expand from 16 to 24 or 32 Channel?

adeel · September 2015

hi, every body i am interested in making 32 channel on a 32 bit BCI board v3... by modifying the daisy module and adding two more AS chips to make 8x4 channels... is there will be any change in software or will it effect data rate ?? is this possible or not ? can some one please help me?

reply should be appreciated

Regards,

thanks

wjcroft · September 2015

There is a serial communications speed issue between the chipKIT and RFduino on the main board. That would make it challenging to add more channels / daisy extensions. See,

http://openbci.com/forum/index.php?p=/discussion/342/adding-wifi-faster-bt-and-other-connections-for-v4

http://openbci.com/forum/index.php?p=/discussion/248/constraints-on-data-rates-thru-dongle

http://openbci.com/forum/index.php?p=/discussion/243/spi-wifi-transfer-eeg-data-to-external-device

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Also this related thread on Bias issues,

http://openbci.com/forum/index.php?p=/discussion/150/multiple-device-setup-and-bias

erasmus · February 2016

[24-channel board configuration query]

I'd like to build a 24channel system that can be used to capture at least 19-channels of EEG and then run it through Neuroguide software to do neurofeedback training.

Can we daisy chain 3 8-channel boards together?

wjcroft · February 2016

@erasmus, hi. I merged your question into this existing thread.

@adeel on this thread has shown his prototype daisy board with space for 3 ADS1299 chips, which with the 1 ADS1299 on the mainboard would result in a 32 channel configuration. Adeel, what are your plans for the board, and how have you modified the firmware to handle the data rate from 32 channels?

The current OpenBCI 8 channel configuration runs at 250 sps. With daisy addon (16 ch), runs at 125 sps. This is because of speed limitations between the chipKIT main processor and the RFduino radio link board. See some of the previous links above for possible workarounds suggested.

Regards,

William

adeel · February 2016

hello Sir , I am glad that you are interested in my work . I have
designed again a new daughter board (own design and changed Bias
Configuration that i have discussed with you before) . My new board is
designed such that to control my 3 ADS as i require for this i simply
use a switch to power down ADS1299 on pin 35 . Yes you are right the
daisy addon runs at 125 sps . this is designed is to control any one of
ADS as i required .. to run full 32 channels I have two strategies ...
(i) update firmware that 16 chnnel will have 125 sps and (ii) is to use a
different communication scheme like WIFI . so i am working on it

expand from 16 to 24 or 32 Channel?

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