ESP32 Smart Parking System with WiFi & IoT | MakeMindz Tutorial

🅿️

ESP32 IoT Projects · Intermediate

ESP32 Smart Parking System with WiFi & IoT

Detect available parking slots in real time, control a servo barrier gate, display status on an LCD, and monitor everything from a live web dashboard.

⚡ ESP32 + WiFi 📡 3× HC-SR04 Sensors 🎯 Intermediate Level 🔧 Wokwi Ready

Project Overview

This project builds a fully intelligent parking management system on an ESP32. Three HC-SR04 ultrasonic sensors continuously monitor whether parking slots are occupied. A servo motor acts as a barrier gate, a 16×2 LCD shows real-time availability, and a beautiful web dashboard lets you monitor and control everything remotely from any browser.

The system also exposes a RESTful JSON API so mobile apps can query slot status and trigger the gate — making it a complete IoT foundation for real-world parking deployments.

ESP32 WiFi HC-SR04 Ultrasonic Sensor Servo Motor LCD 16×2 I2C RESTful API WebServer Buzzer Wokwi

Key Features

🔧 Hardware

3 parking slots with HC-SR04 ultrasonic sensors
16×2 LCD display (I2C at 0x27)
Servo motor barrier gate (0° closed / 90° open)
5 LEDs — 3× green slot, 1× red full, 1× blue WiFi
Buzzer for entry/exit alerts & full warning
ENTRY and EXIT push buttons (INPUT_PULLUP)

📡 Software & IoT

WiFi connectivity with auto-reconnect
Web dashboard with modern gradient UI
Mobile-ready responsive layout
Auto-refresh live updates every 2 seconds
RESTful JSON API endpoints
Entry/exit statistics & uptime tracking
Scalable architecture — add more slots easily

🚗

Auto Slot Detection 15 cm threshold triggers occupied/available status

🚧

Servo Barrier Gate Auto-closes after 3 seconds — no manual reset needed

🌐

Live Web Dashboard See slot status, open gate, view stats from browser

🔌

JSON REST API /api/status · /api/open · /api/stats endpoints

📊

Statistics Tracking Total entries, exits, uptime & WiFi signal strength

🔔

Buzzer Alerts Single beep for entry/exit, triple beep when full

Components Required

Component	Qty	Purpose
ESP32 DevKit V1	1	Main controller with WiFi / dual-core 240 MHz
HC-SR04 Ultrasonic Sensor	3	Detect car presence in each parking slot
Servo Motor (SG90)	1	Barrier gate — 0° closed, 90° open
16×2 LCD (I2C 0x27)	1	Show available/occupied count on-site
Passive Buzzer	1	Entry, exit & "parking full" audio alerts
LED Green	3	Slot available indicators (Slot 1, 2, 3)
LED Red	1	Parking full indicator
LED Blue	1	WiFi connected / heartbeat blink
220Ω Resistors	5	Current limiting for all LEDs
Push Buttons (Green/Red)	2	Manual ENTRY and EXIT triggers

💡

The HC-SR04 operates at 5V. In Wokwi it's connected to VIN (5V pin). In a real ESP32 build, use a voltage divider on the ECHO pin (5V → 3.3V) to protect the GPIO, or use a 3.3V-compatible sensor like the HC-SR04P.

Pin Connections & Wiring

Component	ESP32 Pin	Wire Color
Ultrasonic 1 TRIG	D13	🟠 Orange
Ultrasonic 1 ECHO	D12	🟣 Purple
Ultrasonic 2 TRIG	D14	🟠 Orange
Ultrasonic 2 ECHO	D27	🟣 Purple
Ultrasonic 3 TRIG	D26	🟠 Orange
Ultrasonic 3 ECHO	D25	🟣 Purple
All Ultrasonics VCC	VIN (5V)	🔴 Red
Servo SIG	D15	🟠 Orange
Servo VCC	VIN	🔴 Red
LCD SDA	D21	🔵 Blue
LCD SCL	D22	🟡 Yellow
LCD VCC	3V3	🔴 Red
LED Slot 1 (Green)	D16 via 220Ω	🟢 Green
LED Slot 2 (Green)	D17 via 220Ω	🟢 Green
LED Slot 3 (Green)	D18 via 220Ω	🟢 Green
LED Full (Red)	D19 via 220Ω	🔴 Red
LED WiFi (Blue)	D2 via 220Ω	🔵 Blue
Buzzer	D23	🟠 Orange
ENTRY Button	D32 (INPUT_PULLUP)	🟢 Green
EXIT Button	D33 (INPUT_PULLUP)	🔴 Red

Quick Start: Load in Wokwi

Go to wokwi.com and create a new ESP32 project

Make sure you select ESP32 (not Arduino Uno). The library set is different and includes WiFi, WebServer, and ESP32Servo.

