🔒 ESP32 Smart Home Automation Project

📜 Project Overview

This project is a secure, Wi-Fi-enabled Smart Home Automation System built using the ESP32 microcontroller. It allows real-time control and monitoring of devices (Relays, NeoPixel RGB LEDs, Stepper Motor, DHT22 sensor) through a dynamic WebSocket interface served from the ESP32’s file system (LittleFS).

Only authenticated users can access the control panel using a challenge-response password hashing mechanism without storing the password in the ESP32 memory — ensuring secure, stateless authentication.

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📌 Features

• 🔐 Secure Challenge-Response WebSocket Authentication
• 🌐 Dynamic web interface with WebSocket-based real-time updates
• 🔌 4x Relays: Toggle control via web and physical buttons
• 🌡️ DHT22: Real-time temperature and humidity monitoring
• 🎨 NeoPixel RGB LED: Color control from UI
• 🤀 Stepper Motor: Angular control via slider with auto-reset on boot
• 📲 Works over local Wi-Fi or fallback hotspot
• 💾 Uses LittleFS for HTML, CSS, JS
• 🎯 UUID-based device recognition (up to 5 remembered clients)
• 📉 System info console and log display

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📂 Folder Structure

SmartHome-ESP32/
│
├── data/                      # Web UI files for LittleFS
│   ├── index.html             # Login page
│   ├── control.html           # Smart control panel (after auth)
│   ├── style.css              # Web styling
│   └── script.js              # WebSocket + UI logic
│
├── src/
│   └── main.cpp               # Core firmware code
│
├── platformio.ini             # PlatformIO config
├── README.md                  # Project documentation (this file)
└── credentials_template.h     # Wi-Fi credentials (excluded from repo)

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🧠 Authentication Logic (Password Verification)

We use challenge-response SHA-256 hashing. Password is never stored or transmitted directly. Here's a highlight from main.cpp:

#include <SHA256.h>
#include <Preferences.h>

Preferences preferences;
SHA256 sha256;

// Example password hash (not plain password)
const char* correctHash = "5e884898da28047151d0e56f8dc6292773603d0d6aabbdd..."; // sha256("password")

bool verifyPassword(String userResponse, String challenge) {
    String combined = challenge + "password";  // 'password' is never stored; just shown here for understanding
    sha256.reset();
    sha256.update(combined.c_str(), combined.length());
    uint8_t* result = sha256.result();

    String calculatedHash = "";
    for (int i = 0; i < 32; i++) {
        char hex[3];
        sprintf(hex, "%02x", result[i]);
        calculatedHash += hex;
    }

    return userResponse.equals(calculatedHash);
}

• Server sends a challenge string to the browser.
• Browser JavaScript hashes challenge + password and sends it back.
• ESP32 verifies by recomputing SHA-256 on same.

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🔧 Hardware Setup

• ✅ ESP32 Devkit V1
• ✅ 4x Relays on GPIO 16–19
• ✅ 4x Buttons on GPIO 21–25 (optional debounce)
• ✅ DHT22 Sensor on GPIO 4
• ✅ NeoPixel RGB LED on GPIO 5 (WS2812)
• ✅ Stepper Motor (28BYJ-48 + ULN2003) on GPIOs 26–29
• ✅ Power supply: 5V regulated for relays/motor

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🌍 Web Interface Walkthrough

See screenshots below for better understanding WEB APP 👈 Click Here

Smart Home Web UI

1. Login Page (``)

Login Page 👈 Click Here

• User connects to ESP hotspot SmartHome-ESP32 (PW: 00000000) or home Wi-Fi.
• A random challenge string is shown.
• User enters password → client hashes password + challenge → sends hash.

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2. Main Control Panel (``)

Controls Page 👈 Click Here Top Console:

• Device info: RAM, CPU freq, uptime, IP
• WebSocket client ID
• Scrollable serial monitor logs

Relay Control:

• Toggle buttons for 4 relays
  Example log:

  { "Type": "Control", "Key": "Light-1", "Value": "on" }

DHT22 Sensor Display:

• Live temperature and humidity updates every 2s
  *Example: *Temp: 29.4°C | Humidity: 62%

NeoPixel Control:

• HTML color picker to choose RGB values
  Logs as:

  { "Type": "Control", "Key": "Ambience", "Value": "#ff8800" }

Stepper Motor Slider:

• Angular control via slider (0°–180°)
• Resets to 0° on boot

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🔐 UUID-Based Authorization

• On successful login, ESP stores { username : UUID } in NVS Preferences
• Maintains last 5 UUIDs
• If a known UUID connects, skips login and serves control.html directly

Code snippet:

preferences.begin("uuid-auth", false);
preferences.putString("user1", "UUID-1234");
String uuid = preferences.getString("user1");
preferences.end();

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🧪 Testing Instructions

First Time Setup

1. Power on ESP32, connect to hotspot SmartHome-ESP32 (PW: 00000000)
2. Open 192.168.4.1
3. Enter password (e.g. password123)
4. Control panel opens after successful hash match

Switching to Home Wi-Fi

1. From UI, go to "Update Credentials"
2. Enter your home Wi-Fi SSID and password
3. Restart ESP32 — now it auto-connects

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🛠️ PlatformIO Configuration

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
build_flags =
  -DCORE_DEBUG_LEVEL=3
lib_deps =
  bblanchon/ArduinoJson
  me-no-dev/ESP Async WebServer
  me-no-dev/AsyncTCP

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📓 Future Improvements

• Add OTA firmware updates
• Role-based access (Admin vs Guest)
• MQTT integration with external broker
• Voice assistant control (Alexa/Google)

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🖼️ HardWare Demonstrative

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🖼️ Screenshots & UI

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🖼️ Code & Algorithms

📣 Credits

Developer: Mayur Borgude
Year: 2025
Project Type: B.E. Final Year Embedded + Web IoT System

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📜 License

This project is open-source and free to use under the MIT License. Please give credit where due.