int obstacle = 2;
int buzzer = 13;

void setup() {
  Serial.begin(9600);
  pinMode(buzzer,OUTPUT);

}

void loop() {
  int sensevalue = digitalRead(obstacle)
  Serial.println(obstacle);
  if (obstacle == 1)
  {
    Serial.println("Obstacle is Detected");
    digitalWrite(buzzer, HIGH);
  }
  else{
    Serial.println("obstacle is  not detected");
    digitalWrite(buzzer,LOW);
  }
}