CN211856441U - Online soil pH sensor - Google Patents
Online soil pH sensor Download PDFInfo
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- CN211856441U CN211856441U CN202020587787.7U CN202020587787U CN211856441U CN 211856441 U CN211856441 U CN 211856441U CN 202020587787 U CN202020587787 U CN 202020587787U CN 211856441 U CN211856441 U CN 211856441U
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Abstract
The utility model provides an online soil PH sensor, which comprises a shell, wherein one end of the shell is provided with two metal electrodes, the other end of the shell is provided with a power supply connector, a circuit board is arranged in the shell, one end of the circuit board is connected with the metal electrodes, and the other end of the circuit board is externally connected with a power supply through the power supply connector; the metal electrode is connected with the acquisition circuit, the acquisition circuit is respectively connected with the operational amplifier circuit and the control circuit, the control circuit is connected with the operational amplifier circuit, the power supply circuit is connected with an external power supply through a power supply connector, and the power supply circuit is respectively connected with the acquisition circuit, the operational amplifier circuit and the control circuit. The utility model discloses can use terminal equipment to pass through switching between 485 communication control circuit to can use for a long time in adverse circumstances, metal electrode can not influence measuring result because of using the disconnected chemical reaction of production oxide film.
Description
Technical Field
The utility model relates to a soil detection technology field, more specifically the utility model relates to an online soil PH sensor that says so.
Background
At present, in the whole agricultural internet of things industry, a glass electrode pH sensor is used for online monitoring of the pH value of soil, the sensor comprises a glass electrode, a signal processing converter and a protective cover, the signal processing converter is connected with the glass electrode through a lead, the protective cover is used for covering the glass electrode, and a circuit board is arranged in the signal processing converter. The glass electrode pH sensor is originally used for testing the pH value of a solution by a laboratory instrument or applied to a water treatment system, and is not suitable for being used as an online soil sensor.
There are several main reasons for this:
1. the glass electrode is made of fragile materials and is easy to damage when being buried in soil;
2. the glass electrode needs to be cleaned and maintained by chemical reagents regularly, otherwise, the glass electrode fails and cannot be used, and the farmer does not have the operation skills;
3. the sensor consists of a glass electrode and a signal processing and converting circuit, and has large volume and inconvenient field installation and layout;
4. the glass electrode PH sensor is expensive, is not beneficial to large-scale layout and use, and influences the popularization range of the agricultural Internet of things industry.
In addition, the existing soil PH measurement mainly comprises the steps of uniformly mixing a soil sample with distilled water, and then measuring by using a traditional glass electrode PH sensor, wherein the measurement mode is not suitable for long-term online PH value measurement, mainly because 1, the measurement mode needs to manually collect and uniformly mix the soil sample. 2. The glass electrode pH sensor needs to be scrubbed regularly, and needs to be soaked in a balancing solution when not being measured. 3. The sensors and acquisition circuits are relatively complex.
The later stage has neotype soil PH meter that adopts metal electrode again, and this kind of PH meter adopts aluminium metal electrode and soil to constitute primary cell, thereby calculates the PH value through measuring reaction current, but following going on of electrochemical reaction behind this kind of equipment insertion soil, the metal surface can form the oxide film, and the oxide film can block going on of chemical reaction to make the PH value show partially neutral. And the longer the time, the more neutral the PH value.
For the reasons, the agricultural internet of things industry urgently needs a new online PH sensor to replace a glass electrode sensor so as to meet the industry requirements.
SUMMERY OF THE UTILITY MODEL
To the above problem, an object of the present invention is to provide an online soil PH sensor.
