Home Automation Project Using Blynk ESP32 | IoT Projects 2021

In this IoT project, I have shown how to make an IoT-based Home Automation project using ESP32 and the new Blynk IoT app to control an 8-channel relay module from the manual switch & smartphone.

During the article, I have shown all the steps to make this Blynk home automation system.

This Blynk ESP32 control smart relay has the following features:

1. Control home appliances with WiFi (Blynk IoT app).
2. Control home appliances with Blynk web dashboard.
3. Control home appliances with manual switches or push buttons.
4. Monitor real-time feedback in the Blynk IoT App.
5. Control appliances without WiFi from manual switches.

So, you can easily make this home automation project at home just by using an ESP32 and relay module. Or you can also use a custom-designed PCB for this project.

• ESP32 DEVKIT V1
• Relays 5v (SPDT) (8 no)
• BC547 Transistors (8 no)
• PC817 Optocuplors (8 no)
• 510-ohm 0.25-watt Resistor (8 no) (R1 - R8)
• 1k 0.25-watt Resistors (10 no) (R9 - R18)
• 10k 0.25-watt Resistors (1 no)
• LED 5-mm (10 no)
• 1N4007 Diodes (8 no) (D1 - D8)
• Push Buttons (9 no) or Switches
• Terminal Connectors
• Jumper
• 5V DC supply

This is the complete circuit diagram for this home automation project. I have explained the circuit in the tutorial video.

The circuit is very simple, I have used the GPIO pins D23, D22, D21, D19, D18, D5, D25 & D26 to control the 8 relays.

And the GPIO pins D13, D12, D14, D27, D33, D32, D15 & D4 are connected with Switches to control the 8 relays manually.

The Wi-Fi indicator is connected with the D2(GPIO-2) pin, connected with the blue LED mounted on the ESP32 board.

I have used the INPUT_PULLUP function in Arduino IDE instead of using the pull-up resistors.

I have used a 5V 5A DC power supply.

If the ESP32 is connected with WiFi, then you can control the home appliances from Blynk IoT App.

You also use multiple smartphones to control the appliances with Blynk IoT App. For that, you have to log in same Blynk account from all the smartphones.

In this way, all smartphones will be sink to the Blynk server. You can control, monitor the real-time status of the relays from anywhere in the world with the Blynk App.

You can also control the relays from the switches or pushbuttons.

If the ESP32 is connected with Wi-Fi, you can monitor the real-time feedback in the Blynk IoT App.

And if the Wi-Fi is not connected, still you can control the relays from manual switches.

Please refer to the circuit diagram to connect the switches.

To make the circuit compact and give a professional look, I have designed the PCB after testing all the features of the smart relay module.

You can download the PCB Gerber file of this home automation project from the following link:

https://drive.google.com/uc?export=download&id=1PdSaP8jqHkWgU-L1zeyC8j8qsKTWxw4X

After downloading the Garber file you can easily order the PCB

1. Visit https://jlcpcb.com/ and Sign in / Sign up.

2. Click on the QUOTE NOW button.

3. Click on the "Add Gerber file" button. Then browse and select the Gerber file you have downloaded.

4. Set the required parameter like Quantity, PCB masking color, etc

5. After selecting all the Parameters for PCB click on SAVE TO CART button.

6. Type the Shipping Address.

7. Select the Shipping Method suitable for you.

8. Submit the order and proceed with the payment. You can also track your order from JLCPCB.com.

My PCBs took 2 days to get manufactured and arrived within a week using the DHL delivery option.

PCBs were well packed and the quality was really good at this affordable price.

After that, I have soldered all the components as per the circuit diagram.

Then connect the ESP32 board with the PCB.

For this smart house project, I have used the Blynk IoT Cloud Free plan.

Click on the following link to create a Blynk Cloud account.

https://blynk.cloud/dashboard/register

1. Enter email ID, then click on "Sign Up".
2. You will receive a verification email.
3. Click on Create Password in the email, Then set the password, click on Next.
4. Enter your first name, click on Done.
5. After that Blynk cloud dashboard will open.

Please refer to the following article to configure the Blynk cloud account (Create the template, datastreams, web dashboard)

https://iotcircuithub.com/blynk-iot-platform-setup...

After that create a template for ESP32,

Then create 8 Datastreams with virtual pin V1 to V8 to control 8 relays, and 1 datastream with V9 to turn off all the relays together

Then configure the Web Dashboard to control 8 relays from Blynk Cloud Dashboard.

First, download the code from the following link.

Click Here to Download Code

1. You have to keep all the 10 files in the same folder.
2. Open the .ino file in Arduino IDE.
3. In the code, you have to update the BLYNK_TEMPLATE_ID and BLYNK_DEVICE_NAME.
4. For this project, you have to install the Blynk 1.0.1 library.
5. Now select the "DOIT ESP32 DEVKIT V1" board and proper PORT.
6. Then upload the code to ESP32 Board.

While uploading the code to ESP32, if you see the "Connecting....___" text, then press the BOOT button of the ESP32.

After programming the ESP32, you have to update the WiFi credentials from the Blynk IoT app.

In the tutorial video, I have explained all the steps to update the WiFi credentials to ESP32 through OTA.

1. Select the template that you have already made.
2. Go to the Widget box (on the right) to add widgets. Add 8 Button widgets from Widget Box.
3. Go to Button widget settings.
4. Enter the name, select Datastream, Mode will be Switch. Then exit.
5. After configuring all the Buttons tap on exit.

After the ESP32 connects with the Blynk server, the WiFi indicator LED blinks very slowly.

Before connecting the appliances, please check whether you can control the relay from the Blynk IoT app.

Connect the 8 appliances and external switches with the PCB as per the circuit diagram.

Please take proper safety precautions while working with high voltage.

Connect 5-volt DC supply with the PCB. (I have used my old mobile charger 5V 5Amp)

Turn on the 110V/230V supply and 5V DC supply.

Now you can control your home appliances in a smart way.

I hope you have liked this new Blynk home automation project. I have shared all the required information for this project.

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

Thank you & Happy Learning.