const int echoPin = 2;
const int trigPin = 3;
const int pirPin  = 4;
int pirState = LOW;
const int buzzer = 8;
const int redLed = 9;
const int greenLed = 10;

float duration_us, distance_cm;

void setup() {
  Serial.begin(9600);

  pinMode(trigPin,OUTPUT);
  pinMode(echoPin,INPUT);

  pinMode(pirPin,INPUT);

  pinMode(buzzer,OUTPUT);
  pinMode(redLed,OUTPUT);
  pinMode(greenLed,OUTPUT);
  
}

void loop() {

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration_us = pulseIn(echoPin, HIGH);
  distance_cm = 0.017 * duration_us;


  pirState = digitalRead(pirPin);
  
  if (pirState == HIGH) {
    Serial.println("Motion Detected!");
    if (distance_cm <= 20){
      digitalWrite(buzzer, HIGH);
      digitalWrite(redLed, HIGH); 
      digitalWrite(greenLed, LOW);
      tone(8, 250, 250);
    }
    else if(distance_cm > 20){
      digitalWrite(buzzer, HIGH); 
      digitalWrite(redLed, LOW);
      digitalWrite(greenLed, LOW);
      tone(8, 250, 250);
    }
    delay(500);
  }
      
  if (pirState == LOW) {
    Serial.println("NO Motion!");
    if (distance_cm >= 20 && distance_cm <= 50){
      digitalWrite(buzzer, LOW);
      digitalWrite(redLed, HIGH); 
      digitalWrite(greenLed, HIGH);
    }
    delay(500);
  }

}