The utility model discloses a realize above-mentioned purpose, realize through following technical scheme: an online soil PH sensor comprises a shell, wherein two metal electrodes are arranged at one end of the shell, a power supply connector is arranged at the other end of the shell, a circuit board is arranged in the shell, one end of the circuit board is connected with the metal electrodes, and the other end of the circuit board is externally connected with a power supply through the power supply connector; the metal electrode is connected with the acquisition circuit, the acquisition circuit is respectively connected with the operational amplifier circuit and the control circuit, the control circuit is connected with the operational amplifier circuit, the power supply circuit is connected with an external power supply through a power supply connector, and the power supply circuit is respectively connected with the acquisition circuit, the operational amplifier circuit and the control circuit.
Further, the acquisition circuit includes: a digital control analog switch U4, a resistor R6, a capacitor C10, a capacitor C11, a metal electrode B1 and a metal electrode B2; one pin of the digital control analog switch U4 is connected with the operational amplifier circuit, the three pins of the digital control analog switch U4 are connected with the metal electrode B1, and the five pins, nine pins, ten pins and fourteen pins of the digital control analog switch U4 are respectively connected with the control circuit; six feet, seven feet, eight feet and twelve feet of the digital control analog switch U4 are respectively grounded, and thirteen feet of the digital control analog switch U4 are connected with the metal electrode B2; one end of the capacitor C10 is respectively connected with sixteen pins of the digital control analog switch U4 and one end of the resistor R6, and the other end of the capacitor C10 is grounded; the other end of the resistor R6 is respectively connected with the power supply circuit and one end of the capacitor C11, and the other end of the capacitor C11 is grounded.
Further, the operational amplifier circuit includes: an operational amplifier U2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C1, a capacitor C7, a capacitor C8, a capacitor C9, a diode D1 and a diode D2; one pin of the operational amplifier U2 is connected to one end of the resistor R3, one end of the resistor R5, and one end of the capacitor C9, respectively; two pins of the operational amplifier U2 are respectively connected with one end of a resistor R4, the other end of a resistor R5 and the other end of a capacitor C9, and the other end of the resistor R4 is grounded; the three pins of the operational amplifier U2 are respectively connected with one end of a capacitor C7 and one end of a resistor R2, the other end of the capacitor C7 is grounded, the other end of the resistor R2 is respectively connected with one end of a resistor R1 and one pin of a digital control analog switch U4, and the other end of the resistor R1 is grounded; the four legs of the operational amplifier U2 are grounded; the eight pins of the operational amplifier U2 are respectively connected with the power supply circuit and one end of the capacitor C1, and the other end of the capacitor C1 is grounded; the other end of the resistor R3 is connected with the control circuit, the anode of the diode D1, the cathode of the diode D2 and one end of the capacitor C8, the cathode of the diode D1 is connected with the power supply circuit, and the anode of the diode D2 and the other end of the capacitor C8 are grounded.
Further, the control circuit includes: the single chip microcomputer U3 and the resistor R7; one pin, nine pins, twenty-four pins, thirty-six pins and forty-eight pins of the single chip microcomputer U3 are respectively connected with a power supply circuit; eight feet, twenty-three feet, thirty-five feet and forty-seven feet of the single chip microcomputer U3 are respectively grounded; forty-four pins of the singlechip U3 are connected with a resistor R7 in series and then grounded; eighteen feet of the single chip microcomputer U3 are connected with five feet of the digital control analog switch U4, nineteen feet of the single chip microcomputer U3 are connected with fourteen feet of the digital control analog switch U4, twenty-one feet of the single chip microcomputer U3 are connected with ten feet of the digital control analog switch U4, twenty-two feet of the single chip microcomputer U3 are connected with nine feet of the digital control analog switch U4, and eleven feet of the single chip microcomputer U3 are connected with the other end of the resistor R3.
