#define led 13
int buzzer = 12;
#define trig 11
#define echo 10


// defines variables
long duration; // variable for the duration of sound wave travel
int distance; // variable for the distance measurement

void setup() {
  // put your setup code here, to run once:
  pinMode(trig,OUTPUT);
  pinMode(echo, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(led, OUTPUT);
  Serial.begin(9600);

}

void loop() {
  // put your main code here, to run repeatedly:
  // Clears the trigPin condition
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  // Sets the trigPin HIGH (ACTIVE) for 10 microseconds
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echo, HIGH);
  // Calculating the distance
  distance = duration * 0.0340 / 2; // Speed of sound wave divided by 2 (go and back)
  // Displays the distance on the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");


if (distance > 300){
digitalWrite(led, HIGH);
tone(buzzer,1000);
delay(1000);

digitalWrite(led, LOW);
noTone(buzzer);
delay(1000);

  Serial.println(" Status: Bak Kosong");
}
 
    if(distance<100){
     digitalWrite(led, HIGH);
     tone(buzzer,500);
     delay(1000);

     digitalWrite(led, LOW);
     noTone(buzzer);
     delay(1000);
     Serial.println(" Status: Bak Penuh");
   }
 }