#define TRIG_PIN_LEFT 2
#define ECHO_PIN_LEFT 3
#define TRIG_PIN_RIGHT 4
#define ECHO_PIN_RIGHT 5
#define GREEN_LED_PIN 6
#define YELLOW_LED_PIN 7

const int DISTANCE_THRESHOLD = 100; // Distance in cm to trigger detection
const int DELAY_TIME = 100; // Delay between readings in milliseconds

void setup() {
  pinMode(TRIG_PIN_LEFT, OUTPUT);
  pinMode(ECHO_PIN_LEFT, INPUT);
  pinMode(TRIG_PIN_RIGHT, OUTPUT);
  pinMode(ECHO_PIN_RIGHT, INPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(YELLOW_LED_PIN, OUTPUT);
  Serial.begin(9600);
}

long readUltrasonicSensor(int trigPin, int echoPin) {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  long duration = pulseIn(echoPin, HIGH);
  return duration * 0.034 / 2; // Convert to distance in cm
}

void loop() {
  long distanceLeft = readUltrasonicSensor(TRIG_PIN_LEFT, ECHO_PIN_LEFT);
  long distanceRight = readUltrasonicSensor(TRIG_PIN_RIGHT, ECHO_PIN_RIGHT);
  
  bool leftDetected = distanceLeft < DISTANCE_THRESHOLD;
  bool rightDetected = distanceRight < DISTANCE_THRESHOLD;
  
  if (leftDetected && rightDetected) {
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, HIGH);
    Serial.println("Yellow: Cars detected on both sides");
  } else if (leftDetected || rightDetected) {
    digitalWrite(GREEN_LED_PIN, HIGH);
    digitalWrite(YELLOW_LED_PIN, LOW);
    Serial.println("Green: Car detected on one side");
  } else {
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, LOW);
    Serial.println("Off: No cars detected");
  }
  
  delay(DELAY_TIME);
}