Portable qcm micro-substance monitoring device and method for digital teaching

Abstract

The application provides a portable QCM micro-substance monitoring device and method for digital teaching, which comprises a detection module, a sensor driving module, a lower computer control module based on a single-chip microcomputer, an upper computer control module and a power supply module; the principle of the device is that the quartz crystal has a fixed basic resonance frequency, the molecules of the to-be-measured substance are adsorbed to the surface of the crystal after volatilization, the weight of the wafer increases, the resonance frequency of the crystal decreases, and in the curve diagram of the frequency signal, the change is obviously decreased, so the mass change of the measured substance can be reflected; the application integrates substance detection, hardware control and teaching functions, and can adapt to various use scenarios; through the integrated hardware system and the user-friendly digital teaching platform, the high-precision monitoring of the micro-substance is realized, the intuitive display and interactive control of the data are realized, the functions are diversified, and the system is continuously updated and upgraded, so that the modern digital teaching needs are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of digital teaching, more particularly, to a portable QCM micro-substance monitoring device and method for digital teaching. BACKGROUND

[0002] Quartz Crystal Microbalance (QCM) is a high-sensitivity mass detection technology widely used in the fields of chemistry, biology and material science. QCM technology is based on the piezoelectric effect of quartz crystals, which detects the mass change of substances adsorbed or desorbed from the crystal surface by measuring the change in the resonant frequency of the crystal. In the field of chemical sensing, QCM is used to detect various volatile organic compounds (VOCs) including alcohol homologues, which are of great significance in environmental monitoring and industrial processes.

[0003] However, traditional QCM devices usually require complex setup and operation, which is not conducive to quick start and real-time teaching, making teaching demonstration extremely inconvenient and difficult to meet the needs of digital teaching visualization and portability. Therefore, for the teaching and research of micro-substance monitoring, it is necessary to design a high-precision, portable QCM device. SUMMARY

[0004] In order to overcome the defects of the prior art that it is difficult to meet the needs of digital teaching visualization and portability, the present application provides a portable QCM micro-substance monitoring device and method for digital teaching, which realizes convenient operation of high-precision micro-substance monitoring, intuitive display and interactive control of data, functional diversification, and continuous updating and functional upgrading of the system through integrated hardware system and user-friendly digital teaching platform, thereby meeting the needs of modern digital teaching.

[0005] To solve the above technical problems, the technical solutions of the present application are as follows:

[0006] A portable QCM micro-substance monitoring device for digital teaching, comprising: a detection module, a sensor driving module, a single-chip microcomputer-based lower computer control module and an upper computer control module, and a power supply module;

[0007] The detection module comprises a detection container and a QCM detection probe; the detection container contains the substance to be tested for simulating the detection environment; the QCM detection probe is fixedly arranged inside the detection container, and a quartz crystal sensor is arranged in the QCM detection probe for detecting the mass change of the substance to be tested according to the frequency change of the quartz crystal;

[0008] The QCM detection probe is electrically connected with the sensor driving module and transmits the detected frequency signal to the sensor driving module; the sensor driving module provides an excitation signal for the quartz crystal sensor to make the quartz crystal sensor oscillate at a specific resonance frequency;

[0009] The sensor driving module is also electrically connected with the lower computer control module, which is used to control the sensor driving module and collect the frequency signal in real time and transmit it to the upper computer control module;

[0010] The upper computer control module is in communication connection with the lower computer control module, and the upper computer control module is used to receive and process the frequency signal sent by the lower computer control module and visually display to realize digital teaching;

[0011] The power supply module is used to supply power for the sensor driving module, the lower computer control module and the upper computer control module respectively.

[0012] Preferably, the structure of the QCM detection probe comprises an outer shell, a USB interface, and a detection circuit, a detection pool and a quartz crystal sensor arranged inside the outer shell;

[0013] The USB interface is integrally arranged with the detection circuit; the USB interface is electrically connected with the sensor driving module and is used to transmit the frequency signal;

[0014] The quartz crystal sensor is placed inside the detection pool; the interface of the quartz crystal sensor is fixedly connected with the input end of the detection circuit;

[0015] The outer shell is of detachable structure and is used to replace the sensing wafer coating type of the quartz crystal sensor in the detection pool.

[0016] Preferably, the sensor driving module is specifically a Pierce oscillator circuit;

[0017] The quartz crystal sensor is specifically an AT-cut quartz crystal; the frequency unit of the quartz crystal sensor is generally MHz;

[0018] The lower computer control module is specifically an STM32 single-chip microcomputer;

[0019] The upper computer control module is specifically a microprocessor Raspberry Pi, and the operating system used is RaspberryPi OS.

[0020] Preferably, the lower computer control module is specifically an STM32F407VET6 single-chip microcomputer;

[0021] The lower computer control module uses a 25MHz wafer as an external clock source, which is directly or through a phase-locked loop PLL used for the clock of the lower computer control module.

[0022] The peak detection algorithm is used to detect the frequency signal, so as to improve the measurement accuracy; the TIM4 timer is used to realize real-time calculation of the frequency, and the TIM3 timer is used to extract the trigger value in real time; the frequency signal is measured by the peak detection algorithm and the timer, so that the performance can be improved and the cost can be reduced.

