Light-Powered Frog Robot Swims Without Motor or Battery
Aarhus University researchers built a sub-gram, 3D-printed frog robot that moves using only pulses of near-infrared light.
Updated on Nov. 13, 2026 in Robotics
Researchers at Aarhus University printed a light-powered frog-shaped robot weighing less than a gram that swims without a motor, battery, or wires. The findings were published in Advanced Materials Technologies.
Why it matters
The design shows that soft, untethered swimming machines can be made in a single printing run, without conventional electronics. Its developers see potential uses in inspecting flooded structures and in toys, though the approach remains at an early stage.
The robot weighs less than a gram and is powered by pulses of near-infrared light from a lamp, with six liquid crystal muscles driving a pair of hind legs. Its performance under real-world conditions has not been reported.
The players
Aarhus University
A public research university in Denmark where the light-powered frog robot was built.
University of Luxembourg
A public research university in Luxembourg that partnered with Aarhus University on the research.
The details
The team printed the liquid-crystal muscles and soft silicone body in a single run, forcing liquid-crystal elastomer ink through a printer nozzle. Near-infrared light heats a dye that disrupts polymer molecules and shortens the muscle strips, and early leg designs pushed water toward the head before the researchers changed the joints to drive water back.
Timeline
Earlier this year, MIT researchers shared a light-powered paper-thin swimmer design.
Roadmap
The robot extends liquid-crystal elastomer actuators, a soft material that changes shape under light, into a fully printed, untethered swimmer. It follows a recent MIT light-powered paper swimmer, suggesting a broader push toward soft robots that need no batteries or wires.
For now the robot is a research prototype, so readers will not buy one soon. The team's suggested applications, such as toys and small swimmers for inspecting flooded structures, remain future possibilities rather than available products.
The takeaway
Soft robots that print their muscles and bodies in one step could make small, wireless machines simpler to build. Whether they can move reliably beyond the lab remains to be shown.
Further reading
For more on the field, explore the Robotics section.
Source note: This article includes information reported by New Atlas.
