Harmful gas detection circuit based on SMT32

Abstract

The utility model relates to the technical field of power electronics, in particular to a harmful gas detection circuit based on SMT32. Comprising a main control chip, a display chip, a buzzer, a chlorine gas sensor, a sulfur dioxide gas sensor, a hydrogen sulfide gas sensor, a nitrogen dioxide gas sensor, a resistor, a slide rheostat, a capacitor, a crystal oscillator, a light emitting diode, a triode, a 3V3 power supply, a 5V power supply and a terminal. The gas sensor converts concentration parameters of chlorine, sulfur dioxide, hydrogen sulfide and nitrogen dioxide into digital signals, the STM32 chip realizes protocol conversion and data acquisition, and gas data passes through the LCD display screen and the buzzer, so that data display and early warning functions are realized, and the convenience of environment testing is improved.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, specifically a harmful gas detection circuit based on SMT32. Background Technology

[0002] In certain environmental tests, it is often necessary to apply harmful gases such as chlorine, sulfides, and nitrogen dioxide to the test sample. It is essential to ensure that the concentration of the added gas meets the test requirements.

[0003] Currently, there are many methods for detecting harmful gases on the market. General measurement schemes are highly integrated, and the objects being tested cannot cover all the harmful gases required for the specified test.

[0004] Therefore, it is necessary to design a hazardous gas detection circuit based on SMT32 to realize the concentration measurement and output of chlorine, sulfur dioxide, hydrogen sulfide and nitrogen dioxide, thereby improving the convenience of environmental testing. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hazardous gas detection circuit based on SMT32 to realize the concentration measurement and output of chlorine, sulfur dioxide, hydrogen sulfide and nitrogen dioxide, thereby improving the convenience of environmental testing.

[0006] To achieve the above objectives, this utility model provides a hazardous gas detection circuit based on SMT32, including a main control chip, a display chip, a buzzer, a chlorine gas sensor, a sulfur dioxide gas sensor, a hydrogen sulfide gas sensor, a nitrogen dioxide gas sensor, resistors, a sliding rheostat, capacitors, a crystal oscillator, an LED, a transistor, a 3V3 power supply, a 5V power supply, and terminals. Pin 5 of the main control chip is connected in two paths to one end of the crystal oscillator and one end of capacitor 2. Pin 6 of the main control chip is connected in two paths to the other end of the crystal oscillator and one end of capacitor 3. Pin 7 of the main control chip is connected in two paths to one end of resistor 2 and one end of capacitor 1. The other end of resistor 2 is connected to the 3V3 power supply. Pin 44 of the main control chip is connected to... One end of resistor one is connected. Pins 34 and 37 of the main control chip are connected to pins 3 and 2 of terminal one, respectively. Pin 4 of terminal one is connected to the 3V3 power supply. Pin 38 of the main control chip, after being connected in series with resistor three, is connected to the anode of the LED. Pins 42 and 43 of the main control chip are connected to pins 1 and 2 of terminal two, respectively. Pin 21 of the main control chip, after being connected in series with resistor four, is split into two paths and connected to the base of the transistor and one end of resistor five, respectively. The collector of the transistor is connected to pin 2 of the buzzer. Pin 1 of the buzzer is connected to the 3V3 power supply. Pins 10 to 17 of the main control chip are connected to pins 7 to 14 of the display chip, respectively. Pin 29 of the main control chip... Pins 31 to 31 are connected sequentially to pins 4 to 6 of the display chip. Pin 2 of the display chip is connected in two paths to the 5V power supply and one end of the sliding rheostat. Pin 3 of the display chip is connected to the sliding end of the rheostat. Pin 15 of the display chip is connected to the 5V power supply after being connected in series with resistor 6. Pins 18 and 19 of the main control chip are connected sequentially to the RX and TX pins of the hydrogen sulfide gas sensor, respectively. The VCC pin of the hydrogen sulfide gas sensor is connected in three paths to one end of capacitor 10, one end of capacitor 11, and the 3V3 power supply, respectively. Pins 20 and 39 of the main control chip are connected sequentially to the RX and TX pins of the sulfur dioxide gas sensor, respectively. The VCC pin of the sulfur dioxide gas sensor is connected in three paths. The main control chip's pins are connected in three paths to one end of capacitor twelve, one end of capacitor thirteen, and a 3V3 power supply. Pins 40 and 41 of the main control chip are connected to the RX and TX pins of the chlorine gas sensor, respectively. The VCC pin of the chlorine gas sensor is connected in three paths to one end of capacitor fourteen, one end of capacitor fifteen, and a 3V3 power supply. Pins 45 and 46 of the main control chip are connected to the RX and TX pins of the nitrogen dioxide gas sensor, respectively. The VCC pin of the nitrogen dioxide gas sensor is connected in three paths to one end of capacitor sixteen, one end of capacitor seventeen, and a 3V3 power supply. Pins 1, 9, 24, 36, and 48 of the main control chip are connected to the 3V3 power supply.Pins 8, 23, 35, and 47 of the main control chip; pins 1 and 16 of the display chip; pin 1 of terminal one; pin 3 of terminal two; the other end of capacitor one; the other end of capacitor two; the other end of capacitor three; the other end of capacitor ten; the other end of capacitor eleven; the other end of capacitor twelve; the other end of capacitor thirteen; the other end of capacitor fourteen; the other end of capacitor fifteen; the other end of capacitor sixteen; the other end of capacitor seventeen; the other end of resistor one; the other end of resistor five; the other end of the sliding rheostat; the cathode of the light-emitting diode; the emitter of the transistor; the GND pin of the hydrogen sulfide gas sensor; the GND pin of the sulfur dioxide gas sensor; the GND pin of the chlorine gas sensor; and the GND pin of the nitrogen dioxide gas sensor are grounded.

