#include <SoftwareSerial.h>   // Include  SoftwareSerial  library
SoftwareSerial BT(10, 11);   /*Define pins Rx and Tx on Arduiono, which are connected to Bluetooth.*/

void setup()
{
  BT.begin(9600);       //Initialize serial port which has been created.
  Serial.begin(9600);   //Initialize serial port.
}

void loop()
{
  if (BT.available())   //If data arrives by BT, it is sent by Serial monitor.
  {
    Serial.write(BT.read()); //Data read from Bluetooth module
  }

  if (Serial.available()) //If data arrives by Serial monitor, it is sent by BT.
  {
    BT.write(Serial.read()); //Data read from from Serial monitor.
  }
}