CN211528274U - Soil humidity detection circuit based on frequency domain type - Google Patents
Soil humidity detection circuit based on frequency domain type Download PDFInfo
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- CN211528274U CN211528274U CN201922044090.5U CN201922044090U CN211528274U CN 211528274 U CN211528274 U CN 211528274U CN 201922044090 U CN201922044090 U CN 201922044090U CN 211528274 U CN211528274 U CN 211528274U
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- 239000002689 soil Substances 0.000 title claims abstract description 25
- 238000001514 detection method Methods 0.000 title claims abstract description 18
- 239000000523 sample Substances 0.000 claims abstract description 21
- 238000006243 chemical reaction Methods 0.000 claims abstract description 9
- 238000010521 absorption reaction Methods 0.000 claims description 9
- 230000005540 biological transmission Effects 0.000 claims description 9
- 239000003990 capacitor Substances 0.000 claims description 9
- 230000001012 protector Effects 0.000 claims description 8
- 238000005516 engineering process Methods 0.000 abstract description 2
- 230000007613 environmental effect Effects 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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Abstract
The utility model discloses a soil moisture detection circuit based on frequency domain type, which relates to the field of detection equipment, and adopts the technical scheme that the detection circuit comprises a processor, wherein the processor is electrically connected with an oscillator to form a control path, and the output end of the oscillator is respectively connected with the input end I of an exclusive or comparator and the input end of a probe; the output end of the probe is connected with the second input end of the exclusive-or comparator; the output end of the exclusive-or comparator is connected with the input end of the AD conversion circuit, and the output end of the AD conversion circuit is connected with the input end of the processor. The utility model has the advantages that: the scheme has the advantages of fast response, low cost, convenient use and low environmental requirement, adopts the FDR frequency domain reflection detection technology to detect the soil humidity, utilizes the electromagnetic pulse principle to measure the apparent dielectric constant of the soil according to the propagation frequency of electromagnetic waves in a medium, thereby obtaining the volume water content of the soil, and having the advantages of simplicity, safety, rapidness, accuracy, fixed point continuity, automation, wide range, less calibration and the like.
Description
Technical Field
The utility model relates to a check out test set field, in particular to soil moisture detection circuitry based on frequency domain type.
Background
The soil moisture is also called soil moisture content, and represents a physical quantity of the soil moisture. Is a relative variable of soil moisture content. The traditional mode of gathering soil moisture is probe-type detection method, and this kind of mode installation is maintained and often need dig out a pit, inserts the probe wherein, and the construction is complicated when gathering multilayer soil moisture to measurement accuracy is lower, the error is great, and measuring time is longer, and the life-span is shorter, uses inconvenient scheduling problem.
SUMMERY OF THE UTILITY MODEL
To the technical problem, the utility model provides a soil moisture detection circuitry based on frequency domain type.
The technical scheme is that the device comprises a processor, wherein the processor is electrically connected with an oscillator to form a control path, and the output end of the oscillator is respectively connected with a first input end of an exclusive-or comparator and the input end of a probe; the output end of the probe is connected with the second input end of the exclusive-or comparator;
the output end of the exclusive-or comparator is connected with the input end of the AD conversion circuit, and the output end of the AD conversion circuit is connected with the input end of the processor.
Preferably, the temperature acquisition device further comprises a temperature acquisition circuit connected with the processor, and the temperature acquisition circuit is connected with the temperature probe. The temperature value of the current environment is measured through the thermistor with high precision and resolution, and the humidity value is reasonably compensated according to the mutual relation between the temperature and the humidity so as to improve the accuracy of the measured humidity.
Preferably, an absorption capacitor C4 is provided between the output of the oscillator and the probe.
Preferably, the output end of the probe and the output end of the absorption capacitor C4 are electrically connected with the input end of the exclusive-or comparator through a low-capacitance transmission protector.
Preferably, the type of the oscillator is LTC6905HS 5.
Preferably, the model of the low-capacitance transmission protector is ESD 5305.
Preferably, the model of the exclusive-or comparator is MC74VHC1G86DFT 1.
The embodiment of the utility model provides a beneficial effect that technical scheme brought is: the scheme has the advantages of quick response, low cost, convenient use and low environmental requirement, adopts the FDR (frequency Domain reflection) frequency domain reflection detection technology to detect the soil humidity, utilizes the electromagnetic pulse principle to measure the apparent dielectric constant of the soil according to the transmission frequency of electromagnetic waves in a medium, thereby obtaining the volume water content of the soil, and has the advantages of simplicity, safety, rapidness, accuracy, fixed point continuity, automation, wide range, less calibration and the like.
Drawings
Fig. 1 is a circuit diagram of an embodiment of the present invention.
Fig. 2 is a flowchart of an embodiment of the present invention.
Fig. 3 is a circuit diagram of an oscillator according to an embodiment of the present invention.
