Small processors on tiny circuit boards have been all the rage in the embedded community for years. The Arduino micro-controller has become the default prototyping environment for electronics and embedded users alike, but the platform has always been specifically targeted at existing embedded developers. But the Raspberry Pi has changed that paradigm.

While the Arduino is based on a microcontroller, the Raspberry Pi is actually a complete PC, yet the board itself is no larger than a stack of credit cards. While users of the Arduino have to write all their software from scratch, a Raspberry Pi can run Linux or Windows, as well as any applications written for those platforms.

That means building a webcam would be much easier on a Raspberry Pi, where you could install existing software and camera drivers, write a shell script to push the images to an HTTP directory, and host the whole thing up to the Web with Apache, all on a local Raspberry Pi. And best of all, the Raspberry Pi costs only US$25 a piece.

The project began in 2009 with the formation of a non-profit known as the Raspberry Pi Foundation. The goal was to spark interest in computing and computer science in the classroom by providing a low-cost platform for teaching those topics.

Eben Upton, technical director and application-specific integrated circuits architect at Broadcom, is the founder of the Raspberry Pi Foundation. He said it all began at the University of Cambridge.

“It was an attempt by a group of us at the University in Cambridge to reverse the decline in the numbers and skillsets of applicants taking computer science at the University,” he said. “Obviously it’s grown beyond anything we could have imagined, in large part because of the interest from the maker/hacker community.”

That enthusiasm has seen home users plug Raspberry Pis into their media centers, place them on remote-controlled vehicles, or use them in their home-security and automation systems. Because it is a full computer, there are no limitations on what it can be used for.

“I think it eliminates a lot of the scale advantages in consumer and industrial electronics, and also brings embedded programming within reach of engineers with more traditional desktop or enterprise skillsets,” said Upton. “Compared to a microcontroller, what advantages does the Pi offer? Much more memory, much higher performance, and the ability to run a ‘real’ protected-mode operating system.”

And that opens up a lot of possibilities. Each Raspberry Pi has a built-in HDMI port, so they can easily be used to stream video across a network and onto an HDTV. Each Raspberry Pi also has a USB port and an Ethernet port, meaning each one can be attached to sensors and to the network.

And while the Raspberry Pi continues to evolve (the foundation is working on more versions with different attachments and speeds), it’s certain that the platform will continue to adhere to the low price point and small form factor.