#include <Servo.h>

// Initialising ultrasonic sensor pins
const int trigPin = 9;
const int echoPin = 10;

// Initialising pin for servo motor
const int servoPin = 3;

// Create servo
Servo Servo1;

const unsigned long delayTime = 3000; // Time delay of 3 seconds

// Min distance required for door to open
const int thresholdDistance = 30;

// Setting time as 0
unsigned long lastDetectedTime = 0;
bool gateOpened = false;
bool motionDetected = false;

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

  // Set pin modes for ultrasonic sensor
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  Servo1.attach(servoPin);

  // Gate is initially closed
  Servo1.write(0);
}

void loop() {
  // Simulate motion detection
  simulateMotionDetection();

  // Measure distance
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

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

  // Check if the distance is less than the threshold or if motion is detected
  if (distance < thresholdDistance || motionDetected) {
    // Reset motion detection flag
    motionDetected = false;
    
    // Record the time of detection
    lastDetectedTime = millis();
    
    // Open the gate if it is not already open
    if (!gateOpened) {
      openGate();
      gateOpened = true;
    }
  }

  // Check if the gate has been open for the delay time and close it
  if (gateOpened && (millis() - lastDetectedTime >= delayTime)) {
    closeGate();
    gateOpened = false;
  }

  // Small delay to prevent excessive serial output
  delay(100);
}

void openGate() {
  // Open the gate (set servo to 90 degrees)
  Servo1.write(90);
  Serial.println("Gate opened");
}

void closeGate() {
  // Close the gate (set servo back to 0 degrees)
  Servo1.write(0);
  Serial.println("Gate closed");
}

void simulateMotionDetection() {
  static unsigned long lastMillis = 0;
  unsigned long currentMillis = millis();
  
  // Simulate motion detection every 5 seconds
  if (currentMillis - lastMillis >= 5000) {
    lastMillis = currentMillis;
    motionDetected = true;  // Simulate motion detected
  }
}