#define TRIGGER_PIN 9   // 초음파 센서의 트리거 핀
#define ECHO_PIN 10     // 초음파 센서의 에코 핀
#define LED_PIN_1 2     // LED1 핀
#define LED_PIN_2 3     // LED2 핀
#define LED_PIN_3 4     // LED3 핀
#define MAX_DISTANCE 30 // 측정 가능한 최대 거리 (센서의 스펙에 따라 조절)

void setup() {
  pinMode(LED_PIN_1, OUTPUT);
  pinMode(LED_PIN_2, OUTPUT);
  pinMode(LED_PIN_3, OUTPUT);
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);

  unsigned long duration = pulseIn(ECHO_PIN, HIGH);
  int distance = duration / 58; // 거리를 센티미터로 변환

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  if (distance <= 10) {
    digitalWrite(LED_PIN_1, HIGH);
    digitalWrite(LED_PIN_2, LOW);
    digitalWrite(LED_PIN_3, LOW);
  } else if (distance <= 20) {
    digitalWrite(LED_PIN_1, LOW);
    digitalWrite(LED_PIN_2, HIGH);
    digitalWrite(LED_PIN_3, LOW);
  } else if (distance <= 30) {
    digitalWrite(LED_PIN_1, LOW);
    digitalWrite(LED_PIN_2, LOW);
    digitalWrite(LED_PIN_3, HIGH);
  } else {
    digitalWrite(LED_PIN_1, LOW);
    digitalWrite(LED_PIN_2, LOW);
    digitalWrite(LED_PIN_3, LOW);
  }

  delay(1000); // 1초마다 거리를 업데이트
}