In a world where “supersize” has entered the lexicon, there are some things getting smaller, like cell phones and laptops. Dartmouth researchers have contributed to the miniaturizing trend by creating the world’s smallest untethered, controllable robot. Their extremely tiny machine is about as wide as a strand of human hair, and half the length of the period at the end of this sentence. About 200 of these could march in a line across the top of a plain M&M.

“It’s tens of times smaller in length, and thousands of times smaller in mass than previous untethered microrobots that are controllable,” says [Bruce] Donald. “When we say ‘controllable,’ it means it’s like a car; you can steer it anywhere on a flat surface, and drive it wherever you want to go. It doesn’t drive on wheels, but crawls like a silicon inchworm, making tens of thousands of 10-nanometer steps every second. It turns by putting a silicon ‘foot’ out and pivoting like a motorcyclist skidding around a tight turn.”

Their paper describes a machine that measures 60 micrometers by 250 micrometers (one micrometer is one thousandth of a millimeter). It integrates power delivery, locomotion, communication, and a controllable steering system – the combination of which has never been achieved before in a machine this small. Donald explains that this discovery ushers in a new generation of even tinier microrobots.

McGray, who earned a Ph.D. in Computer Science working on this project in Donald’s lab, adds, “Machines this small tend to stick to everything they touch, the way the sand sticks to your feet after a day at the beach. So we built these microrobots without any wheels or hinged joints, which must slide smoothly on their bearings. Instead, these robots move by bending their bodies like caterpillars. At very small scales, this machine is surprisingly fast.” McGray is currently a researcher at the National Institute of Standards and Technology in Gaithersburg, Md.

Oops!

The work was funded in part by the Department of Homeland Security, Office of Domestic Preparedness through Dartmouth’s Institute for Security Technology Studies (ISTS).

They’ll probably be in trouble for designing something potentially useful.