Back at the Bay Area Maker Faire in May, Arduino announced a big step forward for its hobbyist microcontroller boards: the Arduino Yun, a combination Arduino+Linux board with built-in Wi-Fi. After a few months of silence, Arduino recently announced that the Yun was ready for a September 10 release, and on Monday a new blog post detailed some of the microcontroller's hardware features.
For starters, Arduino doubled its planned 8MB of flash storage and 32GB of RAM to 16MB and 64MB to leave enough free space for user-installed packages. Arduino intends for uploading sketches, or programs, to the Yun to be easier than ever thanks to the built-in b/g/n Wi-Fi module. The Yun will auto-broadcast its presence on a network, so sketches can be uploaded from a computer wirelessly, or transferred the old-fashioned way via micro USB.
The Yun also has 10/100 Mbit Ethernet built-in. Take away Linux and the out-of-box Internet connectivity, and the Yun is an Arduino Leonardo with buffed up memory. It runs on the same ATmega32u4 microcontroller and uses the same 20 input/output pins. The Yun simply adds power and versatility--its Wi-Fi interface can double as an access point, it can draw power via micro USB, a Vin pin, or Power Over Ethernet, and it comes with a Teembo library to pair the Arduino with online APIs.
Arduino sketches and the Linux command line can talk to one another, and the board ships with "a full python installation and package manager" that can be used to install more software. The 16MB of flash can be expanded via microSD. A USB host port offers expandable functionality as well, like connecting a memory stick or webcam.
The Yun will keep its "coming soon" label on the Arduino store until September 10th, when the $68 board will be released to the world. If you care more about Linux and less about Arduino programming, the $35 Raspberry Pi offers a much more powerful processor, and more memory, in an equally tiny package.
(And don't forget to read our practical guide to Arduino boards!)