The Magnet Tag!

// Define includes
#include <Wire.h>        // Wire header file for I2C and 2 wire

// 
int HallAddressWrite = 0x1F;   // Device address
byte X_Axis_Register1 = 0x1;  //

// Declare some variables
int const numOfBytes = 7;
int baudRate = 9600;
byte readByte[numOfBytes];
float counter=0.0;

byte configReg = 0x00;  // Address of Configuration
byte powerMode = 0x05;   // Set to low power mode


void setup() {
  Serial.begin(baudRate);            // Set Serial Port speed
  delay(1000);
  Wire.pins(4, 5);
  Wire.begin();                      // Join the I2C bus as a master

  Wire.beginTransmission(HallAddressWrite);       // Address the sensor
  Wire.write(configReg);              // Address the Configuration register
  Wire.write(powerMode);              // Set the Power Mode to Low
  Wire.endTransmission();             // Stop transmitting
  delay(100);
}

// Main Program Infinite loop
void loop() {


  getBytes(HallAddressWrite, X_Axis_Register1, numOfBytes, readByte); //Read first 8 bytes

  float temp = getTemp();
  if(temp<-50){ //re-read address banks, bad measurement
    while(temp<-50){
      getBytes(HallAddressWrite, X_Axis_Register1, numOfBytes, readByte); //Read first 8 bytes
      temp = getTemp();
    }
  }
  Serial.print("\t");
  getMagX();
  Serial.print("\t");
  getMagY();
  Serial.print("\t");
  getMagZ();

  Serial.println("-----");
  delay(250);

}

float getFrameCounter() { //every ADC conversion the frame is incremented,this function captures that
                          //This would be needed probaly in fast mode to ensure data 
                          //was succesfully written to the registries
  int i;
  int a[8];
  int lsb = readByte[3];
  int tableI[8] = { 0, 0, 0, 0, 1, 1, 0, 0};


  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & lsb)
      a[7 - i] = 1*tableI[7-i];
    else
      a[7 - i] = 0;
    counter += a[7 - i];
  }
  Serial.print(counter);
  return counter;
}

float getTemp()
{
  int i;
  int a[8];
  int b[8];
  int tableI[8] = { -2048, 1024, 512, 256, 0, 0, 0, 0};
  int tableII[8] = {128, 64, 32, 16, 8, 4, 2, 1};
  float Celsius = 0;
  int msb = readByte[3];
  int lsb = readByte[6];

  //msb conversion
  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & msb)
      a[7 - i] = 1 * tableI[7 - i];
    else
      a[7 - i] = 0;
    //    Serial.print(a[7 - i]);Serial.print(" ");
    Celsius += a[7 - i];
  }
  //  Serial.print("\t");
  a[8] = 0; // ascii terminating character

  //lsb conversion
  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & lsb)
      b[7 - i] = 1 * tableII[7 - i];
    else
      b[7 - i] = 0;
    //    Serial.print(b[7 - i]);Serial.print(" ");
    Celsius += b[7 - i];
  }
  //  Serial.print("\t");
  b[8] = 0; // ascii terminating character

  Celsius -= 320;
  Celsius *= 1.1;
  if(Celsius>-50){
    Serial.print(Celsius);
  }
  return Celsius;

}

void getBytes(byte address, byte registry, int numOfBytes, byte* readByte)
{
  Wire.beginTransmission(address);  //Begin Transmission
  //Ask for data register
  Wire.write(registry);
  Wire.endTransmission();             //End Transmission
  delay(20);                        //at least 12msec for ADC conversion and storage
  Wire.requestFrom(address, numOfBytes);     //Request Transmission
  for (int i = 0; i < numOfBytes; i++) {
    readByte[i] = Wire.read();
  }
  Wire.endTransmission();

}

float getMagX()
{
  int i;
  int a[8];
  int b[8];
  int tableI[8] = { -2048, 1024, 512, 256, 128, 64, 32, 16};
  int tableII[8] = {8, 4, 2, 1, 0, 0, 0, 0};
  float magX = 0;
  int msb = readByte[0];
  int lsb = readByte[4];

  //msb conversion
  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & msb)
      a[7 - i] = 1 * tableI[7 - i];
    else
      a[7 - i] = 0;
    //    Serial.print(a[7 - i]);Serial.print(" ");
    magX += a[7 - i];
  }
  //  Serial.print("\t");
  a[8] = 0; // ascii terminating character

  //lsb conversion
  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & lsb)
      b[7 - i] = 1 * tableII[7 - i];
    else
      b[7 - i] = 0;
    //    Serial.print(b[7 - i]);Serial.print(" ");
    magX += b[7 - i];
  }
  //  Serial.print("\t");
  b[8] = 0; // ascii terminating character

  magX *= 0.098 * 10.0; //0.098mT/LSB 10Gauss/mT
  if(abs(magX)<3)   //the sensor has about a 0.2mT | 2Gauss units drift
    magX = 0;       //this is a software filter that suppress most of the noise
  Serial.print(magX);
  return magX;

}

float getMagY()
{
  int i;
  int a[8];
  int b[8];
  int tableI[8] = { -2048, 1024, 512, 256, 128, 64, 32, 16};
  int tableII[8] = {0, 0, 0, 0, 8, 4, 2, 1};
  float magY = 0;
  int msb = readByte[1];
  int lsb = readByte[4];

  //msb conversion
  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & msb)
      a[7 - i] = 1 * tableI[7 - i];
    else
      a[7 - i] = 0;
    //    Serial.print(a[7 - i]);Serial.print(" ");
    magY += a[7 - i];
  }
  //  Serial.print("\t");
  a[8] = 0; // ascii terminating character

  //lsb conversion
  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & lsb)
      b[7 - i] = 1 * tableII[7 - i];
    else
      b[7 - i] = 0;
    //    Serial.print(b[7 - i]);Serial.print(" ");
    magY += b[7 - i];
  }
  //  Serial.print("\t");
  b[8] = 0; // ascii terminating character

  magY *= 0.098 * 10.0; //0.098mT/LSB 10Gauss/mT
  if(abs(magY)<3)    //the sensor has about a 0.2mT | 2Gauss units drift
    magY = 0;        //this is a software filter that suppress most of the noise
  Serial.print(magY);
  return magY;

}

float getMagZ()
{
  int i;
  int a[8];
  int b[8];
  int tableI[8] = { -2048, 1024, 512, 256, 128, 64, 32, 16};
  int tableII[8] = {0, 0, 0, 0, 8, 4, 2, 1};
  float magZ = 0;
  int msb = readByte[2];
  int lsb = readByte[5];

  //msb conversion
  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & msb)
      a[7 - i] = 1 * tableI[7 - i];
    else
      a[7 - i] = 0;
    //    Serial.print(a[7 - i]);Serial.print(" ");
    magZ += a[7 - i];
  }
  //  Serial.print("\t");
  a[8] = 0; // ascii terminating character

  //lsb conversion
  for ( i = 7; i >= 0; i--)
  {
    if ( (1 << i) & lsb)
      b[7 - i] = 1 * tableII[7 - i];
    else
      b[7 - i] = 0;
    //    Serial.print(b[7 - i]);Serial.print(" ");
    magZ += b[7 - i];
  }
  //  Serial.print("\t");
  b[8] = 0; // ascii terminating character

  magZ *= 0.098 * 10.0; //0.098mT/LSB 10Gauss/mT
  if(abs(magZ)<3) //the sensor has about a 0.2mT | 2Gauss units drift
    magZ = 0;     //this is a software filter that suppress most of the noise
  Serial.print(magZ);
  return magZ;

}