#include <wiringPi.h>
#include <stdio.h>

int main( int argc, char** argv )
{
 
  if( wiringPiSetup() == -1 )
    return 1;
 
  pinMode( 1, OUTPUT ); // BCM GPIO pin 18
 
  int i = 0;
  while( 1 )
  {
    digitalWrite( 1, 0 );
    for( i = 0; i < 10; i++ );
    digitalWrite( 1, 1 );
    for( i = 0; i < 10; i++ );
  }

  return 0 ;

}