Paste the diagram.json content

Click the diagram.json tab in Wokwi and replace all content with the JSON from Section 6 below. This loads all components pre-wired.

Paste the sketch.ino code

Click the sketch.ino tab and replace with the code from Section 7. All libraries (WiFi, WebServer, LiquidCrystal_I2C, ESP32Servo) are auto-installed in Wokwi.

Press ▶ Start and check Serial Monitor

WiFi connects in ~10 seconds. The Serial Monitor shows the IP address. Click it to open the live web dashboard in a new browser tab.

📦

Required Libraries: LiquidCrystal_I2C and ESP32Servo. Install via Arduino Library Manager for real hardware builds. These come pre-installed in Wokwi.

Diagram.json (Wokwi)

Copy this into your diagram.json tab in Wokwi to instantly load the fully wired circuit with all 3 ultrasonic sensors, servo, LCD, LEDs, buttons, and buzzer.

diagram.json

{
  "version": 1,
  "author": "ESP32 Smart Parking",
  "editor": "wokwi",
  "parts": [
    { "type": "wokwi-esp32-devkit-v1", "id": "esp32", "top": 0, "left": 0, "attrs": {} },
    { "type": "wokwi-lcd1602", "id": "lcd1", "top": -150, "left": 115.2,
      "attrs": { "pins": "i2c" } },
    { "type": "wokwi-hc-sr04", "id": "ultrasonic1", "top": -240, "left": -150,
      "attrs": { "distance": "400" } },
    { "type": "wokwi-hc-sr04", "id": "ultrasonic2", "top": -240, "left": 0,
      "attrs": { "distance": "400" } },
    { "type": "wokwi-hc-sr04", "id": "ultrasonic3", "top": -240, "left": 150,
      "attrs": { "distance": "400" } },
    { "type": "wokwi-servo", "id": "servo1", "top": 140, "left": -144, "attrs": {} },
    { "type": "wokwi-led", "id": "led1", "top": 280, "left": -140,
      "attrs": { "color": "green" } },
    { "type": "wokwi-led", "id": "led2", "top": 280, "left": -50,
      "attrs": { "color": "green" } },
    { "type": "wokwi-led", "id": "led3", "top": 280, "left": 40,
      "attrs": { "color": "green" } },
    { "type": "wokwi-led", "id": "led4", "top": 280, "left": 130,
      "attrs": { "color": "red" } },
    { "type": "wokwi-resistor", "id": "r1", "top": 318, "left": -144.8, "rotate": 90,
      "attrs": { "value": "220" } },
    { "type": "wokwi-resistor", "id": "r2", "top": 318, "left": -54.8, "rotate": 90,
      "attrs": { "value": "220" } },
    { "type": "wokwi-resistor", "id": "r3", "top": 318, "left": 35.2, "rotate": 90,
      "attrs": { "value": "220" } },
    { "type": "wokwi-resistor", "id": "r4", "top": 318, "left": 125.2, "rotate": 90,
      "attrs": { "value": "220" } },
    { "type": "wokwi-buzzer", "id": "bz1", "top": 140, "left": 336, "attrs": {} },
    { "type": "wokwi-pushbutton", "id": "btn1", "top": 270, "left": 316.8,
      "attrs": { "color": "green", "label": "ENTRY" } },
    { "type": "wokwi-pushbutton", "id": "btn2", "top": 270, "left": 412.8,
      "attrs": { "color": "red", "label": "EXIT" } },
    { "type": "wokwi-led", "id": "led5", "top": 140, "left": 240,
      "attrs": { "color": "blue", "label": "WiFi" } },
    { "type": "wokwi-resistor", "id": "r5", "top": 178, "left": 235.2, "rotate": 90,
      "attrs": { "value": "220" } }
