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How to Set an ESP32 Access Point (AP) for Web Server

The ESP32 can act as a Wi-Fi station, as an access point, or both. In this tutorial we’ll show you how to set the ESP32 as an access point using Arduino IDE.

In most projects with the ESP32, we connect the ESP32 to a wireless router (see our ESP32 web server tutorial). This way we can access the ESP32 through the local network.

In this situation the router acts as an access point and the ESP32 is set as a station. In this scenario, you need to be connected to your router (local network) to control the ESP32.

But if you set the ESP32 as an access point (hotspot), you can be connected to the ESP32 using any device with Wi-Fi capabilities without the need to connect to your router.

In simple words, when you set the ESP32 as an access point you create its own Wi-Fi network and nearby Wi-Fi devices (stations) can connect to it (like your smartphone or your computer).

Here we’ll show you how to set the ESP32 as an access point in your web server projects. This way, you don’t need to be connected to a router to control your ESP32. Because the ESP32 doesn’t connect further to a wired network (like your router), it is called soft-AP (soft Access Point).

Installing the ESP32 board in Arduino IDE

There’s an add-on for the Arduino IDE that allows you to program the ESP32 using the Arduino IDE and its programming language. Follow one of the following tutorials to prepare your Arduino IDE:

ESP32 Access Point

In this example, we’ll modify an ESP32 Web Server from a previous tutorial to add access point capabilities. What we’ll show you here can be used with any ESP32 web server example.

Upload the sketch provided below to set the ESP32 as an access point.

/*********
  Gnd_TO_Vcc
*********/

// Load Wi-Fi library
#include <WiFi.h>

// Replace with your network credentials
const char* ssid     = "ESP32-Access-Point";
const char* password = "123456789";

// Set web server port number to 80
WiFiServer server(80);

// Variable to store the HTTP request
String header;

// Auxiliar variables to store the current output state
String output26State = "off";
String output27State = "off";

// Assign output variables to GPIO pins
const int output26 = 26;
const int output27 = 27;

void setup() {
  Serial.begin(115200);
  // Initialize the output variables as outputs
  pinMode(output26, OUTPUT);
  pinMode(output27, OUTPUT);
  // Set outputs to LOW
  digitalWrite(output26, LOW);
  digitalWrite(output27, LOW);

  // Connect to Wi-Fi network with SSID and password
  Serial.print("Setting AP (Access Point)…");
  // Remove the password parameter, if you want the AP (Access Point) to be open
  WiFi.softAP(ssid, password);

  IPAddress IP = WiFi.softAPIP();
  Serial.print("AP IP address: ");
  Serial.println(IP);
  
  server.begin();
}

void loop(){
  WiFiClient client = server.available();   // Listen for incoming clients

  if (client) {                             // If a new client connects,
    Serial.println("New Client.");          // print a message out in the serial port
    String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected()) {            // loop while the client's connected
      if (client.available()) {             // if there's bytes to read from the client,
        char c = client.read();             // read a byte, then
        Serial.write(c);                    // print it out the serial monitor
        header += c;
        if (c == '\n') {                    // if the byte is a newline character
          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0) {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println("Connection: close");
            client.println();
            
            // turns the GPIOs on and off
            if (header.indexOf("GET /26/on") >= 0) {
              Serial.println("GPIO 26 on");
              output26State = "on";
              digitalWrite(output26, HIGH);
            } else if (header.indexOf("GET /26/off") >= 0) {
              Serial.println("GPIO 26 off");
              output26State = "off";
              digitalWrite(output26, LOW);
            } else if (header.indexOf("GET /27/on") >= 0) {
              Serial.println("GPIO 27 on");
              output27State = "on";
              digitalWrite(output27, HIGH);
            } else if (header.indexOf("GET /27/off") >= 0) {
              Serial.println("GPIO 27 off");
              output27State = "off";
              digitalWrite(output27, LOW);
            }
            
            // Display the HTML web page
            client.println("<!DOCTYPE html><html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
            client.println("<link rel=\"icon\" href=\"data:,\">");
            // CSS to style the on/off buttons 
            // Feel free to change the background-color and font-size attributes to fit your preferences
            client.println("<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}");
            client.println(".button { background-color: #4CAF50; border: none; color: white; padding: 16px 40px;");
            client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
            client.println(".button2 {background-color: #555555;}</style></head>");
            
            // Web Page Heading
            client.println("<body><h1>ESP32 Web Server</h1>");
            
