EEG-SMT Brainbay signal processing

Started by hujiawennn, April 15, 2020, 05:14:17 am

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hujiawennn

April 15, 2020, 05:14:17 am Last Edit: April 15, 2020, 05:22:06 am by hujiawennn Reason: Forget to put the link
Hi, I am new to the brainwave signal processing. I found this 2014 post (https://www.olimex.com/forum/index.php?topic=2350.0) and I really want to replicate similar brainwave patterns produced by LubOlimex. I have both channel 1+ and channel 1- electrodes placed on my temples, and ground electrode on my right hand. Then I loaded the default design called 3d_alpha.con in Brainbay and changed the COM port of data input to the correct one, but the signal coming out of the Chanel 1 of the EEG element to oscilloscope is well above 350 microvolt.

This is what I got:
https://drive.google.com/file/d/1sji6MEfmK9HfG687fHBS_q9S171_ZLIX/view?usp=sharing

I don't know how to fix it... Can someone help me get brainwave signals in the appropriate range? Thanks in advance!

Not sure if this info would be helpful for troubleshooting:
I am using adhesive electrode pads like these (https://www.amazon.com/Red-Dot-Multi-Purpose-Monitoring-Electrode/dp/B01AME7YC0/ref=pd_bxgy_3/132-1460182-7271324?_encoding=UTF8&pd_rd_i=B01AME7YC0&pd_rd_r=a8b14e5f-d275-4f6a-87de-97b2356c5dcc&pd_rd_w=G4pNj&pd_rd_wg=Ae4tI&pf_rd_p=fd08095f-55ff-4a15-9b49-4a1a719225a9&pf_rd_r=W9HRSAFP1SAT6360YKB6&psc=1&refRID=W9HRSAFP1SAT6360YKB6) with 3.5mm jack (https://www.amazon.com/Replacement-Wires-Connectors-Discount-Brand/dp/B01BOJPKIW/ref=sr_1_4?keywords=electrode%2Bconnector&qid=1582494048&s=industrial&sr=1-4&th=1). I actually doubt their functionality...

LubOlimex

Well, you have loaded some project that I haven't tested. In the link of the thread from 2014 that you posted, I used ElecGuru to visualize the data, not BrainBay. For BrainBay I have tested modeeg_test.con and 2chn_test.con. I'd advise testing with those. Also refer to the manual's page 10, it describes how to setup BrainBay:

https://www.olimex.com/Products/EEG/OpenEEG/EEG-SMT/resources/EEG-SMT.pdf
Technical support and documentation manager at Olimex

hujiawennn

Hi LubOlimex, thank you for your quick reply! I went through all the setup steps in the manual about Brainbay and I couldn't find the modeeg_test.con and 2chn_test.con. The manual said they are in the folder Test_Elements and I couldn't find this folder either. How can I get access to these configs? Thanks!

LubOlimex

Use the 4chn.con in BrainBay\CONFIGURATIONS\EEG\alpha you might delte the 3d and 4d channels from the sketch.
Technical support and documentation manager at Olimex

hujiawennn

Hi LubOlimex, I tried 4chn.con and deleted two channels from the design sketch. The oscilloscope shows signals from the two channels are just 0. I do not know why it doesn't collect brainwave signals. Do you have any suggestion on how to fix it? Thanks!

LubOlimex

It seems to properly work here. Did you connect DRL passive electrode? Did you point the correct COM port? Maybe try playing a bit with the settings. Here are three pictures of my setup here:

https://imgur.com/a/sv3aT2f
Technical support and documentation manager at Olimex