int n,i;  
  void setup() 
{
   Serial.begin (115200);
   pinMode(13,OUTPUT); 
}

void loop()
{
  int AN0 = analogRead (A0);
  float V = AN0*5.0/1023;
  Serial.print (V);
  Serial.print(",");
  Serial.println (AN0);

   for(n=0;n<AN0/10;n++)
   {
    digitalWrite(13,1);
    delayMicroseconds(100);
   }
   for(n=102;n>AN0/10;n--)
   {
     digitalWrite(13,0);
     delayMicroseconds(100);
   }
}