A gas sensor integrated system and method based on dynamic temperature modulation

Abstract

A gas sensor integrated system and method based on dynamic temperature modulation, belonging to the field of gas sensors, consists of two parts: a gas detection system and a gas sensor test system; the invention uses a pin header and a gas sensor to build a gas sensor array module, uses a single-chip microcomputer and an external circuit to meet the heating and signal acquisition requirements of different types of gas sensor arrays, and uses a computer to train corresponding classification models for different types of gas sensor arrays, and builds a customized gas detection system based on dynamic temperature modulation; at the same time, a data acquisition card is connected to one end of the gas sensor, and the other end is connected to a computer, and a gas sensor test system is built through computer software Labview, realizing the integrated design of the two systems; it has the advantages of high integration, convenience and speed, and has broad application prospects in the fields of human health and natural environment.

Description

Technical Field

[0001] The present invention belongs to the field of gas sensors, and in particular relates to a gas sensor integrated system and method based on dynamic temperature modulation. Background Art

[0002] With the rapid development of global industry and economy, volatile organic compounds (VOCs) gas pollution has become a serious problem that endangers social security and human health. Therefore, the development of sensitive gas detection systems and the provision of convenient gas sensor testing systems are of great significance to human health and the natural environment. However, the gas detection systems currently developed using gas sensors are mostly static temperature modulation, that is, a constant voltage or current is applied to both ends of the sensor in the gas sensor array, and the final response signal of the resistance value of the gas sensor is obtained by finally measuring the current or voltage value at both ends of the gas sensor. Although this method is simple, it has high power consumption, low accuracy, and a small scope of application when used, and cannot be studied in depth. The gas sensor test system currently used collects gas sensor characteristic signals through a data acquisition card to test the gas sensor. Although this method helps to conduct in-depth research on gas sensors, it has a single function and cannot meet the needs of actual life.

[0003] People have found that when the gas sensor is heated using dynamic temperature modulation technology, the response values ​​of the gas sensor at different temperatures can be obtained, and the gas-sensitive response is expanded in the time dimension. The gas-sensitive response changes from a ratio to a response curve containing type and concentration information, effectively overcoming the problem of reduced recognition accuracy caused by cross-sensitivity of the gas sensor. At the same time, since the amount of signal generated by each gas sensor increases during dynamic temperature modulation, a small number of gas sensors can be used during gas detection to achieve accurate detection of complex environmental gases, reducing heating power consumption, production costs, and system volume. This is of great significance to the gas detection industry and the gas sensor industry, and has a far-reaching impact on human health and the natural environment.

[0004] At present, most of the gas detection systems developed using gas sensors are static temperature modulation, that is, a constant voltage or current is applied to both ends of the gas sensor, and the resistance value of the gas sensor is obtained by measuring the current or voltage value at both ends of the gas sensor as the final characteristic signal. It is not difficult to see that for a single gas sensor, the characteristic signal that can be obtained by static temperature modulation is one-dimensional, and there are problems such as poor selectivity of gas sensors and high heating power consumption. The selectivity problem refers to cross-sensitivity, that is, a single gas sensor is often sensitive to multiple gases in the measured environment, and it is difficult to selectively detect the type and content of a certain gas. Therefore, if the system wants to detect the type and concentration of gases in complex environments, it needs to use a certain number of gas sensors to form a gas sensor array to increase the dimension of the obtained signal. However, this will increase the heating power consumption and the cost of use. At the same time, it can only be used for detection in specific environments and has poor applicability to other environments. Moreover, it is impossible to observe the changes in characteristic signals in real time and intuitively, which is not convenient for in-depth research on gas detection. This cannot meet the requirements for precise detection, diversified detection, energy-saving detection, and in-depth research. It can neither meet the needs of humans to use as few gas sensors as possible to accurately and energy-savingly detect multiple gases in complex environments; nor can it meet the needs of using different types of sensor arrays to detect gases using one system, and its applicability is not strong; nor can it conduct in-depth research on gas detection. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention designs a gas sensor integrated system and method based on dynamic temperature modulation;

[0006] A gas sensor integrated system based on dynamic temperature modulation, consisting of a gas detection system and a gas sensor test system;

[0007] Among them, the gas detection system includes: single chip computer module, gas sensor array module, heating module, signal acquisition module, algorithm recognition module;

[0008] The single-chip microcomputer module is composed of a single-chip microcomputer, a crystal oscillator, a button, a capacitor, a resistor, and a DC power supply; the pins of the single-chip microcomputer are connected to the crystal oscillator, the capacitor, the DC power supply, and the resistor so that the single-chip microcomputer can work normally, and the pins of the single-chip microcomputer are connected to the button to control the state of the heating module;

[0009] The heating module is composed of a digital-to-analog conversion device, an operational amplifier circuit and a transistor, wherein the operational amplifier circuit contains an adjustable resistor A for controlling the heating power; the digital-to-analog conversion device is connected to the operational amplifier circuit to adjust the value range of the heating voltage, and finally the operational amplifier circuit is connected to the transistor to amplify the heating current to form a heating module;

[0010] The gas sensor array module is composed of a pin header connected to a gas sensor; the pin header on the circuit board is connected to the pin of the gas sensor through a DuPont line to form a gas sensor array module;

