Passive portable multi-type pesticide detection system and method based on NFC

Abstract

The invention discloses an NFC-based passive portable multi-type pesticide detection system and method, the NFC-based passive portable multi-type pesticide detection system comprises a circuit module and an electrode, the circuit module comprises a substrate, an NFC coil antenna, an NFC module, a main control module, a DAC module, a dual-channel constant potential module, a negative power supply module and an ADC sub-module, the ADC sub-module is connected with the operational amplifier chip; the circuit module further comprises an external pin module, and the electrode is connected with the external pin module; according to the passive portable multi-type pesticide detection system based on the NFC, the multi-channel constant potential circuit and the NFC technology are combined based on the electrochemical sensing principle, and the passive portable multi-type pesticide detection system is realized through effective power supply control.

Description

Technical Field

[0001] The present invention relates to the technical field of near field communication, and in particular to a passive portable multi-type pesticide detection system and method based on NFC. Background Art

[0002] Today, global agriculture relies heavily on various pesticides, such as insecticides, herbicides, rodenticides, and fungicides, which are widely used to mitigate the impact of various pests on crop health. Therefore, the residues of these pesticides can be identified not only on the surface of crops, but also in soil, air, and water sources. However, repeated exposure to pesticides may lead to diseases such as neurological disorders, autism, Alzheimer's disease, kidney failure, and cancer. However, the current pesticide detection system requires not only very complex steps for detection, but also expensive professional equipment, such as methods based on chromatography-mass spectrometry and Raman spectroscopy. In order to meet the above challenges, it is hoped that a mobile and portable miniaturized device can be realized to achieve better pesticide detection. Electrochemical sensing technology can detect the electrochemical properties of various substances, which can help better realize pesticide detection.

[0003] The existing electrochemical pesticide detection system includes applying current or voltage signals to the biomaterial system through electrochemical electrodes through a constant potential circuit and detecting the electrochemical properties of the biomaterial modified on the electrode surface. Zhao et al. and Chaudhary et al. both used the electrochemical detection principle to complete pesticide detection, but they can only detect a single type of pesticide and do not achieve multiple types of pesticide detection. In addition, they all use battery-powered mobile portable devices. Batteries not only increase costs and increase the size of the device at the expense of portability, but also need to be replaced regularly and cause pollution to the environment.

[0004] Existing technologies are mainly divided into traditional methods based on chromatography, mass spectrometry, Raman spectroscopy, etc. and methods based on electrochemical biosensor principles.

[0005] The former is to detect pesticides from the perspective of the essential composition of the substance. Although the test results are highly accurate, the equipment is large in size, expensive, and requires a complex material pretreatment process and a long test time, making it difficult to apply to on-site portable testing in daily life.

[0006] Although the latter is more suitable for on-site portable detection, the existing portable sensors still have problems such as a single type of pesticide detection and active power supply, which are still far from practical use. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a passive portable multi-type pesticide detection system and method based on NFC, so as to solve the problem of single pesticide detection type and the problem of system power supply mode sacrificing portability in the portable pesticide detection system in the prior art.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solution to achieve the above problems: a passive portable multi-type pesticide detection system based on NFC, including a circuit module and electrodes connected to the circuit module.

[0009] The circuit module includes a substrate and an NFC coil, an NFC module, a main control module, a DAC module, a negative power supply module and a dual-channel constant potential module which are arranged on the substrate and connected in sequence.

[0010] The main control module includes an ADC submodule, and the ADC submodule is connected to the dual-channel constant potential module.

[0011] The circuit module also includes a negative power module arranged on the substrate, and the negative power module is respectively connected to the NFC module, the main control module and the dual-channel constant potential module.

[0012] The circuit module also includes an external pin module arranged on the substrate and connected to the dual-channel constant potential module, and the electrode is connected to the external pin module.

[0013] The present invention also has the following technical features:

[0014] The electrode comprises a first electrode and a second electrode, and the first electrode and the second electrode are respectively connected to the dual-channel constant potential module through an external pin module.

[0015] The first electrode is a screen-printed three-electrode, including a counter electrode, a reference electrode and a working electrode.

[0016] The working electrode of the first electrode is modified with MOF, carboxymethyl chitosan and acetylcholinesterase.

[0017] The second electrode is a screen-printed three-electrode, including a counter electrode, a reference electrode and a working electrode.

[0018] The working electrode of the second electrode is modified with MOF, carboxymethyl chitosan and butyrylcholinesterase.

[0019] The substrate is a two-layer flexible circuit board with a length of 45mm and a width of 34mm.

[0020] The dimensions of the NFC coil antenna are 44mm long, 33mm wide, 3 turns, 0.3mm line width, and 0.5mm line spacing.

[0021] The NFC module uses the NT3H2211 chip.

[0022] The main control module uses the MSP430FR2433 chip.

[0023] The ADC submodule is the internal ADC of the main control module.

[0024] The DAC module uses the AD5689 chip.

[0025] The negative power module uses the ICL7660 chip.

[0026] The dual-channel constant potential module uses the AD8659 chip.

[0027] The present invention also provides a passive portable multi-type pesticide detection method based on NFC, which is completed using the above-mentioned passive portable multi-type pesticide detection system based on NFC. Specifically, it includes the following steps:

[0028] Step 1: Obtain the characteristic spectrum corresponding to the standard pesticide sample solution:

[0029] Standard sample solutions of organophosphorus pesticides of different types and concentrations were prepared and added to the NFC-based passive portable multi-type pesticide detection system. At the same time, iodinated acetylthiocholine solution was added to obtain the characteristic spectra corresponding to the standard sample solutions of organophosphorus pesticides of different types and concentrations.

[0030] Step 2: Obtain the characteristic spectrum corresponding to the pesticide solution of unknown type and concentration:

[0031] A pesticide solution of unknown type and concentration is dripped onto the NFC-based passive portable multi-type pesticide detection system, and iodinated acetylthiocholine solution is also dripped at the same time to obtain a characteristic spectrum corresponding to the pesticide solution of unknown type and concentration.

[0032] Step 3: Compare the characteristic spectrum corresponding to the obtained pesticide solution of unknown type and concentration with the characteristic spectrum corresponding to the standard pesticide sample solution to determine the test result.

