🔌 Smart IoT Home Automation with Blynk & NodeMCU ESP8266

Build your own smart home automation system using a NodeMCU ESP8266 and the Blynk IoT platform. This project lets you control home appliances like fans or lights using your smartphone — from anywhere.

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📚 Table of Contents

• Features
• Required Components
• Circuit Diagram & Connections
• Setting Up Blynk Cloud
• Installing Arduino IDE & Uploading Code
• Connecting Device to Blynk App
• Troubleshooting
• Demo
• License
• Author
• Contributing

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✨ Features

✅ Control up to 4 devices via smartphone
✅ Remembers relay state after reboot (via cloud sync)
✅ Uses Blynk cloud & app (free)
✅ Modular and OTA-ready firmware structure
✅ Easy for beginners to set up and understand

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🧰 Required Components

Component	Quantity	Description
NodeMCU ESP8266	1	Wi-Fi enabled microcontroller
4-Channel Relay Module	1	For controlling appliances
Jumper Wires	As needed	For connecting modules
Power Supply (5V, 2A)	1	To power the NodeMCU and relay board
AC Appliances	1–4	Fan, Light, etc.

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🔌 Circuit Diagram & Connections

Relay Pin	Connect To (NodeMCU)
VCC	VIN (5V)
GND	G
IN1	D1
IN2	D2
IN3	D3
IN4	D4

💡 Optional: Add an LED to D0 and 3.3V to indicate Wi-Fi connection status.

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☁️ Setting Up Blynk Cloud

1. Go to https://blynk.cloud

2. Log in or sign up

3. Create a new template and configure:

   • Virtual pins: V0 = State Memory, V1–V4 = Control pins

4. Copy these details into your Arduino sketch:

#define BLYNK_TEMPLATE_ID "Your_Template_ID"
#define BLYNK_TEMPLATE_NAME "Your_Template_Name"
#define BLYNK_FIRMWARE_VERSION "1.0.0"

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🧪 Installing Arduino IDE & Uploading Code

✅ Install Arduino IDE:

Download Arduino IDE

✅ Add ESP8266 Board Support:

1. Go to File → Preferences

2. Add this to “Additional Board Manager URLs”:

   http://arduino.esp8266.com/stable/package_esp8266com_index.json
   

3. Go to Tools → Board → Boards Manager

4. Search for esp8266 and install it

✅ Upload Code:

• Open the .ino file from this repo
• Replace your Template ID, Wi-Fi SSID, and password
• Select Board: NodeMCU 1.0 (ESP-12E Module)
• Hit Upload

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📲 Connecting Device to Blynk App

1. Install Blynk IoT App → Google Play → App Store

2. Log in and tap + to add a device

3. Select “Discover Nearby”

4. Choose your NodeMCU device

5. Enter Wi-Fi credentials

6. Configure the device dashboard:

   • Add buttons for V1–V4
   • Add switch for V0 to enable state memory

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❓ Troubleshooting

Problem	Solution
Device not detected	Ensure NodeMCU is in pairing mode and powered on
Relay not triggering	Check wiring and pin mapping
Frequent reboots	Use a stable 5V 2A power supply
Upload errors	Verify USB cable, COM port, and correct board selected
Blynk app not responding	Double-check virtual pin assignment and template sync

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🧑‍💻 Contributing

We welcome contributions of any kind:

• 🐛 Report bugs → Submit an issue
• 🌟 Star the repo → Give it a star
• 🛠️ Submit improvements → Open a pull request
• 📈 View repo activity → Repo insights

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📄 License

This project is licensed under the MIT License. See the LICENSE file for details.

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👤 Author

Developed by Apurbo Islam For more cool projects: On GitHub

🚀 Let’s build the future of connected homes, one relay at a time!

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