GUI Data Displayed Differently in Python When Sent via LSL
Situation:
In OpenBCI GUI, the plant bioelectric potential data is displayed correctly. However, when I use LSL to send the data to Python and plot it, the waveform displayed in Python is completely different from what is shown in the GUI. I am unsure if the data is being sent incorrectly or if there is a delay involved.
Ultimately, I plan to send this data to Unity (C#), but first, I want to display the correct waveform in Python. I am confused because the waveform shown in Python is entirely different.
Questions:
- How can I resolve this issue?
- Are there any specific considerations when sending data via LSL to Python?
- If delay is the cause, how can I confirm the delay?
- I would also appreciate any advice on sending data to Unity and handling this process.
Comments
Hi Afcfd,
When sending LSL Time Series EEG data, you have the choice of RAW or FILTERED. The GUI Time Series plot is usually filtered. You can adjust parameters. But the CSV GUI Recording file and LSL RAW is NOT filtered. If you want the data to look like the GUI screen, choose filtered. If you want raw DC potentials, choose raw.
https://docs.openbci.com/Software/OpenBCISoftware/GUIWidgets/#lsl
https://docs.google.com/document/u/1/d/e/2PACX-1vR_4DXPTh1nuiOwWKwIZN3NkGP3kRwpP4Hu6fQmy3jRAOaydOuEI1jket6V4V6PG4yIG15H1N7oFfdV/pub
Actually you don't need to use LSL at all, if you use the Brainflow library.
https://brainflow.org/
https://brainflow.readthedocs.io/en/stable/Examples.html#python-signal-filtering
If you use Brainflow, you can apply whatever filtering you wish.
You mention plant bioelectric potential is your data stream. This probably requires gathering DC level potentials, so you will want to avoid filtering them out.
https://openbci.com/forum/index.php?p=/discussion/201/large-millivolt-data-values-fbeeg-full-band-eeg
Regards, William
Hi William,

I followed the steps you provided and was able to successfully apply the changes!
Thank you very much! I’d like to post this on the forum.
You can post here on the Forum on this thread or a new thread.
And also available is the Community page.
https://docs.openbci.com/GettingStarted/Community/Community/