 
 // sets the role of this unit in hardware.  Connect to GND to be the 'pong' receiver
 // Leave open to be the 'ping' transmitter
-const int role_pin = 1;
+const int role_pin = 0;
 
 //
 // Topology

  if (role == sender)
  {
    // The payload will always be the same, what will change is how much of it we send.
    static char send_payload[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ789012"; //32 byte max
    radio.stopListening(); // stop listening so we can talk.
    printf("Now sending length %i...",next_payload_size);
    radio.write( send_payload, next_payload_size ); // This will block until complete

  //
  // Print preamble
  //
  pinMode(A1,OUTPUT);
  digitalWrite(A1, LOW); // Vcc for MPU6050
  pinMode(5,OUTPUT);
  digitalWrite(5, HIGH); // Vcc for MPU6050
  pinMode(7,OUTPUT);
  digitalWrite(7, HIGH); // Vcc for MPU6050
    
  Serial.begin(115200);
  printf_begin();
  printf("\n\r  \n\r");
