基于STM32单片机的天然气甲烷硫化氢气体检测仪原理图PCB_mq136ad原理图

实物演示视频：
https://www.bilibili.com/video/BV1vS4y1z73k/

功能简介：
0.单片机采用STM32F103C8T6最小系统板
1.采用SGP30传感器可检测二氧化碳浓度
2.利用MQ136可检测硫化氢气体
3.利用MQ-4传感器可检测天然气甲烷等气体

原理图：

PCB：

代码：

#define __MIAN_C
#include "main.h"

/************************* 变量定义 *************************/
CreatByte Flag;
enum _MODE_DF_ dispMode;

char dis[16];
u32 humidity = 0;
volatile uint16_t hmMin= 25;
volatile uint16_t hmMax= 60;
uint16_t temperature = 0;
volatile uint16_t tempMin = 20;
volatile uint16_t tempMax = 40;
uint16_t CO2_CONC = 0;
volatile uint16_t CO2_CONC_Max = 800;
uint16_t CH4_CONC = 0;
volatile uint16_t CH4_CONC_Max = 5;
uint16_t H2S_CONC = 0;
volatile uint16_t H2S_CONC_Max = 5;
u8 volatile setIndex = 0;

/************************* 主函数 *************************/
int main(void)
{

    // 使用HSI，SYSCLK = 4M * RCC_PLLMul_x, x:[2,3,...16],最高是64MH
    HSI_SetSysClock(RCC_PLLMul_2); //使用内部8MHz晶振，并设置PLL输出为8MHz

    // 端口初始化
    GPIO_Config();
    GENERAL_TIM_Init();

    Key_GPIO_Config();
    DelayMs(200);
    DHT11_GPIO_Init();
    SGP30_Init();

    LCD_GPIO_Init();
    LCD_Init();
    LCD_Clear();
    DelayMs(200);

    ADCx_Init();

    while (1)
    {

        if (refreshFlag == 1)
        {
            refreshFlag = 0;
            
            RefreshData(); //刷新数据
            
            if ((humidity <= hmMax && humidity >= hmMin)\
                && (temperature <= tempMax && temperature >= tempMin) \
                && CO2_CONC <= CO2_CONC_Max && CH4_CONC <= CH4_CONC_Max && H2S_CONC <= H2S_CONC_Max) //在范围内蜂鸣器关闭
            {
                BUZZER_OFF;
            }
            else //任一项指标超出阈值范围，蜂鸣器报警
            {
                BUZZER_ON;
            }
            
            if (dispMode == NORMAL) //显示
            {
                DispNormal();
            }
        }
        
        KeyProcess(); //按键检测
    }
}

/************************* 刷新数据 *************************/
void RefreshData(void)
{
    u8 i;
    u32 sgp30_dat;
    
    DHT11_ReadData();
    humidity = U8RH_data_H;
    temperature = U8T_data_H;
    sprintf(dis, "Hm:%2d%% T:%3d", humidity, temperature);

    CH4_CONC = 0;
    H2S_CONC = 0;
    for (i = 0; i < 20; i++)
    {
        CH4_CONC = CH4_CONC + ADC_ConvertedValue[0];
        H2S_CONC = H2S_CONC + ADC_ConvertedValue[1];
    }
    CH4_CONC = CH4_CONC / 20; //取20次平均
    if (CH4_CONC < 368) //去掉零值电压
    {
        CH4_CONC = 0;
    }
    else
    {
        CH4_CONC = (CH4_CONC-368) * 100 / (4096-368); //读取CH4浓度信息
    }
    
    H2S_CONC = H2S_CONC / 20; //取20次平均
    if (H2S_CONC < 123) //去掉零值电压
    {
        H2S_CONC = 0;
    }
    else
    {
        H2S_CONC = (H2S_CONC-123) * 100 / (4096-123); //读取H2S浓度信息
    }
    SGP30_Write(0x20,0x08);
    sgp30_dat = SGP30_Read();//读取SGP30的值
    CO2_CONC = (sgp30_dat & 0xffff0000) >> 16; //读取CO2浓度信息
}

void DispNormal(void) //显示
{
    static uint8_t cnt = 0;
    LCD_DispStr(0, 0, dis);
    LCD_DispOneChar(12, 0, 0xdf);
    LCD_DispOneChar(13, 0, 'C');
    
    //定时切换界面
    cnt++;
    if (cnt < 10)
    {
        sprintf(dis, "CO2:%5dppm   ", CO2_CONC);
        LCD_DispStr(0, 1, dis);
    }
    else if (cnt < 20)
    {
        sprintf(dis, "CH4:%2d%% H2S:%2d%%", CH4_CONC, H2S_CONC);
        LCD_DispStr(0, 1, dis);
    }
    else
    {
        cnt = 0;
    }
}

/************************* 显示湿度阈值设定 *************************/
void DispSetHm(u8 setIndex)
{
    LCD_DispStr(0, 0, "  Set Humidity  ");
    sprintf(dis, "   H:%2d%% L:%2d%%  ", hmMax, hmMin);
    LCD_DispStr(0, 1, dis);
    
    switch (setIndex)
    {
        case 1: LCD_SetCursor(6, 1, 1); break;
        case 2: LCD_SetCursor(12, 1, 1); break;
        default:;
    } 
}

/************************* 显示温度阈值设定 *************************/
void DispSetTemp(u8 setIndex)
{

    LCD_DispStr(0, 0, "Set Temperature ");
    sprintf(dis, "   H:%3d L:%3d  ", tempMax, tempMin);
    LCD_DispStr(0, 1, dis);
    
    switch (setIndex)
    {
        case 1: LCD_SetCursor(7, 1, 1); break;
        case 2: LCD_SetCursor(13, 1, 1); break;
        default:;
    } 
}

/************************* 显示CO2浓度阈值设定 *************************/
void DispSetCO2(u8 setIndex)
{

    LCD_DispStr(0, 0, "  Set CO2 Limit ");
    sprintf(dis, "  Max:%5dppm ", CO2_CONC_Max);
    LCD_DispStr(0, 1, dis);
    
    switch (setIndex)
    {
        case 1: LCD_SetCursor(10, 1, 1); break;
        default:;
    } 
}
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