It sounds like science fiction: put an elastic band or headband on your head and control a robot through it with your mind. But now, a recent investigation has taken it a step further to make this scene an everyday reality. By designing a special three-dimensional structure that does not rely on the sticky conductive gels traditionally used in bulky devices that allow you to control robots with your mind, scientists have created “dry” sensors that can measure brain-force activity, even through hair and regardless of bumps and curves of the head.
Neurologists monitor the electrical signals in the brain using electroencephalography (EEG), in which electrodes are usually placed on the surface of the head. An EEG helps diagnose neurological disorders, but it can also be integrated into brain-machine interfaces, which use brain waves to control an external device, such as a prosthetic limb, a robot, or even a video game. Most non-invasive versions involve the use of “wet” sensors, which are attached to the head using an adhesive gel that can irritate the scalp and sometimes trigger allergic reactions.
An alternative is “dry” sensors, which don’t require gels, but so far none have worked as well as the wet variety. Although nanomaterials such as graphene could be a suitable option, their flat nature and other problematic features make them incompatible with the irregular curves of the human head, especially over long periods.
With all this in mind, a team from the University of Technology Sydney in Australia, including Francesca Iacobbi and Sheikh Naeem Faisal, set out to create a polycrystalline graphene-based 3D sensor that could accurately monitor brain activity without leaving a sticky head.
The team created several 3D graphene-coated structures of various shapes and patterns, each about 10 micrometers thick.
Of the shapes tested, the hexagonal pattern worked best on the curved, hairy surface of the occipital region, which is the point on the head where the brain’s visual cortex is located.
The team attached eight of these sensors to a rubber headband or headband attached to them at the back of the head. When combined with an augmented reality headset that displays visual signals, the electrodes can detect which signal is being seen, then work with a computer to translate the signals into commands that control the movement of a four-legged robot, leaving a person’s hands completely free.
A new sensor design embedded in a blue rubber headband has been used to wirelessly control a quadrupedal robot using only brain waves. (Image: Adapted from ACS Applied Nano Materials, 2023, DOI: 10.1021/acsanm.2c05546. CC BY-NC-ND)
Iacobbi and colleagues present technical details of their innovation in the academic journal ACS Applied Nano Materials, under the title “Noninvasive Sensors for Brain Interfaces–A Machine Based on Micro-Etaxial Graphene.” (fountain: NCYT by Amazings)