[0023] Preferably, the microprocessor Raspberry Pi is provided with two HDMI interfaces, which are respectively used for connecting a touch display and a projector; the touch display is used for user interaction, and the projector is used for multimedia projection teaching demonstration.

[0024] In the case of accessing the network, the microprocessor Raspberry Pi is connected with the projector through the network; in the case of not accessing the network, the microprocessor Raspberry Pi is connected with the projector through the corresponding HDMI interface.

[0025] Preferably, the teaching application software developed based on the Qt platform is built in the host computer control module.

[0026] The teaching application software is used to realize the following operations: data processing, exception handling, self-starting at power-on, multiple experiment re-running, multimedia projection and one-key software upgrading.

[0027] Preferably, the display information of the main interface of the teaching application software includes:

[0028] The number and name of the communication port, the name of the measured substance, the name of the interactive command button, the chart display information, the data input box, the experimental result, the current version of the software and the current running state information;

[0029] The communication port is used to detect the disconnection and connection of the host computer control module and the lower computer control module in real time.

[0030] The interactive command button name includes: theoretical concentration button, data stability button, stop reading button, export information button, view information button and update system button.

[0031] The data input in the data input box includes: the volume of the injected measured substance, the volume of the detection container and the temperature.

[0032] Preferably, the data processing of the teaching application software includes:

[0033] Through the preset host computer and lower computer agreement protocol, the teaching application software reads and analyzes the frequency signal sent by the lower computer control module in real time, calculates the difference ΔF of the frequency change, and filters out the maximum and minimum values of the frequency.

[0034] The preset Qxlsx module in the teaching application software is used to export all frequency signals and results of analysis and calculation thereof into an Excel file; the Excel file contains the collection time and frequency value of the frequency signal.

[0035] The data processing adopts a multi-thread processing mode, which is used for ensuring smooth response of the main interface of the teaching application software and avoiding blocking of the main interface.

[0036] Preferably, the teaching application software is upgraded by using a U disk with a software upgrade installation package.

[0037] The application further provides a portable QCM micro-substance monitoring method for digital teaching, which is based on the above-mentioned portable QCM micro-substance monitoring device for digital teaching and comprises the following steps.

[0038] S1: the QCM detection probe is installed in the detection container, and the lower computer control module and the upper computer control module are started and initialized;

[0039] S2: the lower computer control module controls the sensor driving module to generate an excitation signal and send it to the quartz crystal sensor, so that the quartz crystal sensor oscillates at a specific resonant frequency;

[0040] After the frequency signal is stabilized, the to-be-tested substance is injected into the detection container of the detection module;

[0041] S3: the quartz crystal sensor in the QCM detection probe detects the frequency change of the quartz crystal in real time, generates an electric signal and sends it to the sensor driving module; the sensor driving module receives the electric signal and amplifies and processes it to obtain a frequency signal;

[0042] S4: the lower computer control module collects the frequency signal in real time and transmits it to the upper computer control module;

[0043] S5: the upper computer control module receives and processes the frequency signal sent by the lower computer control module, and visually displays it, thereby realizing digital teaching.

[0044] Compared with the prior art, the technical scheme of the application has the following beneficial effects:

[0045] The application provides a portable QCM micro-substance monitoring device and method for digital teaching, and the basic principle is that the quartz crystal has a fixed basic resonant frequency, the molecules of the to-be-tested substance are adsorbed to the surface of the crystal after volatilization, the weight of the wafer increases, the resonant frequency of the crystal decreases, and in the curve graph of the frequency signal, the change is obviously decreased, so that the mass change of the measured substance can be reflected.

[0046] The application has the following advantages:

[0047] 1) Portability and integration: The device is lightweight and integrates substance detection, hardware control, and teaching functions, making it suitable for various use scenarios. Through the integrated hardware system and user-friendly digital teaching platform, it realizes convenient operation of high-precision monitoring of trace substances, intuitive display and interactive control of data, functional diversification, and continuous updating and functional upgrading of the system, thus meeting the needs of modern digital teaching;

[0048] 2) Stability and repeatability: Ensures controllable experimental conditions and stable and reliable experimental results;

[0049] 3) High-precision monitoring capability: The quartz crystal sensor can accurately monitor small mass changes with high detection precision;

[0050] 4) User-friendly interface: The host computer can directly connect to the touch display device, simplifying operations while realizing intuitive data display;

[0051] 5) Real-time data processing capability: The host computer can quickly analyze data to meet immediate research and teaching needs;

[0052] 6) Multimedia teaching function: The host computer supports multimedia projection, which can enhance teaching interactivity, intuitiveness, and interest;

[0053] 7) Automated system management: The host computer supports self-starting and one-key upgrading, improving user experience;

[0054] 8) Multi-threaded data processing: The host computer supports multi-threaded data processing to ensure efficient data processing and smooth interface;

[0055] 9) Continuous experiment support: The invention supports continuous experiments, greatly improving portability compared to traditional QCM devices while ensuring data continuity;

[0056] 10) Hardware configuration flexibility: The invention uses mainstream control chips, making it easy to upgrade and maintain hardware and thus prolonging the device's lifespan. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 A structure diagram of a portable QCM trace substance monitoring device for digital teaching provided in Example 1.

