Hello,
I wanted to ask how one can use other hardware modules such as a camera for facial expression recording along with EEG recording with OpenBCI devices. Is there any external or internal tools for that?
Sincerely,
Shyamal
The OpenBCI boards have a limited bandwidth connection via a Bluetooth radio channel. Thus you cannot pipe more external data such as camera or facial recognition streams along with the EEG data, for example by connecting some external device to the board. However the boards do provide 'time stamp' information in the recording file or Brainflow data streams. This gives an approximate timing correspondence to other equipment streams you may have. Probably accurate to a few tenths of a second. Time stamps are applied as the EEG data reaches Brainflow library buffer unpacking. So some latency is involved due to OS delays in processing usb data, concurrent scheduling, etc.
If you need more accuracy in the stream synchronizations, you can use the Cyton external trigger capability.
For timestamps BrainFlow uses UNIX timestamp, this counter starts at the Unix Epoch on January 1st, 1970 at UTC. Precision is microsecond, but for some boards timestamps are generated on PC side as soon as radio packets were received.
Comments
Hi Shyamal,
The OpenBCI boards have a limited bandwidth connection via a Bluetooth radio channel. Thus you cannot pipe more external data such as camera or facial recognition streams along with the EEG data, for example by connecting some external device to the board. However the boards do provide 'time stamp' information in the recording file or Brainflow data streams. This gives an approximate timing correspondence to other equipment streams you may have. Probably accurate to a few tenths of a second. Time stamps are applied as the EEG data reaches Brainflow library buffer unpacking. So some latency is involved due to OS delays in processing usb data, concurrent scheduling, etc.
If you need more accuracy in the stream synchronizations, you can use the Cyton external trigger capability.
https://docs.openbci.com/Cyton/CytonExternal/
Brainflow doc:
https://brainflow.readthedocs.io/en/stable/DataFormatDesc.html
William