[0011] The signal acquisition module is composed of an analog-to-digital conversion device, an adjustable resistor B for adjusting the characteristic signal value, and a single chip; one end of the adjustable resistor B is connected to the analog signal input end of the analog-to-digital conversion device, and the other end is connected to a DC power supply, and the digital signal output end of the analog-to-digital conversion device is connected to the single chip microcomputer pin, forming a signal acquisition module;

[0012] The algorithm recognition module is composed of a single chip in the single chip module;

[0013] The single-chip microcomputer module is connected to the digital-to-analog conversion device of the heating module to convert the digital signal in the single-chip microcomputer into an analog voltage signal, and then the heating voltage and heating current value range are adjusted through the operational amplifier circuit and the triode; the emitter of the triode of the heating module is connected to the pin row connected to the pin at one end of the heating resistor of the sensor in the gas sensor array module through the circuit board, and the pin row connected to the pin at the other end of the heating resistor is grounded, and the dynamic heating waveform generated by the heating module is used to heat the gas sensor array; the connection point between the adjustable resistor B and the analog-to-digital conversion device and the pin row connected to the pin at one end of the gas sensitive resistor on the gas sensor are connected to the circuit board. The connection is made through the circuit board, the pin row connected to the pin at the other end of the gas sensitive resistor on the gas sensor is grounded, the voltage division signal on the gas sensitive resistor of the gas sensor is collected in real time, and the single-chip microcomputer is connected to the output end of the analog-to-digital conversion device of the signal acquisition module, so that the characteristic signal collected in the Nth heating cycle is transmitted to the single-chip microcomputer for storage; the characteristic signal collected in the Nth heating cycle by the signal acquisition module is identified using the algorithm in the single-chip microcomputer, and the Nth heating cycle is a dynamic heating cycle in which the dynamic responses of all gas sensors in the gas sensor array in different gas environments are close to stable; the construction of the gas detection system is completed;

[0014] The gas sensor test system includes: a single chip computer module, a heating module, a gas sensor array module, and a gas sensor test module;

[0015] The single chip microcomputer module, the gas sensor array module and the heating module are shared by the gas detection system and the gas sensor test system;

[0016] The gas sensor test module is composed of a data acquisition card, a computer and computer software Labview; the gas sensor test module is formed by connecting the data acquisition card to the computer;

[0017] Connect the connection point of the gas sensor's gas-sensitive resistor and adjustable resistor B to the data acquisition card, adjust the computer software Labview parameters, collect the partial pressure signals of the gas-sensitive resistor in the gas sensor at different times during the dynamic temperature modulation process, and complete the construction of the gas sensor test system;

[0018] The gas detection system and the gas sensor test system simultaneously collect the partial pressure signal on the gas sensitive resistor in the gas sensor during the dynamic temperature modulation process to form a gas sensor integrated system based on dynamic temperature modulation;

[0019] A gas sensor integration method based on dynamic temperature modulation is implemented based on the above-mentioned gas sensor integration system based on dynamic temperature modulation, as shown below:

[0020] Step 1: First, the construction process and function realization of the gas detection system;

[0021] Step 1.1 Design a customized gas sensor array module;

[0022] The pin header is used to provide a path for the gas sensor array, and the pin header and the gas sensor are selected to form a sensor array module;

[0023] When in use, the pin header and the gas sensor pin are connected with Dupont wire to form a gas sensor array module. In different environments, different types of gas sensors that have been put on the market can be used, such as semiconductor gas sensors, electrochemical gas sensors, and optical gas sensors to form a gas sensor array; meeting the use needs of different gas sensors for an integrated system;

[0024] Step 1.2: Build a customized heating module;

[0025] Step 1.2.1: The type of heating waveform is controlled by the single-chip microcomputer and the 8-bit input digital-to-analog conversion device. The output state of the 8-bit pin of the single-chip microcomputer is adjusted to realize the output of different types of dynamic heating waveforms. The integrated system outputs three dynamic heating waveforms, corresponding to sine wave, triangle wave and rectangular wave respectively. During the construction of the heating module, the 8-bit signal input pin of the digital-to-analog conversion device is connected to the 8-bit single-chip microcomputer pin that controls the type of heating waveform; during the operation of the system, the single-chip microcomputer controls the conversion between heating waveforms by detecting the state of the switch that controls the type of heating waveform;

[0026] Step 1.2.2: Using the adjustable resistor A as an external resistor, by adjusting the resistance value of the adjustable resistor A, the voltage range of the dynamic heating waveform can be adjusted, thereby achieving adjustable heating power;

[0027] Step 1.2.3: Considering that different gas sensor arrays often require different response times and heating cycles during detection, a single-chip microcomputer is used to first realize that the heating cycle of the heating waveform is K s. Then the single-chip microcomputer scans the state of the switch that controls the rise of the heating cycle and the switch that controls the fall of the heating cycle. If the switch is pressed and then lifted, the heating cycle will change, realizing the adjustable heating cycle with an adjustment accuracy of H s, where K and H are both greater than or equal to 0.5;

[0028] Step 1.2.4: Use the single chip microcomputer and the external display screen to display the heating waveform and heating cycle in real time;

[0029] The user selects the desired dynamic heating waveform type by controlling the heating waveform type button. The initial waveform is a sine wave. After pressing the button once, the output is a triangle wave. After pressing it again, the output is a rectangular wave. After that, press the button again to output a sine wave for a cycle. The desired heating cycle is selected by pressing the cycle up button and the cycle down button, and each press changes H s, H ≥ 0.5; the desired heating power is selected by the adjustable resistor A;

