#define ECHO_PIN 2
#define TRIG_PIN 15

int ledPin1 = 21;
int ledPin2 = 19;
int ledPin3 = 18;
int ledPin4 = 5;

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(ledPin1. OUTPUT);
  pinMode(ledPin2. OUTPUT);
  pinMode(ledPin3. OUTPUT);
  pinMode(ledPin4. OUTPUT);
}
float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}
void loop() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.034 / 2;
}

if(distance >50 && distance <100){
  Serial.println("Jarak lebih dari 50 cm");
  digitalWrite(ledPin1. HIGH);
  digitalWrite(ledPin2. LOW);
  digitalWrite(ledPin3. LOW);
  digitalWrite(ledPin4. LOW);
  noTone(buzzer);
}

else if (distance >100 && distance <200){
Serial.println("Jarak Kurang dari 50 cm");
  digitalWrite(ledPin1. HIGH);
  digitalWrite(ledPin2. HIGH);
  digitalWrite(ledPin3. LOW);
  digitalWrite(ledPin4. LOW);
  noTone(buzzer);
}