[0033] Step 1 specifically includes the following steps:

[0034] Step 1.1: Use a smartphone with NFC function to bring it close to the NFC coil antenna to activate the NFC coil antenna, send a write command to the NFC module through the NFC coil antenna, write the test parameters and start the test command, then the main control module sends a read command through the I2C interface to read the storage area of ​​the NFC module to obtain the set test parameters and start the test command. When the test starts, the main control module uses the timer interrupt to periodically set the DAC module output voltage through the SPI interface. The output voltage of the DAC module is directly connected to the dual-potential dual-channel constant potential module.

[0035] Step 1.2: Prepare standard sample solutions of organophosphorus pesticides of different types and concentrations, and drop the standard sample solutions of organophosphorus pesticides of different types and concentrations onto the surfaces of the first electrode and the second electrode, respectively, and simultaneously drop acetylthiocholine iodide solution.

[0036] Step 1.3, by performing a potential scan on the first electrode and the second electrode, a chemical reaction of the pesticide standard sample solution occurs on the surface of the first electrode and the second electrode, generating a current signal, and converting the current signal into a voltage signal that is convenient for ADC collection through a dual-potential dual-channel constant potential module.

[0037] Step 1.4: The voltage signal acquired by the ADC is transmitted to the main control module, which encapsulates it into a data packet and writes the data packet into the NFC module.

[0038] Step 1.5, the smart phone reads the measured data by reading the corresponding address of the memory in the NFC module to obtain the characteristic spectra corresponding to the standard sample solutions of the organophosphorus pesticides of different types and concentrations.

[0039] Step 2 specifically includes the following steps:

[0040] Step 2.1: Use a smartphone with NFC function to bring it close to the NFC coil antenna to activate the NFC coil antenna, send a write command to the NFC module through the NFC coil antenna, write the test parameters and start the test command, then the main control module sends a read command through the I2C interface to read the storage area of ​​the NFC module to obtain the set test parameters and start the test command. When the test starts, the main control module uses the timer interrupt to periodically set the DAC module output voltage through the SPI interface. The output voltage of the DAC module is directly connected to the dual-potential dual-channel constant potential module.

[0041] Step 2.2: Pesticide solutions of unknown type and concentration are added dropwise onto the surfaces of the first electrode and the second electrode, respectively, and acetylthiocholine iodide solution is added dropwise at the same time.

[0042] Step 2.3, by performing a potential scan on the first electrode and the second electrode, a chemical reaction of the pesticide standard sample solution occurs on the surface of the first electrode and the second electrode, generating a current signal, and converting the current signal into a voltage signal that is convenient for ADC collection through a dual-potential dual-channel constant potential module.

[0043] Step 2.4: The voltage signal acquired by the ADC is transmitted to the main control module, which encapsulates it into a data packet and writes the data packet into the NFC module.

[0044] Step 1.5, the smartphone reads the measured data by reading the corresponding address of the memory in the NFC module to obtain the characteristic spectrum corresponding to the pesticide solution of unknown type and concentration.

[0045] Compared with the prior art, the present invention has the following technical effects:

[0046] (I) The present invention provides a passive portable multi-type pesticide detection system based on NFC. Based on the electrochemical sensing principle, a multi-channel constant potential circuit is combined with NFC technology to realize a passive portable multi-type pesticide detection system through effective power supply control.

[0047] (II) The present invention provides a passive portable multi-type pesticide detection system based on NFC. A passive portable multi-type pesticide detection system based on NFC uses a multi-channel constant potential circuit combined with NFC technology. It can use commercial smart phones and other smart devices with NFC functions to interact with the system, and complete the detection of multiple pesticides and data transmission through wireless power supply and wireless communication functions; the method of the present application has low equipment cost, is easy to carry, is compatible with various smart phone devices, and can realize the ability to detect multiple pesticides. It can be applied to the scene of on-site portable detection under the condition of meeting sufficient detection accuracy.

[0048] (III) The NFC-based passive portable multi-type pesticide detection system provided by the present invention has high integration, simple structure and is easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The figure is a schematic diagram of the overall structure of the NFC-based passive portable multi-type pesticide detection system of the present invention.

[0050] Figure 2 This is a circuit diagram showing the principle of voltage conversion performed by the negative power module of the present invention based on a charge pump.

[0051] Figure 3 It is the principle diagram of the dual-channel constant potential module of the present invention.

[0052] Figure 4 It is a schematic diagram of the main control module circuit of the present invention.

[0053] Figure 5 FIG. 4 is a schematic diagram of an NFC module circuit of the present invention.

[0054] Figure 6 Schematic diagram of the dual-channel constant potential module circuit of the present invention.

[0055] Figure 7 Schematic diagram of the negative power module circuit of the present invention.

[0056] Figure 8 Schematic diagram of the DAC module circuit of the present invention.

[0057] Fig. 9It is a schematic diagram of the circuit of the external pin module of the present invention.

[0058] Fig.10 This is a schematic diagram of the single-point grounding module circuit of the present invention.

[0059] Fig.11 This is a comparison chart of the results of measuring the same electrode and biomaterial using this system and an electrochemical workstation.

[0060] Fig.12 The following are the results of measuring the same electrodes and biomaterials using different models of smartphones and systems.

[0061] Fig.13 The Pearson similarity confusion matrix diagram is the result of measuring the same electrodes and biomaterials using different models of smartphones and systems.

[0062] Fig.14 It is a confusion matrix diagram of the accuracy of classification results of different types of pesticides.

[0063] Fig.15 It is a confusion matrix diagram of the accuracy of classification results of various types and concentrations of pesticides.

[0064] The meaning of each symbol in the accompanying drawings:

[0065] 1-Circuit module, 2-Electrode.

[0066] 1-1 substrate, 1-2 NFC coil antenna, 1-3 NFC module, 1-4 main control module, 1-5 DAC module, 1-6 dual-channel constant potential module, 1-7 negative power module, 1-8 ADC submodule, 1-9 external pin module.

[0067] 2-1 first electrode, 2-2 second electrode.

[0068] 2-1-1 counter electrode, 2-1-2 working electrode, 2-1-3 reference electrode.

[0069] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0070] All components in the present invention, unless otherwise specified, are components known in the prior art.

[0071] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0072] Embodiment 1:

[0073] This embodiment provides a passive portable multi-type pesticide detection system based on NFC. Figure 1 As shown, it includes a circuit module 1 and an electrode 2 connected to the circuit module 1 .

