Soil EC and humidity multiplexing measuring circuit

Abstract

The utility model discloses a soil EC and humidity multiplexing measuring circuit, and relates to the technical field of soil measurement. The device comprises an EC measuring circuit, a humidity measuring circuit and a multiplexing switching circuit, the EC measuring circuit and the humidity measuring circuit are respectively connected with the multiplexing switching circuit, EC measuring transmitting and receiving signals are connected to a normally-closed port of a signal relay, humidity transmitting and receiving signals are connected to a normally-open port of the signal relay, and the multiplexing switching circuit is connected with the signal relay. And the transmitting probe and the receiving probe are respectively connected to two common ports of the relay. According to the utility model, the single chip microcomputer in the soil sensor is used for controlling the actuation of the relay, so that the switching of EC and humidity signals on the probe is realized, the measurement area is enlarged, the data is accurate, the data authenticity is improved, the cost is saved, and the application prospect is wide.

Description

Technical Field

[0001] The utility model relates to the technical field of soil measurement, in particular to a soil EC and humidity multiplexing measurement circuit. Background Art

[0002] At present, the needle-type soil sensor measures soil EC by using one needle to transmit a signal and another needle to receive a signal. By detecting the received signal, the EC value of the soil is analyzed; the principle of measuring soil humidity is the same. The common soil sensor probe spacing is only about 1 cm, and the measured soil area is very small. In many cases, the true soil data in the entire area cannot be measured. In order to more realistically measure the soil data in the entire area, the test area of ​​the probe needs to be increased. Based on this, it is particularly necessary to design a soil EC and humidity multiplexing measurement circuit. Utility Model Content

[0003] In view of the deficiencies in the prior art, the purpose of the utility model is to provide a soil EC and humidity multiplexing measurement circuit with a reasonable circuit structure design, a larger measurement area, more accurate data, improved data authenticity, and cost savings. It has strong practicality and is easy to promote and use.

[0004] In order to achieve the above-mentioned purpose, the utility model is realized through the following technical scheme: a soil EC and humidity multiplexing measurement circuit, including an EC measurement circuit, a humidity measurement circuit and a multiplexing switching circuit, the EC measurement circuit and the humidity measurement circuit are respectively connected to the multiplexing switching circuit; the EC measurement circuit includes a first operational amplifier-a fifth operational amplifier, a first resistor-a fifteenth resistor, a first capacitor-a ninth capacitor, pin 1 of the first operational amplifier is connected to the first resistor, pin 3 of the first operational amplifier is sequentially connected to the second resistor, the third resistor to pin 4, the node between the second resistor and the third resistor is respectively connected to the fourth resistor, the fifth resistor to pin 3 and pin 4 of the second operational amplifier, pin 1 of the second operational amplifier is connected to the sixth resistor to pin 4 of the first operational amplifier; pin 1 of the third operational amplifier is respectively connected to the seventh resistor and the eighth resistor to the 5V power supply terminal and the ground The third operational amplifier is connected to the 3rd and 4th pins of the third operational amplifier, and a parallel circuit of a ninth resistor and a first capacitor is connected between the 3rd and 4th pins; the 3rd pin of the fourth operational amplifier is connected to one end of the tenth resistor, and the other end of the tenth resistor is respectively connected to the second capacitor and the eleventh resistor to the multiplexing switching circuit and the ground end; the other end of the tenth resistor and the 4th pin of the fourth operational amplifier are connected to a parallel circuit of a twelfth resistor, a thirteenth resistor and a third capacitor; the 4th pin of the fourth operational amplifier is connected to the fourteenth resistor to the 3rd pin of the fifth operational amplifier, and a parallel circuit of a fifteenth resistor and a fourth capacitor is connected between the 3rd and 4th pins of the fifth operational amplifier; the 5th pins of the first operational amplifier, the second operational amplifier, the third operational amplifier, the fourth operational amplifier and the fifth operational amplifier are all connected to the 5V power supply end, and the fifth capacitor, the sixth capacitor, the seventh capacitor, the eighth capacitor and the ninth capacitor are connected in parallel between the 5V power supply end and the ground end.

[0005] The humidity measurement circuit includes a logic chip, a control unit, a sixteenth resistor-an eighteenth resistor, a tenth capacitor-a twelfth capacitor, wherein pin 1 and pin 4 of the control unit are respectively connected to the sixteenth resistor and the tenth capacitor to the ground, pin 4 and pin 3 of the control unit are respectively connected to pin 5 and pin 1 of the logic chip, pin 3 of the control unit is also connected to the seventeenth resistor to pin 2 of the logic chip and a multiplexing switching circuit, pin 5 of the logic chip is connected to the eleventh capacitor to the ground, and pin 4 of the logic chip is sequentially connected to the eighteenth resistor and the twelfth capacitor to the ground.