Further, the power supply circuit includes: a power supply chip U1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a diode PD1 and a piezoresistor TVS 1; one pin of the power supply chip U1 is grounded; two pins of the power chip U1 are respectively connected with four pins of the power chip U1, a cathode of the diode PD1, one end of the voltage dependent resistor TVS1, one end of the capacitor C3 and one end of the capacitor C4, an anode of the diode PD1 is connected with the power supply connector, and the other end of the voltage dependent resistor TVS1, the other end of the capacitor C3 and the other end of the capacitor C4 are respectively grounded; the three pins of the power supply chip U1 are respectively connected with the other end of the resistor R6, the eight pin of the operational amplifier U2, the cathode of the diode D1, one pin of the singlechip U3, the nine pin of the singlechip U3, the twenty-four pin of the singlechip U3, the thirty-six pin of the singlechip U3, the forty-eight pin of the singlechip U3, one end of the capacitor C2 and one end of the capacitor C5, and the other end of the capacitor C2 and the other end of the capacitor C5 are respectively grounded.
Further, the digital control analog switch adopts a CD4052 channel digital control analog switch.
Further, the shell is made of epoxy resin.
Further, the two metal electrodes are respectively an aluminum alloy electrode and a zinc alloy electrode.
Contrast prior art, the utility model discloses beneficial effect lies in: the utility model provides an online soil PH sensor, which adopts an aluminum alloy electrode and a zinc alloy electrode as the reaction electrodes of a primary battery, and soil as a conductive solution to form the primary battery to generate chemical reaction, and the PH value is obtained according to the current generated by the reaction; the utility model discloses a singlechip commonly used in the field can use terminal equipment to realize the switching between acquisition circuit and opposite phase voltage circuit through 485 communication control CD4052 passageway digital control analog switch.
The utility model uses the epoxy resin shell to encapsulate the circuit board and one end of the electrode, the material is firm, and the damage caused by common agricultural activities is not easy to occur; the device does not need regular maintenance and can be used in severe environment for a long time; the agricultural Internet of things system is small in size and convenient to arrange in a farmland; the cost is low, the system can be used in a large scale, and the popularization of an agricultural Internet of things system is facilitated; the soil sample is not required to be collected and uniformly mixed in the measurement, and the soil sample can be directly inserted into farmland soil for measurement; because the two ends of the metal electrode are provided with the voltages with opposite phases and the same frequency in the non-measuring state, the metal electrode cannot generate an oxide film to block chemical reaction due to use, and the measuring result is not influenced.
Therefore, compared with the prior art, the utility model has the substantive characteristics and the progress, and the beneficial effects of the implementation are also obvious.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of the present invention;
fig. 2 is an electrical block diagram of the present invention;
fig. 3 is a schematic diagram of the acquisition circuit and the operational amplifier circuit of the present invention;
fig. 4 is a schematic diagram of a control circuit of the present invention;
fig. 5 is a schematic diagram of the power supply circuit of the present invention;
fig. 6 is an electrode potential diagram of a metal electrode B1 according to the present invention;
fig. 7 is an electrode potential diagram of the metal electrode B2 of the present invention.
In the drawings, each reference numeral denotes:
1. a housing; 2. a metal electrode; 3. and a power supply connector.
Detailed Description
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings.
As shown in fig. 1, the online soil PH sensor comprises a casing 1, two metal electrodes 2 are arranged at one end of the casing 1, a power supply connector 3 is arranged at the other end of the casing 1, and a circuit board is arranged in the casing 1. Wherein, the shell adopts the epoxy resin shell. The two metal electrodes are respectively an aluminum alloy electrode and a zinc alloy electrode.
As shown in fig. 2, one end of the circuit board is connected with the metal electrode, the other end of the circuit board is connected with an external power supply through a power supply connector, the circuit board is provided with a collection circuit, an operational amplifier circuit, a control circuit and a power supply circuit, the metal electrode is connected with the collection circuit, the collection circuit is respectively connected with the operational amplifier circuit and the control circuit, the control circuit is connected with the operational amplifier circuit, the power supply circuit is connected with the external power supply through the power supply connector, and the power supply circuit is respectively connected with the collection circuit, the operational amplifier circuit and the control circuit.
