ESP32 Web-Controlled GPIO Interface

This project demonstrates how to use an ESP32 board as a simple web server to control GPIO pins through HTTP requests. It can be sets up in two different modalities:

1. As a Access Point to permit clients to connect via WiFi (currently disabled)
2. As a WiFi client, connected to an existing network

It exposes an HTTP interface (described below) to change the status of specific digital pins.

NOTE! ESP32 works with 2,4GHz band only.

Features

• Hosts a simple HTML web page at the root (/) with example content.
• Provides an HTTP endpoint (/pin) to control GPIO pin states via query parameters.
• Supports both WiFi Station and Access Point modes.
• Includes error handling for invalid or missing parameters.
• CORS headers enabled for the /pin endpoint.

Requirements

• ESP32 board
• Arduino IDE with ESP32 board support installed
• WiFi credentials (SSID and password)

Installation

1. Clone or copy the code to your local machine.
2. Open the sketch in the Arduino IDE.
3. Install the required libraries (typically included with ESP32 core):
   • WiFi.h
   • WebServer.h
4. Depending on your preferred usage:
   • Update WiFi credentials in setupWiFiStation():

     const char* ssid = "change-me";
     const char* password = "change-me";

   • Update WiFi credentials in setupAccessPoint():

      WiFi.softAP("ESP32-AP", "asdrubale123")

5. Upload the sketch to your ESP32.

Usage

Web Page

Once the ESP32 connects to your network, open a browser and go to the IP address shown in the Serial Monitor. You'll see a simple HTML page at the root path /.

Control GPIO Pins

You can control pins via the /pin endpoint.
Allowed pins: 2, 4, 5, 12, 13, 14, 15, 16, 17
Allowed statuses: ON, OFF

Example URL:

http://<ESP32_IP>/pin?number=13&status=ON

This sets pin 13 to HIGH.

Response

The ESP32 responds with an HTML confirmation showing the pin number and the new status.

Error Handling

• Missing parameters → 400 Bad Request
• Invalid pins → 404 Not Found
• Unknown routes → 404 page with redirect to /

Customization

• You can easily modify the HTML content in the rootHtmlContent variable.
• To enable Access Point mode, uncomment the setupAccessPoint() call in setup() and comment out the WiFi Station mode.

License

This project is open-source and free to use for educational and personal purposes.