  ],
  "connections": [
    ["esp32:TX0", "$serialMonitor:RX", "", []],
    ["esp32:RX0", "$serialMonitor:TX", "", []],
    ["lcd1:GND", "esp32:GND.1", "black", ["h0"]],
    ["lcd1:VCC", "esp32:3V3", "red", ["h0"]],
    ["lcd1:SDA", "esp32:D21", "blue", ["h0"]],
    ["lcd1:SCL", "esp32:D22", "yellow", ["h0"]],
    ["ultrasonic1:VCC", "esp32:VIN", "red", ["h0"]],
    ["ultrasonic1:GND", "esp32:GND.1", "black", ["h0"]],
    ["ultrasonic1:TRIG", "esp32:D13", "orange", ["h0"]],
    ["ultrasonic1:ECHO", "esp32:D12", "purple", ["h0"]],
    ["ultrasonic2:VCC", "esp32:VIN", "red", ["h0"]],
    ["ultrasonic2:GND", "esp32:GND.1", "black", ["h0"]],
    ["ultrasonic2:TRIG", "esp32:D14", "orange", ["h0"]],
    ["ultrasonic2:ECHO", "esp32:D27", "purple", ["h0"]],
    ["ultrasonic3:VCC", "esp32:VIN", "red", ["h0"]],
    ["ultrasonic3:GND", "esp32:GND.1", "black", ["h0"]],
    ["ultrasonic3:TRIG", "esp32:D26", "orange", ["h0"]],
    ["ultrasonic3:ECHO", "esp32:D25", "purple", ["h0"]],
    ["servo1:V+", "esp32:VIN", "red", ["h0"]],
    ["servo1:GND", "esp32:GND.2", "black", ["h0"]],
    ["servo1:SIG", "esp32:D15", "orange", ["h0"]],
    ["led1:A", "r1:1", "green", ["v0"]],
    ["r1:2", "esp32:D16", "green", ["v0"]],
    ["led1:C", "esp32:GND.1", "black", ["v0"]],
    ["led2:A", "r2:1", "green", ["v0"]],
    ["r2:2", "esp32:D17", "green", ["v0"]],
    ["led2:C", "esp32:GND.1", "black", ["v0"]],
    ["led3:A", "r3:1", "green", ["v0"]],
    ["r3:2", "esp32:D18", "green", ["v0"]],
    ["led3:C", "esp32:GND.1", "black", ["v0"]],
    ["led4:A", "r4:1", "red", ["v0"]],
    ["r4:2", "esp32:D19", "red", ["v0"]],
    ["led4:C", "esp32:GND.1", "black", ["v0"]],
    ["led5:A", "r5:1", "blue", ["v0"]],
    ["r5:2", "esp32:D2", "blue", ["v0"]],
    ["led5:C", "esp32:GND.2", "black", ["v0"]],
    ["bz1:1", "esp32:D23", "orange", ["h0"]],
    ["bz1:2", "esp32:GND.2", "black", ["h0"]],
    ["btn1:1.l", "esp32:D32", "green", ["h0"]],
    ["btn1:2.l", "esp32:GND.1", "black", ["h0"]],
    ["btn2:1.l", "esp32:D33", "red", ["h0"]],
    ["btn2:2.l", "esp32:GND.1", "black", ["h0"]]
  ],
  "dependencies": {}
}

Arduino Code

sketch.ino

/*
 * ESP32 SMART PARKING SYSTEM WITH WiFi & IoT
 * MakeMindz.com — IoT Project Series
 *
 * Features: 3× HC-SR04 slots, WiFi web server,
 *           LCD (I2C), Servo gate, LEDs, Buzzer,
 *           Entry/Exit buttons, JSON REST API
 */

#include <WiFi.h>
#include <WebServer.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <ESP32Servo.h>

// ── WiFi Credentials ──────────────────────────
const char* ssid     = "Wokwi-GUEST";
const char* password = "";

// ── Ultrasonic Sensors ─────────────────────────
#define TRIG1 13  #define ECHO1 12   // Slot 1
#define TRIG2 14  #define ECHO2 27   // Slot 2
#define TRIG3 26  #define ECHO3 25   // Slot 3

// ── LEDs ──────────────────────────────────────
#define LED_SLOT1 16   // Green — Slot 1 available
#define LED_SLOT2 17   // Green — Slot 2 available
#define LED_SLOT3 18   // Green — Slot 3 available
#define LED_FULL  19   // Red   — Parking full
#define LED_WIFI  2    // Blue  — WiFi heartbeat