As shown in fig. 3, the acquisition circuit includes: a digital control analog switch U4, a resistor R6, a capacitor C10, a capacitor C11, a metal electrode B1 and a metal electrode B2; one pin of the digital control analog switch U4 is connected with the operational amplifier circuit, the three pins of the digital control analog switch U4 are connected with the metal electrode B1, and the five pins, nine pins, ten pins and fourteen pins of the digital control analog switch U4 are respectively connected with the control circuit; six feet, seven feet, eight feet and twelve feet of the digital control analog switch U4 are respectively grounded, and thirteen feet of the digital control analog switch U4 are connected with the metal electrode B2; one end of the capacitor C10 is respectively connected with sixteen pins of the digital control analog switch U4 and one end of the resistor R6, and the other end of the capacitor C10 is grounded; the other end of the resistor R6 is respectively connected with the power supply circuit and one end of the capacitor C11, and the other end of the capacitor C11 is grounded. The digital control analog switch U4 adopts a CD4052 channel digital control analog switch.
The operational amplifier circuit includes: an operational amplifier U2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C1, a capacitor C7, a capacitor C8, a capacitor C9, a diode D1 and a diode D2; one pin of the operational amplifier U2 is connected to one end of the resistor R3, one end of the resistor R5, and one end of the capacitor C9, respectively; two pins of the operational amplifier U2 are respectively connected with one end of a resistor R4, the other end of a resistor R5 and the other end of a capacitor C9, and the other end of the resistor R4 is grounded; the three pins of the operational amplifier U2 are respectively connected with one end of a capacitor C7 and one end of a resistor R2, the other end of the capacitor C7 is grounded, the other end of the resistor R2 is respectively connected with one end of a resistor R1 and one pin of a digital control analog switch U4, and the other end of the resistor R1 is grounded; the four legs of the operational amplifier U2 are grounded; the eight pins of the operational amplifier U2 are respectively connected with the power supply circuit and one end of the capacitor C1, and the other end of the capacitor C1 is grounded; the other end of the resistor R3 is connected with the control circuit, the anode of the diode D1, the cathode of the diode D2 and one end of the capacitor C8, the cathode of the diode D1 is connected with the power supply circuit, and the anode of the diode D2 and the other end of the capacitor C8 are grounded.
As shown in fig. 4, the control circuit includes: the single chip microcomputer U3 and the resistor R7; one pin, nine pins, twenty-four pins, thirty-six pins and forty-eight pins of the single chip microcomputer U3 are respectively connected with a power supply circuit; eight feet, twenty-three feet, thirty-five feet and forty-seven feet of the single chip microcomputer U3 are respectively grounded; forty-four pins of the singlechip U3 are connected with a resistor R7 in series and then grounded; eighteen feet of the single chip microcomputer U3 are connected with five feet of the digital control analog switch U4, nineteen feet of the single chip microcomputer U3 are connected with fourteen feet of the digital control analog switch U4, twenty-one feet of the single chip microcomputer U3 are connected with ten feet of the digital control analog switch U4, twenty-two feet of the single chip microcomputer U3 are connected with nine feet of the digital control analog switch U4, and eleven feet of the single chip microcomputer U3 are connected with the other end of the resistor R3.
As shown in fig. 5, the power supply circuit includes: a power supply chip U1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a diode PD1 and a piezoresistor TVS 1; one pin of the power supply chip U1 is grounded; two pins of the power chip U1 are respectively connected with four pins of the power chip U1, a cathode of the diode PD1, one end of the voltage dependent resistor TVS1, one end of the capacitor C3 and one end of the capacitor C4, an anode of the diode PD1 is connected with the power supply connector, and the other end of the voltage dependent resistor TVS1, the other end of the capacitor C3 and the other end of the capacitor C4 are respectively grounded; the three pins of the power supply chip U1 are respectively connected with the other end of the resistor R6, the eight pin of the operational amplifier U2, the cathode of the diode D1, one pin of the singlechip U3, the nine pin of the singlechip U3, the twenty-four pin of the singlechip U3, the thirty-six pin of the singlechip U3, the forty-eight pin of the singlechip U3, one end of the capacitor C2 and one end of the capacitor C5, and the other end of the capacitor C2 and the other end of the capacitor C5 are respectively grounded.
