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Others => Biofeedback - EEG, ECG, EKG => Topic started by: hujiawennn on April 15, 2020, 05:14:17 am

Title: EEG-SMT Brainbay signal processing
Post by: hujiawennn on April 15, 2020, 05:14:17 am
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...
Title: Re: EEG-SMT Brainbay signal processing
Post by: LubOlimex on April 15, 2020, 12:56:52 pm
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
Title: Re: EEG-SMT Brainbay signal processing
Post by: hujiawennn on April 15, 2020, 09:54:10 pm
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!
Title: Re: EEG-SMT Brainbay signal processing
Post by: LubOlimex on April 16, 2020, 04:15:25 pm
Use the 4chn.con in BrainBay\CONFIGURATIONS\EEG\alpha you might delte the 3d and 4d channels from the sketch.
Title: Re: EEG-SMT Brainbay signal processing
Post by: hujiawennn on April 17, 2020, 03:39:35 am
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!
Title: Re: EEG-SMT Brainbay signal processing
Post by: LubOlimex on April 22, 2020, 02:26:30 pm
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