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Topic: Open BCI (16ch Daisy) element does not seem to work properly
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Nobuyoshi



Joined: Jan 15, 2019
Posts: 18

PostPosted: May 30, 2021 4:12 PM    Post subject: Open BCI (16ch Daisy) element does not seem to work properly

Hi Jarek,

At this point, the symptoms I have confirmed are as follows

when i use the GUI provided by OpenBCI, i can detect the signal correctly.

When I use the BioEra design file, I cannot detect EEG signals for channels 9-16.
Here is my bpd file: https://drive.google.com/file/d/1-q3H_mPgD4T-0Qo9M1eBcvU41Ku9vsdf/view?usp=sharing

Cyton (1-8ch) works properly, but when Daisy board (9-16ch) is attached, the signal of 9-16ch cannot be detected.

The test signal (generated by the command "[" or "[" https://docs.openbci.com/docs/02Cyton/CytonSDK) can be detected only for channels 1-8.

Best regards,
Nobu
jarek



Joined: Oct 22, 2007
Posts: 886

PostPosted: May 30, 2021 4:23 PM    Post subject:

Did you change the "Channel count" property to "16 channels"?

If so, try this snippet which works fine for me:

http://proatech.com/design/openbci_16channels.bpd
Nobuyoshi



Joined: Jan 15, 2019
Posts: 18

PostPosted: May 30, 2021 4:33 PM    Post subject:

Yes. Of course I have changed the "Number of Channels" property to "16 Channels".

Here's the design file I'm using.
https://drive.google.com/file/d/1-q3H_mPgD4T-0Qo9M1eBcvU41Ku9vsdf/view?usp=sharing

Unlike your design, the pipe type is "float". Is this the reason why it does not work properly?

I will try it later using the snippet you sent me and report back.Thank you.

Nobu
jarek



Joined: Oct 22, 2007
Posts: 886

PostPosted: May 30, 2021 4:50 PM    Post subject:

Your snippet design works fine for me after I removed "C" command (not sure why it was needed).
jarek



Joined: Oct 22, 2007
Posts: 886

PostPosted: May 30, 2021 4:56 PM    Post subject:

I tried again, and now it also works with "C", as supposed to.

I increased the delay time to 100ms. I found that it was necessary with firmware 2.0.1 I have also for other settings.
Nobuyoshi



Joined: Jan 15, 2019
Posts: 18

PostPosted: May 30, 2021 5:51 PM    Post subject:

Thank you for using your board to check my design files.

I bought my cyton board in 2018, so the firmware should be v3.0.0 or later. I thought it was possible that this may have affected this problem.

The command "C" means to make channels 1-16 available.
https://docs.openbci.com/docs/02Cyton/CytonSDK

Anyway, I will check again later. Please wait for my report.

Nobu
Nobuyoshi



Joined: Jan 15, 2019
Posts: 18

PostPosted: May 31, 2021 12:20 AM    Post subject:

Hi Jarek,

I have used the snippet design you sent me to check if it works correctly .

Unfortunately, the signals from the Daisy board are still not displayed correctly.
The signals from the same board and GUI are displayed correctly.

https://drive.google.com/file/d/1iQhYIv_0zs2iyRxW0Ip0cUYITZ4Zepo4/view

The firmware of my board was v3.1.1.

Nobu
jarek



Joined: Oct 22, 2007
Posts: 886

PostPosted: May 31, 2021 9:37 AM    Post subject:

It appears there are differences between the firmware versions. I can only try on version 2.0.1 I have here.

Here is how it looks for me:

http://proatech.com/design/image/cyton_16ch.png

You will notice, that here the measured sample rate is 125, while in your case it is 250, which looks like the daisy board is not attached and the board is sending data in 8 channel mode. Or maybe you have the wifi shield? I am just guessing here.

Try this command: vC[

It will reset the board before changing to 16 channel mode. It works here.

I updated the example design referenced above.
jarek



Joined: Oct 22, 2007
Posts: 886

PostPosted: May 31, 2021 9:44 AM    Post subject:

Hold on. I tried with version 4.184 and I see the same behavior as you do.

Please update BioEra version to 4.187 or later.
Nobuyoshi



Joined: Jan 15, 2019
Posts: 18

PostPosted: May 31, 2021 4:06 PM    Post subject:

Hi Jarek,

Thank you for your detailed review!
I am glad to know that the cause is being identified.

The version of BioEra that I am using is v4.184.
So, i will try to upgrade and check it again.

Best regards,
Nobu
Nobuyoshi



Joined: Jan 15, 2019
Posts: 18

PostPosted: May 31, 2021 6:09 PM    Post subject:

Thanks to your advice, the signals on the Daisy board are now displayed correctly!
Thank you very much.

However, there was another problem. Artifacts on the spikes are visible only in the Daisy board signals(9-16ch).Do you have any solution for this phenomenon?

https://drive.google.com/file/d/1H_gsnxKW1dtVArdN8y4sTazvrtfJof2W/view?usp=sharing

This is not the case when streaming data using the GUI distributed by OpenBCI.

Nobu
jarek



Joined: Oct 22, 2007
Posts: 886

PostPosted: May 31, 2021 7:42 PM    Post subject:

This is just the display and the fact, that the 8 higher channels alternate with 8 lower channels. That means data is not delivered to Polygraph fully synchronized (it is shifted by one packet).

I modified the above snippet example to fix that. Please check it out.
Nobuyoshi



Joined: Jan 15, 2019
Posts: 18

PostPosted: May 31, 2021 8:00 PM    Post subject:

Thank you Jarek,
The display issue has been resolved!
I thought it would be better to connect the 'F_Synchronizer' element also for the synchronized calculation of 16 channels of vector data per sample. Am I correct in my understanding?
jarek



Joined: Oct 22, 2007
Posts: 886

PostPosted: May 31, 2021 8:05 PM    Post subject:

Yes, to make everything perfect you should add synchronizer when using upper 8 channels together with lower 8 channels.
Nobuyoshi



Joined: Jan 15, 2019
Posts: 18

PostPosted: May 31, 2021 10:14 PM    Post subject:

I deeply appreciate your support!
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