[0058] Figure 2 A structure diagram of the detection module provided in Example 2.

[0059] Figure 3 A schematic diagram of the overall structure of the QCM detection probe provided in Example 2.

[0060] Figure 4The internal structure diagram of the QCM detection probe provided in Example 2.

[0061] Figure 5 The circuit diagram of the sensor driving module and the lower computer control module provided in Example 2.

[0062] Figure 6 The main interface diagram of the teaching application software in the upper computer control module provided in Example 2.

[0063] Figure 7 The workflow diagram of the teaching application software in the upper computer control module provided in Example 2.

[0064] Figure 8 The connection diagram of the dual HDMI interface configuration of the microprocessor Raspberry Pi provided in Example 2.

[0065] Figure 9 The frequency change diagram of the existing QCM device detecting the reaction of zinc particles and acid provided in Example 2.

[0066] Figure 10 The frequency change diagram of the portable QCM device detecting the reaction of zinc particles and acid provided in Example 2.

[0067] Figure 11 The flowchart of a portable QCM micro-substance monitoring method for digital teaching provided in Example 3.

[0068] Figure 12 The intermolecular force verification experiment result diagram provided in Example 3. DETAILED DESCRIPTION

[0069] The drawings are only used for illustrative purposes and cannot be understood as limiting the patent;

[0070] In order to better illustrate the embodiments, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual product size;

[0071] For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0072] The technical solutions of the present application will be further described below in combination with the drawings and embodiments.

[0073] Example 1

[0074] As Figure 1 shown, the present embodiment provides a portable QCM micro-substance monitoring device for digital teaching, which comprises a detection module, a sensor driving module, a lower computer control module based on a single-chip microcomputer, an upper computer control module, and a power supply module.

[0075] The detection module comprises a detection container and a QCM detection probe; the detection container contains a to-be-detected substance for simulating a detection environment; the QCM detection probe is fixedly arranged inside the detection container, and a quartz crystal sensor is arranged in the QCM detection probe for detecting the mass change of the to-be-detected substance according to the frequency change of the quartz crystal;

[0076] The QCM detection probe is electrically connected with the sensor driving module and transmits the detected frequency signal to the sensor driving module; the sensor driving module provides an excitation signal for the quartz crystal sensor to make the quartz crystal sensor oscillate at a specific resonance frequency;

[0077] The sensor driving module is also electrically connected with the lower computer control module, and the lower computer control module is used for controlling the sensor driving module and collecting the frequency signal in real time and transmitting the frequency signal to the upper computer control module;

[0078] The upper computer control module is in communication connection with the lower computer control module, and the upper computer control module is used for receiving and processing the frequency signal sent by the lower computer control module and performing visual display to realize digital teaching;

[0079] The power supply module is used for supplying power for the sensor driving module, the lower computer control module and the upper computer control module respectively.

[0080] In the specific implementation process, the basic principle of the device is that two parallel surfaces of the quartz crystal are each plated with a layer of metal electrode, the electrode provides an alternating voltage to the quartz crystal to make it vibrate at a resonance frequency, and the resonance frequency of the crystal can be determined by measuring the frequency of the alternating signal applied to the electrode; when a substance is adsorbed or separated from the surface of the crystal, due to the piezoelectric effect, it will generate a change in electric charge on the electrode, and these changes can be detected by the electrode, and the voltage or current change detected by the electrode is associated with these frequency changes; according to the Sauerbrey equation, the resonance frequency change of the QCM is proportional to the mass of the substance adsorbed or separated on the crystal, so that the resonance frequency change measured by the QCM can be used to quantitatively analyze the mass of the adsorbed substance; in the software digital teaching platform, it is manifested as a decrease in the curve, and the change of the curve and data can be seen in real time;

[0081] In the teaching process, first, the to-be-detected substance is injected into the detection container of the detection module, and the QCM detection probe is immersed in the to-be-detected substance; the lower computer control module and the upper computer control module are started and initialized;

[0082] The lower computer control module controls the sensor driving module to generate an excitation signal and send the excitation signal to the quartz crystal sensor to make the quartz crystal sensor oscillate at a specific resonance frequency;

[0083] The quartz crystal sensor in the QCM detection probe detects the frequency change of the quartz crystal in real time, generates an electrical signal and sends it to the sensor driving module; the sensor driving module receives the electrical signal and amplifies it to obtain the frequency signal;

[0084] The lower computer control module collects the frequency signal in real time and transmits it to the upper computer control module;

[0085] The upper computer control module receives and processes the frequency signal sent by the lower computer control module, and visualizes it to realize digital teaching;

[0086] The device is light and compact, integrating material detection, hardware control and teaching functions, and can adapt to various use scenarios; through the integrated hardware system and user-friendly digital teaching platform, it realizes convenient operation of high-precision monitoring of trace substances, intuitive display and interactive control of data, functional diversification, and continuous updating and functional upgrading of the system, thereby meeting the needs of modern digital teaching.