[0074] The circuit module 1 includes a substrate 1-1 and an NFC coil antenna 1-2, an NFC module 1-3, a main control module 1-4, a DAC module 1-5 and a dual-channel constant potential module 1-6 arranged on the substrate and connected in sequence.

[0075] The main control module 1-4 includes an ADC submodule 1-8, and the ADC submodule 1-8 is connected to the dual-channel constant potential module 1-6.

[0076] The circuit module 1 also includes a negative power module 1-7 arranged on the substrate, and the negative power module 1-7 is respectively connected to the NFC module 1-3, the main control module 1-4 and the dual-channel constant potential module 1-6.

[0077] The circuit module 1 further comprises an external pin module 1-9 arranged on the substrate and connected to the dual-channel constant potential module 1-6, and the electrode 2 is connected to the external pin module 1-9.

[0078] As a preferred embodiment of this invention:

[0079] The electrode 2 includes a first electrode 2-1 and a second electrode 2-2. The first electrode 2-1 and the second electrode 2-2 are connected to the dual-channel constant potential module 1-6 through an external pin module 1-9, respectively.

[0080] The first electrode 2-1 is a screen-printed three-electrode, including a counter electrode 2-1-1, a working electrode 2-1-2 and a reference electrode 2-1-3.

[0081] The working electrode 2-1-2 of the first electrode 2-1 is modified with MOF, carboxymethyl chitosan and acetylcholinesterase; the modification order is MOF, carboxymethyl chitosan and acetylcholinesterase.

[0082] The second electrode 2-2 is a screen-printed three-electrode, including a counter electrode, a working electrode and a reference electrode.

[0083] The working electrode of the second electrode 2-2 is modified with MOF, carboxymethyl chitosan and butyrylcholinesterase; the modification order is MOF, carboxymethyl chitosan and butyrylcholinesterase.

[0084] Modification: Simply put, the material is dissolved in PBS solution, then dripped onto the working electrode surface of the screen-printed electrode, and then the electrode is dried at a certain temperature so that the material adheres to the electrode surface.

[0085] mof is a ZIF-8 suspension (0.1 mg / uL), the solute is zinc imidazolate metal organic framework-8 (ZIF-8), and the solvent is anhydrous ethanol / distilled water / deionized water.

[0086] The solute of PBS solution (0.1 mol / L) is PBS phosphate buffer dry powder, and the solvent is distilled water / deionized water.

[0087] The solute of the carboxymethyl chitosan solution is carboxymethyl chitosan, and the solvent is PBS solution, with a mass fraction of 0.05%.

[0088] The solute of the acetylcholinesterase solution is acetylcholinesterase, the solvent is PBS solution, 0.5u solute, 250uL solvent PBS.

[0089] The solute of butyrylcholinesterase solution is acetylcholinesterase, the solvent is PBS solution, 0.5u solute, 250uL solvent PBS.

[0090] The solute of iodinated acetylthiocholine solution (2mmol / L) is iodinated acetylthiocholine, and the solvent is PBS solution; iodinated acetylthiocholine solution is added dropwise during the test.

[0091] The drying temperature is 30°C.

[0092] The electrodes are screen-printed three electrodes, and the biological materials are acetylcholinesterase and butyrylcholinesterase; during the specific test, iodinated acetylthiocholine solution is added dropwise.

[0093] Screen-printed electrode: An electrode made by printing conductive active materials on an insulating substrate using thick film technology

[0094] An alternative to conventional electrodes for electrochemical analysis in the environmental, clinical or agri-food sectors. They offer significant advantages that make them ideal tools for quality control, scientific research or electrochemistry teaching.

[0095] -Low-cost, maintenance-free disposable electrodes

[0096] -High reproducibility between electrodes

[0097] -Multifunctional and customizable to meet various research needs

[0098] - Small size, powerful function, ideal solution for in situ experiments

[0099] Composition of screen printed electrodes:

[0100] Screen-printed electrodes generally include a substrate for printing electrodes, an outer insulating layer and electrode leads are printed on the substrate, and three electrodes are printed on the substrate.

[0101] The difference in the response of two different biological materials to the same pesticide is used to establish the pesticide signature, so that the system can detect more types and concentrations of pesticides.

[0102] The reason is as follows: when there is only one electrode and one biological material, the current signal generated by it can only correspond to different pesticide concentrations or different pesticide types, and it is impossible to detect the concentration and type of pesticides at the same time. The reason is that the one-dimensional signal cannot map the two-dimensional features one by one. If two electrodes, two detection channels, and two biological materials are used, the purpose is to expand the dimension of the detection signal so that it can support the simultaneous detection of pesticide concentrations and types and improve detection accuracy.

[0103] As a preferred embodiment of this invention:

[0104] The substrate 1-1 uses a two-layer flexible circuit board with a length of 45 mm and a width of 34 mm.

[0105] The dimensions of the NFC coil antenna 1-2 are 44 mm long, 33 mm wide, 3 turns, 0.3 mm line width, and 0.5 mm line spacing.

[0106] NFC modules 1-3 use the NT3H2211 chip.

[0107] The main control modules 1-4 use the MSP430FR2433 chip.

[0108] ADC submodules 1-8 are the internal ADCs of the main control module.

[0109] DAC modules 1-5 use AD5689 chip.

[0110] Negative power supply modules 1-7 use ICL7660 chips.

[0111] The dual-channel constant potential module uses the AD8659 chip.

[0112] Dual-potential dual-channel constant potential module Figure 3 As shown, Figure 3 The above four op amps are included in the AD8659 chip, and there are also four additional resistors. The electrolytic cell solution connects the four electrodes to each other equivalently, so that the first part of the reverse proportional op amp forms a deep negative feedback. The inverting input is connected to the DAC potential output, and the positive potential is input, and the negative potential is output to the reference electrode through the negative feedback resistor R2 and the voltage follower.

[0113] The two working electrodes work in a deep negative feedback state due to the action of feedback resistors R3 and R4. From the "virtual short", it can be seen that the potential of the working electrode is equal to the potential of the in-phase input terminal, and the in-phase input terminal is grounded, so the working electrode is equivalent to the "virtual ground", and its potential is fixed at zero. Therefore, the voltage between the working electrode and the reference electrode is determined by the DAC output.

