Tiny robots working by themselves and communicating only with each other can explore and map buildings, a team of U.S. researchers that built the machines says.

The robots, with advanced autonomous capability, developed by a team from the Georgia Institute of Technology, the University of Pennsylvania and the California Institute of Technology Jet Propulsion Laboratory.

"When first responders -- whether it's a firefighter in downtown Atlanta or a soldier overseas -- confront an unfamiliar structure, it's very stressful and potentially dangerous because they have limited knowledge of what they're dealing with," said Henrik Christensen, a professor in the Georgia Tech College of Computing.

"If those first responders could send in robots that would quickly search the structure and send back a map, they'd have a much better sense of what to expect and they'd feel more confident."

The team developed tiny autonomous robots that operate as a group, carrying sensors and transmitting a detailed floor plan of a building to nearby humans within minutes.

"There is no lead robot, yet each unit is capable of recruiting other units to make sure the entire area is explored," Christensen said. "When the first robot comes to an intersection, it says to a second robot, 'I'm going to go to the left if you go to the right.'"