void compass_scalled_reading(){
compass_read_XYZdata();
compass_x_scalled=compass_x*compass_gain_fact*compass_x_gainError+compass_x_offset;
compass_y_scalled=compass_y*compass_gain_fact*compass_y_gainError+compass_y_offset;
compass_z_scalled=compass_z*compass_gain_fact*compass_z_gainError+compass_z_offset;
}
// --------------------------------------------------------------------------
// This Function calculates the offset in the Magnetometer
// using Positive and Negative bias Self test capability
// This function updates X_offset Y_offset and Z_offset Global variables
// Call Initialize before
void compass_offset_calibration(int select){
// ***********************************************************
// offset_calibration() function performs two taskes
// 1. It calculates the diffrence in the gain of the each axis magnetometer axis, using
// inbuilt self excitation function of HMC5883L (Which is useless if it is used as a compass
// unless you are very unlucy and got a crapy sensor or live at very High or low temperature)
// 2. It calculates the mean of each axes magnetic field, when the Magnetometer is rotated 360 degree
// 3. Do Both
// ***********************************************************
// *****************************************************************************************
// Gain offset estimation
// *****************************************************************************************
if (select == 1 | select == 3){ // User input in the function
// Configuring the Control register for Positive Bais mode
Serial.println("Calibrating the Magnetometer ....... Gain");
Wire.beginTransmission(compass_address);
Wire.write(0x00);
Wire.write(0b01110001); // bit configuration = 0 A A DO2 DO1 DO0 MS1 MS2
/*
A A DO2 DO1 DO0 Sample Rate [Hz] MS1 MS0 Measurment Mode
0 0 = No Average 0 0 0 = 0.75 0 0 = Normal
0 1 = 2 Sample average 0 0 1 = 1.5 0 1 = Positive Bias
1 0 = 4 Sample Average 0 1 0 = 3 1 0 = Negative Bais
1 1 = 8 Sample Average 0 1 1 = 7.5 1 1 = -
1 0 0 = 15 (Default)
1 0 1 = 30
1 1 0 = 75
1 1 1 = -
*/
Wire.endTransmission();
compass_read_XYZdata(); // Disregarding the first data
// Reading the Positive baised Data
while(compass_x<200 | compass_y<200 | compass_z<200){ // Making sure the data is with Positive baised
compass_read_XYZdata();
}
compass_x_scalled=compass_x*compass_gain_fact;
compass_y_scalled=compass_y*compass_gain_fact;
compass_z_scalled=compass_z*compass_gain_fact;
// Offset = 1160 - Data_positive
compass_x_gainError = (float)compass_XY_excitation/compass_x_scalled;
compass_y_gainError = (float)compass_XY_excitation/compass_y_scalled;
compass_z_gainError = (float)compass_Z_excitation/compass_z_scalled;
// Configuring the Control register for Negative Bais mode
Wire.beginTransmission(compass_address);
Wire.write(0x00);
Wire.write(0b01110010); // bit configuration = 0 A A DO2 DO1 DO0 MS1 MS2
/*
A A DO2 DO1 DO0 Sample Rate [Hz] MS1 MS0 Measurment Mode
0 0 = No Average 0 0 0 = 0.75 0 0 = Normal
0 1 = 2 Sample average 0 0 1 = 1.5 0 1 = Positive Bias
1 0 = 4 Sample Average 0 1 0 = 3 1 0 = Negative Bais
1 1 = 8 Sample Average 0 1 1 = 7.5 1 1 = -
1 0 0 = 15 (Default)
1 0 1 = 30
1 1 0 = 75
1 1 1 = -
*/
Wire.endTransmission();
compass_read_XYZdata(); // Disregarding the first data
// Reading the Negative baised Data
while(compass_x>-200 | compass_y>-200 | compass_z>-200){ // Making sure the data is with negative baised
compass_read_XYZdata();
}
compass_x_scalled=compass_x*compass_gain_fact;
compass_y_scalled=compass_y*compass_gain_fact;
compass_z_scalled=compass_z*compass_gain_fact;
// Taking the average of the offsets
compass_x_gainError = (float)((compass_XY_excitation/abs(compass_x_scalled))+compass_x_gainError)/2;
compass_y_gainError = (float)((compass_XY_excitation/abs(compass_y_scalled))+compass_y_gainError)/2;
