Exhaled acetone gas detection device, circuit and detection method

Abstract

The exhaled acetone gas detection device comprises a gas detection module, a data signal processing module, a keyboard input and display module and an alarm module, a circuit of the detection device comprises a single chip microcomputer minimum system circuit, a metal oxide gas sensitive material sensor circuit, a display module circuit, a temperature, humidity and pressure module circuit, an alarm module circuit and a power supply circuit. Meanwhile, the method is noninvasive, rapid and user-friendly, and a technical basis is provided for large-scale screening of diabetes mellitus.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sensors, and specifically relates to an exhaled acetone gas detection device, circuit and detection method based on a metal oxide gas-sensitive sensing material. Background Art

[0002] Early screening for diabetes is crucial for delaying complications. The detection and analysis of acetone concentration in exhaled breath can be used as a new means of early screening for diabetes. The acetone concentration in exhaled breath is a key biomarker for diabetes (an acetone concentration range > 1.8 ppm indicates a diabetes risk). However, the existing detection methods mainly rely on laboratory gas chromatography-mass spectrometry (GC-MS) for inspection. Although this method has high precision, the equipment is expensive, the operation is complex, and professional personnel are required for sample enrichment, which cannot meet the general screening needs in community or home scenarios. In addition, the current commercial acetone sensors are seriously interfered: low-cost metal oxide gas sensors (such as SnO2-based) are easily affected by high humidity (> 90% RH), temperature fluctuations and air pressure changes in exhaled breath, resulting in high detection errors for acetone concentration and unable to meet the precision threshold required for clinical diagnosis. For the existing publicly available exhaled breath portable detectors, the exhaled gas of the human body needs to be dried or filtered to avoid interference from humidity, temperature, pressure or other atmospheres, and lacks a multi-parameter collaborative compensation mechanism, does not integrate a temperature / humidity / pressure real-time monitoring module, and has no threshold alarm function, so it cannot achieve closed-loop health warning. Summary of the Invention

[0003] In order to overcome the above deficiencies in the prior art, the present invention provides an exhaled acetone gas detection device, circuit and detection method. The detection device, circuit and detection method can allow the exhaled gas of the human body to be directly exhaled into the gas detection cavity without treatment, and at the same time realize a multi-dimensional collaborative detection architecture of gas / temperature / humidity / pressure. The acetone concentration signal is compensated in real time through multi-sensor data, an air / temperature / humidity / pressure real-time monitoring module is integrated, and an acetone concentration threshold alarm function can be set to achieve closed-loop health warning.

[0004] In order to achieve the above object, the present invention provides an exhaled acetone gas detection device, characterized in that the device includes a gas detection module, a data signal processing module, a keyboard input and display module, and an alarm module; The gas detection module includes a gas detection cavity and sensors. The gas detection cavity is provided with an exhalation inlet and a gas outlet, and one-way solenoid valves are provided at both the exhalation inlet and the gas outlet. The gas detection cavity is provided with sensors, including a metal oxide gas-sensitive material sensor, a temperature sensor, a humidity sensor and a pressure sensor.

[0005] The data signal processing module includes an AD8616 signal conversion module, an STM32F103 single-chip microcomputer system, and a power amplifier; in the exhaled gas detection cavity, the target gas reacts with the metal oxide gas-sensitive material, and the resistance change corresponding to the detected target gas concentration is converted into an electrical signal and transmitted to the single-chip microcomputer system. The signals of the temperature sensor, humidity sensor, and pressure sensor are transmitted to the single-chip microcomputer system.

[0006] The keyboard input and display module sets the upper limit of the target gas concentration, temperature, humidity, and pressure of the gas detection cavity through buttons and transmits it to the single-chip microcomputer system; the display module uses an LCD1602 liquid crystal display screen, and the data processed and transmitted by the single-chip microcomputer system can display the numerical values of the target gas concentration, temperature, humidity, and pressure in the gas detection cavity on the display screen.

[0007] The alarm module uses a PNP-type triode to amplify the current and achieve level conversion. The alarm upper limit of the target gas concentration is set through buttons. When the detected value exceeds the set threshold, the single-chip microcomputer triggers the alarm function to achieve real-time monitoring and early warning.

