This smart home project has the following features:

1. Home appliances controlled from Mobile using Blynk App

2. Home appliances controlled by temperature & Humidity sensor automatically (In Auto Mode)

3. Home appliances controlled by Dark Sensor automatically (In Auto Mode)

4. Monitor LIVE room temperature & Humidity reading on OLED and Smartphone

5. Home appliances controlled manually with touch switch

6. Control Home appliances through the Internet (WiFi)

Required Components:

1. NodeMCU Board

2. DH11 Sensor

3. LDR

4. 10k Resistors 5 no

5. 1k Resistors 3 no

6. 220-ohm Resistors 2 no

7. BC547 NPN Transistors 2 no

8. Diode 1N4007 2 no

9. Diode 1N4001 1no

10. 5-mm LED (1.5v) 3 no

11. SPDT 5V Relays 2 no

12. Push Switch/ button 4 no (or) TTP223 Touch Sensor (3no)

13. Connectors & jumpers

14. OLED I2C Display (0.96" or 1.3") (Optional)

15. Hi-Link 220V to 5V AC to DC converter

Circuit Diagram

This is the complete circuit diagram for this IoT-based home automation system.

I have used NodeMCU to control the relays.

In Auto mode, the DHT11 temperature & humidity sensor and LDR control the relays automatically according to the room temperature and ambient light.

There 4 pushbuttons connected with NodeMCU i.e, S1, S2, CMODE, RST.

You can also connect the TTP223 Touch sensors instead of pushbuttons.

S1 & S2 to control the relay module manually.

CMODE to change the Mode (Manual Mode, Auto Mode)

RST to reset the NodeMCU

I have used a 110V/220V AC to 5V DC converter to supply the 5 Volt to NodeMCU and relays.

So you can connect directly 110V or 220V AC supply with this smart relay module.

Make the Circuit on Breadboard for Testing

Before designing the PCB, first I have tested the circuit on the breadboard.

During testing, I have uploaded the code to the NodeMCU then tried to control the relays with the pushbuttons, touch switches. Blynk App, temperature sensor, and LDR.

Here RST pin is active low, so the Touch sensor connected with the RST pin should be active low.

Download the attached Code for this NodeMCU project. I have mentioned all the links of the required libraries in the code.

Code Download link:

https://drive.google.com/uc?export=download&id=1YYNdAP82RXpnSHdcrL4j59f_t97e-JEY

Install the Blynk App:

Install the Blynk App from Google play store or App store then add all the required widgets to control the relay module and monitor the temperature and humidity. I have explained all the details in the tutorial video.

I have used the 3 button widgets to control the relay module and change the mode.

And 2 gauge widgets to monitor the temperature and humidity.

For more such Blynk project please visit https://easyelectronicsproject.com/tag/blynk/

Different Mode of the Smart Relay Module:

We can control the smart relay in two modes:

1. Manual Mode

2. Auto Mode

We can easily change the mode with the CMODE button fitted on the PCB or from the Blynk App.

Manual Mode:

In the Manual mode, we can control the relay module from the S1 & S2 touch switches or from the Blynk App.We can always monitor the real-time feedback status of the switches from the Blynk App.

And we can also monitor the temperature and humidity readings on the OLED display as you can see in the pictures.

With the Blynk App, we can control the relay module from anywhere if we have the internet on our smartphone.

Auto Mode:

In Auto mode, the relay module controlled by the DHT11 sensor and LDR.

We can set predefined minimum and maximum temperature and light values in the code.

Temperature Control:

When the room temperature crosses the predefined maximum temperature the relay-1turns on and when the room temperature becomes lesser than the predefined minimum temperature the relay-1 turns off automatically.

LDR Control:

In a similar way when the light level decreases the relay-2 turns on and when the light is sufficient the relay-2 turns off automatically.

I have explained this in detail in the tutorial video.

Designing the PCB:

After testing all the features of the smart relay module on the breadboard, I have designed the PCB to make the circuit compact and give the project a professional look.

Solder All the Components:

After that solder all the components as per the circuit diagram.

Then connect NodeMCU, DHT11, LDR, and OLED display.

Program the NodeMCU:

1. Connect the NodeMCU with the laptop

2. Download the Code. (Attached)

3. Change the Blynk Auth token, WiFi Name, WiFi Password.

4. Change the predefined temperature and light value for Auto Mode as per your requirement

5. Select the NodeMCU 12E board and proper PORT. Then upload the code.

** In this project, you can use both 0.96" OLED and 1.3" OLED displays. I have shared the Code for both OLEDs, upload the code as per the OLED display you are using.

Connect the Home Appliances:

Connect the home appliances as per the circuit diagram.

Please take proper safety precautions while working with high voltage.

Here you can directly connect 110V or 220V AC supply.

** I have not used the touch sensor for the RST pin as it is active LOW.

Place the Complete Circuit Inside a BOX

I have placed the complete circuit inside a plastic box. As I will use this NodeMCU project as Smart Extention BOX.

It will be very useful and easy to use.

Finally, the NodeMCU project is ready.

Turn on the 110V/230V supply.

Now you can control your home appliances in a smart way. I hope you have liked this home automation project. I have shared all the required information for this project.

I will really appreciate it if you share your valuable feedback, Also if you have any query please write in the comment section.

For more such ESP8266 projects please visit our website IotCircuitHub. Thank you for your time & Happy Learning.

https://iotcircuithub.com/esp8266-projects/

https://iotcircuithub.com/esp8266-projects/