A portable VOCs gas detection alarm device with adjustable alarm threshold

Abstract

The utility model belongs to a portable VOCs gas detection alarm device of adjustable alarm threshold value, by integrated signal acquisition module, control processing module, alarm display module, power module, reset unit, crystal unit and control switch composition, signal acquisition module gathers gas resistance signal and will analog conversion signal transmission control processing module with signal and set threshold value compare, exceed preset threshold value, alarm display module initiates alarm, realizes graded early warning function, the utility model supports different application scene custom multistage alarm strategy, breaks through the limitation of traditional equipment threshold fixed, both convenient for the quick replacement and function extension of sensor, and it is favorable to the miniaturization packaging of equipment, thereby truly satisfy the actual application demand of multi -scene, differentiation, visualization.

Description

Technical Field

[0001] This utility model belongs to the technical field of gas detection and alarm equipment, specifically relating to a portable VOCs gas detection and alarm equipment with adjustable alarm threshold. Background Technology

[0002] Hazardous chemicals, as essential raw materials for modern industrial production, are widely used in petroleum, chemical, and pharmaceutical industries, significantly driving their development. With the continuous expansion of the industry, my country's hazardous chemical logistics industry has experienced rapid growth, with an average annual market size growth rate of 11.68%. However, the emission and leakage of toxic and harmful gases generated during the production, storage, transportation, and use of hazardous chemicals are becoming increasingly prominent, posing a serious threat to the ecological environment and public health. Therefore, establishing a rapid and accurate toxic gas detection system has significant practical importance and application value.

[0003] Gas sensor technology has developed rapidly in recent years, achieving a series of significant breakthroughs in sensitivity, response speed, and integration. Combining signal processing technology with intelligent algorithms, gas sensors have enhanced their gas identification and detection capabilities in complex environments. In the field of environmental monitoring, cloud platforms based on gas sensors can accurately detect particulate matter such as PM10 and PM2.5, as well as various VOCs, while simultaneously monitoring temperature and humidity, providing data support for air pollution control. In the medical and health field, artificial olfactory systems, by monitoring metabolic gases such as acetone and isoprene, offer innovative solutions for early disease screening and health assessment.

[0004] However, existing gas sensors still have significant shortcomings in terms of portability and environmental adaptability. First, most high-precision gas detection devices are bulky, heavy, and require external power supplies, making them unsuitable for field operations and mobile monitoring scenarios. Second, current gas sensing systems have limited functionality, failing to simultaneously meet diverse detection needs such as industrial emission monitoring, indoor air quality assessment, and personal health tracking. These limitations severely restrict the widespread application of gas sensing technology in environmental monitoring, healthcare, and emergency response. Overcoming these bottlenecks requires systematic innovation in areas such as miniaturization, low-power technology, and environmental adaptability.

[0005] Chinese patent document (publication number CN222337198U) discloses a device for detecting VOCs gas exhaled by humans. Although it achieves the function of detecting VOCs gas exhaled by humans, it cannot flexibly adjust the alarm threshold of the device to meet the needs of different environments. Chinese patent document (publication number CN222209640U) discloses a device for detecting and alarming harmful gases in household indoor spaces. Although it achieves the function of detecting harmful gases indoors, it cannot intuitively display the device's alarm information, and it also lacks alarm levels, making it impossible to make a corresponding judgment on the degree of environmental hazard. Summary of the Invention

[0006] To overcome the shortcomings of the existing technology, the purpose of this utility model is to provide a portable VOCs gas detection alarm device with adjustable alarm threshold. By integrating a signal acquisition module, control processing module, alarm display module, power supply module, reset unit, crystal oscillator unit, and control switch, the device achieves high integration through miniaturization, meeting the needs of mobile detection and rapid on-site response. Furthermore, the detection threshold can be adjusted according to different application scenarios. In addition, the device also needs to have temperature and humidity detection functions to ensure detection stability in complex environments, thereby truly meeting the practical application needs of multiple scenarios, differentiation, and visualization.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0008] A portable VOCs gas detection alarm device with adjustable alarm threshold includes a development board 1, which contains a signal acquisition module 2, a control processing module 3, an alarm display module 4, a power supply module 5, a reset unit 11, a crystal oscillator unit 12, and a control switch 15.

[0009] The signal acquisition module 2 is used to acquire the concentration of toxic and harmful gases and temperature and humidity in the external environment, and generate corresponding gas concentration signals and temperature and humidity signals to send to the control processing module 3.