[0087] Embodiment 2

[0088] The embodiment provides a portable QCM trace substance monitoring device for digital teaching, which comprises a detection module, a sensor driving module, a lower computer control module based on a single-chip microcomputer and an upper computer control module, and a power supply module;

[0089] As shown in Figure 2 , the detection module comprises a detection container and a QCM detection probe; the detection container contains the substance to be detected (in this embodiment, a gas) for simulating the detection environment; the QCM detection probe is fixedly arranged inside the detection container, and a quartz crystal sensor is arranged in the QCM detection probe for detecting the mass change of the substance to be detected according to the frequency change of the quartz crystal;

[0090] In this embodiment, the detection container is a cylindrical glass cylinder for simulating the gas environment in actual application; the upper cover of the detection cylinder is provided with a USB2.0 socket for fixing the gas detection probe and transmitting data;

[0091] The QCM detection probe is electrically connected with the sensor driving module and transmits the detected frequency signal to the sensor driving module; the sensor driving module provides an excitation signal for the quartz crystal sensor to make the quartz crystal sensor oscillate at a specific resonance frequency;

[0092] The sensor driving module is also electrically connected with the lower computer control module, and the lower computer control module is used for controlling the sensor driving module and collecting the frequency signal in real time and transmitting it to the upper computer control module;

[0093] The upper computer control module is in communication connection with the lower computer control module, and the upper computer control module is used for receiving and processing the frequency signal sent by the lower computer control module and performing visual display, so as to realize digital teaching.

[0094] The power supply module is used for supplying power for the sensor driving module, the lower computer control module and the upper computer control module respectively.

[0095] As shown in the figure, Figure 3 The structure of the QCM detection probe includes a shell, a USB interface, and a detection circuit, a detection pool and a quartz crystal sensor arranged inside the shell; the copper wire is wrapped in glass fiber to reduce the risk of chemical corrosion;

[0096] The USB interface is integrally arranged with the detection circuit; the USB interface is electrically connected with the sensor driving module and is used for transmitting the frequency signal;

[0097] The quartz crystal sensor is placed inside the detection pool; the interface of the quartz crystal sensor is fixedly connected with the input end (metal spring contact) of the detection circuit;

[0098] The shell is a detachable structure, as shown in the figure, Figure 4 The detection pool is a concave circular structure at the center of the shell, and the upper cover and the lower cover of the detection pool are fixed by a magnet, which is used for replacing the sensing wafer coated with different materials;

[0099] The sensor driving module is specifically a Pierce oscillator circuit;

[0100] The quartz crystal sensor is specifically an AT-cut quartz crystal; the frequency of the quartz crystal sensor in the embodiment is 6MHz;

[0101] The lower computer control module is specifically an STM32 single-chip microcomputer;

[0102] The upper computer control module is specifically a microprocessor Raspberry Pi, and the operating system used is RaspberryPi OS;

[0103] As shown in the figure, Figure 5 In the embodiment, the lower computer control module is specifically an STM32F407VET6 single-chip microcomputer;

[0104] The lower computer control module uses a 25MHz wafer as an external clock source, which is directly or through a phase-locked loop (PLL) used for the clock of the lower computer control module;

[0105] The power supply circuit is filtered by a non-polarized capacitor to eliminate high-frequency noise and reduce ripple; the ADC module of the main control chip is configured to adapt to the oscillation signal, and the oscillation output is connected to the ADC input channel; the frequency is calculated using the TIM4 timer, and the trigger value is extracted every second using the TIM3 timer; a peak detection algorithm is used to improve measurement accuracy, and the frequency value is formatted and sent through the USB-to-serial port; this configuration ensures the stability of the system and the accuracy of the measurement;

[0106] The microprocessor Raspberry Pi is provided with two HDMI interfaces for connecting a touch display and a projector respectively; the touch display is used for user interaction, and the projector is used for multimedia projection teaching demonstration;

[0107] In the case of accessing the network, the microprocessor Raspberry Pi is connected with the projector through the network; in the case of not accessing the network, the microprocessor Raspberry Pi is connected with the projector through any one of the HDMI interfaces;

[0108] The teaching application software based on the Qt platform is built in the upper computer control module;

[0109] The teaching application software is used to realize the following operations: data processing, exception handling, self-starting at power-on, multiple experiment re-running, multimedia projection, and one-key software upgrading;

[0110] The display information of the main interface of the teaching application software includes:

[0111] The number and name of the communication port, the name of the measured substance, the name of the interactive command button, the chart display information, the data input box, the experimental result, the current version of the software, and the current running state information;

[0112] The communication port is used to detect the disconnection and connection of the upper computer control module and the lower computer control module in real time;

[0113] The interactive command button name includes: theoretical concentration button, data stability button, stop reading button, export information button, view information button, and update system button;

[0114] The data input into the data input box includes: the volume of the injected measured substance, the volume of the detection container, and the temperature;

[0115] The data processing of the teaching application software includes:

[0116] Through the preset upper and lower computer agreement protocol, the teaching application software reads and analyzes the frequency signal sent by the lower computer control module in real time, calculates the difference ΔF of the frequency change, and filters out the maximum and minimum values of the frequency;

[0117] All frequency signals and results of analysis and calculation thereof are exported as an Excel file based on a preset Qxlsx module in the teaching application software; the Excel file contains collection time and frequency values of the frequency signals;

[0118] The data processing adopts a multi-thread processing mode to ensure smooth response of the main interface of the teaching application software and avoid blocking of the main interface;

[0119] The teaching application software is upgraded by one key by using a U disk with a software upgrade installation package.