During the use, the utility model discloses a singlechip U3 external power supply, frequency 1K opposite phase voltage is applyed respectively to singlechip U3 control eighteen feet, nineteen foot pins on two metal electrodes, realizes the switching between measuring circuit and opposite phase voltage circuit through CD4052 passageway digital control analog switch. When the utility model discloses be in when non-measuring state, 1 and 0 can be write into respectively to CD 4052's address terminal A, B through 485 signals to terminal equipment, and CD4052 can control tripod (Y OUT) and five feet (Y1IN) to switch on this moment, and thirteen feet (X OUT) and fourteen feet (X1IN) switch on, make B1, B2 two electrodes and phase reversal voltage circuit link to each other, make there is the voltage to exist all the time between two electrodes, prevent that the electrode surface from generating the oxide film; when the device receives a signal for starting measurement, the terminal device writes 0 and 0 into the address terminal A, B of the CD4052 through 485 signals respectively, and at this time, the CD4052 controls conduction of YOUT and Y0IN and conduction of X OUT and X0IN, so that the two electrodes are connected with the measurement circuit to start normal measurement; after the measurement is finished, the device receives a measurement stopping signal, the terminal device writes 1 and 0 into the address terminal A, B of the CD4052 through 485 signals respectively, at this time, the CD4052 controls the Y OUT and the Y1IN to be conducted, and the X OUT and the X1IN to be conducted, as shown in fig. 6 and 7, the two electrodes B1 and B2 are connected with a phase-opposite voltage circuit, so that voltage exists between the two electrodes all the time, and an oxide film generated on the surface of the electrode is prevented from influencing the measurement result.
The present invention will be further described with reference to the accompanying drawings and specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teachings of the present invention, and these equivalents also fall within the scope defined in the present application.
Claims (8)
1. An online soil pH sensor is characterized by comprising a shell, wherein one end of the shell is provided with two metal electrodes, the other end of the shell is provided with a power supply connector, a circuit board is arranged in the shell, one end of the circuit board is connected with the metal electrodes, and the other end of the circuit board is externally connected with a power supply through the power supply connector;
the metal electrode is connected with the acquisition circuit, the acquisition circuit is respectively connected with the operational amplifier circuit and the control circuit, the control circuit is connected with the operational amplifier circuit, the power supply circuit is connected with an external power supply through a power supply connector, and the power supply circuit is respectively connected with the acquisition circuit, the operational amplifier circuit and the control circuit.
2. The online soil PH sensor according to claim 1, wherein the acquisition circuit comprises: a digital control analog switch U4, a resistor R6, a capacitor C10, a capacitor C11, a metal electrode B1 and a metal electrode B2;
one pin of the digital control analog switch U4 is connected with the operational amplifier circuit, the three pins of the digital control analog switch U4 are connected with the metal electrode B1, and the five pins, nine pins, ten pins and fourteen pins of the digital control analog switch U4 are respectively connected with the control circuit; six feet, seven feet, eight feet and twelve feet of the digital control analog switch U4 are respectively grounded, and thirteen feet of the digital control analog switch U4 are connected with the metal electrode B2; one end of the capacitor C10 is respectively connected with sixteen pins of the digital control analog switch U4 and one end of the resistor R6, and the other end of the capacitor C10 is grounded; the other end of the resistor R6 is respectively connected with the power supply circuit and one end of the capacitor C11, and the other end of the capacitor C11 is grounded.
