As our skies increasingly crowd with buzzing, hovering, flitting drones, spare a thought for the humble hopping robot. Hopping, a popular form of locomotion in the insect and amphibian worlds, is nearly two orders of magnitude more energy-efficient than flying. Unlike a mosquito that must constantly expend energy to stay aloft, a flea only works out when it jumps.

Those cost savings could also pay off in the world of robotics: A group of small, simple hopping robots could explore a location much more cheaply than flying drones. These robots could find gas leaks in an oil refinery, monitor water and fertilizer usage on a farm, or even explore other planets.

With this in mind, engineers at the University of Washington have created DirectHop, a roughly 1-gram (0.04-ounce) robot that can perform multiple hops in sequence and jump high enough to clear a standard stair step. The robot uses a tiny electric motor and three folding legs to launch itself to a specified jump height with 1-centimeter (0.4-inch) accuracy. After it lands, DirectHop can twitch to right itself and then prepare for another jump.