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Arduino Uno 连接 HMC5883L 磁场传感器模块[/caption]
基本实现代码：
/* @Author: TONYLABS @Date: 2013/03/05 */ #include #include
HMC5883L compass; //@声明 HMC5883L 对象
void setup() { Serial.begin(9600);//@初始化串口 Wire.begin(); //@启动 Wire compass = HMC5883L(); //@实例化 HMC5883L 对象 setupHMC5883L(); //@调用后面的 setupHMC5883L 函数，设置 HMC5883L 对象 }
void loop() { float heading = getHeading(); //@声明浮点数变量 heading Serial.println(heading); //@串口打印输出 heading 的值 delay(100); //@延时100毫秒 }
void setupHMC5883L() { //@配置 HMC5883L 对象，检查I2C是否返回错误代码 int error; error = compass.SetScale(1.3); //@设置放大比率 if(error != 0) Serial.println(compass.GetErrorText(error)); //@检查错误，如有则串口输出该错误 error = compass.SetMeasurementMode(Measurement_Continuous); //@设置测量模式. if(error != 0) Serial.println(compass.GetErrorText(error)); //@检查错误，如有则串口输出该错误 }
float getHeading() { //@获取并计算角速度 MagnetometerScaled scaled = compass.ReadScaledAxis(); //@格式化 float heading = atan2(scaled.YAxis, scaled.XAxis);
//@ if(heading < 0) heading += 2PI; if(heading > 2PI) heading -= 2*PI;
return heading * RAD_TO_DEG; //@弧度转换为角度 } // Reference the I2C Library #include // Reference the HMC5883L Compass Library #include
// Store our compass as a variable. HMC5883L compass; // Record any errors that may occur in the compass. int error = 0;
// Out setup routine, here we will configure the microcontroller and compass. void setup() { // Initialize the serial port. Serial.begin(9600);
Serial.println("Starting the I2C interface."); Wire.begin(); // Start the I2C interface.
Serial.println("Constructing new HMC5883L"); compass = HMC5883L(); // Construct a new HMC5883 compass.
Serial.println("Setting scale to +/- 1.3 Ga"); error = compass.SetScale(1.3); // Set the scale of the compass. if(error != 0) // If there is an error, print it out. Serial.println(compass.GetErrorText(error));
Serial.println("Setting measurement mode to continous."); error = compass.SetMeasurementMode(Measurement_Continuous); // Set the measurement mode to Continuous if(error != 0) // If there is an error, print it out. Serial.println(compass.GetErrorText(error)); }
// Our main program loop. void loop() { // Retrive the raw values from the compass (not scaled). MagnetometerRaw raw = compass.ReadRawAxis(); // Retrived the scaled values from the compass (scaled to the configured scale). MagnetometerScaled scaled = compass.ReadScaledAxis();
// Values are accessed like so: int MilliGauss_OnThe_XAxis = scaled.XAxis;// (or YAxis, or ZAxis)
// Calculate heading when the magnetometer is level, then correct for signs of axis. float heading = atan2(scaled.YAxis, scaled.XAxis);
// Once you have your heading, you must then add your 'Declination Angle', which is the 'Error' of the magnetic field in your location. // Find yours here: http://www.magnetic-declination.com/ // Mine is: 2� 37' W, which is 2.617 Degrees, or (which we need) 0.0456752665 radians, I will use 0.0457 // If you cannot find your Declination, comment out these two lines, your compass will be slightly off. float declinationAngle = 0.0457; heading += declinationAngle;
// Correct for when signs are reversed. if(heading < 0) heading += 2*PI;
// Check for wrap due to addition of declination. if(heading > 2PI) heading -= 2PI;
// Convert radians to degrees for readability. float headingDegrees = heading * 180/M_PI;
// Output the data via the serial port. Output(raw, scaled, heading, headingDegrees);
// Normally we would delay the application by 66ms to allow the loop // to run at 15Hz (default bandwidth for the HMC5883L). // However since we have a long serial out (104ms at 9600) we will let // it run at its natural speed. // delay(66); }
// Output the data down the serial port. void Output(MagnetometerRaw raw, MagnetometerScaled scaled, float heading, float headingDegrees) { Serial.print("Raw:\t"); Serial.print(raw.XAxis); Serial.print(" "); Serial.print(raw.YAxis); Serial.print(" "); Serial.print(raw.ZAxis); Serial.print(" \tScaled:\t");
Serial.print(scaled.XAxis); Serial.print(" "); Serial.print(scaled.YAxis); Serial.print(" "); Serial.print(scaled.ZAxis);
Serial.print(" \tHeading:\t"); Serial.print(heading); Serial.print(" Radians \t"); Serial.print(headingDegrees); Serial.println(" Degrees \t"); }
