The Design And Development Of SSVEP-based BCI System

Brain computer interface (BCI) is a kind of information transfer and device control technology which does not depend on physical movement or language. It provides a new information exchange method for patients who has lost his ability of communication by normal ways. When one subject focused on a stimulus which was flicking in a certain frequency, a kind of brain potential which was called steady state visual evoked potential (SSVEP) would be evoked. SSVEP can be detected easily with few electrodes. It would not be affected by small probability events easily such as eyes blinking and can be classified with high accuracy. SSVEP-based BCI is antijamming and easy to be used.In this paper, a SSVEP stimulus system and an EEG recording system were used for develop a SSVEP-based BCI system. The EEG signal processing module was designed using Matlab system. The stimulus system was developed using the microcontroller called STM32F407. The three channel EEG acquisition system was developed using ThinkGear ASIC. The FFT algorithm was used for EEG signal analysis and the CCA algorithm was used for SSVEP classification.Besides the SSVEP-based BCI system, a camera pan/tilt system which was based on Zigbee wireless commands transfer system was developed. The computer send the movement control commands through Zigbee wireless module based on the classification result of EEG. This system makes the camera pan/tilt system controlled by subjects’ thought.This paper introduced the camera pan/tilt control system system based on BCI experiment. The results showed the feasibility of the SSVEP-based BCI system. This will provides a basic platform for the portable BCI system for its practical application.