#define TRIG  2  
#define ECHO  3  
#define R  9   
#define G 10  
#define B 11  
#define BUZZER 12  
int distance = 0;

void setup() {
  Serial.begin(9600); 
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(R, OUTPUT);
  pinMode(G, OUTPUT);
  pinMode(B, OUTPUT);
  pinMode(BUZZER, OUTPUT);
}

void loop() 
{
  // Measuring the distance
  distance = getDistance();
  
  if (distance >= 255) {
    digitalWrite(R, LOW);
    digitalWrite(G, LOW);
    digitalWrite(B, HIGH);
    noTone(BUZZER); // 
  }
  else if (distance >= 150 && distance < 255) {
    digitalWrite(R, LOW);
    digitalWrite(G, HIGH);
    digitalWrite(B, LOW);
    noTone(BUZZER); 
  } 
  else if (distance >= 0 && distance < 100) {
    digitalWrite(R, HIGH);
    digitalWrite(G, LOW);
    digitalWrite(B, LOW);
    tone(BUZZER, 1000); 
  }
  delay(1000); 
}

int getDistance() {
  digitalWrite(TRIG, LOW); // Set the TRIG pin to LOW to ensure a clean start.
  delayMicroseconds(2);    // Wait for a short duration to ensure stability.
  digitalWrite(TRIG, HIGH); // Set TRIG pin to HIGH to trigger the ultrasonic sensor.
  delayMicroseconds(10); // Keep the TRIG pin HIGH for a specific duration.
  digitalWrite(TRIG, LOW); // Set the TRIG pin back to LOW to end the trigger pulse.

  return pulseIn(ECHO, HIGH) * 0.034 / 2; // Speed of sound (0.034 cm/microsecond)
}