Yun vs Arduino board with ethernet/wifi/-shield ; I need some advice.

I am wondering if i should buy the Yun, or a typical Arduino board with network shield. My decision is more related to code interfacing then it is to price.

I've followed some youtubes, to get some Yun info, and have read about, but i still have some questions left. Maybe someone could help me out on these.

  • Can other small programs run inside the linux shield, or is it a fixed hard coded factory linux rom
  • Can the webserver and the arduino set and get string variables, ea "a hello world"
  • If one would like to send or retrieve specific network packet to other hosts on the netwerk. Then who does it on the Yun. Would it be the Arduino c++ code or would the Linux host handle it.
  • Is it possible to change the look and feel of the Yun Web interface
  • Can the arduino code itself also host a small HTML page, on a different port like http://x.x.x.x:8080 ?

I have not used a "network" shield with an Uno and I have only recently got a Yun.

As far as I can see the Linux side of the Yun will provide very much greater scope for web programming compared to the very limited facilities on an Uno or Mega.


Answering my own questions, might be handy for others,.

  • yes
  • yes
  • most likely the yun code, its the Yun who has Wifi/Lan access; and there is a bridge library to communicate with the yun.
  • Probaply the Linux variant is OPenWRT, its “open” (but might be a lot of work
  • through serial write and bridge library, it should be possible for the yun as a client to retrieve serial data and then display it on a web page for a client, the bridge library acts as a serial connection much as normal arduino would talk over serial back to a PC, …in fact a yun can also still do that besides showing its data over web, basicly you can get 2 serial connections from arduino to PC and to yun

It is not necessary to use the bridge library.

As far as I can see the standard Yun system was designed with the idea that most of the programing would happen on the Arduino side. The bridge system allows the Arduino to access all sorts of Linux features.

However you can disable the bridge and use the Linux side in a way similar to the way this Linux laptop communicates with an Uno, Mega etc.

I am building a Python project which I am hoping will work on my Yun as well as on my PC. The idea is that, when on the Yun, it can work fully without any need for a PC. It will probably be a few days before I am in a position to publish anything. Watch the "Interfacing" section of the Forum.


The Yun is an Arduino Leonardo plus a wifi/linux module running OpenWRT.

The Arduino Leonardo can’t run a webserver. It has the normal input/output pins and can do normal things like any other Leonardo.
Pin 0 (RX) and pin 1 (TX) are used to communicate between the Arduino Leonardo and the wifi/linux module, using the Brigde library.

The wifi/linux module can run on its own, without using the Leonardo. You can do almost anything that OpenWRT can do. Set it as wifi client; make it an wifi Access Point; running webcam streams; running websites; running scripts; make an internet radio; and so on. And all of that at the same time.
You can configure as much as you want. Different ports for a website is no problem.
With the USB host connector, extra flash drives, and devices can be connected.
I hope you have some linux knowledge, but without that you can give it a try, the documentation of OpenWRT is very helpful.

The magic happens with the Bridge library. For example a website that shows information from the Leonardo, then the Bridge library on the Leonardo communicates with the code on the wifi/linux module.
Via the Bridge library, the Leonardo can for example access files on the SD card, or a USB flash drive.