ADS1299 interface with Arduino UNO

Momin_2089Momin_2089 Islamabad , Pakistan

Hi, I have made an EEG module and trying to get data from it using Arduino IDE(I have attached sample code and my PCB schematics). I am using ads1299 with bipolar supply. So far I have just Configured CONFIG3 register and CHnSEL registers as following

ADS.WREG(CONFIG3,0xE0) ;//Enabling internal reference
ADS.WREG(CHnSET,0x68); //Selecting normal mode and closing SRB2

I’m able to get data from all 8 N-channels with respect to SRB2(as a reference electrode).
Problem is I want to include BIAS electrode. As far as I know about BIAS electrode, it is used for noise cancellation in a closed loop form ( As discussed in openBCI site : https://docs.openbci.com/docs/01GettingStarted/02-Biosensing-Setups/EEGSetup ).I want to use my setup same as in the link of openBCI but with all 8 channels.
As there are many BIAS registers in ads1299 so I’m confused about there configuration .It will be great if someone could help me in configuring registers so that if I connect SRB2 to one ear lobe and BIAS to other and all other electrodes on EEG head cap I would get data with much lesser noise.

Comments

  • The bias electrode gets it name from its historical use, with older analog equipment that was powered from AC current, as a source of a tiny bit of cancelling AC voltage to offset mains noise. Filters were not as good back then. A battery powered EEG machine, or modern well isolated electronics in general, does not need a "bias" source, in that sense. So just add it as a ground. With 8 electrodes around the head, I would put the ground electrode in the center, either at the peak of the center scalp or somewhat to the front of that, more or less equidistant from your 8 other wires. Or, if you are using a reference electrode on one ear, you can use the other ear for the ground, just as the tutorial does, even with all the other leads in use.

Sign In or Register to comment.