Consider adding video and mic circuit
In future versions of the OpenBCI hardware, it would be valuable to have video/sound to be integrated into the same circuit. If an inexpensive camera and mic can be mounted on the front of the headset the sensory input that the subject observes can be better correlated to the time-series EEG data. If it is possible to manage the additional power and data storage in the same circuit, it will make it far easier to tag specific points of time in the data during post-analysis.
In clinical EEGs, the patient commonly is required to have a video recording throughout the EEG. This allows the patient to be watched for behavior and sensory input to correlate the brain signals.
Comments
The applications you reference are not short latency evoked potentials, so they don't require millisecond synchrony-- in fact 0.1 second synchrony would be enough. This means that with a modern CPU and good video processing routines you could do all of the above in software -- in a version of the GUI in fact. You connect the CPU clock to the EEG stream and the audiovisual stream, and display them with the computer clock keeping things synchronous enough.
Currently, it's possible to do time-locked experiments using a photoresistor, a custom generated video with colored squares, and Cyton AUX pins.
Here is the link to the tutorial: https://docs.openbci.com/docs/07Examples/VideoExperiment
Hope this helps!
RW