Biauricular reference & OpenBCI

a1eks · December 2018

Hi everybody,

I would like to use bi-auricular reference (mean of A1 & A2) and I would like to avoid wasting additional channel on the board for this purpose, so I wonder if there is an efficient way to take the mean of both electrodes (using resistors) and have a single reference input to the amplifier?

wjcroft · December 2018

Aleks, hi.

The usual way "linked ears" is done, is with a simple Y-connector. I'm not sure a resistor network would give the exact effect you want, since the currents from either ear could back-flow throughout the network. Perhaps something involving one or more op-amps with unity gain.

https://www.google.com/search?q=op+amp+averager

https://www.allaboutcircuits.com/textbook/semiconductors/chpt-8/averager-summer-circuits/

https://masteringelectronicsdesign.com/using-the-summing-amplifier-as-an-average-amplifier/

Regards,

William

Biauricular reference & OpenBCI

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