To modify the OpenBCI architecture to allow more than 16 EEG channels? – PETER GAMMA (Director & Physiologist), MEDITATION RESEARCH INSTITUTE SWITZERLAND (MRIS)

Last Updated on September 22, 2024 by pg@petergamma.org

OpenBCI uses the ADS1299 EEG chip from Texas Instruments.
After studying the architecture of the ADS1299 EEG we came to the conlusion that this chip is suitable for building EEG devices for medical and research grade applications
And also to use it for device up to a large number of channels, for instance by using daisy chain algorithms.
But the OpenBCI architecture is limited to 16 channels.
We could use in principle use 2 x 16 OpenBCI modules to have 32 channels.
But two 16 channel modules cannot be connected to each other directly over a direct data connection from OpenBCI module to OpenBCI module.
As far as we know, such a data bridge would be necessary for this purpose.
For high quality standard EEG devices, all channels need to be sampled at exactly the same time.
This is not possible with the current OpenBCI architecture, since there is no direct connection between two 16 channel EEG modules.
OpenBCI is on the market since 10 years.
It is field proofen to be free from EEG noise.
Many other EEG devices based on the ADS1299 we reviewed in recent yearrs miss such a proof in the field:

Devices with the ADS1299 EEG chip with more than 16 channels: abandoned prototypes with noisy EEG signals?

OpenBCI uses the PIC32MX250F128B microcontroller which uses very little power.
We suppose that the PIC32MX250F128B causes only little or no noise in the EEG signal.
So why not to develop a bridge between two OpenBCI modules, for instance between to OpenBCI Cyton modules.
And then develop an updated firmware which uses daisy chain algorithms to read out as many EEG channels as required from the ADS1299 chips located on different Cyton modules.
Find more about it on www.petergamm.org which ADS1299 EEG devices did not fit for our needs up to the present day:

Peter seems to be one of the view who is interested on the long-term in EEG devices based on the ADS1299 with more than 16 channels. We would like thank everybody for the many demo devices with 32 EEG channels based on the ADS1299, but none of those did fit for our needs up to the present day.