[0007] The main control chip is an STM32F103 series chip, and the display chip is an LCD1602.

[0008] The chlorine gas sensor is model TB200B-CL2-50, the sulfur dioxide gas sensor is model TB200B-ES1-SO2-50, the hydrogen sulfide gas sensor is model TB200B-ES1-H2S-50, and the nitrogen dioxide gas sensor is model TB200B-ES1-NO2-50.

[0009] The 5V power supply is divided into four paths and connected to pin 2 of terminal 3, one end of capacitor 20, pin 1 and pin 3 of the voltage regulator chip, respectively. The 3V3 power supply is divided into nine paths and connected to one end of capacitor 18, one end of capacitor 19, one end of capacitor 7, one end of capacitor 8, one end of capacitor 9, one end of capacitor 4, one end of capacitor 5, one end of capacitor 6, and pin 5 of the voltage regulator chip, respectively. Pin 1 of terminal 3, pin 2 of the voltage regulator chip, the other end of capacitor 18, the other end of capacitor 19, the other end of capacitor 20, the other end of capacitor 7, the other end of capacitor 8, the other end of capacitor 9, the other end of capacitor 4, the other end of capacitor 5, and the other end of capacitor 6 are grounded.

[0010] The voltage regulator chip mentioned is model TLV75533PDBVR.

[0011] Compared with the prior art, this utility model uses a gas sensor to convert the concentration parameters of chlorine, sulfur dioxide, hydrogen sulfide and nitrogen dioxide into digital signals. The STM32 chip realizes protocol conversion and data acquisition, and displays the gas data through an LCD screen and a buzzer to realize data display and early warning functions, thus improving the convenience of environmental testing. Attached Figure Description

[0012] Figure 1 This is the circuit diagram of this utility model.

[0013] Figure 2 This is the power supply circuit diagram for this utility model. Detailed Implementation

[0014] The present invention will now be further described with reference to the accompanying drawings.

