Web Server, here we go..
Hello guys, hope you all safe and sound, knowing how rapid this Covid-19 Pandemic spread. It’s indeed affecting our daily life, but not with our thirst for a new brand knowledge about ESP32. We’ll try to build a web server this time, so here we go!
We’ll try to make a switch to turn LED on and off using web browser this time, so here is our schematic for this experiment. I’ll use GPIO 26 for red LED and 27 for green LED, you can use another compatible pin if you want. don’t forget to use resistor to reduce the voltage so that the voltage doesn’t broke the LED.
After you’ve done building that schematic on your own, we can start to code the ESP32 using Arduino IDE that we have. here the example for you to try it your own. Don’t forget to input Wi-Fi SSID and password that you use to connect to the network.
// Load Wi-Fi library
#include <WiFi.h>
// Replace with your network credentials
const char* ssid = "No Internet Access";
const char* password = "sijingantisongo";// 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("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
// Print local IP address and start web server
Serial.println("");
Serial.println("WiFi connected.");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
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(".buttonred {background-color: #eb5252;}");
client.println(".buttongreen {background-color: #4CAF50;}");
client.println(".buttonoff {background-color: #555555;}</style></head>");
// Web Page Heading
client.println("<body><h1>ESP32 Web Server</h1>");
client.println("<body><h2>Turn LED ON or OFF using the switchs below</h2>");
// Display current state, and ON/OFF buttons for GPIO 26
client.println("<p>GPIO 26 Red - 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 buttonred\">ON</button></a></p>");
} else {
client.println("<p><a href=\"/26/off\"><button class=\"button buttonoff\">OFF</button></a></p>");
}
// Display current state, and ON/OFF buttons for GPIO 27
client.println("<p>GPIO 27 Green - 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 buttongreen\">ON</button></a></p>");
} else {
client.println("<p><a href=\"/27/off\"><button class=\"button buttonoff\">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("");
}
}
After you’ve done compiling and run it in your ESP32, try open your Arduino IDE’s serial monitor and you’ll see something like the pictures below.
Try to open those IP Address in your internet browser and you’ll see the switch to turn the LEDs on and off.
Isn’t it fun to play with these magnificent things?
See ya in our next project!!
P.S. My teammate and I had no problem completing this project because we have our own ESP32 for each one of us so WFO that applied this time does’t bother us significantly , we still can communicate with one another using chat app. But even so, we hope that this pandemic soon to resolve because doing it together is better than doing it alone. Stay safe everyone!!