[0120] In the specific implementation process, in the teaching process, first, the to-be-tested substance is injected into the detection container of the detection module, and the QCM detection probe is immersed in the to-be-tested substance; the lower computer control module and the upper computer control module are started and initialized;

[0121] The lower computer control module controls the sensor driving module to generate an excitation signal and send it to the quartz crystal sensor, so that the quartz crystal sensor oscillates at a specific resonance frequency;

[0122] The quartz crystal sensor in the QCM detection probe detects the frequency change of the quartz crystal in real time, generates an electrical signal and sends it to the sensor driving module; the sensor driving module receives the electrical signal and amplifies and processes it to obtain a frequency signal;

[0123] The lower computer control module collects the frequency signal in real time and transmits it to the upper computer control module;

[0124] The upper computer control module receives and processes the frequency signal sent by the lower computer control module, and performs visual display to realize digital teaching;

[0125] In order to realize digital teaching, a teaching application software is built in the upper computer control module in the embodiment, as shown in Figure 6 The main interface schematic diagram thereof includes a communication port number and name area, a detected substance name display area, an interactive command button area, a chart display area, a data input box area, an experimental report result area, a system current version and system running state display area;

[0126] The communication port number and name system utilizes a QTimer timing triggering detection mechanism to query serial port information provided by QSerialPortInfo; the system can timely identify serial port name and serial port number information and communication port insertion or removal events, and update the system running state display to Connect successful or Connect failure;

[0127] The system current version display will be displayed according to the system upgrade installation package version name;

[0128] The interactive command buttons include a theoretical concentration button, a data stabilization button, a stop reading button, an export information button, a view information button, and an update system button.

[0129] The data input boxes include injection volume, cylinder volume, and temperature. For the parameters of injection volume, cylinder volume, and temperature, the actual situation can be input by the numeric keypad, and integers or decimals can be input. The "<" can delete the input data, the "C" can clear the text box, and the "Enter" can complete the data input. The theoretical concentration calculation button can calculate the theoretical concentration according to the input values of injection volume, cylinder volume, and temperature, and according to the corresponding material frequency formula.

[0130] The system listens to the readyRead signal of the serial port, reads the received data in real time, and analyzes it through the read_serialport slot function. At the same time, the real-time curve is drawn in the chart display area. Since the curve data is dynamically displayed over time, if the user needs to see the curve at the previous time point, the user can touch the screen to zoom in, zoom out, or move the curve, or use the reset to quickly restore the curve to its original loading state.

[0131] In order to more clearly see the change trend of ΔF, after clicking the data stabilization, the vertical and horizontal coordinates of the chart display area will adapt to the difference between the maximum and minimum values.

[0132] In the process of calculating ΔF, a segment of data that meets the standard needs to be intercepted, that is, the unstable and invalid data caused by the first segment of interference is removed, and then the data until the experiment ends is taken. In the data measurement process, the tester subjectively gives a data stabilization mark through the subtle changes of the frequency curve.

[0133] After clicking the data stabilization button, the system will record the time point and frequency value at this time in the background.

[0134] After a period of time of experiment, when the experiment is about to end and the data tends to be stable and no longer fluctuates strongly, after clicking the stop reading button, the system will record the time point and frequency value at the end in the background.

[0135] The start and end time points and frequency value data recorded by the system in the background from clicking the data stabilization button to clicking the stop reading button are stored in the QVector container, and are processed by the C++ STL algorithm to filter out the maximum and minimum values of the data frequency. The difference ΔF of the frequency change is calculated, and the difference of the intermolecular force is obtained by analysis and comparison.

[0136] In this embodiment, the data processing adopts multi-threading technology, which moves the time-consuming algorithm processing operation to the background thread to ensure the smooth response of the main interface;

[0137] When the export information is clicked, the frequency curve from the maximum value time point to the minimum value time point will be displayed in the chart, including the detection substance name, frequency maximum and minimum value, frequency difference, injection volume, cylinder volume, temperature, and theoretical and actual concentration will be displayed;

[0138] In order to improve the efficiency of data processing, reduce repetitive work, and help research and teaching personnel better analyze data later, the Qxlsx module is integrated to enable the system to operate Excel files;

[0139] At the same time, the QProcess component is used to execute system commands to detect the connection state of the U disk, and after successful connection, the System function is used to mount the U disk, and the Excel and Png data files are copied to the U disk to realize convenient data export;

[0140] Clicking the export to U disk button will first detect the U disk. If the U disk is not inserted, data export cannot be performed;

[0141] After inserting the U disk, operate again, click export to U disk again, a save success popup window will pop up, and after clicking confirm, an Excel file and a Png file named with the system time + the name of the measured substance will be generated in the specified directory of the system, and the U disk will also have the same named Excel file and Png file;

[0142] After inserting the U disk into the Windows system, open the Excel file, you can see the complete data of the experiment from beginning to end, as well as the maximum and minimum value time points and frequency values, and the highlighted processing;

[0143] Click the update system button at the bottom right of the interface, a prompt whether to enter the software update page will pop up, click confirm, the system main program will be closed, and a new page one-click system update will pop up;

