void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(26 ,OUTPUT);
  pinMode(27, INPUT);
  pinMode(5, OUTPUT);
}

void loop() {
  digitalWrite(26,1);
  delay(100);
  digitalWrite(26,0);
  float duration = pulseIn(27,1);
  int distance=duration*0.034/2;
  Serial.println(distance);
  if( distance<=200)
  {
    digitalWrite(5, HIGH);
  }
  else{
    digitalWrite(5, LOW);
  }
}