int led = 12;
int echo = 19, trig = 18;
float duraton,des;

void setup() {
  Serial.begin(115200);

  pinMode(led , OUTPUT);
  pinMode(trig , OUTPUT);
  pinMode(echo, INPUT);
  
}

void loop() {

  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  duraton = pulseIn(echo , HIGH);

  des = duraton *0.034/2;

  if (des > 200){
    digitalWrite(led , HIGH);
  }else{
    digitalWrite(led , LOW);
  }
  Serial.println(des);
}