ESP32 Remote LED Control

A beginner IoT project for remotely controlling four physical LEDs connected to an ESP32 over the Internet.

What the project does

A browser changes LED states on a small Flask web server. The ESP32 connects to Wi-Fi and polls the server over HTTPS approximately once per second. The server returns four values such as 1,0,1,0, and the ESP32 converts them into GPIO HIGH/LOW states.

Phone / PC
    |
    | HTTPS
    v
ngrok public URL
    |
    v
Flask server
    ^
    | HTTPS GET /status
    |
ESP32 -> GPIO -> LEDs

ngrok is used to expose the local Flask server to the Internet, allowing the ESP32 and controlling browser to be on different networks.

Hardware

• ESP32-WROOM-32E development board
• Red, green, blue and yellow LEDs
• 4 × 330 Ω resistors
• Breadboard and jumper wires
• USB cable or power bank

LED	GPIO
Red	18
Green	19
Blue	21
Yellow	23

Pinout

ESP32-WROOM-32E documentation and pin descriptions:

https://documentation.espressif.com/esp32-wroom-32e_esp32-wroom-32ue_datasheet_en.html

Repository structure

ArduinoIDE/
  ESP32_Remote_LED_Control/
    ESP32_Remote_LED_Control.ino

VisualStudioCode/
  ESP32_Remote_LED_Control/
    src/
      main.cpp
    platformio.ini

Server/
  app.py
  templates/
    index.html

Photos/
  PhotoOfProject.jpg
  ESP32 WROOM 32E PinOut.png

The Arduino IDE and Visual Studio Code versions use the same Arduino framework and the same ESP32 logic. The Visual Studio Code version is configured for PlatformIO.

Configuration

No personal Wi-Fi credentials or private server addresses are stored in this repository. The firmware contains placeholders:

const char* SSID = "YOUR_WIFI_NAME";
const char* PASSWORD = "YOUR_WIFI_PASSWORD";

const char* SERVER_URL =
  "https://YOUR-NGROK-DOMAIN.ngrok-free.dev/status";

Replace these locally before uploading the firmware. Do not commit your real Wi-Fi password.

Arduino IDE

Install esp32 by Espressif Systems, select ESP32 Dev Module, open the sketch from the ArduinoIDE folder, enter your local configuration, select the correct COM port and upload it.

Visual Studio Code

Install Visual Studio Code and PlatformIO, open VisualStudioCode/ESP32_Remote_LED_Control, enter your local Wi-Fi and ngrok values in src/main.cpp, then build and upload using PlatformIO.

Flask server and ngrok

Install Flask:

pip install flask

Start the local server:

python Server/app.py

It listens on port 5000. In another terminal expose it with ngrok:

ngrok http 5000

ngrok will display a public HTTPS address. Put that address plus /status into SERVER_URL in your local ESP32 firmware.

Example only:

const char* SERVER_URL =
  "https://example.ngrok-free.dev/status";

The real ngrok domain is intentionally not committed to the repository.

Server API

• / — web control page
• /toggle/<color> — toggles one LED
• /status — returns all LED states
• /status/<color> — returns one LED state

The order returned by /status is red, green, blue, yellow.

Security note

client.setInsecure() disables TLS certificate verification. It is convenient for this learning prototype but should be replaced with proper certificate validation in a production system.

License

MIT License.