[0008] The pressure of the inhaled gas in the gas detection cavity can be transmitted to the single-chip microcomputer system according to the pressure value set by the button. The single-chip microcomputer system controls the on-off of the one-way solenoid valves at the exhalation inlet and gas outlet according to the set value to determine the pressure in the gas detection cavity.

[0009] The metal oxide gas-sensitive material sensor includes interdigital electrodes, and a mesoporous α-Fe2O3 hexagonal spindle derived from the metal organic framework MIL-88B of the metal oxide gas-sensitive material or its modified metal oxide is coated on the upper surface of the interdigital electrodes; a silicone rubber heating plate is arranged at the bottom of the interdigital electrodes, and the temperature of the silicone rubber heating plate is adjustable from 50°C to 300°C, and the adjustment accuracy is ±1°C.

[0010] A circuit of an exhaled acetone gas detection device, characterized in that it includes a single-chip microcomputer minimum system circuit, a metal oxide gas-sensitive material sensor circuit, a display module circuit, a temperature, humidity, and pressure module circuit, an alarm module circuit, and a power supply circuit; the metal oxide gas-sensitive material sensor circuit can perform error compensation according to the response information of temperature, humidity, and pressure; through the design of the circuit, the exhalation detection device based on the metal oxide gas-sensitive sensing material can realize the detection, display, and alarm of the acetone concentration of the exhaled target gas.

[0011] A method for detecting exhaled acetone gas, characterized in that it is implemented by using the exhaled acetone gas detection device and circuit described above, and the gas detection method includes the following steps: Step 1: The system and each module start initialization; Step 2: Press the button to set the upper limit of the inhaled gas pressure value in the gas detection cavity, and press the button to set the alarm upper limit of the target gas acetone concentration value; Step 3: Turn on the metal oxide gas-sensing material sensor, preheat the gas-sensing element at a temperature of 220 °C, and wait for the resistance to stabilize; Step 4: Exhale into the gas detection cavity, and stop exhaling after the gas detection cavity reaches the set upper limit of the pressure value; Step 5: Read the concentration data of the target gas acetone on the display screen and check whether the alarm sounds.

[0012] The present invention has the following technical effects: The exhaled acetone gas detection device of the present invention has strong anti-interference ability, integrates a multi-dimensional collaborative detection architecture of gas / temperature / humidity / pressure, compensates the acetone concentration signal in real time through multi-sensor data, and effectively suppresses the measurement errors caused by high humidity (>90% RH), body temperature fluctuations and air pressure changes in exhaled breath; the device of the present invention can directly exhale the exhaled gas of the human body into the gas detection cavity without treatment, realizing detection upon exhalation; the present invention supports setting the acetone concentration alarm threshold by typing, and when the detected value exceeds the limit, it realizes the instant warning of diabetes risk, avoiding the delay of manual interpretation required by traditional devices, and the display screen synchronously outputs four-dimensional data of acetone concentration, temperature, humidity and pressure, providing a multi-dimensional diagnostic basis; the present invention solves the reliability problem of exhaled acetone detection in complex environments with a low-cost and portable design, and is at the same time non-invasive, fast and user-friendly, providing a technical basis for large-scale diabetes screening. Description of the Drawings

[0013] Figure 1 is the overall block diagram of the exhaled acetone gas detection device of the present invention.

[0014] Figure 2 is the minimum system circuit diagram of the single-chip microcomputer of the present invention.

[0015] Figure 3 is the main function and peripheral chart of the single-chip microcomputer of the present invention.

[0016] Figure 4 is the circuit diagram of the metal oxide gas-sensing material sensor of the present invention.

[0017] Figure 5 is the circuit diagram of the display module of the present invention.

[0018] Figure 6 is the pin configuration chart of the display module circuit of the present invention.

[0019] Figure 7 is the circuit diagram of the temperature humidity pressure module of the present invention.

[0020] Figure 8It is the circuit diagram of the alarm module of the present invention.

[0021] Figure 9 It is the power supply circuit diagram of the present invention.

[0022] Figure 10 It is the control flow chart of the present invention.

[0023] Figure 11 It is the flow chart for detecting the acetone concentration of the present invention.

