// Define pins for the first ultrasonic sensor
const int trigPin1 = 9;
const int echoPin1 = 10;

// Define pins for the second ultrasonic sensor
const int trigPin2 = 11;
const int echoPin2 = 12;

// Define pins for the LEDs
const int ledRed = 13;
const int ledGreen = 8;

// Variables to store the duration and distance for both sensors
long duration1, duration2;
int distance1, distance2;

void setup() {
  // Initialize serial communication at 9600 baud rate
  Serial.begin(9600);
  
  // Set trig and echo pins for both sensors
  pinMode(trigPin1, OUTPUT);
  pinMode(echoPin1, INPUT);
  pinMode(trigPin2, OUTPUT);
  pinMode(echoPin2, INPUT);
  
  // Set LED pins as output
  pinMode(ledRed, OUTPUT);
  pinMode(ledGreen, OUTPUT);
}

void loop() {
  // Measure distance with the first sensor
  distance1 = getDistance(trigPin1, echoPin1);
  Serial.print("Distance 1: ");
  Serial.print(distance1);
  Serial.println(" cm");
  
  // Measure distance with the second sensor
  distance2 = getDistance(trigPin2, echoPin2);
  Serial.print("Distance 2: ");
  Serial.print(distance2);
  Serial.println(" cm");
  
  // Determine LED status based on distances
  if (distance1 < 20 || distance2 < 20) {
    // Distance is less than 20 cm
    digitalWrite(ledRed, HIGH);
    digitalWrite(ledGreen, LOW);
  } else {
    // Distance is 20 cm or more
    digitalWrite(ledRed, LOW);
    digitalWrite(ledGreen, HIGH);
  }
  
  // Wait for a bit before the next loop
  delay(1000);
}

// Function to get distance from a sensor
int getDistance(int trigPin, int echoPin) {
  long duration;
  int distance;

  // Clear the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Set the trigPin HIGH for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);

  // Calculate the distance in cm
  distance = duration * 0.034 / 2;
  
  return distance;
}