Arduino气体传感器-BMP180 大气压强传感器

BMP180传感器图片

BMP180传感器介绍

• GPS功能的导航设备借助全球卫星定位系统可以判定设备的经纬平面所处位置，但是无法得知目前的海拔高度。
• 微型高精度气压传感器的出现而有望得以解决。
• Bosch Sensortec开发出一款智能，超小体积，高精度数字传感器BMP180。
• 适合智能的高精度测量和数据采集，输出高精度的压力（或高度）和温度测量数据。
• 与加速度计相互搭配，在没有GPS讯号的环境下，提供可靠的楼层侦测能力，以实现三维(3D)室内导航。
• 本传感器可以检测：温度，大气压强，海拔高度。

BMP180传感器参数

• 工作电压：5V
• 工作范围：-40～+85 ℃
• 压强精度：0.12hPa/m
• 接口类型：4pin 排针和 1.27间距 IDC10座

BMP180传感器引脚定义

如图，模块共有4个引脚，从上到下是5V，GND，SCL,SDA。模块可以通过I2C和单片机通信，5V供电。

BMP180传感器特性曲线

使用示例

目标：测出当前环境下的大气压强和计算出芯片的海拔高度

连线图

• 先连接芯片与单片机（通过I2C接口），按照如下图的方式连接
• 然后UNO通过usb与PC电脑连接。
• 拷贝以下的代码烧录进单片机。

示例代码

/**************************************************************************************/
           /**********************DFRobot.com*****************************/
/***write by Tom Riddler          Jun.16.14***/
/***if you got any progream,please contact me terminaterfxy@hotmail.com***/

#include <Wire.h>
#define BMP180ADD 0xEE>>1  // I2C address of BMP180  
                           //write is (0xEE)     read is (0xEF)       
unsigned char OSS;                            
/**********************MSB      LSB******/
int ac1;           // 0xAA     0xAB
int ac2;           // 0xAC     0xAD
int ac3;           // 0xAE     0xAE
unsigned int ac4;  // 0xB0     0xB1
unsigned int ac5;  // 0xB2     0xB3
unsigned int ac6;  // 0xB4     0xB5
int b1;            // 0xB6     0xB7
int b2;            // 0xB8     0xB9
int mb;            // 0xBA     0xBB
int mc;            // 0xBC     0xBD
int md;            // 0xBE     0xBF
float temperature;  
double pressure;   
double pressure2;
long b5;          
double altitude;  



void setup()
{
  Serial.begin(9600);
  Wire.begin();
  OSS = 2;  // Oversampling Setting           0: single    1: 2 times    2: 4 times   3: 8 times 
  BMP180start();
}

void loop()
{
  calculate();
  show();
  delay(1000);
}

/** calculate centure **/
void calculate()
{
  temperature = bmp180GetTemperature(bmp180ReadUT());
  temperature = temperature*0.1;
  pressure = bmp180GetPressure(bmp180ReadUP());
  pressure2 = pressure/101325;
  pressure2 = pow(pressure2,0.19029496);
  altitude = 44330*(1-pressure2);                            //altitude = 44330*(1-(pressure/101325)^0.19029496);
}

/** print reslut **/
void show()
{
  Serial.print("Temperature: ");
  Serial.print(temperature, 1);                            //10 hexadecimal
  Serial.println(" C");
  Serial.print("Pressure: ");
  Serial.print(pressure, 0);                               //10 hexadecimal
  Serial.println(" Pa");
  Serial.print("altitude:");
  Serial.print(altitude);
  Serial.println("m");
}

/**BMP180 satrt program**/
void BMP180start()
{                     /*MSB*/
  ac1 = bmp180ReadDate(0xAA);                      //get full data
  ac2 = bmp180ReadDate(0xAC);  
  ac3 = bmp180ReadDate(0xAE);  
  ac4 = bmp180ReadDate(0xB0);  
  ac5 = bmp180ReadDate(0xB2);  
  ac6 = bmp180ReadDate(0xB4);  
  b1  = bmp180ReadDate(0xB6);  
  b2  = bmp180ReadDate(0xB8);  
  mb  = bmp180ReadDate(0xBA);  
  mc  = bmp180ReadDate(0xBC);  
  md  = bmp180ReadDate(0xBE);
}

/***BMP180 temperature Calculate***/
short bmp180GetTemperature(unsigned int ut)
{
  long x1, x2;
  x1 = (((long)ut - (long)ac6)*(long)ac5) >> 15;  //x1=((ut-ac6)*ac5)/(2^15)
  x2 = ((long)mc << 11)/(x1 + md);                //x2=(mc*2^11)/(x1+md)
  b5 = x1 + x2;                                   //b5=x1+x2
  return ((b5 + 8)>>4);                           //t=(b5+8)/(2^4)
}

/***BMP180 pressure Calculate***/

long bmp180GetPressure(unsigned long up)
{
  long x1, x2, x3, b3, b6, p;
  unsigned long b4, b7;
  
  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;
  p += (x1 + x2 + 3791)>>4;
  
  return p;
}


/*** Read 1 bytes from the BMP180  ***/

int bmp180Read(unsigned char address)
{
  unsigned char data;
  
  Wire.beginTransmission(BMP180ADD);
  Wire.write(address);
  Wire.endTransmission();
  
  Wire.requestFrom(BMP180ADD, 1);
  while(!Wire.available());
    
  return Wire.read();
}

/*** Read 2 bytes from the BMP180 ***/
int bmp180ReadDate(unsigned char address)
{
  unsigned char msb, lsb;
  Wire.beginTransmission(BMP180ADD);
  Wire.write(address);
  Wire.endTransmission();
  Wire.requestFrom(BMP180ADD, 2);
  while(Wire.available()<2);
  msb = Wire.read();
  lsb = Wire.read();
  return (int) msb<<8 | lsb;
}

/*** read uncompensated temperature value ***/
unsigned int bmp180ReadUT()
{
  unsigned int ut;
  Wire.beginTransmission(BMP180ADD);
  Wire.write(0xF4);                       // Write 0x2E into Register 0xF4
  Wire.write(0x2E);                       // This requests a temperature reading
  Wire.endTransmission();  
  delay(5);                               // Wait at least 4.5ms
  ut = bmp180ReadDate(0xF6);               // read MSB from 0xF6 read LSB from (16 bit)
  return ut;
}

/*** Read uncompensated pressure value from BMP180 ***/
unsigned long bmp180ReadUP()
{
  unsigned char msb, lsb, xlsb;
  unsigned long up = 0;
  
  Wire.beginTransmission(BMP180ADD);
  Wire.write(0xF4);                        // Write 0x34+(OSS<<6) into register 0xF4
  Wire.write(0x34 + (OSS<<6));             // 0x34+oss*64
  Wire.endTransmission(); 
  delay(2 + (3<<OSS));                     // Wait for conversion, delay time dependent on OSS
  
  Wire.beginTransmission(BMP180ADD);
  Wire.write(0xF6);                        // Read register 0xF6 (MSB), 0xF7 (LSB), and 0xF8 (XLSB)
  Wire.endTransmission();
  
  Wire.requestFrom(BMP180ADD, 3); 
  while(Wire.available() < 3);             // Wait for data to become available
  msb = Wire.read();
  lsb = Wire.read();
  xlsb = Wire.read();
  up = (((unsigned long) msb << 16) | ((unsigned long) lsb << 8) | (unsigned long) xlsb) >> (8-OSS);//16 to 19 bit
  return up;
}

示例效果

打开串口调试助手可以看到参数