[0030] It meets the requirements of different gas sensors for heating waveform, heating power and heating cycle when performing gas detection; it meets the requirements of dynamic response testing of gas sensors under different heating waveforms, heating power and heating cycles, and users can clearly understand the adjusted heating waveform and heating cycle;

[0031] Step 1.3: Build a customized signal acquisition module;

[0032] Step 1.3.1: Connect the gas-sensitive resistor of each sensor in the gas sensor array in series with an adjustable resistor B. When collecting signals, ensure that the resistance value of each adjustable resistor B is consistent with the resistance value of the gas-sensitive resistor of the gas sensor connected in series with it in the air and remain unchanged. Then connect one end of the series resistor to a DC power supply and the other end to ground, and collect the divided voltage signal on the gas-sensitive resistor of the gas sensor as a characteristic signal;

[0033] Step 1.3.2: For different types of gas sensors on the gas sensor array, the adjustable resistor connected in series with the gas sensitive resistor of each gas sensor is adjusted according to step 1.3.1, so as to avoid the problem that the characteristic signal change is not obvious due to the adjustable resistor being too large or too small;

[0034] Step 1.3.3: According to the heating cycle finally adjusted by the customized heating module, the sampling period for the heating cycle is set to adjust the sampling period for different types of gas sensor arrays;

[0035] Step 1.3.4: After the heating waveform or heating cycle is changed, the response signal of the gas sensor cannot quickly reach stability, and direct acquisition will obtain unsatisfactory results. The characteristic signal collected from the starting point of the Nth heating cycle after the heating waveform or heating cycle is changed to the end point of the Nth heating cycle is stored in the single-chip microcomputer module. The Nth heating cycle is a dynamic heating cycle in which the dynamic responses of all gas sensors in the gas sensor array in different gas environments are close to stable. The characteristic signal stored before the final selected heating waveform and heating cycle is removed;

[0036] Step 1.3.5: The collected voltage division signal is displayed in real time through the single chip microcomputer and the external display screen;

[0037] After the dynamic heating waveform and heating power selection are completed, the single chip microcomputer starts to collect the gas sensor response signal, presents it in real time through the display screen, and stores the response signal value in the Nth cycle;

[0038] Different gas sensors have different response times. Setting the sampling period and sampling start time can not only meet the different gas sensor detection requirements, but also improve the detection accuracy and system stability.

[0039] Step 1.4: Construction of customizable algorithm recognition module:

[0040] The characteristic signal collected in the signal acquisition module during the Nth heating cycle is transmitted to the recognition algorithm to build an algorithm recognition module;

[0041] Step 1.4.1: First, collect the characteristic signals of a gas sensor array under different gas environments, connect the single-chip microcomputer and the computer using the USB interface, use the serial communication technology to import the finally collected characteristic signals from the single-chip microcomputer to the computer, use the classification algorithm to train the gas recognition model, and then import the model into the single-chip microcomputer;

[0042] Step 1.4.2: Place different types of gas sensor arrays on the gas sensor array module and repeat step 1.4.1;

[0043] Step 1.4.3: Finally, according to the length of the final heating cycle, the characteristic signal is imported into the model matching the heating cycle for solution, and the result of the final model classification is displayed on the display screen;

[0044] For different gas sensor arrays, the response signal values ​​are often different under the same dynamic heating waveform and gas environment. Therefore, the algorithm recognition module meets the detection requirements of various gas sensor arrays.

[0045] Step 2: Construction and function realization of gas sensor test system:

[0046] Step 2.1: Connect the development board and data acquisition card, and the data acquisition card and computer. One end of the data acquisition card is connected to the connection between the gas sensor resistor and the adjustable resistor B in the gas sensor array, and the other end is connected to the computer, completing the construction of the hardware circuit of the gas sensor test system.

[0047] Step 2.2: The user configures the computer software Labview environment, and controls Labview to let the data acquisition card process the transmitted data to obtain a stable and reliable partial pressure signal. Finally, the response curve of the gas sensor is observed in real time on the computer software Labview, realizing the test requirements of the gas sensor for gases in different environments; the gas is a single gas or a mixed gas for testing;

[0048] The gas sensor testing system can observe in real time the values ​​and changing trends of the response signals of different gas sensors under different dynamic heating waveform conditions. When the heating waveform, heating power, and heating cycle suitable for the gas sensor are unknown, it can first test to find the most suitable dynamic heating waveform for the gas sensor array and then perform gas detection.

[0049] Beneficial technical effects of the present invention:

[0050] The gas sensor system integrated system designed by the present invention based on dynamic temperature modulation can detect gases in complex environments using a small number of different types of gas sensors, and can also monitor the changes in the response signals of different types of gas sensors in real time on the computer software Labview. Specifically:

[0051] 1. Dynamic temperature modulation environment construction: Use the microcontroller and peripheral circuits to convert the DC power supply into a dynamic heating waveform to build a dynamic temperature modulation environment, providing a basic environment for subsequent gas detection and sensor testing.

[0052] 2. Meet the detection and testing requirements of different types of gas sensors: Use peripheral switches and adjustable resistors to adjust the heating waveform, heating cycle, heating power and response signal value to achieve the customized requirements of the integrated system.

