關於電子羅盤HMC5883L

Leslie

各位大大好，小的是新手
剛嘗試使用Arduino範例的電子羅盤，想看角度的變化量
但卻發現0-90度雖然是正常的  不過90-180 180-270 270-360 這三個角度內的值都只會分別固定在87度 357度 42度
自己有先看過範例的程式覺得好像是抓值那裏錯了  
想問一下是否有大大可以告訴我哪裡出錯了嗎    是不是需要改.h檔裡的值呢??

圖片是實際操作過的截圖  一旦超過90度   X 、Y分量就會瞬間變成六萬

以下是範例CODE
#include <Wire.h>
// Reference the HMC5883L Compass Library
#include <HMC5883L.h>

// 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");
   
  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();

  int MilliGauss_OnThe_XAxis = scaled.XAxis;// (or YAxis, or ZAxis)
  float heading = atan2(scaled.YAxis, scaled.XAxis);
  float declinationAngle = -0.0457;
  heading += declinationAngle;
  // Correct for when signs are reversed.
  if(heading < 0)
    heading += 2*PI;  
  if(heading > 2*PI)
    heading -= 2*PI;  
  float headingDegrees = heading * 180/M_PI;

  Output(raw, scaled, heading, headingDegrees);

  delay(66);//of course it can be delayed longer.
}


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");
}

超新手

先看看附近是否有磁性物體(如 PC...), 遠離後再測看看
如果沒有, 可以把
setScale 的值由大測試到小
以下是可用的值, 你的程式是用1.3
0.88, 1.3, 1.9, 2.5, 4.0, 4.7, 5.6, 8.1