[0114] Since the reference electrode is connected to the non-inverting input of the voltage follower and it works in a deep negative feedback state, it can be seen from the "virtual disconnection" that there is no current flowing in. The reaction current of the biomaterial can only flow from the working electrode to the counter electrode, and is converted into a voltage signal through the feedback resistors R3 and R4 and connected to the ADC input sampling. The output potential sampling of the op amp is calculated by the following formula:

[0115] V out =I×R+V bias

[0116] Where I is the reaction current, the direction is from the output to the input, the unit is A. R is the feedback resistance, the unit is Ω. V bias is the bias potential of the op amp's non-inverting input. In this case, ground is the zero potential and the unit is V.

[0117] In view of the problem that existing portable pesticide detection systems have only a single type of pesticide to be detected and the system power supply method sacrifices portability, this application provides a passive portable multi-type pesticide detection system based on NFC.

[0118] When a smartphone with NFC function is close to the NFC antenna of the system, it can activate the system and control the system. We use the Android application developed by us to send write commands to the NFC module in the system through the mobile phone RF interface, write test parameters and start test commands.

[0119] Then the system MCU sends a read command through the I2C interface to read the storage area of ​​the NFC module to obtain the set test parameters and start the test command. According to the test parameters, the MCU uses the SPI interface to control the DAC module through the timer module to send different voltage signals to the constant potential circuit.

[0120] The constant potential circuit is connected to the biomaterial through a three-electrode system and applies a preset voltage signal to the biomaterial, causing the biomaterial to produce different electrochemical reactions to generate electrochemical current.

[0121] At the same time, the MCU controls the ADC module through the timer module to detect the voltage signal converted by the IV conversion circuit from the electrochemical current.

[0122] The MCU processes and encapsulates the dual voltage signals of the dual working electrodes collected by the ADC module, and sends a write command through the I2C interface to write the data to the storage area of ​​the NFC module. The smartphone then reads the NFC module data through the NFC radio frequency interface to obtain the dual voltage signals.

[0123] The characteristic spectrum corresponding to the standard pesticide sample solution and the characteristic spectrum corresponding to the pesticide solution of unknown type and concentration are obtained respectively by the above method, and the type and concentration information of the unknown type of pesticide are obtained by comparison.

[0124] DAC module: converts digital signals into analog signals and outputs different potentials according to the set parameters. Controls the potential scanning of the constant potential circuit to complete the detection process.

[0125] ADC submodule: converts analog signals into digital signals, performs sampling at different frequencies according to the set parameters, collects and generates signals, and completes the detection process.

[0126] Dual-channel constant potential module: The operational amplifier chip provides the most basic operational amplifier unit. Through the set operational amplifier unit connection method and combined with the resistor element, a dual-channel constant potential module is formed.

[0127] The dual-channel constant potential module includes a potential control circuit part and two IV conversion circuit parts.

[0128] like Figure 4-10 As shown: the main control module includes a main control chip U1 and peripheral circuits, and the main control chip U1 adopts MSP430FR2433.

[0129] The peripheral circuit includes a switch SW1 , one end of the switch SW1 is connected to the terminal 1 of the main control chip U1 , and the other end is grounded.

[0130] The peripheral circuit further includes a resistor R1 , one end of the resistor R1 is connected to the terminal 1 of the main control chip U1 , and the other end is connected to the terminal 24 of the main control chip U1 .

[0131] The peripheral circuit also includes capacitors C1, C2 and C3. One end of capacitor C1 is connected to terminal 24 of the main control chip U1, and the other end is grounded. One end of capacitor C2 is connected to terminal 24 of the main control chip U1, and the other end is grounded. One end of capacitor C3 is connected to terminal 1 of the main control chip U1, and the other end is grounded.

[0132] Terminal 24 of the main control chip U1 is connected to the power supply, and terminal 23 of the main control chip U1 is connected to terminal 18 of the control chip U1.

[0133] The NFC module includes an NFC chip U3 and peripheral circuits. The NFC chip U3 adopts NT3H2211.

[0134] The peripheral circuit includes a capacitor C6, one end of the capacitor C6 is connected to the terminal 1 of the NFC chip U3, and the other end of the capacitor C6 is connected to the terminal 8 of the NFC chip U3.

[0135] Terminals 1 and 8 of the NFC chip U3 are connected to the NFC coil antenna 1-2.

[0136] The peripheral circuit also includes resistors R5, R6 and R7. One end of resistor R5 is connected to terminal 3 of the NFC chip U3, and the other end is connected to terminal 24 of the main control chip U1. One end of resistor R6 is connected to terminal 4 of the NFC chip U3, and the other end is connected to terminal 24 of the main control chip U1. One end of resistor R7 is connected to terminal 5 of the NFC chip U3, and the other end is connected to terminal 24 of the main control chip U1.

[0137] Terminal 7 of the NFC chip U3 is connected to terminal 24 of the main control chip U1, terminal 5 of the NFC chip U3 is connected to terminal 9 of the main control chip U1, terminal 3 of the NFC chip U3 is connected to terminal 10 of the main control chip U1, terminal 3 of the NFC chip U3 is connected to terminal 10 of the main control chip U1, terminal 4 of the NFC chip U3 is connected to terminal 12 of the main control chip U1, terminal 5 of the NFC chip U3 is connected to terminal 9 of the main control chip U1, and terminal 2 of the NFC chip U3 is connected to the analog ground.

[0138] The DAC module includes a DAC chip U4 and peripheral circuits. The DAC chip U4 adopts AD5689.

[0139] The peripheral circuit includes resistor R11 and resistor R12. One end of resistor R11 is connected to terminal 13 of DAC chip U4, and the other end is connected to terminal 24 of main control chip U1. One end of resistor R12 is connected to terminal 9 of DAC chip U4, and the other end is connected to terminal 24 of main control chip U1.

[0140] The peripheral circuit also includes capacitor C10 and capacitor C11. One end of capacitor C10 is connected to the 3 end of DAC chip U4, and the other end is connected to analog ground. One end of capacitor C11 is connected to the 3 end of DAC chip U4, and the other end is connected to analog ground.

[0141] Terminal 3 of the DAC chip U4 is connected to terminal 24 of the main control chip U1, terminals 2, 7, 8 and 14 of the DAC chip U4 are connected to the analog ground, terminal 6 of the DAC chip U4 is connected to terminal 16 of the main control chip U1, terminal 12 of the DAC chip U4 is connected to terminal 17 of the main control chip U1, terminal 11 of the DAC chip U4 is connected to terminal 13 of the main control chip U1, terminal 10 of the DAC chip U4 is connected to terminal 15 of the main control chip U1,

[0142] The dual-channel constant potential module includes an operational amplifier chip U5 and peripheral circuits. The operational amplifier chip U5 adopts AD8659.

