int CVICALLBACK GETHEADTRACKERDATA (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	static char pathname[MAX_PATHNAME_LEN], dirname[MAX_PATHNAME_LEN];
	int status;
    int  fileFlag;
	int user_seln;
	
	if (event == EVENT_COMMIT) 
	 { 
	HidePanel(panel2);	 
	GetCtrlVal (panel2, PANEL_2_SAVEDATA, &fileFlag);
	
	 if (fileFlag)													 /*Save data is fileFlag is enabled*/
	 {
		 GetProjectDir (dirname);
            status = FileSelectPopup (dirname, "datafile.txt",
                               "Datafiles (*.txt)", "DataFile Storage",
                                VAL_SAVE_BUTTON, 0, 1, 1, 1, pathname);
			 datafilestream = fopen (pathname, "w+");
	 }
	 
	 
/* Start getting data  */
birdStartFrameStream(GROUP_ID);
do 								           /* Until Keypress  */
{
if(birdFrameReady(GROUP_ID))			   /* Check if there's data available */
	
{
BIRDREADING *bird_data;                     /* Moves data into structure*/ 
	
birdGetMostRecentFrame(GROUP_ID,&frame); 	/* Reads data from bird */ 



bird_data = &frame.reading[0];               /* Sets pointer to bird 0 */

                                         

pos[0] = bird_data->position.nX * 36 / 32767.;	   /* Convert data into inches and degrees*/ 
pos[1] = bird_data->position.nY * 36 / 32767.;		/*and scale */
pos[2] = bird_data->position.nZ * 36 / 32767.;
ang[0] = bird_data->angles.nAzimuth * 180. / 32767.;
ang[1] = bird_data->angles.nElevation * 180. / 32767.;
ang[2] = bird_data->angles.nRoll * 180. / 32767.;


printf("%+6.1f %+6.1f %+6.1f ",pos[0], pos[1], pos[2]);			  /* print data  */
printf("%+6.1f %+6.1f %+6.1f \n",ang[0], ang[1], ang[2]);

if(fileFlag)
{
fprintf(datafilestream,"%+6.1f %+6.1f %+6.1f ",pos[0], pos[1], pos[2]);			  /* print data to file  */
fprintf(datafilestream,"%+6.1f %+6.1f %+6.1f \n",ang[0], ang[1], ang[2]);
GetCtrlVal (mpanel, MPANEL_DATAFLOW, &user_seln);
}
} 														/* end if frame ready routine */
}while(user_seln=1); 										/* loop until selection is 1*/
				
printf("\n 	End of data\n");

birdStopFrameStream(GROUP_ID);					  /*Stops streaming of bird data frames*/
birdShutDown(GROUP_ID);
	
		
	}
	return 0;
}