#Introduction

The ESP32 is a powerful microcontroller with built-in Wi-Fi, making it ideal for IoT, smart devices, and wireless communication. Two of its most essential Wi-Fi operating modes are:

• Station Mode (STA)
• Access Point Mode (AP)

#What is Station Mode?

In Station Mode, the ESP32 acts like a Wi-Fi client—it connects to an existing Wi-Fi network, such as your home router or a mobile hotspot. Once connected, the ESP32 can send and receive data through the internet or a local network.

#Example Use Cases:

• Sending sensor data to the cloud
• Fetching online weather or time information
• Remote device control via a smartphone app or web dashboard

#Code:

#include <WiFi.h>

const char* ssid = "YOUR_SSID"; const char* password = "YOUR_PASSWORD";

void setup() { Serial.begin(115200);

WiFi.begin(ssid, password); Serial.print("Connecting to WiFi");

while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); //...... }

Serial.println("\nConnected!"); Serial.print("IP Address: "); Serial.println(WiFi.localIP()); }

void loop() { // Nothing here for now }

#What is Access Point Mode?

In Access Point Mode, the ESP32 creates its own Wi-Fi network (hotspot). Devices like phones or laptops can connect directly to the ESP32 without needing a router or internet access. This is useful for local control or configuration when no internet is available.

#Example Use Cases:

• Offline control of smart devices
• Initial setup/configuration pages
• Peer-to-peer data exchange without the internet

#Example Code:

#include <WiFi.h>

const char* AP_SSID = "ESP32_Hotspot"; const char* AP_PASSWORD = "12345678";

void setup() { Serial.begin(115200);

WiFi.softAP(AP_SSID, AP_PASSWORD); Serial.println("Access Point started"); Serial.print("IP address: "); Serial.println(WiFi.softAPIP()); //192.168.4.1 }

void loop() { // Nothing here yet }

#ESP32 Access Point Mode: Create a Wi-Fi Hotspot to Control an LED

The ESP32 isn't just capable of connecting to Wi-Fi networks—it can also create its own Wi-Fi network using Access Point (AP) Mode. This allows users to connect to the ESP32 directly without a router and control devices like LEDs via a local web interface.

In this guide, we'll set up the ESP32 as an Access Point and host a web page that lets you turn an LED on or off from your browser.

Once set up, your ESP32 will:

• Create a Wi-Fi hotspot called "ESP32_Hotspot"
• Serve a simple web page with ON and OFF buttons
• Control an LED connected to GPIO 2 (you can change this pin if needed)

#Code

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

// Access Point credentials const char* ssid = "ESP32_Hotspot"; const char* password = "12345678";

// Create web server on port 80 WebServer server(80);

// Define LED pin (GPIO 2 for onboard LED) const int ledPin = 2; bool ledState = LOW;

// HTML content to be served const char* htmlPage = R"rawliteral(

ESP32 LED Control

Status: %STATE%

Turn ON Turn OFF )rawliteral";

void handleRoot() { String html = htmlPage; html.replace("%STATE%", ledState ? "ON" : "OFF"); server.send(200, "text/html", html); }

void handleLedOn() { digitalWrite(ledPin, HIGH); ledState = true; handleRoot(); }

void handleLedOff() { digitalWrite(ledPin, LOW); ledState = false; handleRoot(); }

void setup() { Serial.begin(115200); pinMode(ledPin, OUTPUT); digitalWrite(ledPin, ledState);

// Start Access Point WiFi.softAP(ssid, password); Serial.println("Access Point Started"); Serial.print("IP address: "); Serial.println(WiFi.softAPIP());

// Define routes server.on("/", handleRoot); server.on("/led/on", handleLedOn); server.on("/led/off", handleLedOff); server.begin(); }

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

#How to Use It

• Upload the code to your ESP32.
• Open the Serial Monitor at 115200 baud to view the IP address.

Connect your phone or laptop to the Wi-Fi named ESP32_Hotspot using password 12345678.

• Open a browser and enter the IP address from Serial Monitor (e.g., 192.168.4.1).
• Use the buttons to turn the LED ON or OFF!