ESP32: Smart Home Controller

Step 1: Setup Arduino IDE & ESP32 Board

First, ensure your Arduino IDE is set up for ESP32. Install the ESP32 board manager and necessary libraries (e.g., AsyncWebServer, DHT sensor library).

https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json

ESP Async WebServer
DHT sensor library (by Adafruit)

Step 2: Wiring the Components

Connect the relay module and DHT11 sensor to your ESP32. Pay close attention to power (VCC, GND) and signal pins.

Example wiring diagram (Refer to actual pinouts for your module)

• ESP32 GPIO 2 (D2) to Relay IN1
• ESP32 GPIO 4 (D4) to DHT11 Data Pin
• ESP32 3.3V to VCC of DHT11 and Relay
• ESP32 GND to GND of DHT11 and Relay

Step 3: Develop the Firmware (Arduino Sketch)

Write the Arduino sketch that initializes Wi-Fi, creates a web server, reads sensor data, and controls the relays.

#include <WiFi.h>
#include <ESPAsyncWebServer.h>
#include <DHT.h>

// WiFi credentials
const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";

// Relay and DHT pins
const int RELAY_PIN = 2; // Example GPIO pin for relay
const int DHT_PIN = 4;   // Example GPIO pin for DHT11

#define DHTTYPE DHT11 // DHT 11
DHT dht(DHT_PIN, DHTTYPE);

AsyncWebServer server(80); // Create AsyncWebServer object on port 80

void setup() {
    Serial.begin(115200);
    pinMode(RELAY_PIN, OUTPUT);
    digitalWrite(RELAY_PIN, HIGH); // Turn off relay initially (if active low)

    dht.begin();

    // Connect to Wi-Fi
    WiFi.begin(ssid, password);
    Serial.print("Connecting to WiFi..");
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println();
    Serial.print("Connected! IP Address: ");
    Serial.println(WiFi.localIP());

    // Route for web page
    server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
        request->send(200, "text/html",
            "<h1>ESP32 Smart Home</h1>"
            "<p>Temperature: " + String(dht.readTemperature()) + " °C</p>"
            "<p>Humidity: " + String(dht.readHumidity()) + " %</p>"
            "<p>Relay State: " + (digitalRead(RELAY_PIN) == LOW ? "ON" : "OFF") + "</p>" // Assuming active LOW relay
            "<a href=\"/toggle\">Toggle Relay</a>"
        );
    });

    // Route for toggling relay
    server.on("/toggle", HTTP_GET, [](AsyncWebServerRequest *request){
        digitalWrite(RELAY_PIN, !digitalRead(RELAY_PIN)); // Toggle the relay
        request->redirect("/"); // Redirect back to home
    });

    server.begin(); // Start server
    Serial.println("HTTP server started");
}

void loop() {
    // DHT11 reading (can be done periodically or on request)
    // For this simple example, we read on web request.
    // In a real app, you might read every X seconds and store.
}

Remember to replace `YOUR_WIFI_SSID` and `YOUR_WIFI_PASSWORD` with your actual Wi-Fi credentials.

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Step 4: Upload the Code & Test

Select the correct ESP32 board and COM port in Arduino IDE, then upload the sketch. Once uploaded, open the Serial Monitor to see the assigned IP address. Navigate to this IP address in your web browser to control your smart home system.