Build a Simple Web Server with ESP32 to Control an LED

Introduction

The ESP32 is a powerhouse for IoT developers because it has built-in Wi-Fi and Bluetooth. In this tutorial, we won’t just blink an LED; we will build a standalone Web Server hosted entirely on the ESP32. This allows you to control the LED from your smartphone browser without paying for any cloud services.

What You Need

• ESP32 Development Board (DOIT DevKit V1 or similar)
• LED (Any color)
• 330Ω Resistor
• Breadboard & Jumper Wires

The Circuit

The wiring is simple:

1. Connect the Long Leg (+) of the LED to GPIO 2.
2. Connect the Short Leg (-) to the Resistor, and then to GND.

The Code

We will use the WiFi.h and WebServer.h libraries.

#include <WiFi.h>
#include <WebServer.h>

// Replace with your network credentials
const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";

WebServer server(80);

const int ledPin = 2;

void handleRoot() {
  String html = "<h1>ESP32 Web Server</h1>";
  html += "<p><a href=\"/on\"><button>Turn On</button></a></p>";
  html += "<p><a href=\"/off\"><button>Turn Off</button></a></p>";
  server.send(200, "text/html", html);
}

void setup() {
  pinMode(ledPin, OUTPUT);
  // Rest of setup code...
}

void loop() {
  server.handleClient();
}

How to Test It

1. Upload the code to your ESP32.
2. Open the Serial Monitor (115200 baud).
3. Type the IP address into your phone's browser.