// Define the pins for the ultrasonic sensor
const int trigPin = 3;  // Trigger pin
const int echoPin = 2; // Echo pin

int red = 11;
int orange = 12;
int green = 13;


void setup() {
  Serial.begin(9600); // Initialize serial communication
  pinMode(trigPin, OUTPUT); // Set trigger pin as an OUTPUT
  pinMode(echoPin, INPUT);  // Set echo pin as an INPUT

  pinMode(red, OUTPUT);
  pinMode(orange, OUTPUT);
  pinMode(green, OUTPUT);
}

void loop() {
  // Trigger the ultrasonic sensor to send a pulse
  digitalWrite(trigPin, LOW); 
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure the time taken for the pulse to return
  long duration = pulseIn(echoPin, HIGH);

  // Calculate the distance in centimeters
  // Speed of sound is approximately 343 meters per second
  // Distance = (time * speed of sound) / 2
  int distance = duration * 0.0343 / 2;

  // Print the distance to the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  if(distance > 300)
  {
    digitalWrite(red,HIGH);
    digitalWrite(orange,LOW);
    digitalWrite(green,LOW);
  }
  else if(distance > 200 )
  {
    digitalWrite(red,LOW);
    digitalWrite(orange,HIGH);
    digitalWrite(green,LOW);
  }
  else
  {
    digitalWrite(red,LOW);
    digitalWrite(orange,LOW);
    digitalWrite(green,HIGH);
  }

  delay(100); // Wait for a moment before taking the next reading
}