compass_z_gainError = (float)((compass_Z_excitation/abs(compass_z_scalled))+compass_z_gainError)/2;
Serial.print("x_gain_offset = ");
Serial.println(compass_x_gainError);
Serial.print("y_gain_offset = ");
Serial.println(compass_y_gainError);
Serial.print("z_gain_offset = ");
Serial.println(compass_z_gainError);
}
// Configuring the Control register for normal mode
Wire.beginTransmission(compass_address);
Wire.write(0x00);
Wire.write(0b01111000); // bit configuration = 0 A A DO2 DO1 DO0 MS1 MS2
/*
A A DO2 DO1 DO0 Sample Rate [Hz] MS1 MS0 Measurment Mode
0 0 = No Average 0 0 0 = 0.75 0 0 = Normal
0 1 = 2 Sample average 0 0 1 = 1.5 0 1 = Positive Bias
1 0 = 4 Sample Average 0 1 0 = 3 1 0 = Negative Bais
1 1 = 8 Sample Average 0 1 1 = 7.5 1 1 = -
1 0 0 = 15 (Default)
1 0 1 = 30
1 1 0 = 75
1 1 1 = -
*/
Wire.endTransmission();
// *****************************************************************************************
// Offset estimation
// *****************************************************************************************
if (select == 2 | select == 3){// User input in the function
Serial.println("Calibrating the Magnetometer ....... Offset");
Serial.println("Please rotate the magnetometer 2 or 3 times in complete circules with in one minute ............. ");
for(byte i=0;i<10;i++){ // Disregarding first few data
compass_read_XYZdata();
}
float x_max=-4000,y_max=-4000,z_max=-4000;
float x_min=4000,y_min=4000,z_min=4000;
/*
Debug code ------------------------------
*/
if (compass_debug == 1){
Serial.println("Starting Debug data in ");
delay(1000);
Serial.println("3");
delay(1000);
Serial.println("2");
delay(1000);
Serial.println("1");
delay(1000);
Serial.println("0");
Serial.println();
for(byte i=0;i<10;i++){
Serial.print("*");
}
Serial.println("*");
Serial.println("Debug -- (Offset Calibration)");
for(byte i=0;i<10;i++){
Serial.print("*");
}
Serial.println("*");
}
// End Debug code
unsigned long t = millis();
while(millis()-t <= 30000){
compass_read_XYZdata();
compass_x_scalled=(float)compass_x*compass_gain_fact*compass_x_gainError;
compass_y_scalled=(float)compass_y*compass_gain_fact*compass_y_gainError;
compass_z_scalled=(float)compass_z*compass_gain_fact*compass_z_gainError;
if (compass_debug == 1){ //------------------ Debug Data
Serial.print(compass_x_scalled);
Serial.print("\t");
Serial.print(compass_y_scalled);
Serial.print("\t");
Serial.println(compass_z_scalled);
}//--------------------------------- End Debug Data
x_max = max(x_max,compass_x_scalled);
y_max = max(y_max,compass_y_scalled);
z_max = max(z_max,compass_z_scalled);
x_min = min(x_min,compass_x_scalled);
y_min = min(y_min,compass_y_scalled);
z_min = min(z_min,compass_z_scalled);
}
/*
Debug code ------------------------------
*/
if (compass_debug == 1){
Serial.println();
for(byte i=0;i<10;i++){
Serial.print("*");
}
Serial.println("*");
Serial.println("End Debug -- (Offset Calibration)");
for(byte i=0;i<10;i++){
Serial.print("*");
}
Serial.println("*");
}
// End Debug code
compass_x_offset = ((x_max-x_min)/2)-x_max;
compass_y_offset = ((y_max-y_min)/2)-y_max;
compass_z_offset = ((z_max-z_min)/2)-z_max;
Serial.print("Offset x = ");
Serial.print(compass_x_offset);
Serial.println(" mG");
Serial.print("Offset y = ");
Serial.print(compass_y_offset);
Serial.println(" mG");
Serial.print("Offset z = ");
Serial.print(compass_z_offset);
Serial.println(" mG");
}
}
// --------------------------------------------------------------------------
// This Function calculates the offset in the Magnetometer
// using Positive and Negative bias Self test capability
// This function updates X_offset Y_offset and Z_offset Global variables
// Call Initialize before
void compass_calibration(int select){
// ***********************************************************
// offset_calibration() function performs two taskes
