This Autonomous Aquatic Robot Is Smaller Than a Grain of Salt | WIREDSkip to main contentMenuSECURITYPOLITICSTHE BIG STORYBUSINESSSCIENCECULTUREREVIEWSMenuAccountAccountNewslettersBest Office ChairsBone Conduction HeadphonesBest Digital NotebooksBest Motorola PhonesTCL DealDeals DeliveredSecurityPoliticsThe Big StoryBusinessScienceCultureReviewsChevronMoreExpandThe Big InterviewMagazineEventsWIRED InsiderWIRED ConsultingNewslettersPodcastsVideoMerchSearchSearchSign InSign InRitsuko KawaiGearJan 24, 2026 5:00 AMThis Autonomous Aquatic Robot Is Smaller Than a Grain of SaltResearchers have succeeded in developing the smallest fully autonomous robot in history. It measures less than 1 millimeter and can swim underwater for months powered only by light.Photograph: Michael Simari/the University of MichiganCommentLoaderSave StorySave this storyCommentLoaderSave StorySave this storyMiniaturization has long been a challenge in the history of robotics.While engineers have made great strides in the miniaturization of electronics in the past few decades, builders of miniature autonomous robots have not been able to meet the goal of getting them under 1 millimeter in size. This is because small arms and legs are fragile and difficult to manufacture. Above all, the circumstances of the laws of physics change in the microscopic world. Instead of gravity and inertia, drag and viscosity become dominant.Against this backdrop, researchers in the US have announced the results of a study that accomplishes a 40-year-old challenge. A team of researchers from the University of Pennsylvania and the University of Michigan has developed a new robot that is smaller than a grain of salt, measuring only 200 x 300 x 50 micrometers. At 0.3 mm on its longest side, that's far below the 1-mm threshold. Yet it can sense its surroundings, make decisions on its own, and swim and move in water.This experimental robot is smaller than a grain of salt.
Photograph: Marc Miskin/University of PennsylvaniaMoreover, it operates completely autonomously and is not dependent on any external controls such as wires or magnetic fields. The production cost is said to be as low as 1 cent per unit.“We have succeeded in miniaturizing an autonomous robot to 1/10,000th the size of a conventional robot,” says Mark Miskin, one of the researchers, who's an assistant professor of electrical systems engineering at the University of Pennsylvania. “This opens up a whole new scale for programmable robots.”The Electric SlideThe propulsion system developed by Miskin and his team is a breakthrough in conventional robotics. Fish and other large aquatic organisms move forward due to the reaction of water pushing backward, in accordance with the third law of motion in Newtonian mechanics. But pushing water on a microscopic scale is like pushing sludgy tar. The viscosity of the water is so great that small arms and legs can never compete with it.So the researchers adopted a completely new approach. Instead of swimming by moving parts of its body, the new robot moves by generating an electric field around it and gently pushing charged particles in the liquid. The robot exploits the phenomenon that moving charged particles drag nearby water molecules, creating a water current around the robot. It is as if the robot itself is not moving, but the ocean or river is moving.This image shows the movement of charged particles generated around a robot moving in liquid.
Photograph: Lucas Hanson/William Reinhardt/University of PennsylvaniaThe robot is driven by light from an LED and can move a distance equal to its body length in a maximum of one second. The direction of movement can be changed by adjusting the electric field, and the robot can follow complex paths or move in groups like a school of fish.The greatest advantage of this method of movement is its extremely high durability due to the absence of moving parts. According to Miskin, it can swim continuously for months on end.Instagram contentMicro ComputerPropulsion alone is not enough to achieve true autonomy. Autonomous robots must sense their environment and make decisions about how to navigate it. All of this must be controlled by a chip measuring less than 1 mm. David Blau and his team at the University of Michigan took on this challenge.Blau and his team hold the record for building the world's smallest computer. When they first met Miskin at a Defense Advanced Research Projects Agency presentation, they were convinced that their technologies would complement each other perfectly. It took five years for the idea to actually take shape.The biggest obstacle to making the tiny robot work, he says, was power. The robot's solar panels generate only 75 nanowatts of power. That is less than 1/100,000th of the power consumed by a smartwatch. To solve this problem, the team designed a special circuit that operates at extremely low voltages. This successfully reduced the power consumption to a sustainable level.Space constraints were another hurdle. The solar panels took up most of the surface, leaving little space for the computational infrastructure. So the researchers radically rethought the program, which required many instructions, and condensed it into a single special instruction, which they were able to fit into the robot's small memory space.These robots can be manufactured in units of several hundred at once.