[0010] The control processing module 3 compares and analyzes the received gas concentration signal with a preset threshold to generate a gas status signal and an alarm command.

[0011] The alarm display module 4 is used to perform environmental status visualization and graded alarm feedback based on the gas concentration signal, temperature and humidity signal and alarm command output by the control processing module 3.

[0012] The power supply module 5 is used to supply power to the device;

[0013] The reset unit 11 is used to restart the control processing module 3 to restore normal working status;

[0014] The crystal oscillator unit 12 is used to provide a stable clock signal for the control processing module 3;

[0015] The control switch 15 is used to control the switching of the device.

[0016] The signal acquisition module 2 includes: a gas sensor acquisition unit 9 and a temperature and humidity acquisition unit 10;

[0017] The gas sensor acquisition unit 9 adopts a circular pin interface and is connected to the control processing module 3 through the PA1 pin;

[0018] The temperature and humidity acquisition unit 10 is connected to the control processing module 3 via I2C communication through the PB0 and PB1 pins.

[0019] The alarm display module 4 includes: a rotary encoder unit 6, an LED alarm unit 7, and an OLED display unit 8;

[0020] The rotary encoder unit 6 is connected to the control processing module 3 via pins PA6 and PA7.

[0021] The LED alarm unit 7 is connected to the control processing module 3 via pins PA2, PB12, PB13, and PB14.

[0022] The OLED display unit 8 is connected to the control processing module 3I2C via pins PB10 and PB11.

[0023] The power supply module 5 includes: a USB Type-C interface 13 and a step-down unit 14;

[0024] The USB Type-C interface 13 is connected to the step-down unit 14 via the VIN interface. The step-down unit 14 is connected to the control processing module 3 via the VBAT, VDD_1, and VDD_3 pins. The step-down unit 14 is connected to the signal acquisition module 2, the alarm display module 4, the reset unit 11, and the control switch 15 via the VOUT pin.

[0025] The reset unit 11 is connected to the control processing module 3 via the NRST pin.

[0026] The crystal oscillator unit 12 is connected to the control and processing module 3 via PC14, PC15, PD0, and PD1.

[0027] The control switch 15 is connected to the control processing module 3 via the VBAT, VDD_1, and VDD_3 pins.

[0028] The development board 1 is 100-200mm long and 30-50mm wide;

[0029] The control processing module 3, rotary encoder unit 6, LED alarm unit 7, OLED display unit 8, gas sensor acquisition unit 9, temperature and humidity acquisition unit 10, reset unit 11, crystal oscillator unit 12, USB Type-C interface 13, step-down unit 14 and control switch 15 are all small devices integrated on the development board 1 to fit the length and width of the development board 1.

[0030] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0031] 1. This utility model is equipped with a rotary encoder unit 6 to realize dynamic adjustment of alarm threshold. It can customize multi-level alarm strategies according to different application scenarios, breaking through the limitations of fixed thresholds in traditional equipment.

[0032] 2. The gas sensor acquisition unit 9 of this utility model adopts a standardized circular pin interface design, which facilitates the rapid replacement of the sensor and the expansion of its functions.

[0033] 3. The miniaturization of each module unit adopted in this utility model is beneficial to a compact circuit layout and facilitates the miniaturization and packaging of the equipment.

[0034] In summary, the detection device of this utility model can achieve dynamic adjustment of alarm threshold through rotary encoder unit 6, support customized multi-level alarm strategies for different application scenarios, and break through the limitations of fixed threshold of traditional equipment. At the same time, the gas sensor acquisition unit 9 with standardized interface design and compact circuit layout not only facilitates the rapid replacement and functional expansion of sensors, but also facilitates the miniaturization and packaging of the device. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the modular structure of the device described in this utility model.

[0036] Figure 2 This is a schematic diagram of the specific structure of the device described in this utility model.

[0037] Figure 3 This is a schematic diagram of the circuit board of the device described in this utility model.

[0038] Figure 4 This is a line graph showing the experimental results of the device described in this utility model.

[0039] Figure 5 This is a photograph of the actual device described in this utility model.

