SOLVED!!: WORKING WITH GY-87.... EVERYTHING OK BUT HMC5883L NOT WORKING AT ALL

Hello Pistolero992000:

I have a Gy-87 sensor, I have tried your code, but I have exactilly the same problem than NeaWeaR when I try to compile the code:

GY-87_10DOF.ino: In function 'void setup()':
GY-87_10DOF.ino:47: error: 'compass_x_offset' was not declared in this scope
GY-87_10DOF.ino:48: error: 'compass_y_offset' was not declared in this scope
GY-87_10DOF.ino:49: error: 'compass_z_offset' was not declared in this scope
GY-87_10DOF.ino:50: error: 'compass_x_gainError' was not declared in this scope
GY-87_10DOF.ino:51: error: 'compass_y_gainError' was not declared in this scope
GY-87_10DOF.ino:52: error: 'compass_z_gainError' was not declared in this scope
GY-87_10DOF.ino:108: error: 'alpha' was not declared in this scope
GY-87_10DOF.ino: In function 'void Get_Values()':
GY-87_10DOF.ino:136: error: 'alpha' was not declared in this scope

Do we need some addtional header or cpp file to compile
Regards!