The experts were able to make one million four-legged robots fit on a 10cm wafer of silicon.
Each robot is roughly 5 microns thick – one micron being one-millionth of a metre – and 40 microns wide. Their ‘legs’ are made of electrochemical actuators, the front and back pairs powered by different silicon photovoltaics.
The researchers control the movement of the legs by flashing a laser at the front then the back set of photovoltaics. This is how the robot is able to walk, the team behind the project explained in the Nature journal.
However, these robots have some limitations, such as being slower than other swimming robots, not being able to sense their environments, and a lack of integrated control.
“While these robots are primitive in their function – they’re not very fast, they don’t have a lot of computational capability – the innovations that we made to make them compatible with standard microchip fabrication open the door to making these microscopic robots smart, fast and mass producible,” said Professor Itai Cohen, one of the authors of the study.
“This is really just the first shot across the bow that, hey, we can do electronic integration on a tiny robot.”
“Controlling a tiny robot is maybe as close as you can come to shrinking yourself down,” said Professor Marc Miskin, lead author of the study.
“I think machines like these are going to take us into all kinds of amazing worlds that are too small to see.”
The researchers say that they are now looking at ways to give the robots more complicated electronics and onboard computation.
These changes, they hope, could enable the robots to one day be used in a medical setting, inside the human body repairing tissue or exploring the brain.
Reader Q&A: Is it really possible to control a robot with your mind?
Asked by: Ryan Cooke, St Albans
Yes it is. The USA’s Defense Advanced Research Projects Agency (DARPA) has a brain-controlled prosthetic arm for upper limb amputees.
As the user thinks about various movements, the arm picks up the responding brain signals that appear in the remaining nerves at the site of the amputation. With incredible dexterity, the user can remove a letter from an envelope and even move eggs from one box to another.
But away from government-funded research projects, hobbyist and engineer William (Chip) Audette in Vermont controls a small toy robot using his brainwaves. He’s using open hardware called OpenBCI where electrodes on his head pick up brainwaves.
The level of control is crude but is proof that advances in EEG technology, machine learning and robotics really are ushering in an age where we can control devices through the power of thought.
Amy is the Editorial Assistant at BBC Science Focus and looks after all things books, culture and media. She is also a regular interviewer on the Science Focus Podcast. Her interests range from natural history and wildlife, to women in STEM and accessibility tech.