[0053] 3. Construction of gas sensor test system: Using data acquisition card and computer software Labview, the response signal of gas sensor in different gas environments can be monitored in real time.

[0054] On the one hand, these features meet the customizable needs for detection and testing of different types of gas sensors. On the other hand, the use of dynamic temperature modulation technology achieves the goal of precise and energy-saving detection of gases in complex environments. At the same time, users can observe the changes in the response signal of the gas sensor in real time on the computer, meeting the needs of gas sensor testing in different environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic structural diagram of a customized gas detection system based on dynamic temperature modulation according to an embodiment of the present invention;

[0056] Figure 2 The overall architecture diagram of the gas sensor integrated system based on dynamic temperature modulation according to the embodiment of the present invention;

[0057] Figure 3 A schematic diagram of a single chip computer code for controlling a heating waveform to be a sine wave in a customized gas detection system based on dynamic temperature modulation according to an embodiment of the present invention;

[0058] Figure 4 A schematic diagram of a single chip computer code for controlling a heating waveform to be a triangular wave in a customized gas detection system based on dynamic temperature modulation according to an embodiment of the present invention;

[0059] Figure 5 A schematic diagram of a single chip computer code for controlling a heating waveform to be a rectangular wave in a customized gas detection system based on dynamic temperature modulation according to an embodiment of the present invention; DETAILED DESCRIPTION

[0060] The present invention will be further described below in conjunction with the accompanying drawings and embodiments;

[0061] The purpose of the present invention is to provide an integrated gas sensor system and method based on dynamic temperature modulation, which combines a gas detection system and a gas sensor testing system to meet the needs of different types of gas sensor arrays for detecting gases in complex environments using dynamic temperature modulation technology, while monitoring changes in gas sensor response signals in real time, thereby facilitating in-depth and detailed research on gas sensors.

[0062] As attached Figure 2 As shown, a gas sensor integrated system based on dynamic temperature modulation consists of two parts: a gas detection system and a gas sensor testing system;

[0063] Among them, the gas detection system, such as the attached Figure 1 As shown, it includes: a single chip computer module, a gas sensor array module, a heating module, a signal acquisition module, and an algorithm recognition module;

[0064] The single-chip microcomputer module is composed of a single-chip microcomputer, a crystal oscillator, a button, a capacitor, a resistor, and a DC power supply; the pins of the single-chip microcomputer are connected to the crystal oscillator, the capacitor, the DC power supply, and the resistor so that the single-chip microcomputer can work normally, and the pins of the single-chip microcomputer are connected to the button to control the state of the heating module;

[0065] The heating module is composed of a digital-to-analog conversion device, an operational amplifier circuit and a transistor, wherein the operational amplifier circuit contains an adjustable resistor A for controlling the heating power; the digital-to-analog conversion device is connected to the operational amplifier circuit to adjust the value range of the heating voltage, and finally the operational amplifier circuit is connected to the transistor to amplify the current to form a heating module;

[0066] The gas sensor array module is composed of a pin header connected to a gas sensor; the pin header on the circuit board is connected to the pin of the gas sensor through a DuPont line to form a gas sensor array module;

[0067] The signal acquisition module is composed of an analog-to-digital conversion device, an adjustable resistor B for adjusting the characteristic signal value, and a single chip; one end of the adjustable resistor B is connected to the analog signal input end of the analog-to-digital conversion device, and the other end is connected to a DC power supply, and the digital signal output end of the analog-to-digital conversion device is connected to the single chip microcomputer pin, forming a signal acquisition module;

[0068] The algorithm recognition module is composed of a single chip in the single chip module;

[0069] The single-chip microcomputer module is connected to the digital-to-analog conversion device of the heating module to convert the digital signal in the single-chip microcomputer into an analog voltage signal, and then the heating voltage and heating current value range are adjusted through the operational amplifier circuit and the triode; the emitter of the triode of the heating module is connected to the pin at one end of the heating resistor of the sensor in the gas sensor array module through a circuit board, and the other end is grounded, and the dynamic heating waveform generated by the heating module is used to heat the gas sensor; the connection point between the adjustable resistor B and the analog-to-digital conversion device and the pin at one end of the gas sensitive resistor on the gas sensor are connected through a circuit board. The pin row connected to the pin at the other end of the gas-sensitive resistor on the gas sensor is grounded, and the voltage division signal on the gas-sensitive resistor of the gas sensor is collected in real time. The single-chip microcomputer is connected to the output end of the analog-to-digital conversion device of the signal acquisition module, so that the characteristic signal collected in the 10th heating cycle is transmitted to the single-chip microcomputer for storage; the characteristic signal collected in the 10th heating cycle by the signal acquisition module is identified using the algorithm in the single-chip microcomputer. The 10th heating cycle is a dynamic heating cycle in which the dynamic responses of all gas sensors in the gas sensor array in different gas environments are close to being stable; the construction of the gas detection system is completed;

[0070] The gas sensor test system includes: a single chip computer module, a heating module, a gas sensor array module, and a gas sensor test module;

[0071] The single chip microcomputer module, the gas sensor array module and the heating module are shared by the gas detection system and the gas sensor test system;

[0072] The gas sensor test module is composed of a data acquisition card, a computer and computer software Labview; the gas sensor test module is formed by connecting the data acquisition card to the computer;

