Understanding the code

Projects Programming
1

this is the code for compass for HMC6352 i got it from some where on the net cam you explain me what does it do

float angleNextPoint;
int  various angles;
int  directionOfAngle() //i can’t explain it clearly. I can’t even in Greek:P. I only can tell you that this is a routine that calculate the angle the car s
//ould turn in order to “see” the next waypoint”. It return the angle and the direction.

{
  getAngleInDeg();
  // First quadrant
  if((nextLatitude-latitude)>=0 && (nextLongitude-longitude)>0)
  {
    float sintAtan1=fabs(nextLongitude-longitude); //Differencebetween current and stored GEOGRAFICALLongitude
    float sintAtan2=fabs(nextLatitude-latitude); //Difference between current and stored geographical latitude 
    angleNextPoint=atan2(sintAtan1,sintAtan2); //ESTIMATE THEAngleWhosformed byTHE CURRENTANDThe saved geographical Latitude and Longitude

    angleNextPoint=((angleNextPoint*180)/M_PI); //Convert the angle of BY ray in degrees
    variousangles=fabs(angleNextPoint-reading); //MISCELLANEOUS angle to IS THAT WHAT YOU CALCULATE AP MAKES OUR COMPASS
    //CONTROLHOW TO GO Quadrant
    if(reading>angleNextPoint&&variousangles<180)
    {
      servoDir='L';
      return(reading-angleNextPoint);
    }
    else if(reading>angleNextPoint&&variousangles>=180)
    {
      servoDir='R';
      return(360-reading+angleNextPoint);
    }
    else if(reading<angleNextPoint)
    {
      servoDir='R';
      return(angleNextPoint-reading);
    }
    else
    {
      servoDir='S';
      return(0);
    }
  }
  //Second Quarter
  else if((nextLatitude-latitude)<0 && (nextLongitude-longitude)>=0)
  {
    float sintAtan1=fabs(nextLongitude-longitude);
    float sintAtan2=fabs(nextLatitude-latitude);
    angleNextPoint=atan2(sintAtan2,sintAtan1);

    angleNextPoint=((angleNextPoint*180)/M_PI)+90;
    variousangles=fabs(angleNextPoint-reading);

    if(reading>angleNextPoint&&variousangles<180)
    {
      servoDir='L';
      return(reading-angleNextPoint);
    }
    else if(reading>angleNextPoint&&variousangles>=180)
    {
      servoDir='R';
      return(360-reading+angleNextPoint);
    }
    else if(reading<angleNextPoint)
    {
      servoDir='R';
      return(angleNextPoint-reading);
    }
    else
    {
      servoDir='S';
      return(0);
    }
  }
  //Third Quarter
  else if((nextLatitude-latitude)<=0 && (nextLongitude-longitude)<0)
  {
    float sintAtan1=fabs(nextLongitude-longitude);
    float sintAtan2=fabs(nextLatitude-latitude);
    angleNextPoint=atan2(sintAtan1,sintAtan2);

    angleNextPoint=((angleNextPoint*180)/M_PI)+180;
    variousangles=fabs(angleNextPoint-reading);

    if(reading>angleNextPoint)
    {
      servoDir='L';
      return(reading-angleNextPoint);
    }
    else if(reading<angleNextPoint&&variousangles>=180)
    {
      servoDir='L';
      return(360-angleNextPoint+reading);
    }
    else if(reading<angleNextPoint&&variousangles<180)
    {
      servoDir='R';
      return(angleNextPoint-reading);
    }
    else
    {
      servoDir='S';
      return(0);
    }
  }
  //fourth quadrant
  else if((nextLatitude-latitude)>0 && (nextLongitude-longitude)<=0)
  {
    float sintAtan1=fabs(nextLongitude-longitude);
    float sintAtan2=fabs(nextLatitude-latitude);
    angleNextPoint=atan2(sintAtan2,sintAtan1);

    angleNextPoint=((angleNextPoint*180)/M_PI)+270;
    variousangles=fabs(angleNextPoint-reading);

    if(reading>angleNextPoint)
    {
      servoDir='L';
      return(reading-angleNextPoint);
    }
    else if(reading<angleNextPoint&&variousangles>=180)
    {
      servoDir='L';
      return(360-angleNextPoint+reading);
    }
    else if(reading<angleNextPoint&&variousanglesn<180)
    {
      servoDir='R';
      return(angleNextPoint-reading);
    }
    else
    {
      servoDir='S';
      return(0);
    }
  }

}
//====================================
//Routine that reads the COMPASS
//===================================
intgetAngleInDeg() 
{ 
  Wire.beginTransmission(63);
  Wire.send(0x41); 
  Wire.endTransmission();
  delayViaGps(10);
  Wire.requestFrom(63, 2); 
  byte MSB = Wire.receive();
  byte LSB = Wire.receive();
  reading = ((MSB<< 8) + LSB)/10; 
  Serial.print(" reading ");
  Serial.println(reading);
  return(reading);
}
2

This code has a function called

directionOfAngle()

It looks like it is part of someone project. the part you want must be

int getAngleInDeg() 
{ 
  Wire.beginTransmission(63);
  Wire.send(0x41); 
  Wire.endTransmission();
  delayViaGps(10);
  Wire.requestFrom(63, 2); 
  byte MSB = Wire.receive();
  byte LSB = Wire.receive();
  reading = ((MSB<< 8) + LSB)/10; 
  Serial.print(" reading ");
  Serial.println(reading);
  return(reading);
}

This function had an error, and
int  various angles; is an error. This code might be nothing useful.
Dunno. If your compass is serial, this may be how to control it. The other function is using gps data to do stuff.

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