[0144] Click one-click system update without inserting the U disk, the update cannot be completed, and a U disk not inserted prompt will be given;

[0145] After inserting the U disk, the system will automatically detect the new version of the software package and transplant it to the directory of the main program software package started by Raspberry Pi, and a software update success popup window will be given, click immediately run new program, the new version of the software will be directly run, click restart system to run new program, the system will be immediately restarted, and then the new version of the system program will be started after the restart is completed;

[0146] For example Figure 7The working flow diagram of the teaching application software is shown. After the Raspberry Pi is powered on, the teaching application software creates a custom launcher using the Linux system's.Desktop file specification. After the system boot is complete, the executable file in the predefined directory is automatically located and executed;

[0147] The teaching application software can be projected through a network medium or through the other of the two HDMI interfaces. The system detects data from the hardware system in real time through a serial connection. After the host computer receives the data, it displays the data in a chart and also records and displays the experimental report data. The chart data and experimental report data can be exported to a USB drive or viewed in the teaching application software. The chart data is exported in an Excel file and the experimental report data is exported in a Png format.

[0148] When the user issues a one-key update instruction, the Grep command is used in combination with a regular expression to accurately identify the currently running software main process. Subsequently, the Xargs tool is used to convert the identification result into a system command line parameter, and the System function is called to trigger the Kill command to safely terminate the software process. After the software is closed, the U disk is inserted, and the new software package is selected by QDir to replace the old software package. The software package after the replacement is executed to complete the system update.

[0149] After the above process is completed, the system ends the current work period and waits for the next task to start or for user operation.

[0150] To achieve smooth restart of the software, the qApp->exit(0) function is used to exit the current application program, and the exec() system call is used to restart the application program. In addition, the QProcess::startDetached method is used to restart the software package in the original path of the system, ensuring the continuity and stability of the service.

[0151] As Figure 8As shown, the connection diagram of the microprocessor Raspberry Pi configured with a dual HDMI interface, for the Raspberry Pi with two HDMI interfaces, burn the Raspberry Pi OS system to the SD card, build the development environment and complete the teaching application software development, touch display device connected to the HDMI1 of Raspberry Pi, projector connected to HDMI2, USB1 power supply for touch display device; After hardware connection, in the software method, open the config.txt file, change the resolution of the touch display device to the corresponding sentence segment of [hdmi:0][hdmi:1], save the settings, restart the Raspberry Pi, open Screen Configuration: drag HDMI-2 to coincide with HDMI-1, and click OK: two display screens can copy the same picture, and the touch can be used normally;

[0152] In order to verify the performance of the device, the device is compared with the existing QCM device in performance comparison experiment;

[0153] Experiment background: The ordinary high school curriculum standard experiment textbook "Chemical reaction principle" mentions that Zn reacts with dilute H2SO4, and a small amount of CuSO4 solution occurs a primary cell reaction, which can accelerate the reaction rate; Teachers often have difficulty explaining from the perspective of middle school chemistry, and students have not experienced the change of rate through experiments, can students intuitively feel that the addition of CuSO4 can accelerate the reaction rate of Zn and dilute H2SO4, and the QCM device instrument attempts to do so;

[0154] Experimental principle: QCM experimental device is a mass sensor composed of quartz crystal, sensor, reaction device (closed container) and computer software, in the closed container, the gas generated in the container can be adsorbed to the crystal surface, when the gas is adsorbed to the crystal surface, the mass of the crystal changes, through the resonance frequency effect of the crystal, the reaction is shown as the change of frequency in the computer; In general, for observing the reaction rate of Zn and dilute H2SO4, the frequency change can be indirectly reflected by observing the frequency change in the computer;

[0155] Experimental instruments: traditional QCM device and portable QCM device provided in the embodiment;

[0156] Experimental reagents: zinc particles with the same diameter, distilled water, 1moL / L CuSO4 solution, 5moL / L sulfuric acid solution;

[0157] Specific experimental steps:

[0158] For the traditional QCM device and the portable QCM device provided in the embodiment, the following two experiments are carried out respectively:

[0159] Experiment 1: Assemble the QCM device, put silica gel in the reaction device to absorb other gases and water in the device, and wait for the frequency to be stable (change less than 5 Hz within 2 minutes) in the computer software. Take out the silica gel, put 0.5g of Zn particles into the container, wait for the frequency to be stable (change less than 5 Hz within 2 minutes), inject 4mL of 5moL / L sulfuric acid and 1mL of distilled water mixture with a syringe, and observe the frequency change on the computer for 10 minutes;

[0160] Experiment 2: Repeat the steps of Experiment 1, and change the injection of 4mL of 5moL / L sulfuric acid and 1mL of distilled water mixture with a syringe to 4mL of 5moL / L sulfuric acid and 1mL of 1moL / L CuSO4 solution. Observe the frequency change on the computer for 10 minutes;

[0161] In this comparative experiment, the detection performance of the existing QCM device and the portable QCM device provided in this embodiment on the frequency change trend of zinc particles reacting with acid to prepare hydrogen gas is compared, as shown in Figure 9 and 10 The experimental results are shown in the figure;

