Arduino Home Automation Projects: 12 Smart Home DIY Ideas for 2025

Why Arduino for Home Automation?

Arduino makes home automation affordable and customizable. Build your own smart home system for a fraction of commercial solutions, with full control over every aspect.

Essential Components

Relay Control

Relays act as electrically-controlled switches, allowing Arduino (5V logic) to control high-voltage AC devices like lights, fans, and appliances.

// Simple relay control
const int RELAY_PIN = 7;

void setup() {
 pinMode(RELAY_PIN, OUTPUT);
 digitalWrite(RELAY_PIN, HIGH); // Relay OFF (active-low)
}

void lightOn() {
 digitalWrite(RELAY_PIN, LOW); // Relay ON
}

void lightOff() {
 digitalWrite(RELAY_PIN, HIGH); // Relay OFF
}

Motion Detection

PIR (Passive Infrared) sensors detect heat from moving objects. Perfect for automatic lights, security, and presence detection.

const int PIR_PIN = 2;
const int LED_PIN = 13;

void setup() {
 pinMode(PIR_PIN, INPUT);
 pinMode(LED_PIN, OUTPUT);
 delay(30000); // Allow PIR to stabilize
}

void loop() {
 if (digitalRead(PIR_PIN) == HIGH) {
 digitalWrite(LED_PIN, HIGH);
 delay(5000); // Keep light on 5 sec
 } else {
 digitalWrite(LED_PIN, LOW);
 }
}

WiFi Control with ESP8266

The ESP8266 (or ESP32) adds WiFi to your Arduino projects. Control devices from your phone or integrate with Home Assistant.

Project Ideas

Communication Protocols