SimpleWebServerWiFi only for WiFi Link firmware


In this tutorial is shown how to create a simple Web Server for commanding a Led, using the WiFi Link library on the Arduino UNO WiFi.

Use the Arduino IDE 1.8.x  and import the WiFi Link library using the Library Manager.

WiFi Link library



A Led has two legs called Anode(+) and Cathode(-).
Connect the Anode, normally the longer leg, to a 220 OHM Resistor and connect it to pin 9 of the board.
Finally connect the Cathode to GND and plug the board to PC.



Modify the below sketch inserting the name and the password of your network and after upload the code using the Arduino IDE.
This example is written for a WPA encryption network. If you want to use it  for WEP or WPA, change the Wifi.begin() call accordingly.

Make sure that the board uses the WiFi Link firmware.

WiFi Web Server LED Blink

A simple web server that lets you blink an LED via the web.
This sketch will print the IP address of your board (once connected)
to the Serial monitor. From there, you can open that address in a web browser
to turn on and off the LED on pin 9.

If the IP address of your shield is yourAddress:
http://yourAddress/H turns the LED on
http://yourAddress/L turns it off

This example is written for a network using WPA encryption. For
WEP or WPA, change the Wifi.begin() call accordingly.

* Arduino Primo or STAR OTTO or Uno WiFi Developer Edition (with WiFi Link firmware running)
* LED attached to pin 9

created 25 Nov 2012
by Tom Igoe
modified 10 March 2017
by Sergio Tomasello and Andrea Cannistrá

#include <WiFiLink.h>

char ssid[] = "yourNetwork"; // your network SSID (name)
char pass[] = "yourPassword"; // your network password
int keyIndex = 0; // your network key Index number (needed only for WEP)

int status = WL_IDLE_STATUS;
WiFiServer server(80);

void setup() {
Serial.begin(115200); // initialize serial communication
pinMode(9, OUTPUT); // set the LED pin mode

//Check if communication with the wifi module has been established
if (WiFi.status() == WL_NO_WIFI_MODULE_COMM) {
Serial.println("Communication with WiFi module not established.");
while (true); // don't continue:

// attempt to connect to Wifi network:
while ( status != WL_CONNECTED) {
Serial.print("Attempting to connect to Network named: ");
Serial.println(ssid); // print the network name (SSID);

// Connect to WPA/WPA2 network. Change this line if using open or WEP network:
status = WiFi.begin(ssid, pass);
// wait 10 seconds for connection:
server.begin(); // start the web server on port 80
printWifiStatus(); // you're connected now, so print out the status

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

if (client) { // if you get a client,
Serial.println("new client"); // print a message out 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 =; // read a byte, then
Serial.write(c); // print it out the serial monitor
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");

// the content of the HTTP response follows the header:
client.print("Click <a href=\"/H\">here</a> turn the LED on pin 9 on<br>");
client.print("Click <a href=\"/L\">here</a> turn the LED on pin 9 off<br>");

// The HTTP response ends with another blank line:
// break out of the while loop:
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

// Check to see if the client request was "GET /H" or "GET /L":
if (currentLine.endsWith("GET /H")) {
digitalWrite(9, HIGH); // GET /H turns the LED on
if (currentLine.endsWith("GET /L")) {
digitalWrite(9, LOW); // GET /L turns the LED off
// close the connection:
Serial.println("client disonnected");

void printWifiStatus() {
// print the SSID of the network you're attached to:
Serial.print("SSID: ");

// print your WiFi shield's IP address:
IPAddress ip = WiFi.localIP();
Serial.print("IP Address: ");

// print the received signal strength:
long rssi = WiFi.RSSI();
Serial.print("signal strength (RSSI):");
Serial.println(" dBm");
// print where to go in a browser:
Serial.print("To see this page in action, open a browser to http://");


Open  the Serial Monitor and check the ip address:


Open a browser and type the ip address previously shown:

Set the Led

Turn on the Led 9:

Turn on the Led

Turn off the Led 9:

Turn off Led