[0040] In the diagram, 1 is the development board; 2 is the signal acquisition module; 3 is the control processing module; 4 is the alarm display module; 5 is the power supply module; 6 is the rotary encoder unit; 7 is the LED alarm unit; 8 is the OLED display unit; 9 is the gas sensor acquisition unit; 10 is the temperature and humidity acquisition unit; 11 is the reset unit; 12 is the crystal oscillator unit; 13 is the USB Type-C interface; 14 is the step-down unit; and 15 is the control switch. Detailed Implementation

[0041] The structural and working principles of this utility model will be described in detail below with reference to the accompanying drawings. Those skilled in the art can understand and appreciate other advantages and effects of this utility model based on the content disclosed in this specification. It should be noted that the described embodiments are merely examples of some implementations of this utility model, and not exhaustive. All other implementations that can be obtained by those skilled in the art without creative effort based on the content disclosed in this utility model should be covered within the protection scope of this utility model.

[0042] like Figures 1-3 As shown, a portable VOCs gas detection alarm device with adjustable alarm threshold includes a development board 1, which contains a signal acquisition module 2, a control processing module 3, an alarm display module 4, a power supply module 5, a reset unit 11, a crystal oscillator unit 12, and a control switch 15.

[0043] The signal acquisition module 2 is used to acquire the concentration of toxic and harmful gases and temperature and humidity in the external environment, and generate corresponding gas concentration signals and temperature and humidity signals to send to the control processing module 3.

[0044] The control processing module 3 compares and analyzes the received gas concentration signal with a preset threshold to generate a gas status signal and an alarm command. In this embodiment, an STM32 microcontroller is used.

[0045] The alarm display module 4 is used to perform environmental status visualization and graded alarm feedback based on the gas concentration signal, temperature and humidity signal and alarm command output by the control processing module 3.

[0046] The power supply module 5 is used to supply power to the device;

[0047] The reset unit 11 is used to restart the control processing module 3 to restore normal working status;

[0048] The crystal oscillator unit 12 is used to provide a stable clock signal for the control processing module 3;

[0049] The control switch 15 is used to control the switching of the device.

[0050] The signal acquisition module 2 includes: a gas sensor acquisition unit 9 and a temperature and humidity acquisition unit 10;

[0051] The gas sensor acquisition unit 9 uses a circular pin interface as a standard plug-in interface, which is compatible with different series of VOCs sensors and supports plug-and-play replacement to meet the detection requirements of different gases such as benzene and formaldehyde. It is connected to the control and processing module 3 through the PA1 pin.

[0052] The temperature and humidity acquisition unit 10 uses a DHT20 digital temperature and humidity sensor chip, with a humidity detection accuracy of ±2%RH, a temperature detection accuracy of ±0.3℃, and a response time of ≤2 seconds. It communicates with the control processing module 3 via I2C through the PB0 and PB1 pins.

[0053] The alarm display module 4 includes: a rotary encoder unit 6, an LED alarm unit 7, and an OLED display unit 8;

[0054] The rotary encoder unit 6 adopts an EC11 incremental encoder and is connected to the control processing module 3 through PA6 and PA7 pins.

[0055] The LED alarm unit 7 is connected to the control processing module 3 via pins PA2, PB12, PB13, and PB14.

[0056] The OLED display unit 8 uses a 0.96-inch SSD1306 display screen and is connected to the control processing module 3I2C via PB10 and PB11 pins.

[0057] The power supply module 5 includes: a USB Type-C interface 13 and a step-down unit 14, which uses an AMS1117-3.3 step-down chip;

[0058] The USB Type-C interface 13 is connected to the step-down unit 14 via the VIN interface. The step-down unit 14 is connected to the control processing module 3 via the VBAT, VDD_1, and VDD_3 pins. The step-down unit 14 is connected to the signal acquisition module 2, the alarm display module 4, the reset unit 11, and the control switch 15 via the VOUT pin.

[0059] The reset unit 11 is connected to the control processing module 3 via the NRST pin. In this embodiment, the reset unit 11 is implemented using an external manual reset switch, model TS-1101-CW.

[0060] The crystal oscillator unit 12 is connected to the control and processing module 3 via PC14, PC15, PD0, and PD1. In this embodiment, the crystal oscillator unit 12 is an EPSON 32.768kHz surface mount crystal oscillator and a YXC 8MHz surface mount crystal oscillator.

[0061] The control switch 15 is connected to the control processing module 3 via the VBAT, VDD_1, and VDD_3 pins.

[0062] The development board 1 is 100mm long and 32mm wide;

[0063] In one embodiment, a development board 1 with a length of 150mm and a width of 40mm was also designed;

[0064] In another embodiment, a development board 1 with a length of 200mm and a width of 50mm was also designed;

[0065] The control processing module 3, rotary encoder unit 6, LED alarm unit 7, OLED display unit 8, gas sensor acquisition unit 9, temperature and humidity acquisition unit 10, reset unit 11, crystal oscillator unit 12, USB Type-C interface 13, step-down unit 14 and control switch 15 are all small devices integrated on the development board 1 to fit the length and width of the development board 1.

