Using a cap, the system allows users to move forwards, turn left and right, sit and stand by staring at one of five LEDs. Each LED flickers at a different frequency, and when the user focusses attention on a specific LED this frequency is reflected within the electroencephalogram readout.
This signal is identified and used to control the exoskeleton. A key problem has been separating these precise brain signals from those associated with other brain activity, and the highly artificial signals generated by the exoskeleton. “Exoskeletons create lots of electrical ‘noise.’ The electroencephalogram (EEG) signal gets buried under all this noise, but our system is able to separate not only the EEG signal, but the frequency of the flickering LED within this signal,” said team member Dr Klaus-Robert Muller from TU Berlin and Korea University.