            // Display current state, and ON/OFF buttons for GPIO 26  
            client.println("<p>GPIO 26 - State " + output26State + "</p>");
            // If the output26State is off, it displays the ON button       
            if (output26State=="off") {
              client.println("<p><a href=\"/26/on\"><button class=\"button\">ON</button></a></p>");
            } else {
              client.println("<p><a href=\"/26/off\"><button class=\"button button2\">OFF</button></a></p>");
            } 
               
            // Display current state, and ON/OFF buttons for GPIO 27  
            client.println("<p>GPIO 27 - State " + output27State + "</p>");
            // If the output27State is off, it displays the ON button       
            if (output27State=="off") {
              client.println("<p><a href=\"/27/on\"><button class=\"button\">ON</button></a></p>");
            } else {
              client.println("<p><a href=\"/27/off\"><button class=\"button button2\">OFF</button></a></p>");
            }
            client.println("</body></html>");
            
            // The HTTP response ends with another blank line
            client.println();
            // Break out of the while loop
            break;
          } else { // if you got a newline, then clear currentLine
            currentLine = "";
          }
        } else if (c != '\r') {  // if you got anything else but a carriage return character,
          currentLine += c;      // add it to the end of the currentLine
        }
      }
    }
    // Clear the header variable
    header = "";
    // Close the connection
    client.stop();
    Serial.println("Client disconnected.");
    Serial.println("");
  }
}

Customize the SSID and Password

You need to define a SSID name and a password to access the ESP32. In this example we’re setting the ESP32 SSID name to ESP32-Access-Point, but you can modify the name to whatever you want. The password is 123456789, but you can also modify it.

// You can customize the SSID name and change the password
const char* ssid = "ESP32-Access-Point";
const char* password = "123456789";

Setting the ESP32 as an Access Point

There’s a section in the setup() to set the ESP32 as an access point using the softAP() method:

WiFi.softAP(ssid, password);

There are also other optional parameters you can pass to the softAP() method. Here’s all the parameters:

.softAP(const char* ssid, const char* password, int channel, int ssid_hidden, int max_connection)
  • SSID (defined earlier): maximum of 63 characters;
  • password(defined earlier): minimum of 8 characters; set to NULL if you want the access point to be open
  • channel: Wi-Fi channel number (1-13)
  • ssid_hidden: (0 = broadcast SSID, 1 = hide SSID)
  • max_connection: maximum simultaneous connected clients (1-4)

Next, we need to get the access point IP address using the softAPIP() method and print it in the Serial Monitor.

IPAddress IP = WiFi.softAPIP();
Serial.print("AP IP address: ");
Serial.println(IP);

These are the snippets of code you need to include in your web server sketches to set the ESP32 as an access point. To learn how the full web server code works, take a look at the ESP32 Web Server tutorial.

Parts Required

For this tutorial you’ll need the following parts:

  • ESP32 development board –  read ESP32 Development Boards Review and Comparison
  • 2x 5mm LED
  • 2x 330 Ohm resistor
  • Breadboard
  • Jumper wires

Schematic

Start by building the circuit. Connect two LEDs to the ESP32 as shown in the following schematic diagram – one LED connected to GPIO 26, and the other to GPIO 27.

Note: We’re using the ESP32 DEVKIT DOIT board with 36 pins. Before assembling the circuit, make sure you check the pinout for the board you’re using.

ESP32 IP Address

Upload the code to your ESP32 (make sure you have the right board and COM port selected). Open the Serial Monitor at a baud rate of 115200. Press the ESP32 “Enable” button.

The IP address you need to access the ESP32 point will be printed. In this case, it is 192.168.4.1.

Connecting to the ESP32 Access Point

Having the ESP32 running the new sketch, in your smartphone open your Wi-Fi settings and tap the ESP32-Access-Point network:

Enter the password you’ve defined earlier in the code.

Open your web browser and type the IP address 192.168.4.1. The web server page should load:

To connect to the access point on your computer, go to the Network and Internet Settings and select the “ESP32-Access-Point“.

And it’s done! Now, to access the ESP32 web server page, you just need to type the ESP32 IP address on your browser.

Wrapping Up

This simple tutorial showed you how to set the ESP32 as an access point on your web server sketches. When the ESP32 is set as an access point, devices with Wi-Fi capabilities can connect directly to the ESP32 without the need to connect to a router.

You may also like reading:

We hope you’ve found this tutorial useful. If you like ESP32 and you want to learn more,

Thanks for reading.

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Published by Gnd_To_Vcc

Here to spread my knowledge . Knowledge should always be spread not stored.

2 thoughts on “How to Set an ESP32 Access Point (AP) for Web Server

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