[0015] See Figure 1This utility model relates to a hazardous gas detection circuit based on SMT32, comprising a main control chip, a display chip, a buzzer, a chlorine gas sensor, a sulfur dioxide gas sensor, a hydrogen sulfide gas sensor, a nitrogen dioxide gas sensor, resistors, a sliding rheostat, capacitors, a crystal oscillator, an LED, a transistor, a 3V3 power supply, a 5V power supply, and terminals. Pin 5 of the main control chip U1 is connected in two paths to one end of the crystal oscillator X1 and one end of capacitor C2. Pin 6 of the main control chip U1 is connected in two paths to the other end of the crystal oscillator X1 and one end of capacitor C3. Pin 7 of the main control chip U1 is connected in two paths to one end of resistor R2 and one end of capacitor C1. The other end of resistor R2 is connected to the 3V33 power supply. For power connections, pin 44 of the main control chip U1 is connected to one end of resistor R1. Pins 34 and 37 of the main control chip U1 are connected to pins 3 and 2 of terminal P1, respectively. Pin 4 of terminal P1 is connected to a 3V3 power supply. Pin 38 of the main control chip U1, after being connected in series with resistor R3, is connected to the anode of LED D1. Pins 42 and 43 of the main control chip U1 are connected to pins 1 and 2 of terminal P2, respectively. Pin 21 of the main control chip U1, after being connected in series with resistor R4, is split into two paths and connected to the base of transistor Q1 and one end of resistor R5, respectively. The collector of transistor Q1 is connected to pin 2 of buzzer B1. Pin 1 of buzzer B1... The pins are connected to a 3V3 power supply. Pins 10 to 17 of the main control chip U1 are connected to pins 7 to 14 of the display chip LCD1, respectively. Pins 29 to 31 of the main control chip U1 are connected to pins 4 to 6 of the display chip LCD1, respectively. Pin 2 of the display chip LCD1 is split into two paths, one connected to a 5V power supply and the other to one end of the sliding rheostat VR1. Pin 3 of the display chip LCD1 is connected to the sliding end of the rheostat VR1. Pin 15 of the display chip LCD1 is connected to the 5V power supply after being connected in series with resistor R6. Pins 18 and 19 of the main control chip U1 are connected to the RX and TX pins of the hydrogen sulfide gas sensor U2, respectively. The VCC pin of sensor U2 is connected in three paths to one end of capacitor C10 (10), one end of capacitor C11 (11), and a 3V3 power supply. Pins 20 and 39 of the main control chip U1 are connected to the RX and TX pins of sulfur dioxide gas sensor U3, respectively. The VCC pin of sulfur dioxide gas sensor U3 is connected in three paths to one end of capacitor C12 (12), one end of capacitor C13 (13), and a 3V3 power supply. Pins 40 and 41 of the main control chip U1 are connected to the RX and TX pins of chlorine gas sensor U4, respectively. The VCC pin of chlorine gas sensor U4 is connected in three paths to one end of capacitor C14 (14), one end of capacitor C15 (15), and a 3V3 power supply.Pins 45 and 46 of the main control chip U1 are connected to the RX and TX pins of the nitrogen dioxide gas sensor U5, respectively. The VCC pin of the nitrogen dioxide gas sensor U5 is connected in three separate paths to one end of capacitor C16 (sixteenth generation), one end of capacitor C17 (seventeenth generation), and the 3V3 power supply. Pins 1, 9, 24, 36, and 48 of the main control chip U1 are connected to the 3V3 power supply. Pins 8, 23, 35, and 47 of the main control chip U1, pins 1 and 16 of the display chip LCD1, pin 1 of terminal P1, pin 3 of terminal P2, the other end of capacitor C1, and the other end of capacitor C2 are also connected. One end of capacitor C3, the other end of capacitor C10, the other end of capacitor C11, the other end of capacitor C12, the other end of capacitor C13, the other end of capacitor C14, the other end of capacitor C15, the other end of capacitor C16, the other end of capacitor C17, the other end of resistor R1, the other end of resistor R5, the other end of variable resistor VR1, the cathode of LED D1, the emitter of transistor Q1, the GND pin of hydrogen sulfide gas sensor U2, the GND pin of sulfur dioxide gas sensor U3, the GND pin of chlorine gas sensor U4, and the GND pin of nitrogen dioxide gas sensor U5 are grounded.