[0024] Figure 12 It is the flow chart for detecting temperature, humidity and pressure of the present invention.

[0025] Figure 13 It is the flow chart of the display module of the present invention.

[0026] Figure 14 It is the flow chart of the key module of the present invention.

[0027] Figure 15 It is the flow chart of the alarm module of the present invention. Detailed implementation manners

[0028] The following further elaborates on the technical solution of the present invention in combination with the attached drawings and specific embodiments, but it is not used as a basis for any limitation on the invention.

[0029] As Figure 1 shown, an exhaled acetone gas detection device includes a gas detection module, a data signal processing module, a keyboard input and display module, and an alarm module.

[0030] The gas detection module includes a gas detection chamber and sensors. The gas detection chamber is provided with an exhalation inlet and a gas outlet, and one-way solenoid valves are arranged at both the exhalation inlet and the gas outlet; sensors are arranged in the gas detection chamber, including a metal oxide gas-sensitive material sensor, a temperature sensor, a humidity sensor, and a pressure sensor.

[0031] The data signal processing module includes an AD8616 signal conversion module, an STM32F103 single-chip microcomputer system, and a power amplifier; in the exhaled gas detection chamber, the target gas reacts with the metal oxide gas-sensitive material, and the resistance change corresponding to the concentration of the detected target gas is converted into an electrical signal and transmitted to the single-chip microcomputer system, and the signals of the temperature sensor, humidity sensor, and pressure sensor are transmitted to the single-chip microcomputer system.

[0032] The keyboard input and display module sets the target gas concentration and the upper limit of the temperature, humidity, and pressure settings of the gas detection chamber through keys and transmits them to the single-chip microcomputer system; the display module uses an LCD1602 liquid crystal display screen, and the data processed and transmitted by the single-chip microcomputer system can display the concentration, temperature, humidity, and pressure of the target gas in the gas detection chamber on the display screen.

[0033] The alarm module uses a PNP-type triode to amplify the current and achieve level conversion. The upper limit of the alarm for the target gas concentration is set through a button. When the detected value exceeds the set threshold, the single-chip microcomputer triggers the alarm function to achieve real-time monitoring and early warning.

[0034] The pressure of the inhaled gas in the gas detection chamber can be transmitted to the single-chip microcomputer system according to the pressure value set by the button. The single-chip microcomputer system controls the on-off of the one-way solenoid valves at the exhalation inlet and the gas outlet according to the set value to determine the pressure in the gas detection chamber.

[0035] The metal oxide gas-sensitive material sensor includes interdigital electrodes. On the upper surface of the interdigital electrodes, a mesoporous α-Fe2O3 hexagonal spindle derived from the metal-organic framework MIL-88B or its modified metal oxide is coated; a silicone rubber heating plate is arranged at the bottom of the interdigital electrodes, and the temperature of the silicone rubber heating plate is adjustable from 50 °C to 300 °C, and the adjustment accuracy is ±1 °C.

[0036] As Figure 2 and Figure 3 As shown, the STM32F103C8T6 single-chip microcomputer selected for the device of the present invention has 2 built-in AD conversion modules and does not require an external ADC to be added; the STM32 single-chip microcomputer provides 5 serial ports and does not require a dual-serial port module for conversion, bringing higher flexibility and convenience to the system design. The crystal oscillator part of the STM32C8T6 series adopts RTC and a low-load method, with a working frequency of 72 MHz. The single-chip microcomputer has 3 general timers and 1 advanced timer. The single-chip microcomputer has 2 12-bit / 16-channel ADC analog-to-digital conversions, and a 3.3 V voltage regulator chip is used, which can ensure a maximum output current of 300 mA and supports ST-LINK and JTAG debugging and downloading.

[0037] The metal oxide gas-sensitive material is made of a mesoporous α-Fe2O3 hexagonal spindle derived from the metal-organic framework MIL-88B or its modified metal oxide. The gas-sensitive element can convert the acetone concentration signal into resistance. The acetone gas sensor of the present invention adopts a voltage division measurement method, and the principle of the sampling circuit is as Figure 4 shown, where R S is the sensor sampling resistor, and R S is the resistance value of the gas sensor, which is placed on two pins of SIP2-2.52. R S It can be calculated by the formula R5 = (V / V0 - 1) R S , where V is the reference voltage in the measurement circuit, which is a fixed value of 5 V, V0 is the voltage across the sampling resistor, and R5 is the voltage division resistor. An operational amplifier AD8616 is used in the circuit to form a voltage follower.

