Help with 5883L crazyness.

Also, if you can post the code then I can give it a visual inspection, in case anything seems odd.

Also, if you can post the code then I can give it a visual inspection, in case anything seems odd.

Go to https://github.com/screamingtiger/QuadCOP

And look at head.h and heading.cpp

I think I have missed a stip.  there is some code that is setting up gains

I'm not using these but I did think I confirmed I am getting same values as the arduino I was using.

Anyways have a look at the code if you will.  Its pretty simple actually.

The god news is that I can still have a test auto flight today.  Because my magnometer is consistent, I can use it to fly in a square pattern.  I think that will be a good test.  But would love to have this working.

Hi Joey,

I took your code and added ALG_TEST stuff to it and modifying the declinationAngle variable:

//#include "heading.h"
#include <stdio.h>
#include <iostream>


//#include <wiringPi.h>
//#include <wiringPiI2C.h>
#include <math.h>


using namespace std;


// comment out the next line if there is a WiringPi library
#define NO_WIRING


#define SENSORS_GAUSS_TO_MICROTESLA       (100)
#define     PI 3.1415926535897932384626433832795
#define HEADINGADDRESS          0x1e
#define HEADINGDEADBAND 2
#define ALG_TEST 1




static float _hmc5883_Gauss_LSB_XY = 1100.0F;
static float _hmc5883_Gauss_LSB_Z  = 980.0F;






class Heading
{
  public:
  int memsBoard;
  int address;
  float fx,fy,fz;
  short int x,y,z;
  float currentHeading,previousHeading;


  Heading(int address);
  int Initialize();
  float GetHeading();
  bool HeadingReached(double);

};




Heading::Heading(int address)
{
  this->address = address;
}




int Heading::Initialize()
{
  cout << "HEADING INIT here" << endl;
  int t;
  if (ALG_TEST)
  {
  cout << "Heading::Initialize()" << endl;
  return(0);
  }


#ifndef NO_WIRING
  memsBoard = wiringPiI2CSetup(address);
  t = wiringPiI2CWriteReg8(memsBoard,0x02,0x00);
  if(memsBoard < 0)
  return memsBoard;


  if(t < 0)
  return t;


  t = wiringPiI2CWriteReg8(memsBoard,0x01,0x20);
  if(t < 0)
  return t;
#endif
  return 0;

}




float CorrectHeading(float heading)
{
  float _0to90 = -100;
  float _91to180 = -136;
  float _181to270 = -100;
  float _270to360 = 20;


  if(heading >=100 && heading <= 100+90)
  return heading + _0to90;


        if(heading >= 91 && heading <= 180)
                return  heading + _91to180;
        if(heading >=181 && heading <= 271)
                return  heading + _181to270;
        if(heading >=271 && heading <= 360)
                return  heading + _270to360;


  return heading;






}


float Heading::GetHeading()
{
  if (ALG_TEST)
  {
  cout << "Heading::GetHeading" << endl;
  x=-238; // this is 0xff12
  y=-342; // this is 0xfeaa
  z=-479; // this is 0xfe21


  }
#ifndef NO_WIRING
  x  = wiringPiI2CReadReg8(memsBoard,0x03) << 8;
        x |=   wiringPiI2CReadReg8(memsBoard,0x04);


  z = wiringPiI2CReadReg8(memsBoard,0x05) << 8;
        z |=   wiringPiI2CReadReg8(memsBoard,0x06);


  y =  wiringPiI2CReadReg8(memsBoard,0x07) << 8;
        y |=   wiringPiI2CReadReg8(memsBoard,0x08);
#endif
  fx = x;
  fy = y;
  fz = z;


  float heading = atan2(fy,fx);


        float declinationAngle = 0.0404; //0.22;
  heading += declinationAngle;
  if(heading < 0)
    heading += 2*PI;
  if(heading > 2*PI)
    heading -= 2*PI;


  previousHeading = currentHeading;
  currentHeading = heading * 180/M_PI;
  //currentHeading = CorrectHeading(currentHeading);


  return currentHeading;








}






bool Heading::HeadingReached(double heading)
{
        double b = GetHeading();
        if(fabs(b - heading) <= HEADINGDEADBAND)
                return true;
        else
                return false;
}


Heading *magHeading;


int
main(void)
{
  float heading;


  magHeading=new Heading(1);
  heading=magHeading->GetHeading();


  printf("Heading is %lf\n", heading);
  if (ALG_TEST)
  {
  printf("Expected value is 237.48\n");
  }
  return(0);
}

You can compile it on any Linux machine by saving it to a file (called say mag-test.c) and then typing g++ mag-test.c and then you can run it by typing ./a.out

This is the result I get:

Heading::GetHeading
Heading is 237.480469
Expected value is 237.48

So, the algorithm appears working (the code uses the values 0xff12, 0xfeaa and 0xfe21 for the x, y and z values it pretends to read from the sensor,

and expects the output to be around 237.48 because that was the value in the example on the web page I mentioned ( Creative Electronic!: Arduino: simple compass with HMC5883L + Library ).

So, if it doesn't work, then either the code on that site is giving incorrect values (it is a possibility, even though the author claims it works, we must never assume!),

or I2C values read are incorrect.

The latter could occur with faulty or long wiring perhaps, or faulty/counterfeit sensor IC/module for example.

shabaz  Sorry man I got side tracked.  I will be working on this today.  Thanks for your help, I'll post back.