[0006] The multiplexing switching circuit includes a field effect tube, a signal relay, a probe device, a nineteenth resistor and a twentieth resistor. Pin 2 of the signal relay is connected to the node between the second resistor and the third resistor in the EC measurement circuit, pin 7 of the signal relay is connected to the second capacitor, the tenth resistor to pin 3 of the fourth operational amplifier in sequence, pin 4 of the signal relay is connected to pin 2 of the logic chip, pin 5 of the signal relay is grounded, pins 3 and 6 of the signal relay are both connected to the probe device, pin 1 of the signal relay is connected to the nineteenth resistor to the 5V power supply terminal, pin 8 of the signal relay is connected to the drain of the field effect tube, the source of the field effect tube is grounded, and the gate of the field effect tube is connected to the twentieth resistor to the sensor switch.

[0007] Preferably, the probe device adopts a cylindrical probe, with a transmitting probe in the center and receiving probes distributed in a star shape around the transmitting probe. The transmitting probe and the receiving probe are respectively connected to pins 3 and 6 of the signal relay, and pins 3 and 6 of the signal relay are two common ports COM; pins 2 and 7 of the signal relay are normally closed ports NC, connected to the EC measurement circuit; pin 4 of the signal relay is a normally open port NO, connected to the humidity measurement circuit.

[0008] Preferably, the first operational amplifier, the second operational amplifier, the third operational amplifier, the fourth operational amplifier and the fifth operational amplifier are all operational amplifiers GS321A.

[0009] Preferably, the logic chip is the logic chip SN74LVC1G86DCKR.

[0010] Preferably, the signal relay is a signal relay HFD4 / 3-S, and the field effect transistor is an N-channel field effect transistor 2N7002.

[0011] The beneficial effects of the utility model are as follows: the circuit can increase the measuring area of ​​the soil sensor, thereby improving the authenticity of data, making the data more accurate, and saving costs, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The utility model is described in detail below with reference to the accompanying drawings and specific implementation methods;

[0013] Figure 1 This is a circuit diagram of the EC measurement circuit of the utility model;

[0014] Figure 2 The circuit diagram of the humidity measurement circuit of the utility model;

[0015] Figure 3 It is a circuit diagram of the multiplexing switching circuit of the utility model;

[0016] Figure 4It is a schematic diagram of the structure of the probe device of the utility model. DETAILED DESCRIPTION

[0017] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific implementation methods.

[0018] Reference Figure 1-4 This specific implementation adopts the following technical solution: a soil EC and humidity multiplexing measurement circuit, including an EC measurement circuit 1, a humidity measurement circuit 2 and a multiplexing switching circuit 3, wherein the EC measurement circuit 1 and the humidity measurement circuit 2 are respectively connected to the multiplexing switching circuit 3. Specifically, the composition structure and connection relationship of each circuit are as follows:

[0019] The EC measurement circuit 1 includes a first operational amplifier U1 to a fifth operational amplifier U5, a first resistor R1 to a fifteenth resistor R15, and a first capacitor C1 to a ninth capacitor C9. Pin 1 of the first operational amplifier U1 is connected to the first resistor R1, and pin 3 of the first operational amplifier U1 is connected to the second resistor R2, the third resistor R3 to pin 4 in sequence. The node between the second resistor R2 and the third resistor R3 is connected to the fourth resistor R4 and the fifth resistor R5 to pins 3 and 4 of the second operational amplifier U2 respectively. Pin 1 of the second operational amplifier U2 is connected to the sixth resistor R6 to pin 4 of the first operational amplifier U1; pin 1 of the third operational amplifier U3 is connected to the seventh resistor R7 and the eighth resistor R8 to a 5V power supply terminal and a ground terminal respectively, and a parallel circuit of the ninth resistor R9 and the first capacitor C1 is connected between pins 3 and 4 of the third operational amplifier U3; pin 3 of the fourth operational amplifier U4 is connected to the tenth resistor R The first operational amplifier U1, the second operational amplifier U2, the third operational amplifier U3, the fourth operational amplifier U4 and the fifth operational amplifier U5 are connected to the parallel circuit of the 15th resistor R15 and the fourth capacitor C4. The 5th pins of the first operational amplifier U1, the second operational amplifier U2, the third operational amplifier U3, the fourth operational amplifier U4 and the fifth operational amplifier U5 are connected to the parallel circuit of the 15th resistor R15 and the fourth capacitor C4. The 5th pins of the first operational amplifier U1, the second operational amplifier U2, the third operational amplifier U3, the fourth operational amplifier U4 and the fifth operational amplifier U5 are connected to the 5V power supply terminal, and the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8 and the ninth capacitor C9 are connected in parallel between the 5V power supply terminal and the ground terminal.

