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A robot smaller than a grain of sand – and completely autonomous

It is barely larger than a comma on this page, moves through liquids, measures temperatures, and reacts independently to its environment. And best of all, it costs just one US cent. Researchers at the University of Pennsylvania and the University of Michigan have achieved a mini breakthrough: they have built the world's smallest autonomous programmable robot to date.

The device measures just 200 x 300 x 50 micrometers, so it easily fits on the tip of a pin. And yet it packs a punch: a processor, memory, sensors, and an innovative drive—all inside.

The robot that turns light into energy

At the heart of the mini robot is an extremely energy-efficient microchip, which was originally developed as the world's smallest computer. It is powered by tiny solar cells that deliver just 75 nanowatts – a drop in the ocean compared to the energy requirements of normal technology.

To make this work, the team led by researchers David Blaauw and Marc Miskin had to do some serious tinkering. They made the electronics even more efficient and reduced the software code to a minimum. The result: the robot can move, measure, and even store data independently, even though almost all of its space is taken up by solar cells.

Getting around without legs – but with electric thrust

For the propulsion system, the scientists did not choose mini legs or rotors, but a more elegant solution: an ion propulsion system without mechanical parts. It generates an electric field that moves charged particles (ions) in the surrounding liquid – similar to a gentle push underwater. This allows the mini robot to glide, stop, turn, and even swim patterns, depending on how the field is controlled.

And all this without remote control. No magnet, no radio, no external command—the little robot decides for itself what to do.

Temperature measurement with dance code

Particularly clever: the robot has a built-in temperature sensor that can measure to within a third of a degree. And how does such a tiny device transmit its data? By dancing. Yes, you read that right. Its movements encode the temperature, similar to how honeybees do with their famous waggle dances. Researchers can observe and decode these movements under a microscope.

This makes it possible, for example, to monitor the temperature of individual cells—a potential application in medicine or cell research.

A penny for a robot brain: What comes next

The manufacturing costs are sensationally low: the prototype can be produced for around one US cent. And that's just the beginning, say the developers. Future versions will offer more sensors, more complex reactions, and greater mobility—and all this in swarms, i.e., many small units that can perform tasks together.

Marc Miskin sums it up:

"We have demonstrated that it is possible to pack a brain, a sensor, and a drive into something almost invisible—and keep it alive for months."

Numerous applications – but what exactly for?

The technology is impressive, no question about it. But when a functional robot soon costs less than a lollipop, the question arises: Who controls who uses these mini-machines—and for what purpose? The ability to measure individual cells is a step forward. But in the wrong hands, this marvel can quickly become a spy no bigger than a crumb. Miniaturization does not mean that we can think smaller when it comes to legal protection.

Source: heise.de