3. The online soil PH sensor according to claim 2, wherein the operational amplifier circuit comprises: an operational amplifier U2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C1, a capacitor C7, a capacitor C8, a capacitor C9, a diode D1 and a diode D2;
one pin of the operational amplifier U2 is connected to one end of the resistor R3, one end of the resistor R5, and one end of the capacitor C9, respectively;
two pins of the operational amplifier U2 are respectively connected with one end of a resistor R4, the other end of a resistor R5 and the other end of a capacitor C9, and the other end of the resistor R4 is grounded; the three pins of the operational amplifier U2 are respectively connected with one end of a capacitor C7 and one end of a resistor R2, the other end of the capacitor C7 is grounded, the other end of the resistor R2 is respectively connected with one end of a resistor R1 and one pin of a digital control analog switch U4, and the other end of the resistor R1 is grounded; the four legs of the operational amplifier U2 are grounded; the eight pins of the operational amplifier U2 are respectively connected with the power supply circuit and one end of the capacitor C1, and the other end of the capacitor C1 is grounded; the other end of the resistor R3 is connected with the control circuit, the anode of the diode D1, the cathode of the diode D2 and one end of the capacitor C8, the cathode of the diode D1 is connected with the power supply circuit, and the anode of the diode D2 and the other end of the capacitor C8 are grounded.
4. The online soil PH sensor according to claim 3, wherein the control circuit comprises: the single chip microcomputer U3 and the resistor R7;
one pin, nine pins, twenty-four pins, thirty-six pins and forty-eight pins of the single chip microcomputer U3 are respectively connected with a power supply circuit;
eight feet, twenty-three feet, thirty-five feet and forty-seven feet of the single chip microcomputer U3 are respectively grounded; forty-four pins of the singlechip U3 are connected with a resistor R7 in series and then grounded; eighteen feet of the single chip microcomputer U3 are connected with five feet of the digital control analog switch U4, nineteen feet of the single chip microcomputer U3 are connected with fourteen feet of the digital control analog switch U4, twenty-one feet of the single chip microcomputer U3 are connected with ten feet of the digital control analog switch U4, twenty-two feet of the single chip microcomputer U3 are connected with nine feet of the digital control analog switch U4, and eleven feet of the single chip microcomputer U3 are connected with the other end of the resistor R3.
5. The online soil pH sensor of claim 4, wherein the power supply circuit comprises: a power supply chip U1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a diode PD1 and a piezoresistor TVS 1; one pin of the power supply chip U1 is grounded; two pins of the power chip U1 are respectively connected with four pins of the power chip U1, a cathode of the diode PD1, one end of the voltage dependent resistor TVS1, one end of the capacitor C3 and one end of the capacitor C4, an anode of the diode PD1 is connected with the power supply connector, and the other end of the voltage dependent resistor TVS1, the other end of the capacitor C3 and the other end of the capacitor C4 are respectively grounded; the three pins of the power supply chip U1 are respectively connected with the other end of the resistor R6, the eight pin of the operational amplifier U2, the cathode of the diode D1, one pin of the singlechip U3, the nine pin of the singlechip U3, the twenty-four pin of the singlechip U3, the thirty-six pin of the singlechip U3, the forty-eight pin of the singlechip U3, one end of the capacitor C2 and one end of the capacitor C5, and the other end of the capacitor C2 and the other end of the capacitor C5 are respectively grounded.
6. The online soil PH sensor according to claim 2, wherein the digital controlled analog switch is a CD4052 channel digital controlled analog switch.
7. The online soil PH sensor according to claim 1, wherein the housing is an epoxy housing.
8. The on-line soil PH sensor according to claim 1, wherein the two metal electrodes are an aluminum alloy electrode and a zinc alloy electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020587787.7U CN211856441U (en) | 2020-04-17 | 2020-04-17 | Online soil pH sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020587787.7U CN211856441U (en) | 2020-04-17 | 2020-04-17 | Online soil pH sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211856441U true CN211856441U (en) | 2020-11-03 |
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ID=73177359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020587787.7U Active CN211856441U (en) | 2020-04-17 | 2020-04-17 | Online soil pH sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211856441U (en) |
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2020
- 2020-04-17 CN CN202020587787.7U patent/CN211856441U/en active Active
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