector is for gathering direct current signal.

As preferably, described low-pass filter comprises two resistance and two capacity cells.

A kind of soil humidity sensor provided by the invention, its principle of work is: utilize the dielectric property of soil moisture content to measure soil moisture content.Moisture in soil is more, and specific inductive capacity is higher, thus causes electric capacity C larger.Pumping signal, after RC laod network, will inevitably produce phase shift.By using phase detector to compare excitation original signal and the signal after loaded webs phase shift, just phase-shift phase can be measured.Again by low-pass filter, phase detector phase-shift phase out (showing as the square wave of different duty) is converted to direct current signal, facilitates the collection of AD collector, just can measure soil moisture.

Soil humidity sensor of the present invention its there is low price, handy and safe, quick and precisely, fixed point continuously, robotization, wide-range, to demarcate less, advantage that precision is high, applied range, be applicable to water-saving agriculture irrigation, warmhouse booth, flowers or vegetables, grass farm, field such as soil speed survey, plant cultivation, scientific experimentation etc., be particularly suitable for the product that intelligent flowerpot etc. is common.

Accompanying drawing explanation

Fig. 1 is the module frame chart of soil humidity sensor of the present invention;

Fig. 2 is the circuit diagram of soil humidity sensor of the present invention.

Embodiment

Below in conjunction with specific embodiments and the drawings, the present invention will be further described.

Embodiment

Soil humidity sensor as depicted in figs. 1 and 2 comprises crystal oscillator pumping signal Y1, laod network, phase detector U1, low-pass filter and AD collector, the output terminal of described crystal oscillator pumping signal connects laod network and phase detector respectively, described laod network connects described phase detector, and described phase detector connects low-pass filter and AD collector more successively.

Described crystal oscillator pumping signal comprises Enable Pin EN, earth terminal GND, output terminal OUT and power end VCC, and this crystal oscillator pumping signal can produce pumping signal, for encouraging soil load.

Described laod network is RC network, is made up of a resistance R1 and capacitor, and capacitor connects two and visits sheet 6, visits the electric capacity that sheet inserts soil test soil.

Described phase detector comprises earth terminal GND, output terminal Y, power end VCC and two input end A and B, and two input end A and B respectively connect pumping signal crystal oscillator and laod network, carries out phase demodulation respectively to pumping signal with through the signal of laod network phase shift.

Described low-pass filter comprises: input end, for feed-in duty cycle signals; Export termination AD collector, for feed-in direct current signal; Two resistance R2 and R3 and two electric capacity C3 and C4 element; Described resistance R1 and resistance R2 connects, described resistance R2 one end connects input end, the other end of resistance R3 meets output terminal OUT respectively, described electric capacity C3 connects the other end of R2 resistance, electric capacity C3 ground connection, one end of described electric capacity C4 connecting resistance R3, electric capacity C4 ground connection, described AD collector is for gathering direct current signal.

Above embodiment is only be described the preferred embodiment of the present invention; not scope of the present invention is limited; under not departing from the present invention and designing the prerequisite of spirit; the various distortion that the common engineering technical personnel in this area make technical scheme of the present invention and improvement, all should fall in protection domain that claims of the present invention determine.

Claims

1. a soil humidity sensor, it is characterized in that comprising crystal oscillator pumping signal, laod network, phase detector, low-pass filter and AD collector, the output terminal of described crystal oscillator pumping signal connects laod network and phase detector respectively, and described laod network connects described phase detector, and described phase detector connects low-pass filter and AD collector more successively.

2. a kind of soil humidity sensor according to claim 1, it is characterized in that described crystal oscillator pumping signal comprises Enable Pin, earth terminal, output terminal and high level end, this crystal oscillator pumping signal can produce pumping signal, for encouraging soil load.

3. a kind of soil humidity sensor according to claim 1, is characterized in that described laod network is RC network, is made up of a resistance and a capacitor, and capacitor connects two and visits sheet, visits the electric capacity that sheet inserts soil test soil.

4. a kind of soil humidity sensor according to claim 1, it is characterized in that described phase detector comprises earth terminal, output terminal, high level end and two input ends, two input ends respectively connect crystal oscillator pumping signal and laod network, carry out phase demodulation respectively to pumping signal with through the signal of laod network phase shift.

5. a kind of soil humidity sensor according to claim 1, is characterized in that described low-pass filter comprises:

Input end, for feed-in duty cycle signals;

Export termination AD collector, for feed-in direct current signal;

Resistance and capacity cell, one end of described resistance connects input end, and the other end of resistance connects output terminal and capacity cell respectively, described capacity cell ground connection.

6. a kind of soil humidity sensor according to claim 5, is characterized in that described low-pass filter comprises two resistance and two capacity cells.