[0143] The peripheral circuit includes resistor R4, resistor R8, resistor R9 and resistor R10. One end of resistor R4 is connected to terminal 9 of op amp chip U5, and the other end is connected to terminal 8 of op amp chip U5. One end of resistor R8 is connected to terminal 2 of op amp chip U5, and the other end is connected to terminal 1 of DAC chip U4. One end of resistor R9 is connected to terminal 2 of op amp chip U5, and the other end is connected to terminal 7 of op amp chip U5. One end of resistor R10 is connected to terminal 13 of op amp chip U5, and the other end is connected to terminal 14 of op amp chip U5.

[0144] The peripheral circuit includes capacitor C4 and capacitor C9. One end of capacitor C4 is connected to terminal 9 of operational amplifier chip U5, and the other end is connected to terminal 8 of operational amplifier chip U5. One end of capacitor C9 is connected to terminal 13 of operational amplifier chip U5, and the other end is connected to terminal 14 of operational amplifier chip U5.

[0145] Terminal 8 of the operational amplifier chip U5 is connected to terminal 7 of the main control chip U1, terminal 14 of the operational amplifier chip U5 is connected to terminal 8 of the main control chip U1, terminal 4 of the operational amplifier chip U5 is connected to terminal 24 of the main control chip U1, terminal 11 of the operational amplifier chip U5 is connected to the voltage conversion module, and terminals 3, 10 and 12 of the operational amplifier chip U5 are connected to the analog ground.

[0146] The negative power supply module includes a DAC chip U2 and peripheral circuits. The DAC chip U2 adopts ICL7660.

[0147] The peripheral circuit includes capacitor C5, capacitor C7 and capacitor C8. One end of capacitor C5 is connected to terminal 8 of DAC chip U2, and the other end is connected to analog ground. One end of capacitor C7 is connected to terminal 2 of DAC chip U2, and the other end is connected to terminal 4 of DAC chip U2. One end of capacitor C8 is connected to terminal 5 of DAC chip U2, and the other end is connected to analog ground.

[0148] Terminals 3 and 6 of the DAC chip U2 are connected to the analog ground, and terminal 5 of the DAC chip U2 is connected to terminal 11 of the operational amplifier chip U5.

[0149] The external pin module includes a pin header H1, end 1 of the pin header H1 is connected to end 5 of the operational amplifier chip U5, end 2 of the pin header H1 is connected to end 13 of the operational amplifier chip U5, end 3 of the pin header H1 is connected to end 9 of the operational amplifier chip U5, and end 4 of the pin header H1 is connected to end 1 of the operational amplifier chip U5.

[0150] The reference electrode (RE) and counter electrode (CE) of the external pin module are common so there is only one, and the two working electrodes (WE) are separate.

[0151] The first electrode 2-1 and the second electrode 2-2 are both connected to the pin H1. Specifically, the counter electrodes of the first electrode 2-1 and the second electrode 2-2 are connected to the end 1 of the pin H1, the reference electrodes of the first electrode 2-1 and the second electrode 2-2 are connected to the end 4 of the pin H1, the working electrode of the first electrode 2-1 is connected to the end 3 of the pin H1, and the working electrode of the second electrode 2-2 is connected to the end 2 of the pin H1.

[0152] The external pin module also includes a pin header H2, one end of the pin header H2 is connected to one end of the main control chip U1, two ends of the pin header H2 are connected to two ends of the main control chip U1, three ends of the pin header H2 are connected to the 24th end of the main control chip U1, four ends of the pin header H2 are connected to the 23rd end of the main control chip U1, and five ends of the pin header H2 are connected to the 3rd end of the main control chip U1.

[0153] To the right of pin header H2 is the interface between the MCU and the computer, which is used to write code. In actual application, the code has already been written and this pin header H2 is not connected.

[0154] In addition, it also includes an LED module, which includes LED1 and LED2. The positive pole of LED1 is connected to the 19th terminal of the main control chip U1 via the resistor R2, and the negative pole of LED1 is grounded. The positive pole of LED2 is connected to the 24th terminal of the main control chip U1 via the resistor R1, and the negative pole of LED2 is grounded.

[0155] A resistor R13 is also installed on the substrate. The two ends of the resistor R13 are respectively connected to the ground and the pseudo-ground, that is, the digital ground and the analog ground are connected. As an interface for isolating the digital circuit and the analog circuit in circuit design, it can be understood as circuit noise elimination.

[0156] Embodiment 2:

[0157] This embodiment provides a passive portable multi-type pesticide detection method based on NFC, which is implemented using the passive portable multi-type pesticide detection system based on NFC in Example 1. Specifically, it includes the following steps:

[0158] Step 1: Obtain the characteristic spectrum corresponding to the standard pesticide sample solution:

[0159] Standard sample solutions of organophosphorus pesticides of different types and concentrations were prepared and added to the NFC-based passive portable multi-type pesticide detection system. At the same time, iodinated acetylthiocholine solution was added to obtain the characteristic spectra corresponding to the standard sample solutions of organophosphorus pesticides of different types and concentrations.

[0160] Step 2: Obtain the characteristic spectrum corresponding to the pesticide solution of unknown type and concentration:

[0161] A pesticide solution of unknown type and concentration is dripped onto the NFC-based passive portable multi-type pesticide detection system, and iodinated acetylthiocholine solution is also dripped at the same time to obtain a characteristic spectrum corresponding to the pesticide solution of unknown type and concentration.

[0162] Step 3: Compare the characteristic spectrum corresponding to the obtained pesticide solution of unknown type and concentration with the characteristic spectrum corresponding to the standard pesticide sample solution to determine the test result.

[0163] Step 1 specifically includes the following steps:

[0164] Step 1.1: Use a smartphone with NFC function to approach the NFC coil antenna 1-2 to activate the NFC coil antenna 1-2, send a write command to the NFC module 1-3 through the NFC coil antenna 1-2, write the test parameters and start the test command, and then the main control module 1-4 sends a read command through the I2C interface to read the storage area of ​​the NFC module 1-3 to obtain the set test parameters and the start test command. When the test starts, the main control module 1-4 uses the timer interrupt to periodically set the output voltage of the DAC module 1-5 through the SPI interface. The output voltage of the DAC module 1-5 is directly connected to the dual-potential dual-channel constant potential module.