[0162] As can be seen from Figure 10 , the frequency difference of the two experiments is 1475 and 1514, which is very close, indicating that the sulfuric acid can completely react with the Zn particles, so the mass of the generated hydrogen gas is almost the same. As can be seen from the image, the complete reaction of Experiment 1 takes about 500s, and the complete reaction of Experiment 2 takes about 150s, which is much faster than Experiment 1. This indicates that the addition of CuSO4 solution can significantly accelerate the reaction rate of Zn and dilute H2SO4, indicating that the portable QCM device provided in this embodiment is effective and can accurately and intuitively perform visual teaching;

[0163] As can be seen from Figure 9 and Figure 10 , the portable QCM device and the existing QCM device have almost the same performance (frequency difference), but the measurement process of the existing QCM device is cumbersome and not suitable for large-scale promotion in the teaching field. In contrast, the portable QCM device is more suitable for the teaching field, and the traditional QCM device is more suitable for the scientific research and experimental field. The device can be started and stopped at any time, the experimental parameters can be changed at any time, and the measurement process is more convenient;

[0164] In summary, the portable QCM device has almost the same performance as the existing QCM device, is more portable, and is more suitable for digital teaching. In addition, the device is more portable, the equipment is more miniaturized, the integration is higher, the operation process is simpler, and the running is easier, which has a significant advantage;

[0165] The device is light and integrated with substance detection, hardware control and teaching function, which can adapt to various use scenarios; through integrated hardware system and user-friendly digital teaching platform, the high-precision monitoring of trace substances is realized, convenient operation, intuitive display and interactive control of data, diversification of function, continuous updating and upgrading of system, so as to meet the modern digital teaching needs.

[0166] Embodiment 3

[0167] As shown in the embodiment, a portable QCM trace substance monitoring method for digital teaching is provided, which is based on the portable QCM trace substance monitoring device for digital teaching in embodiment 1 or 2, and includes the following steps: Figure 11 S1: install the QCM detection probe inside the detection container, start the lower computer control module and the upper computer control module and initialize;

[0168] S2: the lower computer control module controls the sensor driving module to generate an excitation signal and send it to the quartz crystal sensor, so that the quartz crystal sensor oscillates at a specific resonance frequency;

[0169] After the frequency signal is stable, the measured substance is injected into the detection container of the detection module; the injection method is not limited herein, and in the embodiment, a rubber plug sealed injection hole is opened on the upper cover of the detection container, and the measured substance is injected into the detection container through the injection hole by a syringe;

[0170] S3: the quartz crystal sensor in the QCM detection probe detects the frequency change of the quartz crystal in real time, generates an electric signal and sends it to the sensor driving module; the sensor driving module receives the electric signal and amplifies and processes to obtain a frequency signal;

[0171] S4: the lower computer control module collects the frequency signal in real time and transmits it to the upper computer control module;

[0172] S5: the upper computer control module receives and processes the frequency signal sent by the lower computer control module, and performs visual display to realize digital teaching.

[0173] In the specific implementation process, the embodiment provides a teaching experiment process for verifying intermolecular forces by using a portable QCM device, which is as follows:

[0174] Install the quartz wafer coated with u101 material in the QCM detection probe, put silica gel into the detection container, adsorb the water vapor in the detection container, take out the silica gel after one hour, and continue to wait for 10-30 minutes or so until the frequency is stable (the frequency change is within 5 Hz within 2 minutes);

[0175] ​

[0176] Wait for the frequency signal collected in the host computer control module to be stable, click "data stable", inject 1ml of methanol into the device;

[0177] After about 1 minute, the frequency change curve and specific value can be seen, click "stop reading" to stop collection, and save the experimental data;

[0178] Repeat the above operation to measure the frequency change of ethanol and n-butanol;

[0179] As Figure 12 The experimental test result graph is shown in the figure, and the experimental frequency change graph proves that liquid volatilization overcomes intermolecular force, volatilization is less, the molecules attached to the crystal surface are less, the frequency decreases in the same time, and the intermolecular force of the measured substance is greater; volatilization is more, the molecules attached to the crystal surface are more, the frequency decreases in the same time, and the intermolecular force of the measured substance is smaller; the experimental conclusion is that the intermolecular force is methanol < ethanol < butanol;

[0180] The method makes the qualitative conclusion accurate and the microscopic essence intuitive, helps students to establish the substantial knowledge correlation between unfamiliar concepts and familiar concepts, and scientifically constructs abstract chemical concepts, which not only shows the importance of digital technology in modern education, but also provides a new perspective and tool for chemistry teaching and basic research.

