int pina = A0;
void setup()
{
 pinMode(pina, INPUT);
 Serial.begin(9600);
}
int counter=0;
int cou=0;
int val=1000;
void loop()
{
  if(val<1000)
    counter++;
  val = analogRead(pina);
  if(val>1000)
    cou++;
  if(counter>0)
    cou=0;
  if(cou>=3){
    Serial.write("p");
    cou=0;
  }
  if((counter>=1 && counter<=2) && val>=1000)
  {
    Serial.write("s");
    counter=0;
  }
  if(counter>2 && val>=1000)
  {
    Serial.write("l");
    counter=0;
  }

  delay(400);
}