[0016] The main control chip U1 is an STM32F103 series chip. This chip has abundant on-chip resources, including a DMA controller, CAN controller, USB controller, watchdog timer, multiple timers, and multiple parallel I / O interfaces. It utilizes its pin definitions, interrupt system, timer / counter, and LCD to realize functions such as harmful gas measurement and output. Not only is it low-cost, but it can also transmit bus network data to the host computer via USB, making the connection between various modules simple and convenient.

[0017] Pin 34 of the main control chip U1 is defined as SWDIO, and pin 37 is defined as SWDCLK, used for debugging programs. Pin 38 of the main control chip U1 is defined as USER_LED0, used for custom debugging status lights. Pin 42 of the main control chip U1 is defined as D_USART_TX, and pin 43 is defined as D_USART_RX, used for serial port data transmission for debugging programs. Pin 21 of the main control chip U1 is defined as BEEP, used to connect a buzzer.

[0018] Pins 10 to 17 of the main control chip U1 are defined as LCD_D0 to LCD_D7 respectively, and pins 29 to 31 of the main control chip U1 are defined as LCD_RS, LCD_RW and LCD_E respectively, which are used to connect to the screen display.

[0019] The display chip LCD1 is model LCD1602, which has high resolution and strong anti-interference capability. Pins 4 to 6 of the display chip LCD1 are defined as LCD_RS, LCD_RW, and LCD_E respectively, and are used to connect to the main control chip U1.

[0020] Pin 18 of the main control chip U1 is defined as H2S_TX, and pin 19 is defined as H2S_RX, used for transmitting hydrogen sulfide data with the hydrogen sulfide gas sensor U2. Pin 20 of the main control chip U1 is defined as SO2_TX, and pin 39 is defined as SO2_RX, used for transmitting sulfur dioxide data with the sulfur dioxide gas sensor U3. Pin 40 of the main control chip U1 is defined as CL2_TX, and pin 41 is defined as CL2_RX, used for transmitting chlorine data with the chlorine gas sensor U4. Pin 45 of the main control chip U1 is defined as NO2_TX, and pin 46 is defined as NO2_RX, used for transmitting nitrogen dioxide data with the nitrogen dioxide gas sensor U5.

[0021] The chlorine gas sensor U4 is model TB200B-CL2-50, the sulfur dioxide gas sensor U3 is model TB200B-ES1-SO2-50, the hydrogen sulfide gas sensor U2 is model TB200B-ES1-H2S-50, and the nitrogen dioxide gas sensor U5 is model TB200B-ES1-NO2-50. They collect the concentrations of chlorine, sulfur dioxide, hydrogen sulfide, and nitrogen dioxide gases, convert them into digital signals, and send them to the main control chip U1 for data processing via serial port.

[0022] See Figure 2 The 5V power supply is divided into four paths, which are connected to pin 2 of terminal J1, one end of capacitor C20, pin 1 and pin 3 of voltage regulator chip U6 respectively. The 3V3 power supply is divided into nine paths, which are connected to one end of capacitor C18, one end of capacitor C19, one end of capacitor C7, one end of capacitor C8, one end of capacitor C9, one end of capacitor C4, one end of capacitor C5, one end of capacitor C6, and pin 5 of voltage regulator chip U6 respectively. Pin 1 of terminal J1, pin 2 of voltage regulator chip U6, the other end of capacitor C18, the other end of capacitor C19, the other end of capacitor C20, the other end of capacitor C7, the other end of capacitor C8, the other end of capacitor C9, the other end of capacitor C4, the other end of capacitor C5, and the other end of capacitor C6 are grounded.

[0023] Terminal J1 is used to connect peripherals. The 3V3 power supply is filtered and grounded through capacitors C7, C8, C9, C4, C5, and C6.

[0024] The voltage regulator chip U6 is model TLV75533PDBVR. The power supply section uses the voltage regulator chip U6 to perform on-chip voltage conversion, converting 5V to 3.3V to provide on-chip power for chlorine gas sensor U4, sulfur dioxide gas sensor U3, hydrogen sulfide gas sensor U2, and nitrogen dioxide gas sensor U5.

