/*
int trig = 9;
int echo = 5;


void setup() {
  // put your setup code here, to run once:
 Serial.begin(115200);
 pinMode(trig, OUTPUT);
 pinMode(echo, INPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trig, LOW);
  delayMicroseconds(5);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  long time = pulseIn(echo, HIGH);

  float distance = (340*time)/2;
  Serial.println(distance);
  delay(1000);
}
*/

// Define pin connections
const int TRIGGER_PIN = 13;
const int ECHO_PIN = 12;
const int LED_PINS[] = {7, 6, 5};

void setup() {
  // Initialize pins
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  Serial.begin(9600);
  
  // Initialize LED pins
  for (int i = 0; i < 3; i++) {
    pinMode(LED_PINS[i], OUTPUT);
  }
}

void loop() {
  // Send ultrasonic pulse
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(5);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(5);
  digitalWrite(TRIGGER_PIN, LOW);

  // Measure echo time
  float echoTime = pulseIn(ECHO_PIN, HIGH);

  // Calculate distance
  float distance = (0.034 * echoTime) / 2; // cm/s speed of sound

  Serial.println(distance);

  // Update LEDs based on distance
  updateLEDs(distance);

  delay(1000);
}

void updateLEDs(float distance) {
  // Define distance ranges for LED indicators
  const int CLOSE_RANGE = 30;
  const int FAR_RANGE = 200;

  // Update LED states
  if (distance <= CLOSE_RANGE) {
    // Close range: Red LED
    digitalWrite(LED_PINS[0], HIGH);
    digitalWrite(LED_PINS[1], LOW);
    digitalWrite(LED_PINS[2], LOW);
  } else if (distance > CLOSE_RANGE && distance < FAR_RANGE) {
    // Medium range: Yellow LED
    digitalWrite(LED_PINS[0], LOW);
    digitalWrite(LED_PINS[1], HIGH);
    digitalWrite(LED_PINS[2], LOW);
  } else {
    // Far range: Green LED
    digitalWrite(LED_PINS[0], LOW);
    digitalWrite(LED_PINS[1], LOW);
    digitalWrite(LED_PINS[2], HIGH);
  }
}