Firefly robots “communicate” in flight using colored lights 4.4

Electroluminescent particles in the artificial muscles of microscopic drones glow in different colors, allowing you to track their movements and interact with them right in the air.

Firefly beetles carry special organs in which photochemical reactions can occur, causing their bellies to shine quite brightly in the dark. This glow performs communication functions: with its help, insects look for mating partners, scare off predators, and so on. Now robots are also capable of such interaction.

The miniature machines developed by engineers at the Massachusetts Institute of Technology (MIT) can not only fly, but also “communicate” through electroluminescence. This is described in the message of the MIT press service. The scientists’ article was published in the IEEE Robotics and Automation Letters journal.

The microscopic flying machines that MIT Professor Kevin Chen’s team is working on weigh little more than a paper clip and are not capable of carrying a more or less decent set of sensors and communication tools on board. Therefore, they are usually controlled by a central computer that monitors the position of each individual microdron using an IR video camera.

However, in real “field” conditions, such a system is too unreliable, if only because it is extremely difficult to distinguish each device on the video stream. That is why scientists decided to simplify it, and now a pair of the most ordinary cameras, which are in any modern smartphone, is enough for such a task.

The microdrons themselves were introduced at the end of 2021.

Their main feature was the use of unusual artificial muscles that allow the devices to fly. To do this, the scientists used structures consisting of ultrathin elastomer layers laid with conductive carbon nanotubes and rolled into cylinders. When a current is applied to the nanotubes, the elastic elastomer contracts, causing the cylinder to contract and driving the wings of the device.

To make them glow at the same time, microdrons had to be supplemented with elements with electroluminescent properties — tiny “inserts” that glow when a weak voltage is applied to transparent electrodes. Electroluminescent zinc sulfate particles were introduced into the elastomer of artificial muscles. According to the developers, such an appendage increased the power consumption of the devices by only 3.2 percent, and the mass by only 2.4 percent, without reducing their flight qualities at all.

Chen and his team tested their development in the laboratory, tracking the devices in flight using three iPhone cameras. The data from them was sent to a computer that was able to determine the position of each drone in space with an accuracy of two millimeters. At the same time, a thoughtful selection of fluorescent particles allows you to achieve different colors, and elements in different muscles of the same drone can glow in their own way. In the future, this will allow them to report on their condition and position, organizing control and communication with swarms of such miniature devices.