• THIS IS OLED 0.9 and 1.3 inch I2C Address
  CHANGING I2C ADDRESSES:

  
  SOME I2C interfaces have pins (or solder pads) that can be changed to change the address. They are usually labelled A0-A1-A2 . Here's the way addresses change from a default 0x27 with if you connect address pads together.
•  (1 = Not Connected. 0 = Connected):
  
  

  A0	A1	A2	HEX Address
  1	1	1	0x27
  0	1	1	0x26
  1	0	1	0x25
  0	0	1	0x24
  1	1	0	0x23
  0	1	0	0x22
  1	0	0	0x21
  0	0	0	0x20

  
  
• EEPROM AT24C512 : 
• • I2C scanner. Scanning ...
  • Found address: 81 (0x51)

I2C scanner. Scanning ...
Found address: 39 (0x27)
Done.
Found 1 device(s).

1. // I2C Scanner
   // Written by Nick Gammon
   // Date: 20th April 2011
   
   #include <Wire.h>
   
   void setup() {
     Serial.begin (115200);
   
     // Leonardo: wait for serial port to connect
     while (!Serial) 
       {
       }
   
     Serial.println ();
     
   }  // end of setup
   
   void loop() {Serial.println ("I2C scanner. Scanning ...");
     byte count = 0;
     
     Wire.begin();
     for (byte i = 8; i < 120; i++)
     {
       Wire.beginTransmission (i);
       if (Wire.endTransmission () == 0)
         {
         Serial.print ("Found address: ");
         Serial.print (i, DEC);
         Serial.print (" (0x");
         Serial.print (i, HEX);
         Serial.println (")");
         count++;
         delay (1);  // maybe unneeded?
         } // end of good response
     } // end of for loop
     Serial.println ("Done.");
     Serial.print ("Found ");
     Serial.print (count, DEC);
     Serial.println (" device(s).");
     delay(2000);
     }