Kod Arduino — SmartPark

/*
 * SmartPark — Sistem Pengesanan Parking Arduino
 * Papan: ESP8266 (NodeMCU) atau ESP32
 * Sensor: HC-SR04 Ultrasonic x12
 *
 * Sambungan wiring (contoh untuk 2 sensor pertama):
 *   Sensor 1 TRIG -> D1 (GPIO5)
 *   Sensor 1 ECHO -> D2 (GPIO4)
 *   Sensor 2 TRIG -> D3 (GPIO0)
 *   Sensor 2 ECHO -> D4 (GPIO2)
 *   VCC -> 5V, GND -> GND
 *
 * Ulang pattern TRIG/ECHO untuk slot 3-12 mengikut pin yang tersedia.
 */

#include <ESP8266WiFi.h>     // Guna <WiFi.h> untuk ESP32
#include <ESP8266HTTPClient.h> // Guna <HTTPClient.h> untuk ESP32
#include <ArduinoJson.h>

// =====================
//  KONFIGURASI WIFI
// =====================
const char* WIFI_SSID     = "NAMA_WIFI_ANDA";
const char* WIFI_PASSWORD = "KATA_LALUAN_WIFI";

// =====================
//  KONFIGURASI SERVER
// =====================
// Guna IP awam jika di Vercel, atau IP LAN jika server tempatan
const String SERVER_URL = "https://YOUR_APP.vercel.app/api/parking/update";

// =====================
//  KONFIGURASI SENSOR
// =====================
#define NUM_SLOTS 12
#define OCCUPIED_THRESHOLD_CM 15   // Jarak <= 15cm = slot terisi
#define SEND_INTERVAL_MS 2000      // Hantar data setiap 2 saat

// Pin TRIG dan ECHO untuk setiap slot
// Laraskan mengikut wiring sebenar anda
const int TRIG_PINS[NUM_SLOTS] = {5, 0, 14, 12, 13, 15, 3,  1,  9,  10, 4,  2};
const int ECHO_PINS[NUM_SLOTS] = {4, 2, 12, 13, 15, 3,  1,  16, 10, 9,  2,  14};

// =====================
//  FUNGSI UKUR JARAK
// =====================
float measureDistance(int trigPin, int echoPin) {
  // Hantar pulse ultrasonic
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Baca masa echo kembali (timeout 30ms)
  long duration = pulseIn(echoPin, HIGH, 30000);

  if (duration == 0) {
    return 999.0;  // Tiada objek dikesan
  }

  // Tukar ke cm (kelajuan bunyi = 343 m/s)
  float distanceCm = (duration * 0.0343) / 2.0;
  return distanceCm;
}

// =====================
//  SETUP
// =====================
void setup() {
  Serial.begin(115200);
  delay(100);

  // Set pin sensor
  for (int i = 0; i < NUM_SLOTS; i++) {
    pinMode(TRIG_PINS[i], OUTPUT);
    pinMode(ECHO_PINS[i], INPUT);
  }

  // Sambung WiFi
  Serial.print("Menyambung ke WiFi: ");
  Serial.println(WIFI_SSID);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println();
  Serial.println("WiFi bersambung!");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());
}

// =====================
//  LOOP UTAMA
// =====================
void loop() {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi terputus. Cuba sambung semula...");
    WiFi.reconnect();
    delay(5000);
    return;
  }

  // Baca semua sensor dan bina JSON
  StaticJsonDocument<512> doc;
  JsonArray readings = doc.createNestedArray("readings");

  for (int i = 0; i < NUM_SLOTS; i++) {
    float dist = measureDistance(TRIG_PINS[i], ECHO_PINS[i]);

    JsonObject reading = readings.createNestedObject();
    reading["slotId"]   = i + 1;
    reading["distance"] = (int)dist;

    Serial.print("Slot ");
    // Section: A=1-3, B=4-6, C=7-9, D=10-12
    char sections[] = "AABBCCDD";
    char sec = (i < 3) ? 'A' : (i < 6) ? 'B' : (i < 9) ? 'C' : 'D';
    int secSlot = (i % 3) + 1;
    Serial.print(sec);
    Serial.print(secSlot);
    Serial.print(": ");
    Serial.print(dist);
    Serial.print(" cm — ");
    Serial.println(dist <= OCCUPIED_THRESHOLD_CM ? "TERISI" : "KOSONG");

    // Delay kecil antara sensor untuk elak interferens
    delay(30);
  }

  // Serialkan JSON
  String jsonBody;
  serializeJson(doc, jsonBody);

  // Hantar ke API
  WiFiClient client;
  HTTPClient http;
  http.begin(client, SERVER_URL);
  http.addHeader("Content-Type", "application/json");

  int httpCode = http.POST(jsonBody);

  if (httpCode == HTTP_CODE_OK) {
    Serial.println("Data berjaya dihantar!");
  } else {
    Serial.print("Ralat HTTP: ");
    Serial.println(httpCode);
  }

  http.end();

  delay(SEND_INTERVAL_MS);
}