Researchers from MIT and elsewhere have built a wake-up receiver that communicates using terahertz waves, which enabled them to produce a chip more than 10 times smaller than similar devices. Their receiver, which also includes authentication to protect it from a certain type of attack, could help preserve the battery life of tiny sensors or robots. Scientists are striving to develop ever-smaller internet-of-things devices, like sensors tinier than a fingertip that could make nearly any object trackable. These diminutive sensors have miniscule batteries which are often nearly impossible to replace, so engineers incorporate wake-up receivers that keep devices in low-power "sleep" mode when not in use, preserving battery life. Researchers at MIT have developed a new wake-up receiver that is less than one-tenth the size of previous devices and consumes only a few microwatts of power.

Leave it to the great minds at MIT and Georgia Tech to figure out a way to read the pages of a book without actually opening it. A team of researchers from the two institutions pulled it off with a system they developed that looks like a cross between a camera and a microscope. They said it could someday be used by museums to scan the contents of old books too fragile to handle or to examine paintings to confirm their authenticity or understand the artist's creative process. Writing in the latest issue of the journal Nature Communications, the scientists explained how they used terahertz waves -- a type of radiation situated on the electromagnetic spectrum between microwaves and infrared light -- to read a stack of papers with a single letter handwritten on each page. The device, called a terahertz spectrometer, managed to clearly read only nine pages, though it could see writing on up to 20. "We were very excited because we didn't think we would be able to see as deep as we did," said Barmak Heshmat, a research scientist at the MIT Media Lab.