[0165] In this step, the NFC coil antenna 1-2 is used to perform wireless energy transmission and wireless communication with the smartphone device. Figure 3 The system hardware equipment composition is shown. The size of NFC coil antenna 1-2 is 44mm long, 33mm wide, 3 turns, 0.3mm line width, 0.5mm line spacing, belonging to type 3 antenna. The write test parameters include the starting voltage (Init E), the end voltage (Final E), the increase voltage (Incr E), the amplitude (Amplitude) and the sensitivity (Sensitivity).

[0166] In this step, the main control chip main control module 1-4 of the system is TI's MSP430FR2433, the NFC module 1-3 is NXP's NT3H2211, and two wires are connected between the main control chip main control module 1-4 and the NFC module 1-3, a bidirectional data line SDA, and a clock line SCL. The main control chip main control module 1-4 controls the NFC module 1-3 through the I2C protocol to enable wireless power supply and wireless communication between the system and the smartphone.

[0167] In this step, four lines are connected between the master control module 1-4 and the DAC module 1-5, namely, a SYNC, a clock line SCLK, a data input line SDIN and a data output line SDO, which are compatible with the SPI four-wire protocol and correspond to the slave device chip select line CS / SS, the clock line SCLK, the master device data output slave device data input line MOSI and the master device data input slave device data output line MISO.

[0168] The dual-potential supply of the dual-channel constant potential module is completed by the switch-capacitor voltage converter chip ICL7660, which converts the 3.3V voltage output by the NFC module 1-3 into a -3.3V voltage, thereby widening the voltage range of the dual-channel constant potential module.

[0169] Figure 2 shows the voltage conversion principle circuit, such as Figure 2 As shown in FIG, charge is first accumulated in capacitor C1, and then transferred to capacitor C2, completing voltage reversal; Figure 3 shows a dual-channel constant potential module, such as Figure 3 As shown in the figure, it consists of an inverse proportional op amp circuit, a voltage follower circuit and two IV conversion circuits (transimpedance op amp circuits). In the dual-channel circuit constant potential circuit, by setting the reference electrode potential, the voltage between the two working electrodes and the reference electrode is adjusted, so that the chemical reaction current flows to the counter electrode at the two working electrodes. At the same time, the reaction current converts the current signal into a voltage signal through two independent IV conversion circuits. Data acquisition is to collect the voltage values ​​converted from these two currents.

[0170] The detection principle of our system is to obtain different specific reactions of multiple materials to the same pesticide, thereby increasing the dimensional information of the detection signal, so that the system can support the detection of pesticide concentration and type. The dual-channel constant potential module is used to obtain two signals at the same time. On the one hand, it reduces the detection time and is more suitable for on-site rapid detection scenarios. On the other hand, supporting dual-channel detection at the same time will also bring double burden to the power supply voltage range of the constant potential circuit.

[0171] First, when the single-channel constant potential circuit is working, the reference electrode and the working electrode are kept at a constant voltage. However, since the current generated by the chemical reaction of the material flows directly between the working electrode and the counter electrode, the counter electrode potential will change with the direction of the current. It is necessary to ensure that the potential range of the counter electrode is within the power supply range of the constant potential circuit.

[0172] Secondly, in a single-power-supply constant potential circuit, we must use DAC to set a suitable initial potential for the working electrode. A too high potential will compress the detection range and accuracy of the ADC, and a too low potential will compress the reference electrode potential scanning range. In the potential scanning of pesticide detection, the reference electrode potential needs to be lower than the working electrode potential. In addition, controlling the initial potential of the working electrode through DAC is easily affected by the device and brings thermal noise, which affects the detection accuracy.

[0173] Finally, in the implementation of the dual-channel constant potential circuit, the current generated by the chemical reaction of the materials of the two working electrodes is superimposed on the counter electrode, causing a greater change in the potential of the counter electrode. This poses a greater challenge to our NFC-powered system.

[0174] In order to maintain low power consumption and achieve accurate detection on this mobile and portable system, we have to consider not bringing additional impact to the system while widening the voltage range. We adopted the solution of converting negative voltage instead of increasing the voltage. The solution of widening the voltage range by increasing the voltage brings about greater power consumption of DAC circuit, ADC circuit and constant potential circuit, and the working electrode potential is easily affected by device noise and the final detection accuracy. The solution of supplying power through negative voltage dual power supply only increases the power consumption of constant potential circuit, brings a wider potential range of counter electrode, and the initial potential of the working electrode can be grounded to get rid of the influence of device noise.

[0175] Step 1.2: Prepare standard sample solutions of organophosphorus pesticides of different types and concentrations, and drip the standard sample solutions of organophosphorus pesticides of different types and concentrations onto the surfaces of the first electrode 2-1 and the second electrode 2-2, respectively, and simultaneously drip acetylthiocholine iodide solution.

[0176] In this step, the pesticide dripping needs to cover the entire electrode, and the biomaterial and pesticide react on the electrode surface, which serves as the basis for pesticide detection.

[0177] Step 1.3, by performing potential scanning on the first electrode 2-1 and the second electrode 2-2, the pesticide standard sample solution is prompted to undergo a chemical reaction on the surface of the first electrode 2-1 and the second electrode 2-2 to generate a current signal, and the current signal is converted into a voltage signal that is convenient for ADC collection through a dual-potential dual-channel constant potential module.

[0178] In step 1.4, the voltage signal acquired by the ADC is transmitted to the main control module 1-4, and the main control module 1-4 encapsulates the signal into a data packet and writes the data packet into the NFC module 1-3.

[0179] In this step, ADC uses the internal ADC of the main control chip MSP430FR2433, which has an accuracy of 10 bits and a maximum sampling rate of 200k times per second.

[0180] Step 1.5, the smart phone reads the measured data by reading the corresponding address of the memory in the NFC module 1-3, and obtains the characteristic spectrum corresponding to the standard sample solutions of the organophosphorus pesticides of different types and concentrations. The characteristic spectrum is a current-voltage curve diagram.

