ihcode

void setup()
  {  
  pinMode (2,OUTPUT);  
  pinMode (5,OUTPUT);
  pinMode (8,OUTPUT);
  }  

  void loop()
  {  
  digitalWrite(2, HIGH);
  digitalWrite(8, HIGH);  
  long duration, inches, cm;  
  pinMode(3, OUTPUT);
  digitalWrite(3, LOW);  
  delayMicroseconds(2);  
  digitalWrite(3, HIGH);  
  delayMicroseconds(5);  
  digitalWrite(3, LOW);  
  pinMode (4, INPUT); 
  duration = pulseIn(4, HIGH);  
  inches = microsecondsToInches(duration);
  cm = inches*2.54 ;
   
  if (cm < 10 )
  { 
  analogWrite(6,255); 
  }
  else if (cm < 50)
  { 
  analogWrite(6,200); 
  }
  else if (cm < 100)
  { 
  analogWrite(6,150); 
  }
  else
  {  
  analogWrite(6,0); 
  }
  }  
  long microsecondsToInches(long microseconds)
  {  
  return microseconds / 74 / 2;
  }