How OpenVibe recognize channels from OpenBCI device

About the GUI application to design signal processing pipelines
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mhadji05
Posts: 21
Joined: Tue Mar 16, 2021 9:37 am

How OpenVibe recognize channels from OpenBCI device

Post by mhadji05 »

Hello all,

I have a couple of questions.

How does OpenVibe recognize which channel comes from a specific sensor on the OpenBCI device? Logically I have to adjust it somehow.

I have OpenBCI device and I m trying to run MI example. The box Reference channel must be removed because there are ear-clips as reference?

mhadji05
Posts: 21
Joined: Tue Mar 16, 2021 9:37 am

Re: How OpenVibe recognize channels from OpenBCI device

Post by mhadji05 »

Hello all,

I have 2 questions.

How does OpenVibe recognize which channel comes from a specific sensor on the OpenBCI device? Logically I have to adjust it somehow.

I have OpenBCI device and I m trying to run MI example. The box Reference channel must be removed because there are ear-clips as reference?

I appreciate any help!

Thomas
Posts: 68
Joined: Wed Mar 04, 2020 3:38 pm

Re: How OpenVibe recognize channels from OpenBCI device

Post by Thomas »

Hi,

You can set the names of the different channels in the acquisition server directly.
To do so, click on "Driver Properties", and then, at the bottom of the window that appeared, click on "Change channel names".

Once done, the acquisition client box in the designer will receive the channels with the names you set in the server.

Yes, if the OpenBCI kit processes the reference using the earlobe electrode, then you can remove the Reference box from the MI scenario.

Hope this helps,
Thomas

mhadji05
Posts: 21
Joined: Tue Mar 16, 2021 9:37 am

Re: How OpenVibe recognize channels from OpenBCI device

Post by mhadji05 »

I m not sure if I understand.

Lets say I set indexes in OpenVibe : 1, 2, 3, 4, 5, 6, 7, 8 respectively -> O1, O2, P7, P8, C3, C4, FP1, FP2

I need to Connect the cable of O1 electrode on the N1P pin and O2 electrode on the N2P pin on the OpenBCI ganglion board and etc.?

If I connect the O1 electrode in N2P pin and O2 in N1P pin on the OpenBCI ganglion board it's a must to be set on OpenVibe O1 as Index 2 and O2 as Index 1?

Did I understand right?

And what about if i connect daisy board too? There are also 8 pins with names N1P,..., N8P.
The electrode I placed in N1P pin on daisy board must be set as Index 9 on OpenVibe the electrode placed in N2P pin on daisy board must be set as Index 10, etc.?

And Finally on acquisition server If i choose OpenBCI Says: 8 EEG Channels and 3 Accelerometer Channels and
if i tick daisy says: 16 EEG Channels and 3 Accelerometer Channels.

Which are that channels and are the last 3 channels the Accelerometer Channels in both cases?
Specifically for 8 channels Accelerometer Channels are: 9, 10, 11 ?
and for 16 channels Accelerometer Channels are: 17, 18, 19 ?

Please let me understand.
Thanks.

Thomas
Posts: 68
Joined: Wed Mar 04, 2020 3:38 pm

Re: How OpenVibe recognize channels from OpenBCI device

Post by Thomas »

The channels 1 to 8 are in the same order as the pins on the board.
Mapping them in the driver properties of the acquisition server depends on what pin each electrode is connected to.

So yes, you understood correctly. :)

I have never played with OpenBCI but from what I read, I would say that you are also right for the second question, and that the 3 acc channels should be the 9,10,11 for 8 channels and 17,18,19 for 16 channels.

Cheers,
Thomas

mhadji05
Posts: 21
Joined: Tue Mar 16, 2021 9:37 am

Re: How OpenVibe recognize channels from OpenBCI device

Post by mhadji05 »

Thomas thanks for your response.

What are these 3 accelerometer channels and what are their use?

I don't think I have something like this in OpenBCI device. I have only 2 earclips and my 8 or 16 electrode channels.

What should I put as accelerometer channels?

Thanks,
M.

Thomas
Posts: 68
Joined: Wed Mar 04, 2020 3:38 pm

Re: How OpenVibe recognize channels from OpenBCI device

Post by Thomas »

Looking at the specs of the cyton board, there seem to be a 3 axis accelerometer on the board.

It is called "LIS3DH accelerometer", and you can find its specs on the link too.

Hope this helps,

Thomas

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