It’s like something out of sci-fi: don a special electronic cloak and control the robot with your mind. And now, a study recently published in ACS Applied Nano Materials has taken a step to make it a reality. By creating a unique 3D structure (The sensor that could one day operate ‘mind-controlled’ robots) that does not rely on shiny conductive gels, the team has created a “dry” sensor that can measure the electrical activity of the brain, even among hair and bumps and curves and face.
Doctors use electroencephalography (EEG) to analyze electrical signals from the brain, where special electrodes are implanted or placed on the head. EEG helps diagnose neurological diseases, but it can also be used in “brain and machine”, which uses brain waves to control an external device, such as a prosthesis, robot or even video games. Many non-invasive versions involve using a “water” sensor that sticks to the scalp with a sticky gel that can irritate the scalp and sometimes cause an allergic reaction.
As an alternative, researchers have developed ‘dry’ sensors that do not require gels, but so far none work with different liquid specifications. Although nanomaterials such as graphene may be a suitable choice, their flat and irregular nature makes them incompatible with the uneven parts of the human head, especially in the long term. Therefore, Francesca Iacopi and her colleagues wanted to create a 3D sensor based on polycrystalline graphene that can accurately monitor brain activity without any interference.
The team created several 3D structures with graphene of different shapes and sizes, each about 10µm thick. In the model tested, the hexagonal system works best on the curvy, hairy part of the occipital region – the area under the head where the visual cortex of the brain is located. The team incorporated eight of these sensors into a flexible headband, which held them on the back of the head.
When paired with an augmented reality headset that displays signals, the electrodes can detect the signal being viewed, and work with a computer to translate the signals into commands that control the movement of a four-legged robot – completely hands-free. Although the new electrodes aren’t yet perfect as liquid sensors, the researchers say the work represents the first step in developing a robust, easy-to-use dry sensor to help expand the applications of brain-machine interfaces.
Source: ACS