Fig. 4 is a circuit diagram of the low capacitance transmission protector according to the embodiment of the present invention.
Fig. 5 is a circuit diagram of an exclusive or comparator according to an embodiment of the present invention.
Fig. 6 is a circuit diagram of a temperature compensation part according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, unless otherwise specified, "a plurality" means two or more.
In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.
Example 1
Referring to fig. 1 to 6, the utility model provides a soil moisture detection circuit based on frequency domain type, which comprises a processor, wherein the processor is electrically connected with an oscillator to form a control path, and the output end of the oscillator is respectively connected with the first input end of an exclusive or comparator and the first input end of a probe; the output end of the probe is connected with the second input end of the exclusive-or comparator;
the output end of the exclusive-or comparator is connected with the input end of the AD conversion circuit, and the output end of the AD conversion circuit is connected with the input end of the processor.
The temperature acquisition circuit is connected with the processor and is connected with the temperature probe. The temperature value of the current environment is measured through the thermistor with high precision and resolution, and the humidity value is reasonably compensated according to the mutual relation between the temperature and the humidity so as to improve the accuracy of the measured humidity.
An absorption capacitor C4 is arranged between the output end of the oscillator and the probe.
The output end of the probe and the output end of the absorption capacitor C4 are electrically connected with the input end of the exclusive-or comparator through a low-capacitance transmission protector.
The model of the oscillator is LTC6905HS 5.
The model of the low-capacitance transmission protector is ESD 5305.
The model of the exclusive-or comparator is MC74VHC1G86DFT 1.
When the utility model is used, according to the flow chart,
controlling 4 feet of the frequency oscillator through the processor, so that 5 feet emit pulses with fixed frequency;
the electromagnetic pulse square waves emitted in the first step are input to a pin 1 of a U2 exclusive-or comparator, and simultaneously reach a probe through R10 and an absorption capacitor C4 so as to enter a measured object, and due to the fact that dielectric constants of the measured object are inconsistent, a phase difference can be formed between charging and discharging time of the absorption capacitor C4 and the probe; the humidity signal is converted into a capacitance value through the circuit and finally converted into a frequency signal to be output.
In the second step, the pulse at the probe and absorption capacitor C4 passes through the 2 pin of U2 in the input of the low-capacitance transmission protector;
the two paths of pulses with phase difference pass through a U2, are compared to output square wave signals at 4 pins,
the square wave signal output in the fourth step enters an AD conversion circuit to obtain an AD value;
sixthly, measuring the temperature value of the current environment through a thermistor with high precision and resolution, and reasonably compensating the humidity value according to the correlation between the temperature and the humidity so as to improve the accuracy of the measured humidity;
and eighthly, calculating and temperature compensating the data obtained in the fourth step through a linear fitting algorithm so as to further obtain the humidity value of the measured object.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.
Claims (7)
1. A soil humidity detection circuit based on a frequency domain type is characterized by comprising a processor, wherein the processor is electrically connected with an oscillator to form a control path, and the output end of the oscillator is respectively connected with the first input end of an exclusive-or comparator and the first input end of a probe; the output end of the probe is connected with the second input end of the exclusive-or comparator;
the output end of the exclusive-or comparator is connected with the input end of the AD conversion circuit, and the output end of the AD conversion circuit is connected with the input end of the processor.
2. The frequency domain based soil moisture detection circuit of claim 1 further comprising a temperature acquisition circuit coupled to said processor, said temperature acquisition circuit coupled to a temperature probe.
3. The frequency domain based soil moisture detection circuit of claim 2 wherein an absorption capacitor is disposed between the output of the oscillator and the probe.
4. The frequency domain based soil moisture detection circuit of claim 3 wherein the output of said probe and said absorption capacitor are electrically connected to the input of said XOR comparator through a low capacitance transmission protector.
5. The frequency domain based soil moisture detection circuit as claimed in claim 1, wherein the oscillator is of type LTC6905HS 5.
6. The frequency domain based soil moisture detection circuit of claim 4 wherein said low capacitance transmission protector is of the type ESD 5305.
7. The frequency domain based soil moisture detection circuit of claim 1 wherein said exclusive or comparator is of type MC74VHC1G86DFT 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922044090.5U CN211528274U (en) | 2019-11-22 | 2019-11-22 | Soil humidity detection circuit based on frequency domain type |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922044090.5U CN211528274U (en) | 2019-11-22 | 2019-11-22 | Soil humidity detection circuit based on frequency domain type |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211528274U true CN211528274U (en) | 2020-09-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922044090.5U Active CN211528274U (en) | 2019-11-22 | 2019-11-22 | Soil humidity detection circuit based on frequency domain type |
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| Country | Link |
|---|---|
| CN (1) | CN211528274U (en) |
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2019
- 2019-11-22 CN CN201922044090.5U patent/CN211528274U/en active Active
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