[0073] Connect the connection point of the gas sensor's gas-sensitive resistor and adjustable resistor B to the data acquisition card, adjust the computer software Labview parameters, collect the partial pressure signals of the gas-sensitive resistor in the gas sensor at different times during the dynamic temperature modulation process, and complete the construction of the gas sensor test system;

[0074] The gas detection system and the gas sensor test system simultaneously collect the partial pressure signal on the gas sensitive resistor in the gas sensor during the dynamic temperature modulation process to form a gas sensor integrated system based on dynamic temperature modulation;

[0075] A gas sensor integration method based on dynamic temperature modulation is implemented based on the above-mentioned gas sensor integration system based on dynamic temperature modulation, as shown below:

[0076] Step 1: First, the construction process and function realization of the gas detection system;

[0077] Step 1.1 Design a customized gas sensor array module;

[0078] The pin header is used to provide a path for the gas sensor array, and the pin header and the gas sensor are selected to form a sensor array module;

[0079] When in use, the pin header and the gas sensor pin are connected with Dupont wire to form a gas sensor array module. In different environments, different types of gas sensors that have been put on the market can be used, such as semiconductor gas sensors, electrochemical gas sensors, and optical gas sensors to form a gas sensor array; meeting the use needs of different gas sensors for an integrated system;

[0080] Step 1.2: Build a customized heating module;

[0081] Step 1.2.1: The type of heating waveform is controlled by the single-chip microcomputer and the 8-bit input digital-to-analog conversion device. The output state of the single-chip microcomputer 8-bit pin is adjusted to realize different types of dynamic heating waveform output, as shown in the attached Figure 3 , Attachment Figure 4 , Attachment Figure 5 As shown, the integrated system can output three dynamic heating waveforms, corresponding to sine wave, triangle wave and rectangular wave respectively. During the construction of the heating module, the 8-bit signal input pin of the digital-to-analog conversion device is connected to the 8-bit microcontroller pin that controls the type of heating waveform; during the operation of the system, the microcontroller controls the conversion between the heating waveforms by detecting the state of the switch that controls the type of heating waveform;

[0082] Step 1.2.2: Using the adjustable resistor A as an external resistor, by adjusting the resistance value of the adjustable resistor A, the voltage range of the dynamic heating waveform can be adjusted, thereby achieving adjustable heating power;

[0083] Step 1.2.3: Considering that different gas sensor arrays often require different response times and heating cycles during detection, a single-chip microcomputer is used to first realize a heating cycle of 1s for the heating waveform. Then the single-chip microcomputer scans the status of the switch that controls the rise of the heating cycle and the switch that controls the fall of the heating cycle. If the switch is pressed and then lifted, the heating cycle will change, realizing that the heating cycle can be adjusted within 1-100s, and the adjustment accuracy is 1s.

[0084] Step 1.2.4: Use the single chip microcomputer and the external display screen to display the heating waveform and heating cycle in real time;

[0085] The user selects the desired dynamic heating waveform type by controlling the heating waveform type button. The initial waveform is a sine wave. After pressing the button once, the output is a triangle wave. After pressing it again, the output is a rectangular wave. After that, the button is pressed again to output a sine wave for a cycle. The desired heating cycle is selected by pressing the cycle up button and the cycle down button, and each press changes by 1s. The desired heating power is selected by the adjustable resistor A.

[0086] It meets the requirements of different gas sensors for heating waveform, heating power and heating cycle when performing gas detection; it meets the requirements of dynamic response testing of gas sensors under different heating waveforms, heating power and heating cycles, and users can clearly understand the adjusted heating waveform and heating cycle;

[0087] Step 1.3: Build a customized signal acquisition module;

[0088] Step 1.3.1: Connect the gas-sensitive resistor of each sensor in the gas sensor array in series with an adjustable resistor B. When collecting signals, ensure that the resistance value of each adjustable resistor B is consistent with the resistance value of the gas-sensitive resistor of the gas sensor connected in series in the air and remain unchanged. Then connect one end of the series resistor to a 5V DC power supply and the other end to ground, and collect the divided voltage signal on the gas-sensitive resistor of the gas sensor as a characteristic signal.

[0089] Step 1.3.2: For different types of gas sensors on the gas sensor array, the adjustable resistor B connected in series with the gas sensitive resistor of each gas sensor is adjusted according to step 1.3.1, so as to avoid the problem that the characteristic signal change is not obvious due to the adjustable resistor value being too large or too small;

[0090] Step 1.3.3: According to the heating cycle finally adjusted by the customized heating module, the sampling period for the heating cycle is set to adjust the sampling period for different types of gas sensor arrays;

[0091] Step 1.3.4: After the heating waveform or heating cycle is changed, the response signal of the gas sensor cannot quickly reach stability, and direct acquisition will obtain unsatisfactory results. The characteristic signal collected from the starting point of the 10th heating cycle after the heating waveform or heating cycle is changed to the end point of the 10th heating cycle is stored in the single-chip microcomputer module. The 10th heating cycle is a dynamic heating cycle in which the dynamic responses of all gas sensors in the gas sensor array in different gas environments are close to stability. The characteristic signal stored before the final selected heating waveform and heating cycle is removed;

[0092] Step 1.3.5: The collected voltage division signal is displayed in real time through the single chip microcomputer and the external display screen;

[0093] After the dynamic heating waveform and heating power selection are completed, the single chip microcomputer starts to collect the gas sensor response signal, presents it in real time through the display screen, and stores the response signal value within the 10th cycle;

[0094] Different gas sensors have different response times. Setting the sampling period and sampling start time can not only meet the different gas sensor detection requirements, but also improve the detection accuracy and system stability.