Photograph: Maya Lassiter/University of PennsylvaniaTiny DancerThe robot is equipped with an electronic sensor that can detect minute temperature changes. However, because its microscopic body can't carry robust communications components, the robot uses a method borrowed from the insect kingdom to transit the measurements it detects.The robot is programmed to translate the sensor readings into “dance moves.” The researchers use a microscope to observe the robot's movements and decode the information. “This is very similar to the way honeybees communicate with each other,” Blau explains.In addition to this, each robot is given a unique ID and is designed to upload different instructions to different units. This allows multiple robots to play different roles in performing large tasks collaboratively.Each individual robot is equipped with a complete onboard computer that can receive and execute instructions autonomously.
Photograph: Miskin Lab/Blaauw LabAccording to the team, this is the first time a complete computer with a processor, memory, and sensors has been mounted on a robot less than 1 mm in size. The micro-robot functions on the same scale as a microbe, which could be useful for applications such as helping doctors monitor individual cells and helping engineers assemble tiny devices.This story was originally published in WIRED Japan and has been translated from Japanese. The original was edited by Daisuke Takimoto.CommentsBack to topTriangleYou Might Also LikeIn your inbox: WIRED's most ambitious, future-defining storiesDoes the “war on protein” exist?Big Story: China’s renewable energy revolution might save the worldThe race to build the DeepSeek of Europe is onWatch our livestream replay: Welcome to the Chinese centuryTopicsrobotsroboticschipsComputersRead MoreHow Does the Hive Mind Work in Pluribus?The “Joining” seems to connect people via radio waves. Let’s dig into the physics at play.The Oceans Just Keep Getting HotterFor the eighth year in a row, the world’s oceans absorbed a record-breaking amount of heat in 2025. It was equivalent to the energy it would take to boil 2 billion Olympic swimming pools.Behold the Manifold, the Concept that Changed How Mathematicians View SpaceIn the mid-19th century, Bernhard Riemann conceived of a new way to think about mathematical spaces, providing the foundation for modern geometry and physics.AI’s Hacking Skills Are Approaching an ‘Inflection Point’AI models are getting so good at finding vulnerabilities that some experts say the tech industry might need to rethink how software is built.Google Gemini Is Taking Control of Humanoid Robots on Auto Factory FloorsGoogle DeepMind and Boston Dynamics are teaming up to integrate Gemini into a humanoid robot called Atlas.Poor Sleep Quality Accelerates Brain AgingResearch shows that people who sleep poorly tend to have brain age that is older than their actual age. Chronic inflammation in the body caused by poor sleep likely plays a part.People Who Drink Bottled Water on a Daily Basis Ingest 90,000 More Microplastic Particles Each YearDrinking water in plastic bottles contains countless particles too small to see. New research finds that people who drink water from them on a daily basis ingest far more microplastics than those who don’t.Welcome to the Future of Noise CancelingThe next generation of noise reduction is currently being developed in R&D labs around the world. Take a look at what's to come.OpenAI Invests in Sam Altman’s New Brain-Tech Startup Merge LabsMerge Labs has emerged from stealth with $252 million in funding from OpenAI and others. It aims to use ultrasound to read from and write to the brain.A Brain Mechanism Explains Why People Leave Certain Tasks for LaterNew research has discovered that a neural circuit may explain procrastination. Scientists were able to disrupt this connection using a drug.The Best Smart Bird Feeders for Backyard BirdingThese bird feeders come with cameras and connected apps to let you see and learn about the birds in your neighborhood.The Earth Is Nearing an Environmental Tipping PointToday’s global coral bleaching events are the worst kind of climate warning.Wired CouponsSquarespace Promo CodeExclusive 10% Off Squarespace Promo CodeLG Promo CodeBuy an eligible French Door Refrigerator and get a free Single Door Refrigerator (up to $515 value)!Dell Coupon Code10% off Dell Coupon Code for New CustomersSamsung Promo CodeSamsung Promo Code: 10% off TVsCanon Promo Code10% off Canon promo code with upgradeDoorDash Promo Code$25 off $25+ DoorDash Promo Code for New CustomersWIRED is obsessed with what comes next. Through rigorous investigations and game-changing reporting, we tell stories that don’t just reflect the moment—they help create it. When you look back in 10, 20, even 50 years, WIRED will be the publication that led the story of the present, mapped the people, products, and ideas defining it, and explained how those forces forged the future. WIRED: For Future Reference.SubscribeNewslettersTravelFAQWIRED StaffWIRED EducationEditorial StandardsArchiveRSSSite MapAccessibility HelpReviewsBuying GuidesStreaming GuidesWearablesCouponsGift GuidesAdvertiseContact UsManage AccountJobsPress CenterCondé Nast StoreUser AgreementPrivacy PolicyYour California Privacy Rights© 2026 Condé Nast. All rights reserved. WIRED may earn a portion of sales from products that are purchased through our site as part of our Affiliate Partnerships with retailers. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Condé Nast. Ad ChoicesSelect international siteUnited StatesLargeChevronItaliaJapónCzech Republic & SlovakiaFacebookXPinterestYouTubeInstagramTiktok

