【便携式环境状态检测器】温度与大气压检测

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【便携式环境状态检测器】温度与大气压检测 [复制链接]

 

BMP085是一款环境温度与大气压检测器件，它也是以I2C接口来工作，其处理方式与BH1750光照强度传感器的使用有很大的相似性，温度与大气压检测显示如下图所示。

检测效果显示图

 

BMP0850所使用的引脚为：

GPIO13---SDA

GPIO11---SCL

BMP085的初始化函数为：

voidInit_BMP085(void)
{
         ac1 = Multiple_read(0xAA);
         ac2 = Multiple_read(0xAC);
         ac3 = Multiple_read(0xAE);
         ac4 = Multiple_read(0xB0);
         ac5 = Multiple_read(0xB2);
         ac6 = Multiple_read(0xB4);
         b1 =  Multiple_read(0xB6);
         b2 =  Multiple_read(0xB8);
         mb =  Multiple_read(0xBA);
         mc =  Multiple_read(0xBC);
         md =  Multiple_read(0xBE);
}

读取温度的函数为：

long bmp085ReadTemp(void)
{
    BMP085_Start();
    BMP085_Send_Byte(BMP085_SlaveAddress);
    while(BMP085_Wait_Ack());
    BMP085_Send_Byte(0xF4);
    while(BMP085_Wait_Ack());
    BMP085_Send_Byte(0x2E);
    while(BMP085_Wait_Ack());
    BMP085_Stop();
    vTaskDelay(1);
    return (long) Multiple_read(0xF6);
}

 

读取大气压的函数为：

long bmp085ReadPressure(void)
{
    long pressure = 0;
    BMP085_Start();
    BMP085_Send_Byte(BMP085_SlaveAddress);
    while(BMP085_Wait_Ack()){}
    BMP085_Send_Byte(0xF4);
    while(BMP085_Wait_Ack()){}
    BMP085_Send_Byte(0x34);
    while(BMP085_Wait_Ack()){}
    BMP085_Stop();
    vTaskDelay(1);
    pressure = Multiple_read(0xF6);
    pressure&= 0x0000FFFF;
    return pressure;
}

 

BMP085数值转换函数为：

void bmp085Convert(void)
{
      unsigned int ut;
      unsigned long up;
      long x1, x2, b5, b6, x3, b3, p;
      unsigned long b4, b7;
      ut = bmp085ReadTemp();
      up = bmp085ReadPressure();
      x1 = (((long)ut - (long)ac6)*(long)ac5) >> 15;
      x2 = ((long) mc << 11) / (x1 + md);
      b5 = x1 + x2;
      temperature1 = ((b5 + 8) >> 4);
      b6 = b5 - 4000;
      x1 = (b2 * (b6 * b6)>>12)>>11;
      x2 = (ac2 * b6)>>11;
      x3 = x1 + x2;
      b3 = (((((long)ac1)*4 + x3)<<OSS) + 2)>>2;
      x1 = (ac3 * b6)>>13;
      x2 = (b1 * ((b6 * b6)>>12))>>16;
      x3 = ((x1 + x2) + 2)>>2;
      b4 = (ac4 * (unsigned long)(x3 + 32768))>>15;
      b7 = ((unsigned long)(up - b3) * (50000>>OSS));
      if (b7 < 0x80000000)
        p = (b7<<1)/b4;
      else
        p = (b7/b4)<<1;
      x1 = (p>>8) * (p>>8);
      x1 = (x1 * 3038)>>16;
      x2 = (-7357 * p)>>16;
      pressure = p+((x1 + x2 + 3791)>>4);
}

温度大气压检测的主程序为：

void app_main(void)
{
    configure_led();
    configure_Oled();
    OLED_Init();
    OLED_Clear();
    OLED_ShowString(0,0,"ESP32-S2-Kaluga",16);
    OLED_ShowString(16,2,"OLED & BMP085",16);
    BMP085_Init();
    Init_BMP085();
    OLED_ShowString(0,4,"t=     C",16);
    OLED_ShowString(0,6,"p=       KPa",16);
    while (1) {
        blink_led();
        s_led_state = !s_led_state;
        vTaskDelay(CONFIG_BLINK_PERIOD / portTICK_PERIOD_MS);
        bmp085Convert();
        OLED_ShowNum(24,4,temperature1/10,3,16);
        OLED_ShowNum(24,6,pressure/100,5,16);
    }
}