[0066] The working principle of this utility model is as follows:

[0067] Signal acquisition module 2 is used to acquire toxic and harmful gas concentration signals and temperature and humidity signals from the external environment, and generates corresponding gas concentration signals and temperature and humidity signals to be sent to control processing module 3. Control processing module 3 compares and analyzes the received concentration signals with preset thresholds to generate gas status signals and alarm commands. Temperature and humidity detection unit 10 communicates with control processing module 3 via I2C protocol at a rate of 400kHz to achieve temperature and humidity data synchronization once per second. Alarm display module 4 performs environmental status visualization and graded alarm feedback based on the gas concentration signals, temperature and humidity signals and alarm commands output by control processing module 3. OLED display unit 8 is connected to control processing module 3 via I2C protocol and dynamically displays gas concentration values, real-time temperature and humidity, user-defined alarm thresholds and current alarm levels at a refresh rate of 10Hz. Rotary encoder unit 6 has a 90° phase difference between the A / B two-phase signals. The rotation direction is decoded through the timer input capture function of STM32 microcontroller. The threshold adjustment step accuracy is ±1ppm, the adjustment range covers 0-1000ppm, and the adjustment results are stored in real time to the on-chip EEPROM. LED alarm unit 7 adopts a four-level alarm rule design. Specifically, as the detected gas concentration increases step by step and reaches a preset threshold, the number of LED alarm indicators increases linearly with the alarm level. This visual mapping between the increasing number of lit LED indicators and the degree of gas concentration exceeding the limit dynamically reflects the environmental hazard level, achieving visualized classification and identification of the hazard level. The step-down unit 14 converts the externally input 5V DC power supply to a stable 3.3V output. Its input voltage range is 4.75V-12V, with a maximum output current of 800mA and a conversion efficiency ≥90%. A 10μF tantalum capacitor is connected in parallel at the output to suppress voltage ripple. The reset unit 11 is implemented as a surface-mount push-button switch, directly connected to the NRST pin and GND of the control processing module 3. Pressing and holding for 2 seconds manually resets the entire system, forcing the control processing module 3 to restart and return to normal operation. The crystal oscillator unit 12 is specifically implemented by using an 8MHz quartz crystal oscillator, connected to the OSC_IN / OSC_OUT pins of the STM32 microcontroller, with a matching load capacitor of 20pF and a frequency stability of ±50ppm, providing a reference clock for stable system operation.

[0068] Although the present invention has been described in detail above through general description and specific embodiments, those skilled in the art will readily conceive of certain modifications or improvements based on the technical solutions disclosed herein. Therefore, all such modifications or improvements made based on ordinary technical knowledge in the art, without departing from the essential technical solution of the present invention, should be covered within the protection scope of the present invention.

[0069] Application Example 1

[0070] This invention is applied to the detection of acetone gas in VOCs within a confined space, using a gas sensor based on Au / ZnO sensitive material (Sensors.2024,24,8100). During acetone detection, the sensor acquires a resistance signal and transmits the analog-to-digital conversion signal to the control processing module 3. The signal is compared with a PWM encoder to set threshold values ​​(150, 250, 350, and 450 correspond to 30ppm, 60ppm, 90ppm, and 120ppm respectively, referring to…). Figure 4 When the concentration of acetone is compared with the preset threshold, four red alarm indicator lights illuminate, and the alarm level of the device continuously increases with the increase of acetone concentration. Figure 5 As shown, the OLED screen intuitively displays the signal sampling value, preset threshold, and alarm level, facilitating rapid data acquisition. Therefore, this device can provide graded warnings for detected acetone gas based on preset thresholds. Compared with existing electronic nose devices for odor pollutants (publication number CN215812673U), the gas detection alarm device of this invention has a size of 100mm × 32mm × 10mm, featuring miniaturization and portability.