[0095] Step 1.4: Construction of customizable algorithm recognition module:

[0096] The characteristic signal collected in the signal acquisition module during the 10th heating cycle is transmitted to the recognition algorithm to build an algorithm recognition module;

[0097] Step 1.4.1: First, collect the characteristic signals of a gas sensor array under different gas environments, connect the single-chip microcomputer and the computer using the USB interface, use the serial communication technology to import the finally collected characteristic signals from the single-chip microcomputer to the computer, use the classification algorithm to train the gas recognition model, and then import the model into the single-chip microcomputer;

[0098] Step 1.4.2: Place different types of gas sensor arrays on the gas sensor array module and repeat step 1.4.1;

[0099] Step 1.4.3: Finally, according to the length of the final heating cycle, the characteristic signal is imported into the model matching the heating cycle for solution, and the result of the final model classification is displayed on the display screen;

[0100] For different gas sensor arrays, the response signal values ​​are often different under the same dynamic heating waveform and gas environment. Therefore, the algorithm recognition module meets the detection requirements of various gas sensor arrays.

[0101] Step 2: Construction and function realization of gas sensor test system:

[0102] Step 2.1: Connect the development board and data acquisition card, and the data acquisition card and computer. One end of the data acquisition card is connected to the connection between the gas sensor resistor and the adjustable resistor B in the gas sensor array, and the other end is connected to the computer, completing the construction of the hardware circuit of the gas sensor test system.

[0103] Step 2.2: The user configures the computer software Labview environment, and controls Labview to let the data acquisition card process the transmitted data to obtain a stable and reliable partial pressure signal. Finally, the response curve of the gas sensor is observed in real time on the computer software Labview, realizing the test requirements of the gas sensor for gases in different environments; the gas is a single gas or a mixed gas for testing;

[0104] The gas sensor testing system observes in real time the values ​​and changing trends of the response signals of different gas sensors under different dynamic heating waveform conditions. When the heating waveform, heating power, and heating cycle suitable for the gas sensor are unknown, the system first tests to find the most suitable dynamic heating waveform for the gas sensor array and then performs gas detection.

[0105] The following is the test data obtained by applying the system method of the present invention in this embodiment:

[0106] When the resistance controlling the heating power in the integrated system is 12.40k, the maximum heating voltage of the sine wave can be 4.70V and the minimum heating voltage can be 0.01V while ensuring that the dynamic heating waveform is not distorted;

[0107] When the resistance for controlling the heating power is 20.00k, the maximum heating voltage of the sine wave is 7.96V and the minimum heating voltage is 0.31V while ensuring that the dynamic heating waveform is not distorted;

[0108] Therefore, when using a sine wave to heat the gas sensor, the adjustable resistor that controls the heating power can be adjusted to change arbitrarily within the range of 12.40-20.0k to adjust the range of the heating power. At the same time, according to the resistance value of the sensor heating resistor, the heating current should not exceed the maximum saturation current of the transistor.

[0109] When the resistance for controlling the heating power in the integrated system is 4.60k, the maximum heating voltage of the triangular wave can be 1.24V and the minimum heating voltage can be 0.04V while ensuring that the dynamic heating waveform is not distorted;

[0110] When the resistance for controlling the heating power is 20.00k, the maximum heating voltage of the triangular wave can be 7.65V and the minimum heating voltage can be 2.45V while ensuring that the dynamic heating waveform is not distorted;

[0111] Therefore, when using a triangular wave to heat the gas sensor, the adjustable resistance value that controls the heating power can be adjusted within 4.60-20.0k to adjust the range of the heating power. At the same time, according to the resistance value of the sensor heating resistor, the heating current should not exceed the maximum saturation current of the transistor.

[0112] When the resistance for controlling the heating power in the integrated system is 1.60k, the maximum heating voltage of the rectangular wave can be 0.12V and the minimum heating voltage can be 0.00V while ensuring that the dynamic heating waveform is not distorted;

[0113] When the resistance for controlling the heating power is 20.00k, the maximum heating voltage of the rectangular wave can be 8.61V and the minimum heating voltage can be 0.00V while ensuring that the dynamic heating waveform is not distorted;

[0114] Therefore, when using a rectangular wave to heat the gas sensor, the adjustable resistance that controls the heating power can be adjusted to change arbitrarily within 1.60-20.0k to adjust the range of the heating power. At the same time, according to the resistance value of the sensor heating resistor, the heating current should not exceed the maximum saturation current of the transistor.