// ── Other Peripherals ─────────────────────────
#define SERVO_PIN  15
#define BUZZER_PIN 23
#define ENTRY_BTN  32
#define EXIT_BTN   33
// I2C: SDA = D21, SCL = D22 (ESP32 default)

// ── Global Objects ────────────────────────────
LiquidCrystal_I2C lcd(0x27, 16, 2);
Servo barrierGate;
WebServer server(80);

// ── State Variables ───────────────────────────
bool slot1Occupied = false, slot2Occupied = false, slot3Occupied = false;
int  availableSlots = 3;
const int totalSlots = 3;
const int THRESHOLD_DISTANCE = 15; // cm

bool          gateOpen     = false;
unsigned long gateOpenTime = 0;
const unsigned long GATE_AUTO_CLOSE = 3000;
const int GATE_CLOSED = 0, GATE_OPEN = 90;

unsigned long totalEntries = 0, totalExits = 0, systemUptime = 0;
bool wifiConnected = false;

// ──────────────────────────────────────────────
// SETUP
// ──────────────────────────────────────────────
void setup() {
  Serial.begin(115200);

  // LCD
  lcd.init(); lcd.backlight(); lcd.clear();
  lcd.setCursor(0,0); lcd.print("ESP32 PARKING");
  lcd.setCursor(0,1); lcd.print("Initializing...");

  // Pins
  pinMode(TRIG1,OUTPUT); pinMode(ECHO1,INPUT);
  pinMode(TRIG2,OUTPUT); pinMode(ECHO2,INPUT);
  pinMode(TRIG3,OUTPUT); pinMode(ECHO3,INPUT);
  pinMode(LED_SLOT1,OUTPUT); pinMode(LED_SLOT2,OUTPUT);
  pinMode(LED_SLOT3,OUTPUT); pinMode(LED_FULL,OUTPUT);
  pinMode(LED_WIFI,OUTPUT);
  pinMode(BUZZER_PIN,OUTPUT);
  pinMode(ENTRY_BTN,INPUT_PULLUP);
  pinMode(EXIT_BTN,INPUT_PULLUP);

  barrierGate.attach(SERVO_PIN);
  barrierGate.write(GATE_CLOSED);

  testLEDs();
  connectWiFi();
  setupWebServer();

  lcd.clear();
  lcd.setCursor(0,0); lcd.print("SYSTEM READY!");
  lcd.setCursor(0,1);
  if (wifiConnected) { lcd.print("IP:"); lcd.print(WiFi.localIP().toString().substring(0,11)); }
  else               { lcd.print("WiFi: Offline"); }
  delay(2000);
  systemUptime = millis();
}

// ──────────────────────────────────────────────
// LOOP
// ──────────────────────────────────────────────
void loop() {
  server.handleClient();
  checkParkingSlots();
  updateLCD();
  updateLEDs();

  // Entry button
  if (digitalRead(ENTRY_BTN) == LOW) {
    delay(50);
    if (digitalRead(ENTRY_BTN) == LOW) { handleEntry(); while(digitalRead(ENTRY_BTN)==LOW); }
  }
  // Exit button
  if (digitalRead(EXIT_BTN) == LOW) {
    delay(50);
    if (digitalRead(EXIT_BTN) == LOW) { handleExit(); while(digitalRead(EXIT_BTN)==LOW); }
  }
  // Auto-close gate after 3 seconds
  if (gateOpen && (millis() - gateOpenTime > GATE_AUTO_CLOSE)) closeGate();

  // WiFi LED heartbeat blink every 1 second
  static unsigned long lastBlink = 0;
  if (wifiConnected && millis() - lastBlink > 1000) {
    digitalWrite(LED_WIFI, !digitalRead(LED_WIFI));
    lastBlink = millis();
  }
  delay(200);
}

// ── Ultrasonic Distance Reading ────────────────
long getDistance(int trig, int echo) {
  digitalWrite(trig, LOW);  delayMicroseconds(2);
  digitalWrite(trig, HIGH); delayMicroseconds(10);
  digitalWrite(trig, LOW);
  long dur = pulseIn(echo, HIGH, 30000);
  return dur * 0.034 / 2;
}

