The Arduino Yún has been unveiled as the first of a family of wifi products that combine Arduino with Linux by using a system on a chip running Linino, a customized version of OpenWRT.
According to the Arduino blog, which reported the new board minutes after Massimo Banzi announced it in San Fransisco at the Bay Area Maker Faire, in Chinese Yún means “cloud” and the purpose of this board to make it simple to connect to complex web services directly from Arduino.
Banzi, creator of the Arduino, explained that the Yún's internal architecture combines a classic Arduino Leonardo (based on the Atmega32u4 processor) with a wifi system-on-a-chip, namely an Atheros AR9331 running Linino, which is a MIPS GNU/Linux based on OpenWRT. The Yún also has a Standard-A type USB connector and a micro-SD card plug, for additional storage. It is expected to be available at the end of June at a cost of $69 plus taxes.
Until now Arduino enthusiasts wanting to put their devices on the internet have had to buy a relatively expensive shield and still faced the problem of limited memory. With the Yún, as soon as it is switched on, it becomes an Access point, creating a wifi network named "Arduino" which can easily be added to a home network.
The Bridge library on the Arduino Yún delegates all network connections and processing of HTTP transactions to the Linux machine. By using this library in your sketches, you can link the 32u4 to Linux, launching programs and scripts, passing them parameters (sensor readings for example) and reading their output. It supports Shell and Python scripts out-of-the-box and you can install a wide range of open source software and tools. Arduino is partnering with Temboo to provide access to more than a hundred APIs to take advantage of data from multiple platforms, such as Twitter, Facebook and PayPal.
At the price quoted the Yún isn't as cheap as say a Raspberry Pi with a USB dongle but the price difference might well be worth it to have the more powerful range of interface options and simpler programming of the Arduino. The Yún is just right for a lot of projects.