Claims

1. A gas sensor integration method based on dynamic temperature modulation, which is implemented based on a gas sensor integration system based on dynamic temperature modulation, wherein the gas sensor integration system based on dynamic temperature modulation consists of two parts: a gas detection system and a gas sensor test system; wherein: The gas detection system includes: a single chip computer module, a gas sensor array module, a heating module, a signal acquisition module, and an algorithm recognition module; the gas sensor test system includes: a single chip computer module, a heating module, a gas sensor array module, and a gas sensor test module; wherein the single chip computer module, the gas sensor array module, and the heating module are shared by the gas detection system and the gas sensor test system, and the method specifically includes the following steps: Step 1: First, the construction process and function realization of the gas detection system; Step 1.1 Design a customized gas sensor array module; The pin header is used to provide a path for the gas sensor array, and the pin header and the gas sensor are selected to form a sensor array module; When in use, the pin header and the gas sensor pin are connected with Dupont wire to form a gas sensor array module. In different environments, different types of gas sensors that have been put on the market can be used to form a gas sensor array, including semiconductor gas sensors, electrochemical gas sensors, and optical gas sensors; meeting the use needs of different gas sensors for integrated systems; Step 1.2: Build a customized heating module; Step 1.2.1: The type of heating waveform is controlled by the single-chip microcomputer and the 8-bit input digital-to-analog conversion device. The output state of the 8-bit pin of the single-chip microcomputer is adjusted to realize the output of different types of dynamic heating waveforms. The integrated system outputs three dynamic heating waveforms, corresponding to sine wave, triangle wave and rectangular wave respectively. During the construction of the heating module, the 8-bit signal input pin of the digital-to-analog conversion device is connected to the 8-bit single-chip microcomputer pin that controls the type of heating waveform; during the operation of the system, the single-chip microcomputer controls the conversion between heating waveforms by detecting the state of the switch that controls the type of heating waveform; Step 1.2.2: Using the adjustable resistor A as an external resistor, by adjusting the resistance value of the adjustable resistor A, the voltage range of the dynamic heating waveform can be adjusted, thereby achieving adjustable heating power; Step 1.2.3: Considering that different gas sensor arrays often require different response times and heating cycles during detection, a single-chip microcomputer is used to first realize that the heating cycle of the heating waveform is K s. Then the single-chip microcomputer scans the state of the switch that controls the rise of the heating cycle and the switch that controls the fall of the heating cycle. If the switch is pressed and then lifted, the heating cycle will change, realizing the adjustable heating cycle with an adjustment accuracy of Hs, where K and H are both greater than or equal to 0.5; Step 1.2.4: Use the single chip microcomputer and the external display screen to display the heating waveform and heating cycle in real time; The user selects the desired dynamic heating waveform type by controlling the heating waveform type button. The initial waveform is a sine wave. After pressing the button once, the output is a triangle wave. After pressing it again, the output is a rectangular wave. After that, the button is pressed again to output a sine wave for a cycle. The desired heating cycle is selected by pressing the cycle up button and the cycle down button, and each press changes Hs, H≥0.

5. The desired heating power is selected by the adjustable resistor A. It meets the requirements of different gas sensors for heating waveform, heating power and heating cycle when performing gas detection; it meets the requirements of dynamic response testing of gas sensors under different heating waveforms, heating power and heating cycles, and users can clearly understand the adjusted heating waveform and heating cycle; Step 1.3: Build a customized signal acquisition module; Step 1.4: Construction of customizable algorithm recognition module: The characteristic signal collected in the signal acquisition module during the Nth heating cycle is transmitted to the recognition algorithm to build an algorithm recognition module; Step 2: Construction and function realization of gas sensor test system.

2. A gas sensor integration method based on dynamic temperature modulation according to claim 1, characterized in that: The single-chip microcomputer module is composed of a single-chip microcomputer, a crystal oscillator, a button, a capacitor, a resistor, and a DC power supply; the pins of the single-chip microcomputer are connected to the crystal oscillator, the capacitor, the DC power supply, and the resistor so that the single-chip microcomputer can work normally, and the pins of the single-chip microcomputer are connected to the button to control the state of the heating module; The heating module is composed of a digital-to-analog conversion device, an operational amplifier circuit and a transistor, wherein the operational amplifier circuit contains an adjustable resistor A for controlling the heating power; the digital-to-analog conversion device is connected to the operational amplifier circuit to adjust the value range of the heating voltage, and finally the operational amplifier circuit is connected to the transistor to amplify the heating current to form a heating module; The gas sensor array module is composed of a pin header connected to a gas sensor; the pin header on the circuit board is connected to the pin of the gas sensor through a DuPont line to form a gas sensor array module; The signal acquisition module is composed of an analog-to-digital conversion device, an adjustable resistor B for adjusting the characteristic signal value, and a single chip; one end of the adjustable resistor B is connected to the analog signal input end of the analog-to-digital conversion device, and the other end is connected to a DC power supply, and the digital signal output end of the analog-to-digital conversion device is connected to the single chip microcomputer pin, forming a signal acquisition module; The algorithm recognition module is composed of a single chip in the single chip module; The single-chip microcomputer module is connected to the digital-to-analog conversion device of the heating module to convert the digital signal in the single-chip microcomputer into an analog voltage signal, and then the heating voltage and heating current value range are adjusted through the operational amplifier circuit and the triode; the emitter of the triode of the heating module is connected to the pin row connected to the pin at one end of the heating resistor of the sensor in the gas sensor array module through the circuit board, and the pin row connected to the pin at the other end of the heating resistor is grounded, and the dynamic heating waveform generated by the heating module is used to heat the gas sensor array; the connection point between the adjustable resistor B and the analog-to-digital conversion device and the pin row connected to the pin at one end of the gas sensitive resistor on the gas sensor are connected to the circuit board. The connection is made through a circuit board, and the pin row connected to the pin at the other end of the gas sensitive resistor on the gas sensor is grounded. The voltage division signal on the gas sensitive resistor of the gas sensor is collected in real time, and the single-chip microcomputer is connected to the output end of the analog-to-digital conversion device of the signal acquisition module, so that the characteristic signal collected in the Nth heating cycle is transmitted to the single-chip microcomputer for storage; the characteristic signal in the Nth heating cycle collected by the signal acquisition module is identified using the algorithm in the single-chip microcomputer, and the Nth heating cycle is a dynamic heating cycle in which the dynamic responses of all gas sensors in the gas sensor array in different gas environments tend to be stable; the construction of the gas detection system is completed.