// ── Check All Parking Slots ───────────────────
void checkParkingSlots() {
  bool p1 = slot1Occupied, p2 = slot2Occupied, p3 = slot3Occupied;
  slot1Occupied = (getDistance(TRIG1,ECHO1) > 0 && getDistance(TRIG1,ECHO1) < THRESHOLD_DISTANCE);
  slot2Occupied = (getDistance(TRIG2,ECHO2) > 0 && getDistance(TRIG2,ECHO2) < THRESHOLD_DISTANCE);
  slot3Occupied = (getDistance(TRIG3,ECHO3) > 0 && getDistance(TRIG3,ECHO3) < THRESHOLD_DISTANCE);
  if (p1!=slot1Occupied) logSlotChange(1,slot1Occupied);
  if (p2!=slot2Occupied) logSlotChange(2,slot2Occupied);
  if (p3!=slot3Occupied) logSlotChange(3,slot3Occupied);
  availableSlots = (!slot1Occupied) + (!slot2Occupied) + (!slot3Occupied);
  if (availableSlots == 0) alertParkingFull();
}

// ── LCD Update ────────────────────────────────
void updateLCD() {
  lcd.clear();
  lcd.setCursor(0,0); lcd.print("Available: "); lcd.print(availableSlots); lcd.print("/"); lcd.print(totalSlots);
  lcd.setCursor(0,1);
  lcd.print("S1:"); lcd.print(slot1Occupied ? "X" : "O");
  lcd.print(" S2:"); lcd.print(slot2Occupied ? "X" : "O");
  lcd.print(" S3:"); lcd.print(slot3Occupied ? "X" : "O");
}

// ── LED Update ────────────────────────────────
void updateLEDs() {
  digitalWrite(LED_SLOT1, !slot1Occupied);
  digitalWrite(LED_SLOT2, !slot2Occupied);
  digitalWrite(LED_SLOT3, !slot3Occupied);
  digitalWrite(LED_FULL,  availableSlots == 0);
}

// ── Entry Handler ─────────────────────────────
void handleEntry() {
  totalEntries++;
  if (availableSlots > 0) {
    openGate();
    digitalWrite(BUZZER_PIN, HIGH); delay(200); digitalWrite(BUZZER_PIN, LOW);
    lcd.clear(); lcd.setCursor(0,0); lcd.print("WELCOME!");
    lcd.setCursor(0,1); lcd.print("Gate Opening..."); delay(1500);
  } else {
    lcd.clear(); lcd.setCursor(0,0); lcd.print("SORRY!");
    lcd.setCursor(0,1); lcd.print("PARKING FULL");
    for (int i=0; i<3; i++) { digitalWrite(BUZZER_PIN,HIGH); delay(200); digitalWrite(BUZZER_PIN,LOW); delay(200); }
    delay(1000);
  }
}

// ── Exit Handler ──────────────────────────────
void handleExit() {
  totalExits++;
  openGate();
  digitalWrite(BUZZER_PIN,HIGH); delay(200); digitalWrite(BUZZER_PIN,LOW);
  lcd.clear(); lcd.setCursor(0,0); lcd.print("THANK YOU!");
  lcd.setCursor(0,1); lcd.print("Please Exit..."); delay(1500);
}

// ── Gate Control ──────────────────────────────
void openGate() {
  if (!gateOpen) { barrierGate.write(GATE_OPEN); gateOpen=true; gateOpenTime=millis(); }
}
void closeGate() {
  if (gateOpen) { barrierGate.write(GATE_CLOSED); gateOpen=false; }
}

// ── Alerts & Logging ──────────────────────────
void alertParkingFull() {
  static unsigned long lastAlert=0;
  if (millis()-lastAlert > 5000) {
    Serial.println("⚠️ PARKING LOT FULL!");
    for(int i=0;i<2;i++){digitalWrite(LED_FULL,HIGH);delay(200);digitalWrite(LED_FULL,LOW);delay(200);}
    digitalWrite(LED_FULL,HIGH); lastAlert=millis();
  }
}
void logSlotChange(int slot, bool occupied) {
  Serial.printf("Slot %d → %s | Available: %d/%d\n", slot, occupied?"OCCUPIED":"FREE", availableSlots, totalSlots);
}

// ── LED Test on Boot ──────────────────────────
void testLEDs() {
  digitalWrite(LED_SLOT1,HIGH); digitalWrite(LED_SLOT2,HIGH); digitalWrite(LED_SLOT3,HIGH);
  digitalWrite(LED_FULL,HIGH); digitalWrite(LED_WIFI,HIGH); delay(500);
  digitalWrite(LED_SLOT1,LOW); digitalWrite(LED_SLOT2,LOW); digitalWrite(LED_SLOT3,LOW);
  digitalWrite(LED_FULL,LOW); digitalWrite(LED_WIFI,LOW); delay(500);
}

