//Sensor Ultrasonik
const int trigPin = 9;
const int echoPin = 10;
const int buzzer = 11;
const int ledPin_Biru = 13; 
const int ledPin_Merah = 12; 

long duration;
int distance;
int safetyDistance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(ledPin_Biru, OUTPUT); 
  pinMode(ledPin_Merah, OUTPUT); 
  Serial.begin(9600);
}

void loop() {
 digitalWrite(trigPin, LOW);
 delayMicroseconds(2);

 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10);
 digitalWrite(trigPin, LOW);

 duration = pulseIn(echoPin, HIGH);

 distance = duration * 0.034 / 2;

 safetyDistance = distance;
 if (safetyDistance <= 50) {
  digitalWrite(buzzer, HIGH);
  digitalWrite(ledPin_Biru, HIGH);
  digitalWrite(ledPin_Merah, LOW);
 } else if (safetyDistance > 50 && safetyDistance < 300) {
  digitalWrite(buzzer, HIGH);
  digitalWrite(ledPin_Merah, HIGH); 
    digitalWrite(ledPin_Biru, LOW); 
 } else {
  digitalWrite(buzzer, LOW);
  digitalWrite(ledPin_Biru, LOW); 
  digitalWrite(ledPin_Merah, LOW); 
 }
 Serial.print("Distance: ");
 Serial.println(distance); 
 
}