Poor data quality, plotted in EEGLAB / Matlab

Comments

• retiutut Louisiana, USA

  February 2023

  For issues such as this, it's very important to share the code that you have written in Matlab.
• Saima Pakistan

  February 2023

  I simply opened OpenBCI saved file in ".txt" format in EEGLAB and plot its channel data ony....no processing no filter just EEGLAB channel plot command
• Saima Pakistan

  February 2023 edited February 2023

  Step # 01: I just use this code to open .txt file in matlab and function [data] = open_files()

    % Prompt user for filename
     [fname, fdir] = uigetfile( ...
     { '*.txt*', 'Text Files (*.txt*)'; ...
       '*.xlsx', 'Excel Files (*.xlsx)'; ...
       '*.csv*', 'Text Files (*.csv)'}, ...
       'Pick a file');
    % Create fully-formed filename as a string
     filename = fullfile(fdir, fname);
    % Check that file exists
     assert(exist(filename, 'file') == 2, '%s does not exist.', filename);
    % Read in the data, skipping the 5 first rows
     data = csvread(filename,5,1);
  end
  

  Step # 02: I saved this file in .mat format with the command given below:
  save('raw.mat','ans')
  Step# 03: I opened this mat file in EEG lab and click on Channel plot....
  Plz help me.i am a PHD scholar and bougth this OpenBCI device with lot of difficulty
• wjcroft Mount Shasta, CA

  February 2023

  Have you tried some of Irene's tutorials?

  https://irenevigueguix.wordpress.com/category/research-tools/eeglab/

  If the time series data plots look ok with OpenBCI_GUI, but distorted with Matlab or EEGLAB, then your import and filtering in those apps must be sub-optimal. Remember that the recording file is RAW data values, and must be pre-filtered to look like what is showing with the GUI. Typical bandpass would be from say .5 Hz to 45 Hz. And also helps to have a mains frequency notch at your local mains, 50 or 60 Hz.

  William
• Saima Pakistan

  February 2023

  The code i shared above to open OPENBCI .TXT file in matlab has been taken from "https://irenevigueguix.wordpress.com/2016/04/22/loading-openbci-datasets-in-eeglab/" tutorial. but i will look for any filtering technique has been shared in this tutorial. Thank you so much for your time....
• wjcroft Mount Shasta, CA

  February 2023

  When Irene wrote those tutorials, the CSV format was somewhat different than currently. Examine the CSV file and make any code changes necessary.
• Saima Pakistan

  February 2023

  I followed Irene tutorial to open OpenBCI .txt file in MATLAB and separated its AUX and channel data as Irene did ...and it worked wonderfully .Now i will read more tutorial as i have few stimulus videos and i will collect data using LSL ......
  Thank you...Stay blessed
• Saima Pakistan

  February 2023 edited February 2023

  I have plotted the OPENBCI .TXT file in EEGLAB properly, but as in my experiment i will have to collect data using LSL in matlab as i need to show the visual stimuli simultaneously. I have used the code mentioned below to collect data but its plot is in a straight line or squares in data attached in file. Do i need to inlet two streams for AUX and EEG separately as i have seen in few codes of github

  %% instantiate the library
  disp('Loading the library...');
  lib = lsl_loadlib();
  % resolve a stream...
  disp('Resolving an EEG stream...');
  result = {};
  while isempty(result)
  result = lsl_resolve_byprop(lib,'type','EEG'); end
  % create a new inlet
  disp('Opening an inlet...');
  inlet = lsl_inlet(result{1});
  disp('Now receiving data...');
  
• Saima Pakistan

  February 2023 edited February 2023

  Sir can you please guide do i need to keep only one stream opened on OpenBCI gui...I did all three streams in Time Series and EEG data as shown in the picture attached