“Robot pebbles” — smarter than your average rocks
So you’ve cracked a piston way out in horror-movie country? No problem, as long as you brought your trusty bag of programmable sand, say researchers Kyle Gilpin and Daniela Rus from MIT’s Computer Science and Artificial Intelligence Laboratory. They’ve been hard at work on a system of matter that can form a replica of an object — at the same size or bigger — without needing any additional equipment. So far, the limits of engineering matter have prevented the duo from reducing the system’s individual particles, a.k.a. sand grains, past 1 cubic centimeter (Gilpin and Rus have been calling the large grains “robot pebbles” in the meantime), but they hope to eventually cut the size down to millimeters, allowing for near-perfect replicas. Here’s how they did it. — JACQUELINE DETWILER
1. To make the sand, the researchers needed tiny computers that could communicate with and attach to one another. They settled on blocks containing microprocessors with just 2 kilobytes of working memory and electropermanent magnets, which can turn their magnetism on and off to make connections.
2. When an object is placed in the bag of smart sand, the grains have to first learn its shape. This requires algorithms that allow the grains to determine where they are in the bag, and where they are in relation to the object. The sand that surrounds the object “talks” until it understands the whole shape.
3. Once the grains know what to replicate, they transmit that information to another set of grains in the bag, which make connections until they create a copy of the original object. When completed, the replica can be removed from the bag and any extra grains will just fall off. Et voilà! A new piston.
ILLUSTRATION BY JAMES PROVOST