[0181] The same or similar reference signs correspond to the same or similar parts;

[0182] The positional relationship described in the drawings is only used for example illustration, and cannot be understood as a limitation to the patent;

[0183] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the implementation modes are not required or can not be exhausted. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A portable QCM micro-substance monitoring device for digitized teaching, characterized in that, The application relates to a QCM (Quartz Crystal Microbalance) teaching device. The device comprises a detection module, a sensor driving module, a single-chip microcomputer-based lower computer control module and an upper computer control module, and a power supply module. The detection module comprises a detection container and a QCM detection probe; the detection container contains a to-be-detected substance and is used for simulating a detection environment; the QCM detection probe is fixedly arranged in the detection container, a quartz crystal sensor is arranged in the QCM detection probe, and the QCM detection probe is used for detecting the mass change of the to-be-detected substance according to the frequency change of the quartz crystal. The QCM detection probe is electrically connected with the sensor driving module and transmits the detected frequency signal to the sensor driving module; the sensor driving module provides an excitation signal for the quartz crystal sensor, so that the quartz crystal sensor oscillates at a specific resonance frequency. The structure of the QCM detection probe comprises an outer shell, a USB interface and a detection circuit, a detection pool and a quartz crystal sensor arranged in the outer shell. The USB interface is integrally arranged with the detection circuit; the USB interface is electrically connected with the sensor driving module and is used for transmitting the frequency signal. The quartz crystal sensor is arranged in the detection pool; an interface of the quartz crystal sensor is fixedly connected with an input end of the detection circuit. The outer shell is a detachable structure and is used for replacing the sensing wafer coating type of the quartz crystal sensor in the detection pool. The sensor driving module is further electrically connected with the lower computer control module; the lower computer control module is used for controlling the sensor driving module and collecting the frequency signal in real time and transmitting the frequency signal to the upper computer control module. The upper computer control module is in communication connection with the lower computer control module; the upper computer control module is used for receiving and processing the frequency signal transmitted by the lower computer control module and performing visual display to realize digital teaching. The power supply module is used for supplying power for the sensor driving module, the lower computer control module and the upper computer control module. The sensor driving module is specifically a Pierce oscillator circuit. The quartz crystal sensor is specifically an AT-cut quartz crystal. The lower computer control module is specifically an STM32 single-chip microcomputer. The upper computer control module is specifically a microprocessor Raspberry Pi, and the operating system used is Raspberry PiOS. The teaching application software based on the Qt platform is built in the upper computer control module. The teaching application software is used for realizing the following operations: data processing, exception processing, self-starting at power-on, multiple experiment re-running, multimedia screen projection and software one-key upgrading. The data processing of the teaching application software comprises the following steps: Through a preset upper-lower computer agreement protocol, the teaching application software reads and analyzes the frequency signal transmitted by the lower computer control module in real time, calculates the difference value Delta F of the frequency change, and selects the maximum value and the minimum value of the frequency. Based on the Qxlsx module preset in the teaching application software, all the frequency signals and the analysis and calculation results thereof are jointly exported as an Excel file; the Excel file comprises the collection time and the frequency value of the frequency signal. The data processing adopts a multi-thread processing mode, so as to ensure the smooth response of the main interface of the teaching application software and avoid the blocking of the main interface.

2. The portable QCM micro-substance monitoring device for digitized teaching according to claim 1, characterized in that, The lower computer control module is specifically an STM32F407VET6 single-chip microcomputer. The lower computer control module uses a 25MHz wafer as an external clock source, and directly or through a phase-locked loop (PLL) is used for the clock of the lower computer control module. A peak detection algorithm is used to detect the frequency signal, so as to improve the measurement accuracy; a TIM4 timer is used to realize real-time calculation of the frequency, and a TIM3 timer is used to extract the trigger value in real time.

3. The portable QCM micro-substance monitoring device for digitized teaching according to claim 1, characterized in that, The microprocessor Raspberry Pi is provided with two HDMI interfaces, which are respectively used for connecting a touch display and a projector; the touch display is used for user interaction, and the projector is used for multimedia projection teaching demonstration. In the case of having accessed the network, the microprocessor Raspberry Pi is connected with the projector through the network; in the case of not having accessed the network, the microprocessor Raspberry Pi is connected with the projector through the corresponding HDMI interface.

4. The portable QCM micro-substance monitoring device for digitized teaching according to claim 1, characterized in that, The display information of the main interface of the teaching application software includes: The number and name of the communication port, the name of the measured substance, the name of the interactive command button, the chart display information, the data input box, the experimental result, the current version and the current running state information of the software; The communication port is used for real-time detection of the disconnection and connection of the upper computer control module and the lower computer control module; The interactive command button name includes: theoretical concentration button, data stability button, stop reading button, export information button, view information button and update system button; The data input box inputs the data including the volume of the injected measured substance, the volume and the temperature of the detection container.

5. The portable QCM micro-substance monitoring device for digitized teaching according to claim 1, characterized in that, The U disk with the software upgrade installation package is used to perform software one-key upgrade on the teaching application software.

6. A portable QCM micro-substance monitoring method for digitalized teaching based on the portable QCM micro-substance monitoring device for digitalized teaching according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1: installing the QCM detection probe inside the detection container, starting the lower computer control module and the upper computer control module and initializing; S2: the lower computer control module controls the sensor driving module to generate an excitation signal and send it to the quartz crystal sensor, so that the quartz crystal sensor oscillates at a specific resonant frequency; After the frequency signal is stable, the measured substance is injected into the detection container of the detection module; S3: the quartz crystal sensor in the QCM detection probe detects the frequency change of the quartz crystal in real time, generates an electric signal and sends it to the sensor driving module; the sensor driving module receives the electric signal, amplifies and processes it to obtain a frequency signal; S4: the lower computer control module collects the frequency signal in real time and transmits it to the upper computer control module; S5: the upper computer control module receives and processes the frequency signal sent by the lower computer control module, and performs visual display, realizing digital teaching.

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