Weekly IoT Classes for School & College Students

#include <Servo.h>

// Pin definitions
#define IR_ENTRY   2   // IR sensor at entry gate
#define IR_SLOT1   3   // IR sensor for Slot 1
#define IR_SLOT2   4   // IR sensor for Slot 2

#define LED_SLOT1  5   // LED for Slot 1 (ON = occupied)
#define LED_SLOT2  6   // LED for Slot 2 (ON = occupied)

#define SERVO_PIN  9   // Servo motor — gate barrier

Servo gateServo;

const int totalSlots = 2;
int availableSlots = totalSlots;

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

  pinMode(IR_ENTRY, INPUT);
  pinMode(IR_SLOT1, INPUT);
  pinMode(IR_SLOT2, INPUT);

  pinMode(LED_SLOT1, OUTPUT);
  pinMode(LED_SLOT2, OUTPUT);

  gateServo.attach(SERVO_PIN);
  gateServo.write(0); // Gate closed

  Serial.println("Smart Car Parking System Ready");
}

void loop() {
  // IR module reads LOW when a car blocks the beam
  bool slot1Occupied = (digitalRead(IR_SLOT1) == LOW);
  bool slot2Occupied = (digitalRead(IR_SLOT2) == LOW);

  digitalWrite(LED_SLOT1, slot1Occupied ? HIGH : LOW);
  digitalWrite(LED_SLOT2, slot2Occupied ? HIGH : LOW);

  availableSlots = totalSlots - (slot1Occupied + slot2Occupied);
  Serial.print("Available Slots: ");
  Serial.println(availableSlots);

  bool carAtEntry = (digitalRead(IR_ENTRY) == LOW);

  if (carAtEntry && availableSlots > 0) {
    openGate();
    delay(3000);   // hold gate open so the car can pass
    closeGate();
  } else if (carAtEntry && availableSlots == 0) {
    Serial.println("Parking Full — Entry Denied");
  }

  delay(300);
}

void openGate() {
  gateServo.write(90);  // barrier up
  Serial.println("Gate Opened");
}

void closeGate() {
  gateServo.write(0);   // barrier down
  Serial.println("Gate Closed");
}