As Joseph Jacobson is fond of pointing out, for all the gains in semiconductor chip performance over the past few decades, a typical integrated circuit-the brains behind your computer-is still far too expensive for most people on the planet. "Look at the way [a chip] is made," he says, punching the air with one hand while directing a PowerPoint presentation with the other. Fabricating a high-quality logic chip like Intel's Pentium processor, he points out, takes "two weeks, seven days a week, 24 hours a day. Chip fabrication facilities like the ones that Intel has are a $1.6 billion tool. And there are very few people on the globe who can touch that tool."

Jacobson's solution: a "desktop fab" able to print circuits directly on a substrate, such as plastic, without the expense and hassle of a multibillion-dollar manufacturing facility. Jacobson, head of the Printed PC Group at MIT's Media Lab, has already managed to print rudimentary but working transistors using an "ink" consisting of nanometer-sized semiconductor particles. "Our goal is to follow the trajectory silicon took, and start printing processors with perhaps several hundred transistors, moving to thousands and then more," says Jacobson. "We should be able to demonstrate a very simple processor in the next 12 to 18 months." And he predicts that printed logic chips with the speed and power of a Pentium could eventually be possible, making microchips available for a fraction of the time and expense associated with conventional manufacturing.

If Jacobson's vision becomes reality, it could change everything in computer hardware. Printed electronics could be cheap enough to find their way into everything from "wallpaper" able to display changeable images to custom-designed logic circuitry. A chip fab on every desktop could bring about the day when individuals download the architecture of integrated circuits the way they download software today. It could, in short, transform hardware manufacturing much the way the "open-source" movement has changed how software is written. Indeed, at his most visionary, Jacobson contends printed logic could give rise to an open-source hardware movement where chips are custom-designed via the Internet and printed by the consumer in about the same time it takes to print out a Web page. You could, says Jacobson, "download the chip design from the Web, tie in some modifications from some guy in India, and boom-out comes the device."

It's lunchtime in Jacobson's lab, a windowless room with tangles of colored cable dangling from the walls and ceiling and a row of chemical hoods set along one wall. Jacobson's enthusiasm is contagious, and the cramped lab is obviously where he and his handful of students spend most of their time, even when they're eating. "What we're interested in is give me a piece of plastic and in a few seconds I'll give you back a Pentium,' or something of that complexity," he says between mouthfuls. "I'm serious about that. Not slower than a Pentium; indistinguishable from a Pentium."