Phone Calls with the Power of the Mind: A Study on the BCI System by Using SSVEP Signals

<p>Electroencephalography (EEG) is a physiological technique used to measure human or animal brain activity. Typically, electrodes are placed on the scalp to record the electrical signals produced by neural activity in the brain's cortical surface. EEG is an important signal source for Brain-Computer Interfaces (BCIs) and provides a reliable basis for implementing human-machine interaction based on BCIs. Additionally, BCIs have provided new application scenarios for EEG signal research. Steady-State Visual Evoked Potential (SSVEP) is a stable, frequency-specific oscillating EEG signal produced under visual stimulation from a flickering light source. It is commonly used as an input signal for BCI technology due to its stable signal strength, easy detectability and recognizability, and quick adaptability by users. In this study, we developed a BCI system for making phone calls using EEG signals based on SSVEP. We independently developed a 4x3 digit dial stimulator that flashes each digit at different frequencies. The stimulator can be operated on a smartphone or tablet. We acquired the subject's EEG signals with an OpenBCI 8-channel EEG device and classified the real-time collected EEG data containing SSVEP stimulation signals using a pre-trained LDA classifier. The classification results were transmitted via Bluetooth to the phone, which then made a phone call. Five subjects were involved in the experiment, and each subject was required to perform 120 trials. The LDA classifier achieved an average accuracy of 93%, which means that the BCI system we developed based on SSVEP can effectively make phone calls using EEG signals. This study has successfully developed a novel interaction method with high accuracy and stability, significantly advancing the realization of BCI systems in real-life scenarios.</p>