[0071] Application Example 2

[0072] This invention is applied to the detection of xylene gas in VOCs within a confined space, using a gas sensor based on WO3-1%E+Au sensitive material (Micromachines.2025,16,646.). During xylene detection, the sensor acquires a resistance signal and transmits the analog-to-digital conversion signal to the control processing module 3. The signal is compared with the threshold values ​​set by the PWM encoder (50, 100, 150, and 200 correspond to 5ppm, 10ppm, 20ppm, and 40ppm, respectively). If the preset threshold is exceeded, four red alarm indicator lights illuminate, and the alarm level increases with the xylene concentration. The OLED screen intuitively displays the signal sampling value, preset threshold, and alarm level, facilitating rapid data acquisition. Therefore, this device can provide graded warnings for detected xylene gas based on preset thresholds. Compared with existing portable electronic nose devices for beer recognition (Publication No. CN119667082A), the gas detection alarm device of this invention can dynamically adjust the alarm threshold and customize multi-level alarm strategies according to different application scenarios.

Claims

1. A portable VOCs gas detection alarm device with adjustable alarm threshold, comprising a development board (1), characterized in that, The development board (1) integrates a signal acquisition module (2), a control processing module (3), an alarm display module (4), a power supply module (5), a reset unit (11), a crystal oscillator unit (12), and a control switch (15); The signal acquisition module (2) includes a gas sensor acquisition unit (9) and a temperature and humidity acquisition unit (10), which are used to acquire the concentration of toxic and harmful gases and temperature and humidity in the external environment, and generate corresponding gas concentration signals and temperature and humidity signals to send to the control processing module (3). The gas sensor acquisition unit (9) adopts a circular pin interface and is connected to the control processing module (3); The temperature and humidity acquisition unit (10) is connected to the control processing module (3) via I2C communication; The control processing module (3) compares and analyzes the received gas concentration signal with a preset threshold to generate a gas status signal and an alarm command. The alarm display module (4) includes a rotary encoder unit (6), an LED alarm unit (7), and an OLED display unit (8), which are used to perform environmental status visualization and graded alarm feedback based on the gas concentration signal, temperature and humidity signal and alarm command output by the control processing module (3). The rotary encoder unit (6) is connected to the control processing module (3); The LED alarm unit (7) is connected to the control processing module (3); The OLED display unit (8) is connected to the control processing module (3) via I2C communication; The power supply module (5) includes a USB Type-C interface (13) and a step-down unit (14) for supplying power to the device; The USB Type-C interface (13) is connected to the step-down unit (14), and the step-down unit (14) is connected to the control processing module (3); the step-down unit (14) is connected to the signal acquisition module (2), the alarm display module (4), the reset unit (11), and the control switch (15); The reset unit (11) is used to restart the control processing module (3) to restore normal working status; The crystal oscillator unit (12) is used to provide a stable clock signal for the control processing module (3); The control switch (15) is used to control the switching of the device.

2. The apparatus of claim 1, wherein, The gas sensor acquisition unit (9) is connected to the control processing module (3) via the PA1 pin; The temperature and humidity acquisition unit (10) is connected to the control processing module (3) via I2C communication through the PB0 and PB1 pins.

3. The apparatus of claim 1, wherein, The rotary encoder unit (6) is connected to the control processing module (3) via PA6 and PA7 pins; The LED alarm unit (7) is connected to the control processing module (3) via pins PA2, PB12, PB13, and PB14. The OLED display unit (8) is connected to the control processing module (3) via I2C communication through the PB10 and PB11 pins.

4. The apparatus of claim 1, wherein, The USB Type-C interface (13) is connected to the step-down unit (14) via the VIN interface. The step-down unit (14) is connected to the control processing module (3) via the VBAT, VDD_1, and VDD_3 pins. The step-down unit (14) is connected to the signal acquisition module (2), the alarm display module (4), the reset unit (11), and the control switch (15) via the VOUT pin.

5. The apparatus of claim 1, wherein, The reset unit (11) is connected to the control processing module (3) via the NRST pin.

6. The apparatus of claim 1, wherein, The crystal oscillator unit (12) is connected to the control processing module (3) via PC14, PC15, PD0, and PD1.

7. The apparatus of claim 1, wherein, The control switch (15) is connected to the control processing module (3) via the VBAT, VDD_1, and VDD_3 pins.

8. The apparatus of any one of claims 1 to 7, wherein, The development board (1) is 100-200mm long and 30-50mm wide; The control processing module (3), rotary encoder unit (6), LED alarm unit (7), OLED display unit (8), gas sensor acquisition unit (9), temperature and humidity acquisition unit (10), reset unit (11), crystal oscillator unit (12), USB Type-C interface (13), step-down unit (14) and control switch (15) are all small devices integrated on the development board (1) to fit the length and width of the development board (1).

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