[0020] It is worth noting that the first operational amplifier U1, the second operational amplifier U2, the third operational amplifier U3, the fourth operational amplifier U4 and the fifth operational amplifier U5 are all operational amplifiers GS321A.

[0021] The humidity measurement circuit 2 includes a logic chip U6, a control unit U7, a sixteenth resistor R16-an eighteenth resistor R18, a tenth capacitor C10-a twelfth capacitor C12, pins 1 and 4 of the control unit U7 are respectively connected to the sixteenth resistor R16 and the tenth capacitor C10 to the ground, pins 4 and 3 of the control unit U7 are respectively connected to pins 5 and 1 of the logic chip U6, pin 3 of the control unit U7 is also connected to the seventeenth resistor R17 to pin 2 of the logic chip U6 and the multiplexing switching circuit 3, pin 5 of the logic chip U6 is connected to the eleventh capacitor C11 to the ground, and pin 4 of the logic chip U6 is sequentially connected to the eighteenth resistor R18 and the twelfth capacitor C12 to the ground; the logic chip U6 adopts the logic chip SN74LVC1G86DCKR.

[0022] The multiplexing switching circuit 3 includes a field effect transistor Q1, a signal relay LS1, a probe device J1, a nineteenth resistor R19 and a twentieth resistor R20. Pin 2 of the signal relay LS1 is connected to the node between the second resistor R2 and the third resistor R3 in the EC measurement circuit 1. Pin 7 of the signal relay LS1 is connected in sequence to the second capacitor C2, the tenth resistor R10 to the third pin of the fourth operational amplifier U4. Pin 4 of the signal relay LS1 is connected to the second pin of the logic chip U6. Pin 5 of the signal relay LS1 is grounded. Pins 3 and 6 of the signal relay LS1 are both connected to the probe device J1. Pin 1 of the signal relay LS1 is connected to the nineteenth resistor R19 to the 5V power supply terminal. Pin 8 of the signal relay LS1 is connected to the drain of the field effect transistor Q1, the source of the field effect transistor Q1 is grounded, and the gate of the field effect transistor Q1 is connected to the twentieth resistor R20 to the sensor switch. The signal relay LS1 adopts the signal relay HFD4 / 3-S, and the field effect transistor Q1 adopts the N-channel field effect transistor 2N7002.

[0023] In this specific embodiment, the probe device J1 adopts a cylindrical probe, with a transmitting probe in the center and receiving probes distributed in a star shape around the transmitting probe. The transmitting probe and the receiving probe are respectively connected to pins 3 and 6 of the signal relay LS1. Pins 3 and 6 of the signal relay LS1 are two common ports COM; pins 2 and 7 of the signal relay LS1 are normally closed ports NC, connected to the EC measurement circuit 1; pin 4 of the signal relay LS1 is a normally open port NO, connected to the humidity measurement circuit 2.

[0024] In this specific embodiment, the EC measurement and humidity measurement reuse the same probe, which is switched by the internal circuit of the soil sensor, wherein the transmitting and receiving signals of the EC measurement are connected to the two normally closed ports NC of the signal relay LS1, the transmitting and receiving signals of the humidity are connected to the normally open port NO of the signal relay LS1, and the transmitting probe and the receiving probe are respectively connected to the two common ports COM of the relay. The circuit controls the contact of the relay through the single chip microcomputer inside the soil sensor to realize the switching of the EC and humidity signals on the probe.

[0025] Compared with traditional soil sensors, this specific implementation has a larger measurement area, and the measured data is closer to the real soil data. Moreover, through the multiplexing function, it can not only improve the authenticity of the data but also save costs, and has broad market application prospects.

