Design and Implementation of a BCI System Based on Steady-State Visual Evoked Potentials

In recent years, Brain-computer interface (BCI) based on electroencephalogram (EEG) is an active topic in brain function research. BCI provides a direct communication and control channel for sending messages and instructions from brain to external computers or other electronic devices. However, the EEG signals are very faint and often corrupted by noises such as power line noise, EMG, EOG etc.. EEG signal acquisition is very critical for the BCI system. In the paper, a circuit for EEG signal acquisition is designed. The circuit module is mainly composed of protection circuit, instrumentation amplifier, common mode rejection (CMR) circuit, gain adjustable amplifiers and filters. Finally, a BCI system based on SSVEP sets up by this hardware circuit´s platform. The experimental results show that the circuit is effective with good amplification ability and high CMR, and it is very suitable for the BCI system.