The Raspberry Pi is a computer the size of a credit card. To use it, you need a keyboard and mouse, a monitor, and an SD card with Linux. The Raspberry Pi is powered by USB. The creator, Eben Upton at the University of Cambridge in Britain, is surprised at how popular the Pi has become in the few short months it's been available.

From John Bigg's New York Times story about Eben and his computer:

The Raspberry Pi Foundation began selling the computers in February of last year. They soon could not keep them in stock.

“We honestly were thinking of this as a 1,000- to 5,000-unit opportunity,” Mr. Upton said. “The thing we didn’t anticipate was this whole other market of technically competent adults who wanted to use it. We’re selling to hobbyists.”

…

Mr. Upton said he was “blown away” by the reception the Pi had gotten online.

“I’m not aware of a company that has gone from a standing start to a million in a year,” he said. “It’s quite a wild ride. I don’t get a lot of sleep at the moment.”

Matt Richardson, a frequent contributor to Boing Boing and a MAKE staffer, co-wrote this excellent introduction, called Getting Started with Raspberry Pi.

Here's a cute way to gimmick a keyboard out of a grid of beercans, using Raspberry Pis and Arduinos:

We did this at Webstock, event which took place in Bucharest in September. Staropramen, one of the sponsors of the event asked us for an innovative way to offer a trip to Prague to one of the event's guests.

So, we came up with a keyboard made out of 44 Staropramen beer cans. Each beer can was a key, and whenever someone touched it, the corresponding letter appeared on a large plasma screen (just like any regular computer keyboard).

And the surprise was fantastic! The user experience and engagement overcame any expectation. Every single person who attended Webstock tried the keyboard and participated to the contest.

Behind the scene, the system is built around an Arduino board and a few capacitive controllers (just like the ones which are inside smartphones' touch screens), connected to a Raspberry PI board which controls the plasma screen display.

The Beer Cans Keyboard Movie (via Hacker News)

A team of computer scientists at the University of Southampton in the UK created a supercomputer out of 64 Raspberry Pi matchbox Linux-on-a-chip computers and Lego. The team included six year old James Cox, the son of project lead Professor Simon Cox, "who provided specialist support on Lego and system testing."

Here's a PDF with instructions for making your own Raspberry Pi/Lego supercomputer.

Professor Cox comments: “As soon as we were able to source sufficient Raspberry Pi computers we wanted to see if it was possible to link them together into a supercomputer. We installed and built all of the necessary software on the Pi starting from a standard Debian Wheezy system image and we have published a guide so you can build your own supercomputer.”

The racking was built using Lego with a design developed by Simon and James, who has also been testing the Raspberry Pi by programming it using free computer programming software Python and Scratch over the summer. The machine, named “Iridis-Pi” after the University’s Iridis supercomputer, runs off a single 13 Amp mains socket and uses MPI (Message Passing Interface) to communicate between nodes using Ethernet. The whole system cost under £2,500 (excluding switches) and has a total of 64 processors and 1Tb of memory (16Gb SD cards for each Raspberry Pi). Professor Cox uses the free plug-in ‘Python Tools for Visual Studio’ to develop code for the Raspberry Pi.

Professor Cox adds: “The first test we ran – well obviously we calculated Pi on the Raspberry Pi using MPI, which is a well-known first test for any new supercomputer.”

Engineers Build Supercomputer Using Raspberry Pi, Lego [Parity News]

Southampton engineers a Raspberry Pi Supercomputer [Press release]

(Images: Simon J Cox 2012)