#include <VirtualWire.h> //This Library is for wireless rx and tx modules

#define led 13         // For good visual realization that everything is working fine.......
#define receive_msg 9


void setup()
{
  delay(1000);       // Just to stop for startup
  Serial.begin(9600);
  pinMode(led,OUTPUT);

  vw_set_rx_pin(receive_msg); // Set the pin as RX to receive message
  vw_setup(2400);             // TO setup the baud rate
  
  vw_rx_start();
}
void loop()
{
  byte buf[VW_MAX_MESSAGE_LEN];      // 'buf' array to store the message.......you can change the 'byte' to 'uint8_t'......if you dont know what does 'uint8_t' means plzz visit http://blog.oscarliang.net/arduino-difference-byte-uint8-t-unsigned-cha/
  byte buflen = VW_MAX_MESSAGE_LEN;  // To store the message length in buflen
  
  if(vw_get_message(buf, &buflen))      //this switches true if any message is received ......I dont really known why the pointer operator is required
  {
    int i;
    digitalWrite(led,HIGH);            // The led goes High if the receiver gets any message
    
    for(i = 0; i < buflen; i++)        // This for loop is a bit confusing part......
    {
      int convt = int(buf[i]);         // Converting the distance to integer type because the HC-SR04 sends the value from 0-200.....and byte = 2^7 = 0 to 127
      if(convt<0)                      // This is required coz if the value 'convt' is greater than 127 then it will turn -ve........ e.g. int = 128,129,130.....,200 ---> byte = -128,-127,-126...... ,-(200-256)[ i.e. 128+128=256
         convt = int(buf[i])+256;
      Serial.print("Got: ");
      Serial.print(i+1);               // Signifes from which sensor di it get the data from 1 means left......2 means right
      Serial.println(". ");
      Serial.print(convt);            // Print the converted message/integer
      Serial.println(' ');
    }
    Serial.println();
    digitalWrite(led,LOW);            //LED goes off to signify that data transmission is completed ..........or is stopped
  }
}