// ── WiFi Connection ───────────────────────────
void connectWiFi() {
  WiFi.mode(WIFI_STA); WiFi.begin(ssid, password);
  int attempts=0;
  while (WiFi.status()!=WL_CONNECTED && attempts<20) { delay(500); attempts++; }
  wifiConnected = (WiFi.status()==WL_CONNECTED);
  if (wifiConnected) {
    digitalWrite(LED_WIFI,HIGH);
    Serial.println("✓ WiFi: " + WiFi.localIP().toString());
  }
}

// ── Web Server Setup ──────────────────────────
void setupWebServer() {
  if (!wifiConnected) return;
  server.on("/",           handleRoot);
  server.on("/api/status", handleAPIStatus);
  server.on("/api/open",   handleAPIOpen);
  server.on("/api/stats",  handleAPIStats);
  server.begin();
  Serial.println("✓ Web server at http://" + WiFi.localIP().toString());
}

// ── API: Status JSON ──────────────────────────
void handleAPIStatus() {
  String json = "{";
  json += "\"available\":"  + String(availableSlots) + ",";
  json += "\"occupied\":"   + String(totalSlots-availableSlots) + ",";
  json += "\"slot1\":"      + String(slot1Occupied?"true":"false") + ",";
  json += "\"slot2\":"      + String(slot2Occupied?"true":"false") + ",";
  json += "\"slot3\":"      + String(slot3Occupied?"true":"false") + ",";
  json += "\"gate\":\""     + String(gateOpen?"open":"closed") + "\"";
  json += "}";
  server.send(200, "application/json", json);
}

// ── API: Open Gate ────────────────────────────
void handleAPIOpen() {
  if (availableSlots > 0) { openGate(); server.send(200, "text/plain", "Gate opened!"); }
  else                     { server.send(403, "text/plain", "Parking full!"); }
}

// ── API: Stats JSON ───────────────────────────
void handleAPIStats() {
  String json = "{";
  json += "\"totalEntries\":" + String(totalEntries) + ",";
  json += "\"totalExits\":"   + String(totalExits)   + ",";
  json += "\"uptime\":"       + String((millis()-systemUptime)/1000) + ",";
  json += "\"wifiRSSI\":"     + String(WiFi.RSSI())  + ",";
  json += "\"freeHeap\":"     + String(ESP.getFreeHeap()) + "}";
  server.send(200, "application/json", json);
}

// ── Root Web Dashboard ────────────────────────
void handleRoot() {
  // Full HTML dashboard with slot cards, stats, live fetch, entry/exit buttons
  // Auto-updates every 2 seconds via fetch('/api/status')
  // See the Wokwi simulation for the complete HTML source
  String html = "<!DOCTYPE html><html><head>";
  html += "<meta name='viewport' content='width=device-width,initial-scale=1'>";
  html += "<title>ESP32 Smart Parking</title>";
  html += "<script>setInterval(()=>fetch('/api/status').then(r=>r.json()).then(d=>{";
  html += "document.getElementById('av').textContent=d.available;";
  html += "document.getElementById('oc').textContent=d.occupied;";
  html += "}),2000);</script></head><body style='font-family:sans-serif;padding:20px'>";
  html += "<h2>🅿️ Smart Parking</h2>";
  html += "<p>Available: <strong id='av'>" + String(availableSlots) + "</strong> / 3</p>";
  html += "<p>Occupied: <strong id='oc'>"  + String(totalSlots-availableSlots) + "</strong></p>";
  html += "<p>IP: " + WiFi.localIP().toString() + " | Uptime: " + String((millis()-systemUptime)/1000) + "s</p>";
  html += "<button onclick=\"fetch('/api/open').then(r=>r.text()).then(alert)\">Open Gate</button>";
  html += "</body></html>";
  server.send(200, "text/html", html);
}

LED Status Reference

🟢 Slot LED ON That slot is free & available

⬛ Slot LED OFF That slot is occupied by a car

🔴 Red LED ON Parking lot full — entry denied

🔵 Blue LED Blink WiFi connected — 1 sec heartbeat

🔔 1× Buzzer Beep Successful entry or exit

🚨 3× Buzzer Beeps Entry denied — parking full

Step-by-Step: How to Test

▶ Start the Simulation

Click Play in Wokwi. All 5 LEDs flash once (LED test). The LCD shows "Initializing…" then "SYSTEM READY!". WiFi connects within ~10 seconds.

