Electronic devices and their components are becoming smaller and smaller as technology advances. Now, Northwestern University engineers have created what they’re calling the smallest-ever, remote-controlled walking robot.

At only half a millimeter wide, the tiny robot crabs are smaller than a flea. They walk, crawl, bend, twist, and jump. 

The robot is not powered by electricity or complicated hardware. Rather, the power and movement comes from phase changes with the device’s shape-memory alloy material.

The device reverts to its “remembered” shape when heated. The Northwestern researchers used a scanned laser beam to heat different parts of the robot’s body. As the robot’s body changes phases under different temperatures, it moves. In this case, the laser is the “remote control” and determines the robot’s motion and walking direction.

“Our technology enables a variety of controlled motion modalities and can walk with an average speed of half its body length per second,” Yonggang Huang, mechanical engineering and civil and environmental engineering professor, said in a news release. “This is very challenging to achieve at such small scales for terrestrial robots.”

The robot manufacturing technique that the researchers introduced eight years ago can be used to develop a variety of differently shaped and sized devices. This version is a crab because of a “creative whim” that amused the researchers’ students. Similar versions have resembled inchworms, crickets, and beetles. 

Last year, these researchers introduced a tiny, winged, motorless microchip that can fly. Its applications include environmental monitoring to detect pollution.

The new crab robot could perform tasks inside confined spaces, especially for applications where batteries or electricity are less practical. For example, future versions could prove useful during surgeries to stop internal bleeding or clear clogged arteries.