Scientists put a computer into a salt-sized robot

Source: PortaldoBitcoin Original Title: Scientists Put Computer in Salt Grain-Sized Robot Original Link: Researchers have just miniaturized autonomous robots to the size of a salt grain. And these robots can think — in a way.

A team from the University of Pennsylvania and the University of Michigan (USA) built microscopic machines — measuring 200 by 300 by 50 micrometers, the size of a salt grain — that swim in liquids, detect temperature changes, make autonomous decisions, and operate for months at a time. Each unit costs about one cent to produce.

These tiny robots are completely autonomous. No wires, magnetic fields, or external control via joystick. Just a tiny computer, sensors, and a propulsion system compressed into something almost invisible to the naked eye.

“We reduced the size of autonomous robots by 10,000 times,” said Marc Miskin, assistant professor at Penn Engineering. “This opens up a whole new scale for programmable robots.”

The innovation solves a problem that has challenged robotics for 40 years: how to build machines that operate independently below one millimeter. Electronics have continued to shrink, but robots have not kept pace. The physics at this level is challenging — Miskin explained that pushing water at this scale is like pushing tar, and tiny arms or legs simply break.

Therefore, the team completely abandoned conventional designs. Instead of bending or flexing limbs, these robots generate an electric field that displaces charged particles in the surrounding liquid. These ions drag water molecules with them, creating movement.

A sequence of timelapse images projected of tracer particles near a robot composed of three interconnected motors.

This approach works because it has no moving parts. The electrodes are sturdy enough to be repeatedly transferred between samples with a micropipette without damage. Powered by LED light, they continue swimming for months.

The tiny solar panels powering these robots produce only 75 nanowatts. To enable operation, the Michigan team developed circuits that operate at extremely low voltages, reducing consumption by more than 1,000 times. They also had to completely rethink how the software works, condensing what would normally require multiple instructions into single, specialized commands that fit into microscopic memories.

The result: the first sub-millimeter robot with a complete computer. Processor, memory, sensors — the full package. No one had done this before at this scale.

These robots can detect temperature with an accuracy of up to one-third of a degree Celsius — six-tenths of a degree Fahrenheit for those who prefer the imperial system. They can move toward warmer regions or report temperature values that serve as indicators of cellular activity — potentially monitoring individual cells.

To communicate their measurements, the researchers created a special instruction that encodes data in the “ripples” of a small dance performed by the robot. Scientists observe through a microscope and decode the message. It’s like bee communication, explained David Blaauw, professor of Electrical and Computer Engineering at the University of Michigan.

The robots are programmed by light pulses, which also power them. Each has a unique address, allowing researchers to load different programs into different units. They can work independently or in coordination, moving in patterns similar to fish schools, reaching speeds of up to one body length per second.

Future versions may store more complex programs, integrate new sensors, or operate in more hostile environments. The current design is a platform — its propulsion system works with electronics that can be manufactured at scale and low cost.

“This is really just the first chapter,” said Miskin. “We’ve shown that it’s possible to put a brain, a sensor, and a motor into something almost invisible and make it survive and operate for months.”

“When you have this foundation,” he added, “it’s possible to add all kinds of intelligence and functionality.”