// 1. It calculates the diffrence in the gain of the each axis magnetometer axis, using
// inbuilt self excitation function of HMC5883L (Which is useless if it is used as a compass
// unless you are very unlucy and got a crapy sensor or live at very High or low temperature)
// 2. It calculates the mean of each axes magnetic field, when the Magnetometer is rotated 360 degree
// 3. Do Both
// ***********************************************************
// *****************************************************************************************
// Gain offset estimation
// *****************************************************************************************
if (select == 1 | select == 3){ // User input in the function
// Configuring the Control register for Positive Bais mode
Serial.println("Calibrating the Magnetometer ....... Gain");
Wire.beginTransmission(compass_address);
Wire.write(0x00);
Wire.write(0b01110001); // bit configuration = 0 A A DO2 DO1 DO0 MS1 MS2
/*
A A DO2 DO1 DO0 Sample Rate [Hz] MS1 MS0 Measurment Mode
0 0 = No Average 0 0 0 = 0.75 0 0 = Normal
0 1 = 2 Sample average 0 0 1 = 1.5 0 1 = Positive Bias
1 0 = 4 Sample Average 0 1 0 = 3 1 0 = Negative Bais
1 1 = 8 Sample Average 0 1 1 = 7.5 1 1 = -
1 0 0 = 15 (Default)
1 0 1 = 30
1 1 0 = 75
1 1 1 = -
*/
Wire.endTransmission();
compass_read_XYZdata(); // Disregarding the first data
// Reading the Positive baised Data
while(compass_x<200 | compass_y<200 | compass_z<200){ // Making sure the data is with Positive biased
compass_read_XYZdata();
}
compass_x_scalled=compass_x*compass_gain_fact;
compass_y_scalled=compass_y*compass_gain_fact;
compass_z_scalled=compass_z*compass_gain_fact;
// Offset = 1160 - Data_positive
compass_x_gainError = (float)compass_XY_excitation/compass_x_scalled;
compass_y_gainError = (float)compass_XY_excitation/compass_y_scalled;
compass_z_gainError = (float)compass_Z_excitation/compass_z_scalled;
// Configuring the Control register for Negative Bais mode
Wire.beginTransmission(compass_address);
Wire.write(0x00);
Wire.write(0b01110010); // bit configuration = 0 A A DO2 DO1 DO0 MS1 MS2
/*
A A DO2 DO1 DO0 Sample Rate [Hz] MS1 MS0 Measurment Mode
0 0 = No Average 0 0 0 = 0.75 0 0 = Normal
0 1 = 2 Sample average 0 0 1 = 1.5 0 1 = Positive Bias
1 0 = 4 Sample Average 0 1 0 = 3 1 0 = Negative Bais
1 1 = 8 Sample Average 0 1 1 = 7.5 1 1 = -
1 0 0 = 15 (Default)
1 0 1 = 30
1 1 0 = 75
1 1 1 = -
*/
Wire.endTransmission();
compass_read_XYZdata(); // Disregarding the first data
// Reading the Negative baised Data
while(compass_x>-200 | compass_y>-200 | compass_z>-200){ // Making sure the data is with negative baised
compass_read_XYZdata();
}
compass_x_scalled=compass_x*compass_gain_fact;
compass_y_scalled=compass_y*compass_gain_fact;
compass_z_scalled=compass_z*compass_gain_fact;
// Taking the average of the offsets
compass_x_gainError = (float)((compass_XY_excitation/abs(compass_x_scalled))+compass_x_gainError)/2;
compass_y_gainError = (float)((compass_XY_excitation/abs(compass_y_scalled))+compass_y_gainError)/2;
compass_z_gainError = (float)((compass_Z_excitation/abs(compass_z_scalled))+compass_z_gainError)/2;
Serial.print("x_gain_offset = ");
Serial.println(compass_x_gainError);
Serial.print("y_gain_offset = ");
Serial.println(compass_y_gainError);
Serial.print("z_gain_offset = ");
Serial.println(compass_z_gainError);
}
// Configuring the Control register for normal mode
Wire.beginTransmission(compass_address);
Wire.write(0x00);
Wire.write(0b01111000); // bit configuration = 0 A A DO2 DO1 DO0 MS1 MS2
/*
A A DO2 DO1 DO0 Sample Rate [Hz] MS1 MS0 Measurment Mode
0 0 = No Average 0 0 0 = 0.75 0 0 = Normal
0 1 = 2 Sample average 0 0 1 = 1.5 0 1 = Positive Bias
1 0 = 4 Sample Average 0 1 0 = 3 1 0 = Negative Bais
1 1 = 8 Sample Average 0 1 1 = 7.5 1 1 = -
1 0 0 = 15 (Default)
1 0 1 = 30
1 1 0 = 75
1 1 1 = -
*/
Wire.endTransmission();
}
