How do I use Arduino and node.js?

Question

I am new to Arduino, however I have experience in web development, lately I have been using, meteor js and the mean stack for different projects. However, I am open to trying any language for development.

What I am trying to do is build a simple application to control the LED on the Arduino over the web.

I am working with another person, and the Arduino will be behind a firewall so I am not sure how to access it via the internet. I do have access to an Arduino Uun that I can use for testing at home which does have linio connected via bridge, which I don't quite understand what that does.

I've also heard of this, but would like to stay away from third party builds as much as possible if I can do it myself.

Whats the common way to do this with an Arduino behind a firewall? How do I do this with a Arduino Yun? Is it easier with a Yun?

Answer 1

I am working on similar project that uses internet to communicate with external device (mobile). I am reading data from sensors and passing them over the web with web sockets. I am using Arduino Yun for this project and Spacebrew (for web sockets communication). It's very interesting approach but quite a challenge in some cases. You will probably run into asynchronous/synchronous problem, which in my case lead me to running some Python scripts on Yun triggered from Processing code. I am currently running Spacebrew server on my VPN, so I can connect my Yun left at home and use my iphone from everywhere to get the readings.

It's also worth mentioning Yun comes with pre-installed Temboo library, which is great starting point for web communication. The configuration is really easy and quick. You will also find official documentation very handy and easy to understand. It's really great starting point for experimenting with web-like applications integrated with Arduino Yun.

Spacebrew

• http://docs.spacebrew.cc/

  Spacebrew is an open, dynamically re-routable software toolkit for choreographing interactive spaces. Or, in other words, a simple way to connect interactive things to one another. Every element you hook up to the system can subscribe to, and publish data feeds.

• http://github.com/Spacebrew/pySpacebrew

  This repo contains the Spacebrew Library for Python along with documentation and example apps.

• http://github.com/julioterra/yunSpacebrew

  The Spacebrew Yun library features two main components - a set of python scripts that run on the linino, and a library that runs on the atmel chip. You find there information how to install both of these components so that you can connect to Spacebrew from an Arduino sketch.

Temboo

Yun has also build in Temboo library, it's a great way to start experimenting, once you prove the concept you can start narrowing your environment and moving away if you don't want to use 3rd parties software.

• http://www.temboo.com/arduino

  The Temboo Library makes it easy to connect to over 100 web-based resources and services with Processing. Currently you can find libraries for Android, Arduino, iOS, Java, Node.js, PHP, Processing, Python, REST API, Ruby, Twyla

Node.js

You can also run node.js on the Yun itself, here's good article and some packages ready to install:

• http://giorgiocefaro.com/blog/installing-node-js-on-arduino-yun

• https://github.com/giorrrgio/nodejs-linino

  This is an openwrt package for node. It probably only works on mips (not mipsel, or arm). It runs an outdated v8 as well.

What is Bridge library for Arduino Yun?

You also asked about Bridge library. As you know Yun has two processors on board, one is running your Processing code, the other one has Linux on it (Linino). Bridge basically simplifies communication between them so they can "talk" to eachother, more information here:

• http://arduino.cc/en/Reference/YunBridgeLibrary

  (Taken from arduino.cc documentation:)

  The Arduino Yún has two processors on board. One is an ATmega32U4 like on the Arduino Leonardo. The other is an Atheros 9331, running Linux and the OpenWRT wireless stack, which enables the board to connect to WiFi and Ethernet networks. It is possible to call programs or custom scripts on the Linux system through the Arduino to connect with various internet services.

  The Bridge library simplifies communication between the ATmega32U4 and the AR9331. It inherits from Stream, and many of the methods should be familiar from Serial and other derivatives of Stream.

  Bridge commands from the 32U4 are interpreted by Python on the AR9331. Its role is to execute programs on the GNU/Linux side when asked by Arduino, provide a shared storage space for sharing data like sensor readings between the Arduino and the Internet, and receiving commands from the Internet and passing them directly to the Arduino.

  Bridge allows communication in both directions, acting as an interface to the the Linino command line.

Where to start?

I would start with Temboo if I were you, it's a great learning curve and quite simple step to start. You will also learn and understand how the board works and how you can communicate with "external world". Once you have proof of concept, start experimenting with different libraries and improving the approach. Perhaps you will find Spacebrew more handy later or even discover different solutions.

Answer 2

first of all you need to have clear what you need to do. Arduino UNO is just a microcontroller with a serial (over USB) connection. To make your arduino accessible from the internet, it need to be connected with the internet, or to have something that act like a bridge. You can use an ethernet shield, a wifi shiled, or a YUN witch is an arduino UNO + a micro linux with has ethernet and wifi (programmable in phyton, or the chip can command the linux sending command to bash shell using the special bridge library) You can even connect arduin on the pc by usb and create a bridge program, or, if your firewall/router is a unlocked linux/similar, you can use it.

How many option, and we event startint to decide how o talk with it. As you want to use node.sj, you can use socket or get/post. Using socket is faster, lighter, and can create a pull connection, and js wil be a requisite. With get/post you don't even need js, pure html form will do.

then, after you decided witch sistem you like (arduino as http server or plain socket) you can open the corresponding port on the firewall/nat. but is just the last part