[0181] Step 2 specifically includes the following steps:

[0182] Step 2.1: Use a smartphone with NFC function to approach the NFC coil antenna 1-2 to activate the NFC coil antenna 1-2, send a write command to the NFC module 1-3 through the NFC coil antenna 1-2, write the test parameters and start the test command, and then the main control module 1-4 sends a read command through the I2C interface to read the storage area of ​​the NFC module 1-3 to obtain the set test parameters and the start test command. When the test starts, the main control module 1-4 uses the timer interrupt to periodically set the output voltage of the DAC module 1-5 through the SPI interface. The output voltage of the DAC module 1-5 is directly connected to the dual-potential dual-channel constant potential module.

[0183] Step 2.2: A pesticide solution of unknown type and concentration is dripped onto the surface of the first electrode 2 - 1 and the second electrode 2 - 2 , respectively, and an iodinated acetylthiocholine solution is dripped at the same time.

[0184] Step 2.3, by performing potential scanning on the first electrode 2-1 and the second electrode 2-2, the pesticide standard sample solution is prompted to undergo a chemical reaction on the surface of the first electrode 2-1 and the second electrode 2-2 to generate a current signal, and the current signal is converted into a voltage signal that is convenient for ADC collection through a dual-potential dual-channel constant potential module.

[0185] In step 2.4, the voltage signal acquired by the ADC is transmitted to the main control module 1-4, and the main control module 1-4 encapsulates the signal into a data packet and writes the data packet into the NFC module 1-3.

[0186] Step 1.5, the smart phone reads the measured data by reading the corresponding address of the memory in the NFC module 1-3, and obtains the characteristic spectrum corresponding to the pesticide solution of unknown type and concentration.

[0187] After we have established characteristic maps of different pesticides and different concentrations, when new data comes in, we can compare it with the map we have established, and the most similar one is our test result.

[0188] Mobile phone software settings: Use a smartphone that supports NFC as a reader, the model is MI9. And use the application software to control the smartphone to set system parameters, send commands, wirelessly power supply and receive processing data through the NFC radio frequency interface.

[0189] Electrode material setting: The electrode uses screen-printed three electrodes, and the biological materials are acetylcholinesterase and butyrylcholinesterase. Nine organophosphorus pesticides are used, namely methyl parathion, chlorpyrifos, dimethoate, trichlorfon, profenofos, glyphosate, acephate, isothiocyanate and cypermethrin. The pesticide concentration is set to 5 values, namely 10 -15 mol / L、10 -13 mol / L、10 -11 mol / L、10 -9 mol / L and 10 -7 mol / L as the standard pesticide sample solution.

[0190] Experimental method parameter setting: The electrochemical voltage scanning method uses differential pulse voltammetry (DPV), and the voltage scanning direction is forward scanning. The parameters are set as starting voltage 0.4V, cut-off voltage 0.9V, growth voltage 0.05V, pulse width 0.05s, and pulse period 0.5s.

[0191] Experiment 1: The goal of Experiment 1 is to verify the effective performance of the system. The system is compared with a professional electrochemical workstation (CHInstruments, 620E). The same electrodes and biomaterials are used to measure the workstation and the system.

[0192] The test results of experiment 1 are as follows: Fig.11 The figure shows the comparison of the test results of the system of the present application and the professional electrochemical workstation under the same parameters for the same target. Fig.11 As shown, the curve has two peaks. The first peak is the peak of the substrate ion in the solution, which is not within the scope of our research. The second peak is the peak of the electrolysis current of acetylcholine after the catalytic product of acetylcholinesterase, which is our target data for pesticide detection. It can be seen that the system of this application can maintain good consistency with the measurement data of a professional electrochemical workstation. Although the current curve caused by noise has slight fluctuations, the complete redox current of the reactant can be accurately captured. It can be proved that the performance of the system of this application is similar to that of a professional electrochemical workstation, with high data accuracy.

[0193] Experiment 2: The goal of Experiment 2 is to verify whether the system is compatible with different models of smartphones and the impact of different mobile phone hardware parameters (antenna parameters) on the system power supply stability. We used 6 different models of mobile phones, namely mi9, RedmiK30S Ultra, OPPO Reno3 Pro, Redmi K60, iQOO 11S, vivo x60 pro and Redmi K40Pro. We used different smartphones to measure the same electrodes and biomaterials with the system of this application.

[0194] The test results of Experiment 2 are as follows: Fig.12 The raw data of 6 different models of smartphone devices and the system of the present application measuring the same electrodes and biomaterials are shown. It can be seen that they have similar current curves, and the positions and sizes of the peaks are relatively close. Fig.13 The Pearson similarity matrix of the curve data is shown. The similarity of different curves is as high as 96% at the lowest, which proves that our system has high robustness.

[0195] Experiment 3: The goal of Experiment 3 is to verify the comprehensive detection performance of the system. Test the accuracy of pesticide type detection and pesticide concentration detection. We use 9 pesticides, 5 concentrations of each pesticide. The same label is repeated 3 times as a repeatability experiment.

[0196] The test results of experiment three are as follows: Fig.14 The confusion matrix of the detection results for different types of pesticides is shown. From the results, it can be seen that the system can accurately distinguish different types of pesticides, and the average detection accuracy of the system reaches 93.3%. Fig.15 The confusion matrix of the detection results of nine pesticides at different concentrations is shown. It can be seen from the figure that, in the case of a specified pesticide type, the system achieved an average detection rate of 98.5% of the pesticide concentration, and only two of the 135 data sets were detected incorrectly. It can be proved that the system of this application can not only perform qualitative pesticide identification, but also achieve a high accuracy in pesticide quantitative analysis.

[0197] The above technical solutions are only preferred specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be conceived by any technician familiar with the field within the technical scope disclosed by the present invention without creative work are all covered within the protection scope of the present invention.

Claims

1. A passive portable multi-type pesticide detection system based on NFC, comprising a circuit module (1) and an electrode (2) connected to the circuit module (1), characterized in that: The circuit module (1) comprises a substrate (1-1) and an NFC coil antenna (1-2), an NFC module (1-3), a main control module (1-4), a DAC module (1-5) and a dual-channel constant potential module (1-6) which are arranged on the substrate (1-1) and connected in sequence; The circuit module (1) further comprises a negative power module (1-7) arranged on the substrate (1-1), wherein the negative power module (1-7) is respectively connected to the NFC module (1-3), the main control module (1-4) and the dual-channel constant potential module (1-6); The main control module (1-4) includes an ADC submodule (1-8), and the ADC submodule (1-8) is connected to the dual-channel constant potential module (1-6); The circuit module (1) further comprises an external pin module (1-9) arranged on the substrate (1-1) and connected to the dual-channel constant potential module (1-6), and the electrode (2) is connected to the external pin module (1-9).

