Ic2_Scanner.ino

// i2c_scanner
 //
 // This program (or code that looks like it)
 // can be found in many places.
 // For example on the Arduino.cc forum.
 // The original author is not know.
 //
 // This sketch tests the standard 7-bit addresses
 // from 0 to 127. Devices with higher bit address
 // might not be seen properly.
 //
 // Adapted to be as simple as possible by Arduino.cc user Krodal
 //
 // June 2012
 // Using Arduino 1.0.1
 //

#include <Wire.h>

void setup()
 {
   Wire.begin();

  Serial.begin(9600);
   Serial.println("\nI2C Scanner");
 }

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

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

  nDevices = 0;
   for(address = 0; 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.println(" !");

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

  delay(8000);           // wait 8 seconds for next scan
 }