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_24_arduSerie_Arduino_Bluetooth_Compass.ino

/*
  Project name:
     ABC Project: Arduino, Bluetooth and Compass V1.0 - 24 #arduSerie
     (ABC project - Arduino, Bluetooth and Compass Project!!!)
     Flavour III - Final Result
     Hex File: _24_arduSerie_Arduino_Bluetooth_Compass.ino
  Revision History:
     20161231:
       - from How To Make a Compass using Arduino and Processing IDE
         by Dejan Nedelkovski
http://howtomechatronics.com/projects/how-to-make-a-compass-using-arduino-and-processing-ide/
  Description:
     We will implement a compass connected to the arduino via bluetooth.   
     We used the HC-06 bluetooth dongle, GY-85 board, which sensor used 
     are only HMC5883L out of three.
     
  MCU  :           Arduino 1.6.12 - @16MHz       http://www.arduino.cc/
  HC-06:           Wireless RF Transceiver Bluetooth HC-06 Slave Module               
                    RS232/TTL for Arduino http://www.ebay.com/bhp/hc-06
  GY-85:           https://github.com/madc/GY-85
  
  Connections:
      See Official youtube channel vids:
      GY-85:         BT:
      SDA-A4         RXD-1K2+2K2 RESISTOR VOLTAGE DIVISOR+ARDU'S PIN 1 TX
      SDL-A5         TXD-PIN 0 ARDUINO's RX
      3V3-3V3        VCC-5V 
      GND-GND        GND-GND  
    
  Based on:   How To Make a Compass using Arduino and Processing IDE by 
               Dejan Nedelkovski
               and 
               TECHBITAR (HAZIM BITAR) EMAIL: techbitar.gmail.com
                      
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License v3 as published by
    the Free Software Foundation
*/
//////////////////////////////////////////////////////////////////////////////////
// REMIXED BY: TECHBITAR (HAZIM BITAR)
// LICENSE: PUBLIC DOMAIN
// DATE: MAY 2, 2012
// CONTACT: techbitar at gmail dot com
#include <Wire.h> //I2C Arduino Library
#define Magnetometer_mX0 0x03  
#define Magnetometer_mX1 0x04  
#define Magnetometer_mZ0 0x05  
#define Magnetometer_mZ1 0x06  
#define Magnetometer_mY0 0x07  
#define Magnetometer_mY1 0x08  
int mX0, mX1, mX_out;
int mY0, mY1, mY_out;
int mZ0, mZ1, mZ_out;
float heading, headingDegrees, headingFiltered, declination;
float Xm,Ym,Zm;
#define Magnetometer 0x1E //I2C 7bit address of HMC5883
void setup() {
  Serial.begin(9600);
  delay(50);
  //Serial.begin(115200);
  Wire.begin();
  delay(100);
  
  Wire.beginTransmission(Magnetometer); 
  Wire.write(0x02); // Select mode register
  Wire.write(0x00); // Continuous measurement mode
  Wire.endTransmission();
}
void loop() {
   //---- X-Axis
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mX1);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mX0 = Wire.read();
  }
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mX0);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mX1 = Wire.read();
  }
  //---- Y-Axis
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mY1);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mY0 = Wire.read();
  }
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mY0);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mY1 = Wire.read();
  }
  
  //---- Z-Axis
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mZ1);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mZ0 = Wire.read();
  }
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mZ0);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mZ1 = Wire.read();
  }
  
  //---- X-Axis
  mX1=mX1<<8;
  mX_out =mX0+mX1; // Raw data
  // From the datasheet: 0.92 mG/digit
  Xm = mX_out*0.00092; // Gauss unit
  //* Earth magnetic field ranges from 0.25 to 0.65 Gauss, so these are the values that we need to get approximately.
  //---- Y-Axis
  mY1=mY1<<8;
  mY_out =mY0+mY1;
  Ym = mY_out*0.00092;
  //---- Z-Axis
  mZ1=mZ1<<8;
  mZ_out =mZ0+mZ1;
  Zm = mZ_out*0.00092;
  // ==============================
  //Calculating Heading
 
   heading = atan2(Ym, Xm);
 
  // Correcting the heading with the declination angle depending on your     
  // location
  // You can find your declination angle at:   
  // http://www.ngdc.noaa.gov/geomag-web/
  // At my location it's 4.2 degrees => 0.073 rad
  // My city = -12.44 degrees = > -0.23
  // http://www.magnetic-declination.com/
  // declination = 0.073; 
  
  declination = -0.23; 
  heading += declination;
  
  // Correcting when signs are reveresed
  
  if(heading <0) heading += 2*PI;
  
  // Correcting due to the addition of the declination angle
  
  if(heading > 2*PI)heading -= 2*PI;
  headingDegrees = heading * 180/PI; // The heading in Degrees unit
  
  // Smoothing the output angle / Low pass filter 
  
  headingFiltered = headingFiltered*0.85 + headingDegrees*0.15;
  
  //Sending the heading value through the Serial Port to Processing IDE
  
  Serial.println(headingFiltered);
  
  delay(50);
}