Soon, computers that fit on a pen tip, compact radios that need no tuning!

WASHINGTON - Inventions are increasingly working towards making devices more compact, such as a prototype implantable eye pressure monitor for glaucoma patients or a compact radio that needs no tuning.

These devices, created at the University of Michigan, are slowly and surely heralding an era of millimeter-scale systems in the computing world.

They could one day track pollution, monitor structural integrity, perform surveillance, or make virtually any object smart and trackable.

Researchers use Bell’s Law, which says that there’s a new class of smaller, cheaper computers about every decade. With each new class, the volume shrinks by two orders of magnitude and the number of systems per person increases.

“When you get smaller than hand-held devices, you turn to these monitoring devices,” said David Blaauw.

“The next big challenge is to achieve millimeter-scale systems, which have a host of new applications for monitoring our bodies, our environment and our buildings. Because they’re so small, you could manufacture hundreds of thousands on one wafer. There could be 10s to 100s of them per person and it’s this per capita increase that fuels the semiconductor industry’s growth.”

Blaauw and Dennis Sylvester’s new system, which is targeted toward medical applications, is a pressure monitor designed to be implanted in the eye to conveniently and continuously track the progress of glaucoma, a potentially blinding disease.

“This is the first true millimeter-scale complete computing system,” Sylvester said.

It wakes every 15 minutes to take measurements and consumes an average of 5.3 nanowatts. To keep the battery charged, it requires exposure to 10 hours of indoor light each day or 1.5 hours of sunlight. It can store up to a week’s worth of information.

David Wentzloff and doctoral student Kuo-Ken Huang have developed a compact consolidated radio with an on-chip antenna. The crystal reference keeps time and selects a radio frequency band. Integrating the antenna and eliminating this crystal significantly shrinks the radio system. Wentzloff’s is less than 1 cubic millimeter in size.

He and Huang’s key innovation is to engineer the new antenna to keep time on its own and serve as its own reference.

“The radio on our chip doesn’t need external tuning. Once you deploy a network of these, they’ll automatically align at the same frequency,” said Wentzloff.

The researchers are now working on lowering the radio’s power consumption so that it’s compatible with millimeter-scale batteries.

The researchers will present papers on each at the International Solid-State Circuits Conference (ISSCC) in San Francisco. (ANI)