Study on a Novel Flow-Controllable Semidry Electrode for EEG Signal Acquisition

Traditional electrodes often face a series of problems when collecting electroencephalogram (EEG) signals. The lack of conductive medium between the dry electrode and the skin results in high contact impedance, which degrades the quality of the collected signal. When the wet electrode is used, the conductive gel evaporates quickly, and the operation is complex. A conventional semidry electrode’s conductive fluid flow is ineffectively controlled, wasting conductive fluid in the process. To solve these concerns, this article proposes a novel semi-dry electrode, which has a smaller contact impedance than the conventional dry electrode and is more portable than the wet electrode. The unique valve structure of the electrode allows the flow of conductive fluid to be controlled, which makes the electrode less conductive liquid than the conventional semidry electrode. In addition, the tip structure of the electrode is designed to pass through thick hair more effectively, ensuring that the conductive fluid is in full contact with the skin. This semidry electrode uses a bipolar electrode setup to collect EEG signals from construction equipment operators. The results show that the novel electrode has a strong correlation with the EEG signal features collected by the traditional wet electrode. The semidry electrode can effectively detect the mental fatigue state of construction equipment operators, and the classification accuracy is 99.16%.