const int triggerPin = 8;
const int echoPin = 7;
const int Led1 = 4;
int buzzer = 3;

long durasi; 
int jarak;

void setup() {
  pinMode(triggerPin, OUTPUT);
  pinMode(Led1, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(echoPin, INPUT);

  Serial.begin(9600);
}

void loop() {
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  durasi = pulseIn(echoPin, HIGH);
  jarak = durasi*0.034/2;
  Serial.println(jarak); 

  if(jarak <= 100){
    digitalWrite(Led1, HIGH);
    digitalWrite(buzzer, HIGH);
    
  }
  else if (jarak>100) {
    digitalWrite(Led1, LOW) ;
  }
}