I2C

#include <Wire.h>

/*
   scanner for devices on i2c bus
*/

void setup()
{
  Wire.begin();

  Serial.begin(9600);
  while (!Serial);             // Leonardo: wait for serial monitor
  Serial.println("\nI2C Scanner");
}

#define BPRT(x) Serial.println(x)
void knownIDs()
{
  BPRT("0x68 / 0x69 MPU6050 acc/gyro");
  BPRT("0x77 / BMP085/180/280 pressure");
  BPRT("0x1E / HMC5983 magn compass");
  // more to come
}

void loop()
{
  byte error, address;
  int nDevices;

  Serial.println("Scanning...");

  nDevices = 0;
  for (address = 1; address < 127; address++ )
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address < 16)
        Serial.print("0");
      Serial.print(address, HEX);
      Serial.print("  (");
      Serial.print(address);
      Serial.println(")");
      nDevices++;
    }
    else if (error == 4)
    {
      Serial.print("Unknow error at address 0x");
      if (address < 16)
        Serial.print("0");
      Serial.print(address, HEX);
    }
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");

  knownIDs();
  delay(1000);           // wait 5 seconds for next scan
}