Aim

To control an LED or fan from a smartphone app using IoT.

Requirements

• Hardware / Simulation Tools:
  • Arduino Uno

  • Wi-Fi Module (ESP8266 or ESP32)

  • LED / Small fan motor

  • Jumper wires, breadboard

  • Smartphone with Blynk app or online IoT dashboard

Steps

Step 1: Build the Circuit

• Connect LED or Fan to Arduino:
  • LED → Digital Pin (D9), resistor in series

  • Fan → Motor driver or transistor with digital pin

• Connect Wi-Fi Module (ESP8266) to Arduino:
  • VCC → 3.3V

  • GND → GND

  • TX → RX, RX → TX

Step 2: Prepare the Mobile App (Blynk)

• Download and install Blynk app on your phone.

• Create a new project: Select “Arduino Uno” + Wi-Fi (ESP8266).

• Add a Button widget on the dashboard.

• Set button to Digital Pin D9.

Step 3: Connect Arduino to Blynk

• In the Arduino IDE, write code that connects to your Wi-Fi and links with the Blynk server.

• Upload the program.

Step 4: Test Remote Control

• Open the app and press the button.

• The LED/fan should turn ON.

• Press again, and it should turn OFF.

Step 5: Extend the Idea

• Try adding two buttons (one for LED, one for Fan).
  
• Add Timer widget to switch OFF automatically after a certain time.
• Discuss: What would happen if internet connection breaks?