Open-source hardware has a loud and passionate following in the hobbyist community. In 2005, O'Reilly Media began publishing Make magazine, a quarterly how-to guide for all sorts of engineering and science projects. Make now has more than 100,000 subscribers and has spawned events known as Maker Faires, which are a cross between souped-up science fairs and high-tech craft shows. Last spring, 65,000 professionals and amateurs flocked to the San Francisco Bay Area Maker Faire to demonstrate projects that ranged from arts and crafts to engineering and science--and many that blurred the boundaries. And as they showed off their creations, attendees also shared ideas and met potential collaborators.

Around the time that Make was getting off the ground, Eric Wilhelm '99, SM '01, PhD '04, launched the Instructables website, which provides a template for step-by-step instructions that lets people document their engineering projects online. Since its users are allowed to comment on other people's projects, Instructables has created a vibrant community of technology enthusiasts who share information on building just about anything--including a computer mouse made from an actual dead mouse, an eight-foot-long match, and biodiesel fuel. (See Wilhelm's profile as a TR35 winner in the September/October issue of Technology Review.)

Andrew "Bunnie" Huang '97, MEng '97, PhD '02, another MIT entrepreneur, cofounded a company called Chumby to sell soft cubes, the size of a tissue box, equipped with a screen, a simple embedded computer, and a Wi-Fi connection. The Chumby, as it is called, can be used to display data from the Internet, such as Flickr photos or weather forecasts, or to tune in an Internet radio station. From the outset, Huang and his cofounders decided to make the Chumby open source so that customers could modify the basic unit to suit their own purposes. In essence, Huang has created a platform for building other devices. Huang himself has provided instructions for adding a higher-resolution screen, and more whimsically, he's posted instructions for turning two Chumbys into a remote-controlled car and hand-held controller. By making the Chumby hackable, Huang and his collaborators are creating a community of customers invested in helping with ongoing product development.

"Because of the Internet, and because of computing tools, the practice [of sharing hardware designs] has become much more powerful and practical," says von Hippel. In the past, he says, he would have had to mail out circuit diagrams or a drawing of a new robot arm to a couple of people and wait for their responses. Now, he can mock up an idea in a CAD program or one of several software systems that allow researchers to design microprocessors and radios, and blast the plans out to a user group, collaborators, or even visitors to his personal website. The feedback is almost immediate.