IoT Project Using ESP32 Blynk With Fan Speed Control and Sensor

In this IoT project, I have shown how to make IoT-based Smart Home Automation using ESP32 Blynk with the Fan Speed control, sensor, and IR remote control relay with real-time feedback.

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 ceiling fan speed with Blynk, IR Remote, & selector switch.
3. Control home appliances with an IR remote.
4. Control home appliances with manual switches or push buttons.
5. Monitor real-time room temperature in the Blynk IoT App
6. Monitor real-time feedback in the Blynk IoT App.
7. Control appliances, and fan speed without WiFi.

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.

Required components:

• ESP32 DevKIT V1
• 4-channel 5V SPDT Relay Module
• DHT11 Sensor
• TSOP1838 IR Receiver (with metallic case)
• Switches or Pushbuttons
• Any IR Remote
• 4-step Fan Regulator OR (2.2uf & 3.3uf 250V Capacitor, 2.2-ohm 1/2W Resistors, 220k 1/4W Resistors, and 4-step selector switch)

The circuit is very simple, I have used the GPIO pins D23, D22, D21 & D19 to control the 4 relays.

And the GPIO pins D13, D12, D14 & D27 are connected with switches, and GPIO D33, D32, D15 & D4 are connected with a 4-step selector switch to control the 4 relays manually.

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

IR remote receiver (TSOP1838) connected with D35. And the DHT11 sensor is connected with the RX2 (GPIO16).

I have used a 5V mobile charger to supply the smart relay module.

Please take proper safety precautions while working with high voltage.

Control the speed of the ceiling fan from anywhere in the world from the Blynk IoT App. If the WiFi is connected, you can also monitor the real-time feedback in the Blynk.

You can use any IR remote to control the fan speed. I have used 2 buttons to increase and decrease the fan speed from the IR remote.

You can also use a selector switch to control the fan speed manually if the WiFi is not connected.

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

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

This way, all smartphones will be in the sink to the Blynk server. You can control, and monitor the real-time status of the relays, room temperature & humidity from anywhere in the world in the Blynk IoT App.

You can always control the relays from the IR remote or switches. For this project, you can use any IR remote.

I have explained how to get the IR codes (HEX codes) from any remote in the following steps.

Please refer to the circuit diagram to connect the switches.

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

You can download the PCB Gerber, BOM, and "pick and place" files of this ESP32 control relay PCB from the following link:

GitHub link to Download PCB Gerber File

For this project, I have the JLC SMT Service while ordering the PCB.

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1. Visit https://jlcpcb.com/ and Sign in / Sign up.
2. Click on the QUOTE NOW button.
3. Click on the "Add your 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. Select the Assemble side and SMT Quantity.
6. Now upload the BOM and PickAndPlace files.
7. Now confirm all the components which you want to be soldered by SMT services.
8. Click on SAVE TO CART button.

1. Type the Shipping Address.
2. Select the Shipping Method suitable for you.
3. Submit the order and proceed with the payment.

You can also track your order from the JLCPCB. My PCBs took 3 days to manufacture and arrived within a week using the DHL delivery option.

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

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 your 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, and click on Next.
4. Enter your first name, and click on Done.

After that Blynk cloud dashboard will open.

Create a New Template in Blynk Cloud

First, you have to create a template in the Blynk cloud.

1. Click on New Template.
2. Enter a template name, select the hardware as ESP32, and the connection type will be WiFi.
3. Then click on DONE.

You will get the BLYNK_TEMPLATE_ID and BLYNK_DEVICE_NAME after creating the temple.

After that, you have to create Datastreams. Here I will control 4 relays, so I have to create 4 Datastreams. And for Fan Speed Control 1 Datastream.

Steps to add Datastreams.

1. Go to the Datastreams tab.
2. Click on New Datastream and select Virtual Pin.
3. Enter a name, select the virtual pin V1, and the datatype will be Integer.
4. Then click on Create.

In a similar way, create 4 datastreams with virtual pin V1 to V4. And 1 datastream (V5) to turn off all the relays. And for Fan Speed Control 1 Datastream (V0) with MAX value 4 & MIN value = 0.

And for the Temperature and humidity, I have used V6, & V7 (Please refer to the picture or tutorial video).

Now go to the Web Dashboard tab.

Drag and drop 4 Switch widgets and 2 Level widgets.

Go to the settings of each widget, and select a Datastream.

Please refer to the tutorial video for more details.

Then click on Save to save the template.

Steps to add a device to the Blynk IoT cloud:

1. First, go to Device, then click on "New Device".
2. Click on "From template".
3. Select the Template, and give the device name.
4. Click on Create.

Then in the device info tab, you will get the Blynk Auth Token, Template ID, and Device Name. All these details will be required in the code.

Now, to get the HEX codes from the remote, first, we have to connect the IR receiver output pin with GPIO D35.

And give the 5V across the VCC and GND. The IR receiver must have a metallic casing, otherwise, you may face issues.

Then follow the following steps to get the HEX codes

1. Install the IRremote library in Arduino IDE
2. Download the attached code, and upload it to ESP32.
3. Open Serial Monitor with Baud rate 9600.
4. Now, press the IR remote button.
5. The respective HEX code will populate in the serial monitor.

Save all the HEX codes in a text file.

For programming the ESP32 on PCB, I have used another ESP32 development board.

Download and install the following libraries in Arduino IDE

• Blynk Library (1.0.1): https://github.com/blynkkk/blynk-library
• AceButton Library (1.9.2): https://github.com/bxparks/AceButton
• IRremote Library (3.6.1): https://github.com/Arduino-IRremote/Arduino-IRremote
• DHT Library (1.4.3): https://github.com/adafruit/DHT-sensor-library

Now open the main sketch (code).

1. In the code, you have to update the BLYNK_TEMPLATE_ID, BLYNK_DEVICE_NAME, Auth Token, WiFi Credentials.
2. Then update the HEX codes of the IR remote as shown in the tutorial video.
3. After that, select the DOIT ESP32 DEVKIT V1 board and proper PORT.
4. Then upload the code to ESP32 Board.

While uploading the code to ESP32, if you use the PCB then you will see the "Connecting....___" text, then press and hold the BOOT button and then press the EN button, after that release both buttons.

1. Install the Blynk IoT app from Google Play Store or App Store. Then log in.
2. Go to Developer Mode.
3. Tap on the template that you have already made.
4. Now go to the Widget box (on the right) to add widgets.
5. Add 5 Button widgets and 2 Gauge widgets from Widget Box.
6. Go to the Button widget settings.
7. Enter the name, select Datastream, Mode will be Switch. Then exit.
8. After setting all the Buttons tap on exit.

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

I hope you have liked this new Blynk IoT 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 queries please write in the comment section.

Thank you & Happy Learning.