3. A gas sensor integration method based on dynamic temperature modulation according to claim 1, characterized in that: The gas sensor test module is composed of a data acquisition card, a computer and computer software Labview; the gas sensor test module is formed by connecting the data acquisition card to the computer; Connect the connection point of the gas sensor's gas-sensitive resistor and adjustable resistor B to the data acquisition card, adjust the computer software Labview parameters, collect the partial pressure signals of the gas-sensitive resistor in the gas sensor at different times during the dynamic temperature modulation process, and complete the construction of the gas sensor test system; The gas detection system and the gas sensor test system simultaneously collect the partial pressure signal on the gas sensitive resistor in the gas sensor during the dynamic temperature modulation process to form a gas sensor integrated system based on dynamic temperature modulation.

4. A gas sensor integration method based on dynamic temperature modulation according to claim 1, characterized in that: Step 1.3 is as follows: Step 1.3.1: Connect the gas-sensitive resistor of each sensor in the gas sensor array in series with an adjustable resistor B. When collecting signals, ensure that the resistance value of each adjustable resistor B is consistent with the resistance value of the gas-sensitive resistor of the gas sensor connected in series with it in the air and remain unchanged. Then connect one end of the series resistor to a DC power supply and the other end to ground, and collect the divided voltage signal on the gas-sensitive resistor of the gas sensor as a characteristic signal; Step 1.3.2: For different types of gas sensors on the gas sensor array, the adjustable resistor connected in series with the gas sensitive resistor of each gas sensor is adjusted according to step 1.3.1, so as to avoid the problem that the characteristic signal change is not obvious due to the adjustable resistor being too large or too small; Step 1.3.3: According to the heating cycle finally adjusted by the customized heating module, the sampling period for the heating cycle is set to adjust the sampling period for different types of gas sensor arrays; Step 1.3.4: After the heating waveform or heating cycle is changed, the response signal of the gas sensor cannot quickly reach stability, and direct acquisition will obtain unsatisfactory results. The characteristic signal collected from the starting point of the Nth heating cycle after the heating waveform or heating cycle is changed to the end point of the Nth heating cycle is stored in the single-chip microcomputer module. The Nth heating cycle is a dynamic heating cycle in which the dynamic responses of all gas sensors in the gas sensor array in different gas environments are close to stable. The characteristic signal stored before the final selected heating waveform and heating cycle is removed; Step 1.3.5: The collected voltage division signal is displayed in real time through the single chip microcomputer and the external display screen; After the dynamic heating waveform and heating power selection are completed, the single chip microcomputer starts to collect the gas sensor response signal, presents it in real time through the display screen, and stores the response signal value in the Nth cycle; Different gas sensors have different response times. Setting the sampling period and sampling start time can not only meet the different gas sensor detection requirements, but also improve the detection accuracy and system stability.

5. A gas sensor integration method based on dynamic temperature modulation according to claim 1, characterized in that: Step 1.4 is as follows: Step 1.4.1: First, collect the characteristic signals of a gas sensor array under different gas environments, connect the single-chip microcomputer and the computer using the USB interface, use the serial communication technology to import the finally collected characteristic signals from the single-chip microcomputer to the computer, use the classification algorithm to train the gas recognition model, and then import the model into the single-chip microcomputer; Step 1.4.2: Place different types of gas sensor arrays on the gas sensor array module and repeat step 1.4.1; Step 1.4.3: Finally, according to the length of the final heating cycle, the characteristic signal is imported into the model matching the heating cycle for solution, and the result of the final model classification is displayed on the display screen; For different gas sensor arrays, under the same dynamic heating waveform and gas environment, the response signal values ​​are often different. Therefore, the algorithm recognition module meets the detection requirements of various gas sensor arrays.

6. A gas sensor integration method based on dynamic temperature modulation according to claim 1, characterized in that: Step 2 is as follows: Step 2.1: Connect the development board and data acquisition card, and the data acquisition card and computer. One end of the data acquisition card is connected to the connection between the gas sensor resistor and the adjustable resistor B in the gas sensor array, and the other end is connected to the computer, completing the construction of the hardware circuit of the gas sensor test system. Step 2.2: The user configures the computer software Labview environment, and controls Labview to let the data acquisition card process the transmitted data to obtain a stable and reliable partial pressure signal. Finally, the response curve of the gas sensor is observed in real time on the computer software Labview, realizing the test requirements of the gas sensor for gases in different environments; the gas is a single gas or a mixed gas for testing; The gas sensor testing system can observe in real time the values ​​and changing trends of the response signals of different gas sensors under different dynamic heating waveform conditions. When the heating waveform, heating power, and heating cycle suitable for the gas sensor are unknown, it can first test to find the most suitable dynamic heating waveform for the gas sensor array and then perform gas detection.

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