2. The NFC-based passive portable multi-type pesticide detection system as claimed in claim 1, characterized in that: The electrode (2) comprises a first electrode (2-1) and a second electrode (2-2), and the first electrode (2-1) and the second electrode (2-2) are respectively connected to a dual-channel constant potential module (1-6) via an external pin module (1-9).

3. The NFC-based passive portable multi-type pesticide detection system as claimed in claim 2, characterized in that: The first electrode (2-1) is a screen-printed three-electrode, including a counter electrode (2-1-1), a working electrode (2-1-2) and a reference electrode (2-1-3); The working electrode (2-1-2) of the first electrode (2-1) is modified with MOF, carboxymethyl chitosan and acetylcholinesterase; The second electrode (2-2) is a screen-printed three-electrode, including a counter electrode, a working electrode and a reference electrode; The working electrode of the second electrode (2-2) is modified with MOF, carboxymethyl chitosan and butyrylcholinesterase.

4. The NFC-based passive portable multi-type pesticide detection system as claimed in claim 1, characterized in that: The substrate (1-1) is a two-layer flexible circuit board with a length of 45 mm and a width of 34 mm; The dimensions of the NFC coil antenna (1-2) are 44 mm in length, 33 mm in width, 3 turns, 0.3 mm in line width, and 0.5 mm in line spacing; The NFC module (1-3) adopts the NT3H2211 chip; The main control module (1-4) adopts MSP430FR2433 chip; The ADC submodule (1-8) is an internal ADC of the main control module; The DAC module (1-5) adopts AD5689 chip; The negative power module (1-7) adopts ICL7660 chip; The dual-channel constant potential module adopts the IAD8659 chip.

5. A passive portable multi-type pesticide detection method based on NFC, characterized in that: The method is implemented by using the NFC-based passive portable multi-type pesticide detection system as described in any one of claims 1 to 4, and specifically comprises the following steps: Step 1: Obtain the characteristic spectrum corresponding to the standard pesticide sample solution: Prepare standard sample solutions of organophosphorus pesticides of different types and concentrations and drip them onto the NFC-based passive portable multi-type pesticide detection system, and simultaneously drip iodinated acetylthiocholine solution to obtain characteristic spectra corresponding to standard sample solutions of organophosphorus pesticides of different types and concentrations; Step 2: Obtain the characteristic spectrum corresponding to the pesticide solution of unknown type and concentration: A pesticide solution of unknown type and concentration is dripped onto the NFC-based passive portable multi-type pesticide detection system, and iodinated acetylthiocholine solution is dripped at the same time to obtain a characteristic spectrum corresponding to the pesticide solution of unknown type and concentration; Step 3: Compare the characteristic spectrum corresponding to the obtained pesticide solution of unknown type and concentration with the characteristic spectrum corresponding to the standard pesticide sample solution to determine the test result.

6. The NFC-based passive portable multi-type pesticide detection method according to claim 5, characterized in that: Step 1 specifically includes the following steps: Step 1.1: Use a smart phone with NFC function to approach the NFC coil antenna (1-2), activate the NFC coil antenna (1-2), send a write command to the NFC module (1-3) through the NFC coil antenna (1-2), write the test parameters and the start test command, then the main control module (1-4) sends a read command to read the storage area of ​​the NFC module (1-3) to obtain the set test parameters and the start test command. When starting the test, the main control module (1-4) sets the output voltage of the DAC module (1-5), and the output voltage of the DAC module (1-5) is directly connected to the dual-potential dual-channel constant potential module; Step 1.2: preparing standard sample solutions of organophosphorus pesticides of different types and concentrations, and dripping the standard sample solutions of organophosphorus pesticides of different types and concentrations onto the surfaces of the first electrode (2-1) and the second electrode (2-2), respectively, and simultaneously dripping iodized acetylthiocholine solution; Step 1.3, by performing a potential scan on the first electrode (2-1) and the second electrode (2-2), a chemical reaction of the pesticide standard sample solution occurs on the surface of the first electrode (2-1) and the second electrode (2-2), generating a current signal, and converting the current signal into a voltage signal through a dual-potential dual-channel constant potential module; Step 1.4, the voltage signal acquired by the ADC is transmitted to the main control module (1-4), and the main control module (1-4) encapsulates the signal into a data packet and writes the data packet into the NFC module (1-3). Step 1.5, the smart phone reads the measured data by reading the corresponding address of the memory in the NFC module (1-3), and obtains the characteristic spectra corresponding to the standard sample solutions of the organophosphorus pesticides of different types and concentrations.

7. The NFC-based passive portable multi-type pesticide detection method according to claim 6, characterized in that: Step 2 specifically includes the following steps: Step 2.1: Use a smart phone with NFC function to approach the NFC coil antenna (1-2), activate the NFC coil antenna (1-2), send a write command to the NFC module (1-3) through the NFC coil antenna (1-2), write the test parameters and the start test command, then the main control module (1-4) sends a read command to read the storage area of ​​the NFC module (1-3) to obtain the set test parameters and the start test command. When starting the test, the main control module (1-4) sets the output voltage of the DAC module (1-5), and the output voltage of the DAC module (1-5) is directly connected to the dual-potential dual-channel constant potential module; Step 2.2: dripping a pesticide solution of unknown type and concentration onto the surface of the first electrode (2-1) and the second electrode (2-2), respectively, and simultaneously dripping an acetylthiocholine iodide solution; Step 2.3, by performing a potential scan on the first electrode (2-1) and the second electrode (2-2), a chemical reaction of the pesticide standard sample solution occurs on the surface of the first electrode (2-1) and the second electrode (2-2), generating a current signal, and converting the current signal into a voltage signal through a dual-potential dual-channel constant potential module; In step 2.4, the voltage signal acquired by the ADC is transmitted to the main control module (1-4), and the main control module (1-4) encapsulates the signal into a data packet and writes the data packet into the NFC module (1-3). Step 1.5, the smart phone reads the measured data by reading the corresponding address of the memory in the NFC module (1-3) to obtain the characteristic spectrum corresponding to the pesticide solution of unknown type and concentration.

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