The University of Michigan and the University of Pennsylvania have achieved a remarkable feat of engineering, developing the smallest fully autonomous robot ever created – a device measuring less than a grain of salt. This groundbreaking innovation, detailed by Mark Miskin of the University of Pennsylvania, represents a 40-year-old challenge in robotic miniaturization. The robot’s size, a mere 200 x 300 x 50 micrometers, pushes the boundaries of programmable robotics, opening up entirely new scales for exploration and application.

Unlike traditional robots reliant on external controls such as wires or magnetic fields, this micro-robot operates independently, propelled by an innovative electric field-based propulsion system. Researchers successfully mimic the movement of aquatic organisms like fish, adapting to the extreme viscosity of water at a microscopic level. Instead of relying on moving parts, the robot generates an electric field, attracting and pushing charged particles within the liquid, effectively "swimming" without the constraints of physical appendages. This approach ensures unparalleled durability, theoretically allowing the robot to operate continuously for months.

Crucially, this achievement extends beyond mere miniaturization. The robot is equipped with a sophisticated, self-contained computer – a microchip measuring under 1 millimeter – developed by David Blau and his team at the University of Michigan. This micro-computer, functioning as the robot's “brain,” handles sensing its surroundings and making decisions autonomously.

The propulsion and computational systems are intrinsically linked. Powering this tiny robot is a critical hurdle. The solar panels generate a paltry 75 nanowatts – less than 1/100,000th of a smartwatch’s power. An ingenious low-voltage circuit mitigates this, achieving sustainable operation. Space constraints were also a major consideration, demanding a condensed program, drastically reducing the amount of instructions the robot could execute.

Furthermore, the robot’s sensory input relies on a novel “dance move” translation system. Recognizing that conventional communication methods, like radio waves, are impractical at this scale, researchers developed a method where the robot's subtle movements are observed and interpreted using a microscope, effectively decoding the data. This is similar to how honeybees communicate their location and resources. The robot’s ability to collect and relay information is key to its autonomous operation.

Adding to its capabilities, each robot is uniquely identified, allowing for collaborative tasks. The team designed multiple robots to work together, contributing to large-scale projects. This decentralized control represents a significant step towards swarm robotics.

The implications of this achievement are far-reaching. This technology could be instrumental in applications such as monitoring individual cells within the human body, offering a new tool for medical diagnostics and research. The ability to assemble tiny devices with autonomous robots represents a potential revolution. This groundbreaking work continues to push the envelope of what’s possible in robotics, promising a future where micro-robots play a vital role in diverse fields.