#include <Servo.h>

const int pirPin = 2;        // PIR motion sensor pin
const int servoPin = 9;      // Pin to which the servo motor is connected
const int trigPin = 12;      // Trig pin of the HC-SR04 (UDS)
const int echoPin = 11;      // Echo pin of the HC-SR04 (UDS)
const int greenLedPin = 7;   // Green LED pin
const int redLedPin = 6;     // Red LED pin
const int thresholdDistance = 20; // Threshold distance to trigger red LED (in cm)
const int maxDistance = 50;  // Maximum distance considered for green LED (in cm)

Servo lidServo;

void setup() {
  pinMode(pirPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(greenLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  lidServo.attach(servoPin);
  Serial.begin(9600);
}

void loop() {
  bool motionDetected = digitalRead(pirPin) == HIGH;
  
  if (motionDetected) {  // If motion is detected
    digitalWrite(greenLedPin, HIGH); // Turn on green LED
    openLid();                        // Open the lid
    delay(5000);                      // Wait for 5 seconds
    closeLid();                       // Close the lid
    digitalWrite(greenLedPin, LOW);  // Turn off green LED
  } else {  // If no motion is detected
    long duration, distance;
    
    // Triggering the ultrasonic sensor
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    
    // Reading the echo pin to calculate distance
    duration = pulseIn(echoPin, HIGH);
    
    // Calculating distance in cm
    distance = duration * 0.034 / 2;
    
    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");
    
    // Checking if garbage is detected
    if (distance < thresholdDistance) {
      digitalWrite(redLedPin, HIGH); // Turn on red LED
    } else {
      digitalWrite(redLedPin, LOW); // Turn off red LED
      
      // Checking if bin has more space
      if (distance < maxDistance) {
        digitalWrite(greenLedPin, HIGH); // Turn on green LED
      } else {
        digitalWrite(greenLedPin, LOW); // Turn off green LED
      }
    }
  }
}

void openLid() {
  lidServo.write(90); // Rotate servo to open the lid
}

void closeLid() {
  lidServo.write(0); // Rotate servo to close the lid
}