TOY0058

    Barometric Pressure Sensor(SKU:TOY0058) Contents       1 Introduction 1.1 Applications 2 Specification 3 Pin Definition 4 Documents 5 Characteristic Curve 6 Sample 6.1 Sample Code Introduction Nowadays,there are more and more navigation device with GPS function can be avilabled in electronic market.But along with high precision micro pressure sensor came, a problem solved that we can not know the current altitude,even we can using GPS to determine the location of the equipments.Bosch Sensortec developed a smart, ultra small size, high precision digital sensor BMP180 to fit high precision measurement and data acquisition for intelligence with high accuracy output of pressure (or height) and temperature measurement data. Applications    Temprerature Monitoring Pressure Monitoring Altitude Monitoring  3D navigating in the complex indoor spaces(cooperate with accelerometer) Specification     Input voltage：5V Operating temperature：-40～+85 measure accuracy：0.12hPa/m Interface：IIC Digital Output x1 Pin Definition The definition of Barometric Pressure Sensor sensor pin is 1. 2. 3. 4. +5V GND SCL SDA Pin Definition Characteristic Curve Sample TOY0058 diagram The result in Serial Monitor Sample Code /**************************************************************************** **********/ /**********************DFRobot.com*****************************/ /***write by Tom Riddler Jun.16.14***/ /***if you got any progream,please contact me terminaterfxy@hotmail.com***/ #include #define BMP180ADD 0xEE>>1 // I2C address of BMP180 //write is (0xEE) unsigned char OSS; /**********************MSB int ac1; // 0xAA LSB******/ 0xAB read is (0xEF) 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 times 3: 8 times BMP180start(); } void loop() { calculate(); show(); delay(1000); } 0: single 1: 2 times 2: 4 /** 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); 30*(1-(pressure/101325)^0.19029496); //altitude = 443 } /** 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); ac2 = bmp180ReadDate(0xAC); ac3 = bmp180ReadDate(0xAE); ac4 = bmp180ReadDate(0xB0); ac5 = bmp180ReadDate(0xB2); //get full data 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 >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)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 = (b78); 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()