Researchers at the University of Pennsylvania and University of Michigan "have created the world’s smallest fully programmable, autonomous robots," according to a recent announcement.

The announcement calls them "microscopic swimming machines that can independently sense and respond to their surroundings, operate for months and cost just a penny each." * Barely visible to the naked eye, each robot measures about 200 by 300 by 50 micrometers, smaller than a grain of salt. Operating at the scale of many biological microorganisms, the robots could advance medicine by monitoring the health of individual cells and manufacturing by helping construct microscale devices. Powered by light, the robots carry microscopic computers and can be programmed to move in complex patterns, sense local temperatures and adjust their paths accordingly... "We’ve made autonomous robots 10,000 times smaller," says Marc Miskin, Assistant Professor in Electrical and Systems Engineering at Penn Engineering and the papers’ senior author. "That opens up an entirely new scale for programmable robots."* The announcement describes them as "the first truly autonomous, programmable robots at this scale" (as described in two recent academic articles). The team had to design a new propulsion system that utilized the unique locomotion physics in the microscopic realm, according to the university’s announcement. So the robots "generate an electrical field that nudges ions in the surrounding solution." *Those ions, in turn, push on nearby water molecules, animating the water around the robot’s body. "It’s as if the robot is in a moving river," says Miskin, "but the robot is also causing the river to move." The robots can adjust the electrical field that causes the effect, allowing them to move in complex patterns and even travel in coordinated groups, much like a school of fish, at speeds of up to one body length per second...

To be truly autonomous, a robot needs a computer to make decisions, electronics to sense its surroundings and control its propulsion, and tiny solar panels to power everything, and all that needs to fit on a chip that is a fraction of a millimeter in size. This is where David Blaauw’s team at the University of Michigan came into action... The robots are programmed by pulses of light that also power them. Each robot has a unique address that allows the researchers to load different programs on each robot. "This opens up a host of possibilities," adds Blaauw, "with each robot potentially performing a different role in a larger, joint task."

• Thanks to long-time Slashdot reader fahrbot-bot for sharing the news. *