[0025] After the detection circuit is started, the host computer realizes protocol conversion communication, controls the chlorine gas sensor U4, sulfur dioxide gas sensor U3, hydrogen sulfide gas sensor U2, and nitrogen dioxide gas sensor U5 to collect data, controls the main control chip U1 to complete data processing, and outputs the data through the display chip LCD1.

[0026] The terminal used in this utility model circuit can adopt a modular design, including a control module, a measurement module, a display module, and a power supply module. The control module mainly includes a main control chip U1. The measurement module mainly includes a chlorine gas sensor U4, a sulfur dioxide gas sensor U3, a hydrogen sulfide gas sensor U2, and a nitrogen dioxide gas sensor U5. The display module mainly includes a buzzer B1 and a display chip LCD1. The power supply module mainly includes a voltage regulator chip U6. This modular design facilitates program debugging, modification, and porting, and also benefits future terminal performance maintenance and functional upgrades.

[0027] In this invention, the gas sensor converts the concentration parameters of chlorine, sulfur dioxide, hydrogen sulfide, and nitrogen dioxide into digital signals. An STM32 chip performs protocol conversion and data acquisition, and the gas data is displayed on an LCD screen and a buzzer, providing data display and early warning functions, thus improving the convenience of environmental testing. The hazardous gas measurement range of this invention is 10 ppb-25 ppm.

Claims

1. A hazardous gas detection circuit based on SMT32, comprising a main control chip, a display chip, a buzzer, a chlorine gas sensor, a sulfur dioxide gas sensor, a hydrogen sulfide gas sensor, a nitrogen dioxide gas sensor, resistors, a sliding rheostat, capacitors, a crystal oscillator, light-emitting diodes, transistors, a 3V3 power supply, a 5V power supply, and terminals, characterized in that: Pin 5 of the main control chip (U1) is connected in two paths to one end of the crystal oscillator (X1) and one end of capacitor 2 (C2). Pin 6 of the main control chip (U1) is connected in two paths to the other end of the crystal oscillator (X1) and one end of capacitor 3 (C3). Pin 7 of the main control chip (U1) is connected in two paths to one end of resistor 2 (R2) and one end of capacitor 1 (C1). The other end of resistor 2 (R2) is connected to a 3V3 power supply. Pin 44 of the main control chip (U1) is connected to one end of resistor 1 (R1). Pins 34 and 37 of the main control chip (U1) are connected to pins 3 and 2 of terminal 1 (P1) respectively. Pin 4 of terminal 1 (P1) is connected to a 3V3 power supply. For power connection, pin 38 of the main control chip (U1) is connected in series with resistor 3 (R3) and then to the anode of the LED (D1). Pins 42 and 43 of the main control chip (U1) are connected to pins 1 and 2 of terminal 2 (P2) respectively. Pin 21 of the main control chip (U1) is connected in series with resistor 4 (R4) and then splits into two paths, connecting to the base of transistor (Q1) and one end of resistor 5 (R5) respectively. The collector of transistor (Q1) is connected to pin 2 of buzzer (B1). Pin 1 of buzzer (B1) is connected to the 3V3 power supply. Pins 10 to 17 of the main control chip (U1) are connected to pins 7 to 14 of the display chip (LCD1) respectively. Pins 29 to 31 of the main control chip (U1) are connected to pins 4 to 6 of the display chip (LCD1) in sequence. Pin 2 of the display chip (LCD1) is connected in two paths to a 5V power supply and one end of a sliding rheostat (VR1). Pin 3 of the display chip (LCD1) is connected to the sliding end of the sliding rheostat (VR1). Pin 15 of the display chip (LCD1) is connected to the 5V power supply after being connected in series with resistor R6. Pins 18 and 19 of the main control chip (U1) are connected to the RX and TX pins of the hydrogen sulfide gas sensor (U2) in sequence. The VCC pin of the hydrogen sulfide gas sensor (U2) is connected in three paths to one end of capacitor C10. One end of capacitor eleven (C11) and the 3V3 power supply are connected. Pins 20 and 39 of the main control chip (U1) are connected to the RX and TX pins of the sulfur dioxide gas sensor (U3) respectively. The VCC pin of the sulfur dioxide gas sensor (U3) is connected in three separate paths to one end of capacitor twelve (C12), one end of capacitor thirteen (C13), and the 3V3 power supply. Pins 40 and 41 of the main control chip (U1) are connected to the RX and TX pins of the chlorine gas sensor (U4) respectively. The VCC pin of the chlorine gas sensor (U4) is connected in three separate paths to one end of capacitor fourteen (C14), one end of capacitor fifteen (C15), and the 3V3 power supply.Pins 45 and 46 of the main control chip (U1) are connected to the RX and TX pins of the nitrogen dioxide gas sensor (U5) respectively. The VCC pin of the nitrogen dioxide gas sensor (U5) is connected in three separate paths to one end of capacitor 16 (C16), one end of capacitor 17 (C17), and the 3V3 power supply. Pins 1, 9, 24, 36, and 48 of the main control chip (U1) are connected to the 3V3 power supply. Pins 8, 23, 35, and 47 of the main control chip (U1), pins 1 and 16 of the display chip (LCD1), pin 1 of terminal 1 (P1), pin 3 of terminal 2 (P2), the other end of capacitor 1 (C1), the other end of capacitor 2 (C2), and capacitor 3... The other end of capacitor C3, the other end of capacitor 10 (C10), the other end of capacitor 11 (C11), the other end of capacitor 12 (C12), the other end of capacitor 13 (C13), the other end of capacitor 14 (C14), the other end of capacitor 15 (C15), the other end of capacitor 16 (C16), the other end of capacitor 17 (C17), the other end of resistor 1 (R1), the other end of resistor 5 (R5), the other end of the sliding rheostat (VR1), the cathode of LED (D1), the emitter of transistor (Q1), the GND pin of hydrogen sulfide gas sensor (U2), the GND pin of sulfur dioxide gas sensor (U3), the GND pin of chlorine gas sensor (U4), and the GND pin of nitrogen dioxide gas sensor (U5) are grounded.