📋 Find the IP Address

Open the Serial Monitor tab (bottom of Wokwi). Look for the line: ✓ WiFi: 10.0.0.2. Click that link to open the web dashboard.

🚗 Simulate a Car in Slot 1

Click the HC-SR04 ultrasonic1 sensor in Wokwi. Change the distance value from 400 cm to 10 cm. Slot 1's green LED turns OFF, the LCD updates to "Available: 2/3", and the web dashboard reflects the change in 2 seconds.

🚧 Fill All Slots

Set all three ultrasonic sensors to 10 cm. The red FULL LED turns ON, the LCD shows "Available: 0/3", and pressing ENTRY triggers 3 buzzer beeps with "PARKING FULL" on LCD.

🟢 Press the ENTRY Button

With a free slot available, press the green ENTRY button. The buzzer beeps once, LCD shows "WELCOME! Gate Opening…", and the servo rotates to 90°. It auto-closes after 3 seconds.

🔴 Press the EXIT Button

Press the red EXIT button. The buzzer beeps, LCD shows "THANK YOU! Please Exit…", and the gate opens then auto-closes. The exit counter increments in /api/stats.

🌐 Use the REST API

Access /api/status for live slot JSON, /api/open to trigger the gate remotely, and /api/stats for entry/exit totals, uptime, WiFi RSSI, and free heap memory.

▶ Try it Live in Wokwi Simulator

No hardware required — run the full smart parking simulation instantly in your browser. Adjust ultrasonic distances, press buttons, and watch the web dashboard update live.

🔗 Open Free Simulation

💡

Pro Tip: After starting the simulation, click each HC-SR04 sensor individually to change its distance value. Set to 10 cm to mark a slot occupied, and 400 cm to make it available again. Watch the LCD, LEDs, and web dashboard all update in real time.

ROBOTICS

Search This Blog

Smart Parking System Using Ultrasonic Sensors WITH ESP 32

ESP32 Smart Parking System with WiFi & IoT

Project Overview

Key Features

🔧 Hardware

📡 Software & IoT

Components Required

Pin Connections & Wiring

Quick Start: Load in Wokwi

Go to wokwi.com and create a new ESP32 project

Paste the diagram.json content

Paste the sketch.ino code

Press ▶ Start and check Serial Monitor

Diagram.json (Wokwi)

Arduino Code

LED Status Reference

Step-by-Step: How to Test

▶ Start the Simulation

📋 Find the IP Address

🚗 Simulate a Car in Slot 1

🚧 Fill All Slots

🟢 Press the ENTRY Button

🔴 Press the EXIT Button

🌐 Use the REST API

▶ Try it Live in Wokwi Simulator

Comments

Post a Comment

try for free

Best 15 IoT Projects Using ESP32 for Beginners & Advanced Makers in 2026

BEST 25 ARDUINO WOKWI SIMULATOR PROJECTS

Top 20 Raspberry Pi Projects for Beginners - Complete Guide 2026

Intermediate Projects (Build Your Skills)

Advanced Projects (Master Level)

Smart Parking System Using Ultrasonic Sensors WITH ESP 32

ESP32 Smart Parking System with WiFi & IoT

Project Overview

Key Features

🔧 Hardware

📡 Software & IoT

Components Required

Pin Connections & Wiring

Quick Start: Load in Wokwi

Go to wokwi.com and create a new ESP32 project

Paste the diagram.json content

Paste the sketch.ino code

Press ▶ Start and check Serial Monitor

Diagram.json (Wokwi)

Arduino Code

LED Status Reference

Step-by-Step: How to Test

▶ Start the Simulation

📋 Find the IP Address

🚗 Simulate a Car in Slot 1

🚧 Fill All Slots

🟢 Press the ENTRY Button

🔴 Press the EXIT Button

🌐 Use the REST API

▶ Try it Live in Wokwi Simulator

More ESP32 Projects

Comments

Post a Comment

try for free

Best 15 IoT Projects Using ESP32 for Beginners & Advanced Makers in 2026

BEST 25 ARDUINO WOKWI SIMULATOR PROJECTS

Top 20 Raspberry Pi Projects for Beginners - Complete Guide 2026

Intermediate Projects (Build Your Skills)

Advanced Projects (Master Level)