#include  <Wire.h>//library for I2C
                  byte own_address = 4; //set own adress.
                  void setup()
		 {
                    Wire.begin(own_address); //enter the bus on specified address
                    Wire.onReceive(receiveEvent);//set the board as reveicer and call a function called receiveEvent
                    pinMode(13, OUTPUT);//set the pin of the led built in as an output
                    digitalWrite(13, LOW);//set the led builtin as low in the begining of the code
                  }//close void setup
                  void loop() 
		{
                  }
                  void receiveEvent(int howMany)
		 {
                    while (Wire.available())
		 {//while the serial comunication is available using the wire library
                      char c = Wire.read();//use  character variable called "c" to store de value of the message sent from the host
                      if(c=='H')
			{//check the condition if the variable "c" equals the character "H"
                        digitalWrite(13,HIGH);//if this is thruth then turn LED on
                     	 }//close first if
                      else if(c=='L')
			{other whise check if the value of the variable "c" is equal to the character "L"
                        digitalWrite(13,LOW);// if this condition is true then turn LED off
                      }//close second if
                    }//close while
                  }//close void receiveEvent