what is the I2C address of Arduino UNO board and how to modify i2c address

Projects Programming
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Riva:

ranjeetray:
Thanks for your kind reply. But this Link doesn't say anything about the I2C address of Arduino Board and method to modify the I2C address.

From the page link...

Description
Initiate the Wire library and join the I2C bus as a master or slave. This should normally be called only once.
Parameters
address: the 7-bit slave address (optional); if not specified, join the bus as a master.

Thanks for your reply. I am running the following code on one Arduino UNO board and trying to reading the I2C address of another Arduino UNO board using SCL and SDA wires on pin A5 and A4 but I am not getting any value. I have used pull up register also 4.7Kohm at 5V.

#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 <= 130; 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
}

Kindly suggest me , what is wrong here.