Data format for playback

ArpitBArpitB India
in OpenBCI_GUI

I have collected some PPG data and accelerometer data and I have it in csv format, I want to visualise it using OpenBCI GUI using the "playback from file" as the data source, but I don't find the format in which I need to keep my PPG and accelerometer data for uploading it to GUI.

I found few sample datasets along with the open BCI like 'meditation.txt' and want to know what does each column represent

%OpenBCI Raw EEG Data
%Number of channels = 8
%Sample Rate = 250 Hz
%Board = OpenBCI_GUI$BoardCytonSerial
0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
0, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.014, 0.826, 0.532,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0, 1557936889064, 12:14:49.064
1, 45997.52, 37487.45, -22369.71, -26183.10, -12716.55, -24777.78, -10055.49, -3746.69, 0.014, 0.826, 0.532,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0, 1557936889071, 12:14:49.071
2, 46077.20, 37578.29, -22259.92, -26035.54, -12632.74, -24711.80, -9977.57, -3650.20, 0.014, 0.826, 0.532,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0, 1557936889071, 12:14:49.071
3, 46157.

Comments

  • wjcroftwjcroft Mount Shasta, CA

    Arpit, hi.

    The first column is a sample index from 0 to 255, then repeats. Next 8 columns are the channel samples, in microvolts. Next 3 values are the accelerometer or Aux registers. Then at the very end some time stamps.

    When reading from Cyton, you need to filter out the DC offset, which can be in the millivolts range. That's why you see the large channel values above.

    https://openbci.com/forum/index.php?p=/discussion/201/large-millivolt-data-values-fbeeg-full-band-eeg

    William

  • wjcroftwjcroft Mount Shasta, CA

    Another program you can use for viewing CSV, EDF, BDF, etc. format recordings, is EDFBrowser.

    https://www.teuniz.net/edfbrowser/

  • ArpitBArpitB India

    Thanks for the response William, regarding the 8 columns for EEG channels in data format, is it also possible to use 16 channels EEG in the data format?

  • wjcroftwjcroft Mount Shasta, CA

    With Cyton+Daisy, it's a similar ordering: sample index, channels 1-16, xyz accel.

  • retiututretiutut Louisiana, USA
    edited June 2021

    These sample data files were updated using a python script, and do not contain the latest header generated by the GUI using BrainFlow.

    Here is what to expect from GUI v5.05 and Cyton 8ch:

    %OpenBCI Raw EEG Data
%Number of channels = 8
%Sample Rate = 250 Hz
%Board = OpenBCI_GUI$BoardCytonSerial
Sample Index, EXG Channel 0, EXG Channel 1, EXG Channel 2, EXG Channel 3, EXG Channel 4, EXG Channel 5, EXG Channel 6, EXG Channel 7, Accel Channel 0, Accel Channel 1, Accel Channel 2, Other, Other, Other, Other, Other, Other, Other, Analog Channel 0, Analog Channel 1, Analog Channel 2, Timestamp, Other, Timestamp (Formatted)
0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 192.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.625077630168395E9, 0.0, 2021-06-30 13:27:10.168
1.0, -5816.885032282476, -5622.402503776849, -5777.054223663119, -5705.193365239306, -109557.4554273433, -124029.49470633206, -138962.58341820043, -159042.85419498137, 0.152, 0.962, 0.212, 192.0, 4.0, 192.0, 30.0, 16.0, 6.0, 160.0, 0.0, 0.0, 0.0, 1.625077630184416E9, 0.0, 2021-06-30 13:27:10.184
2.0, -5914.115120663062, -5850.390297220981, -5694.755100578678, -5817.734398571778, -109639.64279170547, -123836.62150342722, -138998.6591337513, -158975.08370579287, 0.152, 0.962, 0.212, 192.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.625077630191868E9, 0.0, 2021-06-30 13:27:10.191
  • omaromar Seattle

    @retiutut sorry to revive an old thread, but I've been searching all over the forums for a clear description of these CSV headers. Here are the headers in my CSV (cyton 8 channels, with two External Digital Pin inputs)

    |Sample Index|EXG Channel 0      |EXG Channel 1      |EXG Channel 2     |EXG Channel 3      |EXG Channel 4     |EXG Channel 5      |EXG Channel 6      |EXG Channel 7      |Other             |Other             |Other              |Other               |Other               |Other               |Other              |Other              |Accel Channel 0    |Accel Channel 1    |Accel Channel 2    |Other              |Other              |Other              |EDA Channel 0      |PPG Channel 0     |PPG Channel 1     |Other             |Other              |Other              |Battery Info Channel|Timestamp            |Other|Timestamp (Formatted)   |
|------------|-------------------|-------------------|------------------|-------------------|------------------|-------------------|-------------------|-------------------|------------------|------------------|-------------------|--------------------|--------------------|--------------------|-------------------|-------------------|-------------------|-------------------|-------------------|-------------------|-------------------|-------------------|-------------------|------------------|------------------|------------------|-------------------|-------------------|--------------------|---------------------|-----|------------------------|
|0.0         | 1.767795648969976 | 8.4074083040309   | 22.24531620353713| 34.834772577936384| 49.59055132582444| 52.752033251932545| 79.79215868409109 | 127.27732421798589| 75.31250658377779| 90.17374456131353| 216.03298257614455| 117.73086708091061 | 53.53214904923507  | 73.22362121434635  | 95.79246658454727 | 99.36501396551876 | 0.8295511593409954| 0.9654570269949413| 0.918377698466763 | 0.8299224680402416| 0.9945494997933017| 0.9481668177244434| 0.9602756424281892| 5285.395926968172| 4914.190791922313| 36.60624681897809| 1052.0798616609368| 1031.9386959084607| 80.13982352872704  | 1.6364331754390292E9| 0.0 | 2021-11-08 20:46:15.439|
|1.0         | 3.5586194529582884| 14.729448789228563| 35.66193284930434| 45.27584386433256 | 67.4609496382832 | 90.25389769559939 | 114.58335689795808| 61.736792086720534| 36.23089353248737| 17.11067645831909| -26.28044550310643| -101.48472509499696| -142.83430047822827| -180.63924628329613| -194.0661490975578| -74.08854344888627| 0.9970992491938636| 0.9882041703069938| 0.8144826387057175| 0.9141404920530251| 0.8121454841275177| 0.8830385558082079| 0.9023153291159675| 5332.981020337097| 5121.139933892803| 36.59539058393287| 1068.7065049822518| 1063.9393593409209| 83.63015986051195  | 1.6364331754437675E9| 0.0 | 2021-11-08 20:46:15.443|
    • EXG Channel (0-7): The 8 (EXoGenous ?) channels from the EEG
    • 8x Other: ???
    • Accel Channel (0-2): Accelerometer data. But Since Accel is turned off if Digital Read is being used, what do these numbers represent?
    • 3x Other: ???
    • EDA Channel 0: ??? (maybe it's something from Emotibit... but why does it have non-zero value in my CSV which isn't using any Emotibit?)
    • PPG Channel 0-1: ??? (same as EDA Channel)
    • 3x Other: ???
    • Battery Info Channel: Suggests Battery level of the board, but is jumping up and down between 80 - 99
    • Timestamp: ⌚
    • Other: ???
    • Timestamp (formatted): ????

    I also noticed that you have a Github issue assigned to document this. I would be happy to fork and contribute to the docs if I can get an unambiguous explanation of the headers (importantly, if/how the GUI CSV output changes if the board is in a different mode or setup with Analog/Digital read).

    Thanks a lot!

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