[0026] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A soil EC and humidity multiplexing measurement circuit, characterized in that: The invention comprises an EC measurement circuit (1), a humidity measurement circuit (2) and a multiplexing switching circuit (3), wherein the EC measurement circuit (1) and the humidity measurement circuit (2) are respectively connected to the multiplexing switching circuit (3); the EC measurement circuit (1) comprises a first operational amplifier (U1) to a fifth operational amplifier (U5), a first resistor (R1) to a fifteenth resistor (R15), a first capacitor (C1) to a ninth capacitor (C9), a pin 1 of the first operational amplifier (U1) is connected to the first resistor (R1), and a pin 3 of the first operational amplifier (U1) is sequentially connected to a second resistor ( The node between the second resistor (R2) and the third resistor (R3) is connected to the fourth resistor (R4) and the fifth resistor (R5) to the third and fourth pins of the second operational amplifier (U2), respectively; the first pin of the second operational amplifier (U2) is connected to the sixth resistor (R6) to the fourth pin of the first operational amplifier (U1); the first pin of the third operational amplifier (U3) is connected to the seventh resistor (R7) and the eighth resistor (R8) to the 5V power supply terminal and the ground terminal, respectively; the ninth resistor (R9) is connected between the third and fourth pins of the third operational amplifier (U3) The third pin of the fourth operational amplifier (U4) is connected to one end of the tenth resistor (R10), the other end of the tenth resistor (R10) is respectively connected to the second capacitor (C2), the eleventh resistor (R11) to the multiplexing switching circuit (3), and the ground end, the other end of the tenth resistor (R10) and the fourth pin of the fourth operational amplifier (U4) are connected to a parallel circuit of a twelfth resistor (R12), a thirteenth resistor (R13) and a third capacitor (C3), the fourth pin of the fourth operational amplifier (U4) is connected to the fourteenth resistor (R14) to the fourth operational amplifier (U4), and the fourth pin of the fourth operational amplifier (U4) is connected to the fourth operational amplifier (U4). A parallel circuit of a fifteenth resistor (R15) and a fourth capacitor (C4) is connected between the 3rd pin of the fifth operational amplifier (U5) and the 3rd pin and the 4th pin of the fifth operational amplifier (U5); the 5th pins of the first operational amplifier (U1), the second operational amplifier (U2), the third operational amplifier (U3), the fourth operational amplifier (U4) and the fifth operational amplifier (U5) are all connected to a 5V power supply terminal, and a fifth capacitor (C5), a sixth capacitor (C6), a seventh capacitor (C7), an eighth capacitor (C8) and a ninth capacitor (C9) are connected in parallel between the 5V power supply terminal and the ground terminal; The humidity measurement circuit (2) comprises a logic chip (U6), a control unit (U7), a sixteenth resistor (R16)-an eighteenth resistor (R18), a tenth capacitor (C10)-a twelfth capacitor (C12), wherein pin 1 and pin 4 of the control unit (U7) are respectively connected to the sixteenth resistor (R16) and the tenth capacitor (C10) to the ground, pin 4 and pin 3 of the control unit (U7) are respectively connected to pin 5 and pin 1 of the logic chip (U6), pin 3 of the control unit (U7) is also connected to the seventeenth resistor (R17) to pin 2 of the logic chip (U6) and a multiplexing switching circuit (3), pin 5 of the logic chip (U6) is connected to the eleventh capacitor (C11) to the ground, and pin 4 of the logic chip (U6) is sequentially connected to the eighteenth resistor (R18) and the twelfth capacitor (C12) to the ground; The multiplexing switching circuit (3) includes a field effect tube (Q1), a signal relay (LS1), a probe device (J1), a nineteenth resistor (R19) and a twentieth resistor (R20), wherein the second pin of the signal relay (LS1) is connected to the node between the second resistor (R2) and the third resistor (R3) in the EC measurement circuit (1), the seventh pin of the signal relay (LS1) is connected to the second capacitor (C2), the tenth resistor (R10) and the third pin of the fourth operational amplifier (U4) in sequence, and the signal relay Pin 4 of (LS1) is connected to pin 2 of the logic chip (U6), pin 5 of the signal relay (LS1) is grounded, pins 3 and 6 of the signal relay (LS1) are connected to the probe device (J1), pin 1 of the signal relay (LS1) is connected to the nineteenth resistor (R19) to the 5V power supply terminal, pin 8 of the signal relay (LS1) is connected to the drain of the field effect tube (Q1), the source of the field effect tube (Q1) is grounded, and the gate of the field effect tube (Q1) is connected to the twentieth resistor (R20) to the sensor switch.

2. A soil EC and humidity multiplexing measurement circuit according to claim 1, characterized in that: The probe device (J1) uses a cylindrical probe, with a transmitting probe in the center and receiving probes distributed in a star shape around the transmitting probe. The transmitting probe and the receiving probe are respectively connected to pins 3 and 6 of the signal relay (LS1). Pins 3 and 6 of the signal relay (LS1) are two common ports COM.

3. The soil EC and humidity multiplexing measurement circuit according to claim 1, characterized in that: Pins 2 and 7 of the signal relay (LS1) are normally closed ports NC, connected to the EC measurement circuit (1); and pin 4 of the signal relay (LS1) is a normally open port NO, connected to the humidity measurement circuit (2).

4. The soil EC and humidity multiplexing measurement circuit according to claim 1, characterized in that: The first operational amplifier (U1), the second operational amplifier (U2), the third operational amplifier (U3), the fourth operational amplifier (U4) and the fifth operational amplifier (U5) are all operational amplifiers GS321A.

5. The soil EC and humidity multiplexing measurement circuit according to claim 1, characterized in that: The logic chip (U6) is a logic chip SN74LVC1G86DCKR.

6. The soil EC and humidity multiplexing measurement circuit according to claim 1, characterized in that: The signal relay (LS1) adopts the signal relay HFD4 / 3-S, and the field effect tube (Q1) adopts the N-channel field effect tube 2N7002.

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