2. The harmful gas detection circuit based on SMT32 according to claim 1, characterized in that: The main control chip (U1) is an STM32F103 series chip, and the display chip (LCD1) is an LCD1602.

3. The harmful gas detection circuit based on SMT32 according to claim 1, characterized in that: The chlorine gas sensor (U4) is model number TB200B-CL2-50, the sulfur dioxide gas sensor (U3) is model number TB200B-ES1-SO2-50, the hydrogen sulfide gas sensor (U2) is model number TB200B-ES1-H2S-50, and the nitrogen dioxide gas sensor (U5) is model number TB200B-ES1-NO2-50.

4. The harmful gas detection circuit based on SMT32 according to claim 1, characterized in that: The 5V power supply is divided into four paths, which are respectively connected to pin 2 of terminal 3 (J1), one end of capacitor 20 (C20), pin 1 and pin 3 of the voltage regulator chip (U6). The 3V3 power supply is divided into nine paths, which are respectively connected to one end of capacitor 18 (C18), one end of capacitor 19 (C19), one end of capacitor 7 (C7), one end of capacitor 8 (C8), one end of capacitor 9 (C9), one end of capacitor 4 (C4), one end of capacitor 5 (C5), and one end of capacitor 6 (C6). One end of the capacitor is connected to pin 5 of the voltage regulator chip (U6), and pin 1 of terminal 3 (J1), pin 2 of the voltage regulator chip (U6), the other end of capacitor 18 (C18), the other end of capacitor 19 (C19), the other end of capacitor 20 (C20), the other end of capacitor 7 (C7), the other end of capacitor 8 (C8), the other end of capacitor 9 (C9), the other end of capacitor 4 (C4), the other end of capacitor 5 (C5), and the other end of capacitor 6 (C6) are grounded.

5. A hazardous gas detection circuit based on SMT32 according to claim 4, characterized in that: The voltage regulator chip (U6) mentioned is model number TLV75533PDBVR.

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