Freeduino is Arduino-compatible
Freeduino began as a collaborative project to publish open-source Arduino-compatible production files. The files that resulted from this project allow users to create boards that are 100% functionally, electrically and physically compatible with Arduino hardware. Over time, Freeduino has come to mean hardware that is "Arduino-compatible".
Freeduino is Trademark-free
Arduino is the name of the official Arduino microcontroller project, hosted at arduino.cc. Although "Arduino" is not offically registered (trademark registration was refused in the US in June 2009, based on the fact that Arduino is "primarily merely a surname"), it is generally respected by the Arduino/Freeduino community as the property of the Arduino team. This means using the Arduino name on your products is a community no-no.
Freeduino, on the other hand, comes with a free and unrestricted license to use the Freeduino name, for any use. Branding products as Freeduino instead allows users to build on the established knowledge and open-source licenses of the Arduino project without having to worry about the slim possibility of trademark infringement. This means that you can take the files you find here, make products, brand them as Freeduino and sell them- or do whatever you want with them- without asking. While definitive policies for open-source hardware have not yet been developed, this 'freedom of use' policy is similar to the Open Source Initiative's Open Source Definition.
Freeduino is an experiment in decentralized hardware design.
Freeduino is a free-form version of the Arduino, in that is not developed under a centralized design process.There is no Freeduino team, or anyone to ask permission of: anyone, anywhere, can design and produce a Freeduino product, no questions asked, no royalties paid. It's sort of like electronic harware anarchy- or democracy, depending on how you look at it. We derived the Freeduino files from Arduino for exactly this reason: to see what the Arduino project would have looked like if it had open hardware distribution and manufacturing.
So far, the experiment has turned out well: for example, unbeknownst to the Freeduino project, some fine folks in Toronto, Canada downloaded the Freeduino files and modified them to work on DB-9 serial. Now they sell them online! Everyone wins, which is just the way we like it. Click on the image to buy one.
Here is a more recent Freeduino hack: the ARP 1.0, by Robotics India. They kindly give us credit on thier board, calling it "Freeduino-based"!