[0038] AsFigure 5 and Figure 6 As shown in Figure 6 , the present invention uses an LCD1602 liquid crystal display as the output display. The display screen has two lines of output, with 16 characters per line. The LCD1602 liquid crystal screen display utilizes the characteristics of liquid crystals to display the desired graphics or numbers by changing the voltage control area, and communicates with the P0 port of the single-chip microcomputer.

[0039] As Figure 7 shown, the module consists of a resistive humidity sensor element, an NTC temperature measurement element, a piezoresistive pressure measurement element, and an 8-bit single-chip microcomputer. The acquisition process is that the single-chip microcomputer first initiates a start signal and sends it to the sensing element through the I / O pin. Then the sensing element sends a response to the single-chip microcomputer, and the single-chip microcomputer processes the detected data and displays the value on the LCD liquid crystal display screen.

[0040] As Figure 8 shown, a PNP type triode is used to amplify the current and achieve level conversion, so that the buzzer can work properly. When the acetone concentration exceeds the set upper limit value, the STM32F103 single-chip microcomputer outputs a high-level signal. After this signal is amplified by the triode, it drives the buzzer to work and emits an alarm sound. Through the cooperation of the triode and the pull-up resistor, it is ensured that the buzzer works within the safe current range, thus playing a stable and reliable alarm function.

[0041] As Figure 9 shown, the power supply of the single-chip microcomputer is powered by direct current 5V. The power supply module includes a power socket and a power switch. The power socket is used to connect the power plug, and the power switch is used to control the on and off of the entire device circuit.

[0042] A detection method for exhaled acetone gas, characterized in that it is implemented by using the detection device and circuit for exhaled acetone gas as shown in Figures 1 - 9 shown, and the control flow chart of the gas detection method is as shown in Figure 10 shown, and specifically includes the following steps: Step 1: Initialize the system and each module; Step 2: Set the upper limit value of the pressure of the inhaled gas in the gas detection cavity by pressing the button, and set the alarm upper limit value of the target gas acetone concentration by pressing the button; Step 3: Turn on the metal oxide gas-sensitive material sensor, preheat the gas-sensitive element at a temperature of 220°C, and wait for the resistance to stabilize; Step 4: Exhale into the gas detection cavity, and stop exhaling after the gas detection cavity reaches the set upper limit value of the pressure; Step 5: Read the concentration data of the target gas acetone on the display screen and check whether the alarm sounds.

[0043] Among them, as Figure 11The acetone concentration detection process shown below uses a mesoporous α-Fe2O3 hexagonal spindle derived from the metal-organic framework MIL-88B or its modified metal oxide as a gas-sensitive element to form a gas-sensitive component. The fitting curve formula between the sampling resistance and the acetone concentration and the compensation error are obtained. After being sampled by a voltage follower composed of an AD8616 power amplifier, it is input into a single-chip microcomputer for data processing to obtain the final concentration result.

[0044] As Figure 12 In the temperature, humidity, and pressure detection process shown below, after the power is turned on, the sensor module starts to work. First, the STM32F103 single-chip microcomputer sends a start signal to the sensor. After receiving the signal, the sensor sends a response to the single-chip microcomputer and outputs the collected data. The sensor converts the data information into an electrical signal or other required forms of data. After receiving the data, the single-chip microcomputer performs internal calculations to obtain the data value and displays the result on the LCD1602 liquid crystal display in real time.

[0045] As Figure 13 In the display module process shown below, after the device is powered on, it is first initialized. The screen of the LCD1062 liquid crystal display is cleared, and the internal storage is emptied. The single-chip microcomputer controls the brightness and display content of the display screen and displays the detected data value on the liquid crystal display. When setting the upper limit of the alarm value, the key operation changes the value in real time, writes the command of the content to be displayed into the pin, and then the display screen executes the instruction to display the content.

