Autonomous robots smaller than a grain of salt!

Engineers have pushed the boundaries of what is possible by developing robots that measure only about 0.02 cm x 0.03 cm x 0.005 cm (200 x 300 x 50 micrometers). These machines are smaller than a grain of salt and operate at the level of biological microorganisms. The latter opens up completely new possibilities in medicine and industry.

At the microscopic level, physical forces such as fluid drag and viscosity are extremely powerful. Instead of using traditional legs or fins, these robots use electric fields to manipulate ions in the surrounding fluid. The ions then push water molecules, allowing the robot to swim at a speed of one body length per second. Because the system has no moving parts, the robots are extremely durable.

The biggest challenge was to fit the processor, memory, sensors and solar cells into such a small area. The solar cells cover most of the robot, but they produce only 75 nanowatts of power – that’s more than 100,000 times less than a smartwatch uses. To make the robots run on so little energy, they developed ultra-efficient circuits that reduce consumption by more than a thousand times.

The robots are equipped with sensors that measure temperature with an accuracy of up to 0.33°C. They communicate their findings in a unique way: through small, rhythmic movements or “dances” that researchers observe under a microscope and then decode. This method is reminiscent of the communication between bees in a hive.

These robots represent the foundation for a future where microscopic machines could monitor the health of individual cells in the human body or help build complex nanotechnology devices.