Online SSVEP

This repository holds code for using the brainflow library with an OpenBCI Cyton board to make a real-time (online) steady-state visually evoked potential (SSVEP) brain-computer interface (BCI) demo.

main.py: the online BCI system

Modules/: Each file should contain documentation on classes & functions

• stream_data.py: A custom class that uses the brainflow library to connect and stream from the Cyton Board
• preprocessing.py: Class that contains functions to segment, filter, and save data
• ssvep_handler.py: Classes that generate harmonics and uses canonical correlation analysis (CCA) to classify SSVEP data, and functions that perform and return signal-to-noise ratio (SNR)
• stim_pres.py: Code related to stimulus presentation (i.e., flickering stimuli to elicit SSVEP)
• maintenence.py: Code related to listening for the 'esc' key and raising stop flags

Other:

• sim_ssvep_data.npy: simulated SSVEP data in shape (8, 15000)
  • 8 channels, 15000 samples (60 seconds at 250 Hz Sample Rate)
  • Simulated SSVEP signal changes between [9.25, 11.25, 13.25, 15.25] Hz every 10 seconds

Links/Reference

LSL:

• https://docs.openbci.com/Software/CompatibleThirdPartySoftware/LSL/
• https://github.com/openbci-archive/OpenBCI_LSL

Brainflow

• https://brainflow.readthedocs.io/en/stable/Examples.html#python
• https://brainflow.readthedocs.io/en/stable/UserAPI.html#python-api-reference