[0046] As Figure 13 In the key module process shown below, in the main program, the detection is looped. When the low-level signal of the key is detected, the single-chip microcomputer generates a signal interruption and enters the key subroutine. The keys respectively represent addition, subtraction, confirmation, and return.

[0047] As Figure 14 In the alarm module process shown below, after the main function is executed, it continuously detects whether an interruption occurs. First, the upper limit of the acetone concentration alarm is set through the key, and then it is detected whether the upper limit value is exceeded. The alarm method is that the buzzer emits a sound.

Claims

1. An exhaled acetone gas detection device, characterized in that, The device includes a gas detection module, a data signal processing module, a keyboard input and display module, and an alarm module; The gas detection module includes a gas detection chamber and sensors. The gas detection chamber is provided with an exhalation inlet and a gas outlet, and one-way solenoid valves are provided at both the exhalation inlet and the gas outlet. The gas detection chamber is provided with sensors, including a metal oxide gas-sensitive material sensor, a temperature sensor, a humidity sensor, and a pressure sensor; The data signal processing module includes an AD8616 signal conversion module, an STM32F103 single-chip microcomputer system, and a power amplifier; in the exhaled gas detection chamber, the target gas reacts with the metal oxide gas-sensitive material, and the resistance change corresponding to the detected target gas concentration is converted into an electrical signal and transmitted to the single-chip microcomputer system. The signals of the temperature sensor, humidity sensor, and pressure sensor are transmitted to the single-chip microcomputer system; The keyboard input and display module sets the upper limit of the target gas concentration, temperature, humidity, and pressure of the gas detection chamber through keys and transmits it to the single-chip microcomputer system; the display module uses an LCD1602 liquid crystal display screen, and the data processed and transmitted by the single-chip microcomputer system can display the concentration, temperature, humidity, and pressure of the target gas in the gas detection chamber on the display screen; The alarm module uses a PNP-type triode to amplify the current and achieve level conversion. The alarm upper limit of the target gas concentration is set through keys. When the detected value exceeds the set threshold, the single-chip microcomputer triggers the alarm function to achieve real-time monitoring and early warning; The pressure of the inhaled gas in the gas detection chamber can be transmitted to the single-chip microcomputer system according to the pressure value set by the keys. The single-chip microcomputer system controls the opening and closing of the one-way solenoid valves at the exhalation inlet and the gas outlet according to the set value to determine the pressure in the gas detection chamber; The metal oxide gas-sensitive material sensor includes interdigital electrodes. A metal oxide gas-sensitive material metal-organic framework MIL-88B-derived mesoporous α-Fe2O3 hexagonal spindle or its modified metal oxide is coated on the upper surface of the interdigital electrodes; a silicone rubber heating plate is arranged at the bottom of the interdigital electrodes, and the temperature of the silicone rubber heating plate is adjustable from 50°C to 300°C, and the adjustment accuracy is ±1°C.

2. The exhaled acetone gas detection device according to claim 1, wherein, The circuit of the detection device includes a single-chip microcomputer minimum system circuit, a metal oxide gas-sensitive material sensor circuit, a display module circuit, a temperature, humidity, and pressure module circuit, an alarm module circuit, and a power supply circuit; the metal oxide gas-sensitive material sensor circuit can perform error compensation according to the response information of temperature, humidity, and pressure; through the design of the circuit, the exhalation detection device based on the metal oxide gas-sensitive sensing material can realize the detection, display, and alarm of the acetone concentration of the exhaled target gas.

3. A method for detecting exhaled acetone gas, characterized in that, It is implemented by using the exhalation detection device and circuit based on the metal oxide gas-sensitive sensing material as described in any one of claims 1 to 2. The gas detection method includes the following steps: Step 1: The system and each module start initialization; Step 2: Set the upper limit of the pressure value of the inhaled gas in the gas detection chamber through keys, and set the alarm upper limit of the target gas acetone concentration value through keys; Step 3: Turn on the metal oxide gas-sensitive material sensor and let the gas-sensitive element preheat at a temperature of 220°C until the resistance is stable; Step 4: Exhale into the gas detection chamber and stop exhaling after the gas detection chamber reaches the upper limit of the set pressure value; Step 5: Read the concentration data of the target gas acetone on the display screen and check whether the alarm sounds.

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