I'm trying to set up a simple web-server with Arduino Yun without an SD card, i.e via REST, if I understood it right (I'm new to some of these stuff). I want to be able to "get" data (sent by Arduino) through a jQuery script and show the user a formatted HTML page.

Here I provide you a simplified version of my Arduino sketch:

#include <Bridge.h>
#include <YunServer.h>
#include <YunClient.h>

const byte internalLED = 13;

YunServer server;

void setup() {
  pinMode(internalLED, OUTPUT);
  digitalWrite(internalLED, HIGH);     // Turn the led on to advise about bridge begin in progress
  Bridge.begin();          // Let's activate the Yun Bridge...
  ledBlink(150);           // ...bridge activation done (user sees a blink)
  // server.listenOnLocalhost();       // Listen for incoming connection only from localhost (no one from the external network could connect)
  server.begin();          // Let's acrivate the Yun server...
  ledBlink(150);           // ...server activation done (user sees a blink)

void loop() {
  YunClient client = server.accept();  // Get clients coming from server
  if (client)                          // Is there a new client?
    client.print(77);                  // Send a "77" to client (e.g. browser)
    client.stop();                     // Close connection and free resources.

void ledBlink(int delayTime) {
  digitalWrite(internalLED, HIGH); // Turn (or keep) the LED on
  digitalWrite(internalLED, LOW);  // Turn (or keep) the LED off

My Arduino Yun is connected via WiFi with static IP ( to the same network of my laptop, and they can ping each other. Right now, if I insert into my browser the address

I correctly receive a simple «77» (no quotes or \r\n)

But I cannot "get" it when opening the page get_test.html (which is on my harddisk, not in the SD):

<!DOCTYPE html>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
    $.get("", {}, function(data,status){
      alert("Data: " + data + "\nStatus: " + status);

This is strange to me because this html code works if I change the address inside the "get" request with https://dl.dropboxusercontent.com/u/12389503/demo_test.txt which consists only of a «21» (no \r\n). The problem is I don't even receive the alert when the address is the IP of Arduino, but the board is receiving the request since I can see the led blinking once, as expected. I'm running out of tests, any suggestion is welcome.

1 Answer 1


Whenever making ajax calls from/to different hosts (as your pc and the yun) you should use JSONP.

  • 1
    Thank you, I finally got it working today. I created a JSONP message as you told me. I changed in the sketch from client.print(77); to client.println("temperature({\"value\": 77});");. My jQuery request is now $.ajax({url: '', dataType: 'jsonp', jsonpCallback: 'temperature', success: function(result){alert("Value received through JSONP is "+result.value)}});
    – Kar.ma
    Sep 25, 2014 at 16:14

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