Recording OpenBCI at the same time [resolved]

ihgumilarihgumilar Auckland
edited February 2021 in Cyton

Hi,
Does anyone here have an experience of recording brain signals simultaneously with two OpenBCI running at the same time ? I am wondering should the signals interfere with one another? After comparing the data of 3 pairs, I tried to plot them and it showed that it looks like the same for people who are in the same pair, eg. S1-S2 . Here is the example that I would like to share. Both participants have shown the same plot.

Thanks

Comments

  • wjcroftwjcroft Mount Shasta, CA

    ...recording brain signals simultaneously with two OpenBCI running at the same time ?

    Can you clarify what you mean by "two OpenBCI running at the same time?"

    Your time series shows some kind of anomaly. How many Cyton's are you using? How many simultaneous apps? How is the Cyton data getting into your plotting program? Etc.

    William

  • ihgumilarihgumilar Auckland

    I am actually recording two different brains at the same time in the same room with two openBCI caps. The time series are perfectly in line. I tried with one pair where each openBCI is recording in different PCs- running two scripts in different PC. I also tried to plug two dongles into the same PC (yet different COM port) - running two scripts in the same PC . Yet, I still have the same data when it is plotted in MNE. When I looked at them with eye balling, it shows a quite different somehow a little bit.
    I can share my data if you would like to see

    Thanks

  • wjcroftwjcroft Mount Shasta, CA

    Do you have the two different Cyton's, setup on two different radio channels? Expand Section 5, Optional Settings. There you can read out or set your radio channel. Each pair (Cyton+Dongle), must be on a unique radio channel. Both Cyton's cannot be on the same radio channel. Otherwise they will interfere with each other.

    https://docs.openbci.com/docs/01GettingStarted/01-Boards/CytonGS#5-optional-settings

  • ihgumilarihgumilar Auckland
    edited February 2021

    Thank you very much. I am able now to change the radio channel and give a unique channel for each pair (Cyton + Dongle) - each dongle was attached to a different PC.

    However, when I plugged in the two dongles on the same PC, it showed in the GUI that there are two COM ports (eg. COM3 & COM5). However, when I tried to change the unique radio channel for one COM port, it also changed the other one. So, it is basically they are always connected to the same radio channels as both dongles are connected on the same PC. Do you have any advice ? I would love to run the two OpenBCI hardware on the same PC so that the synchronization is perfectly in line.

    Thanks

    Do you have the two different Cyton's, setup on two different radio channels? Expand Section 5, Optional Settings. There you can read out or set your radio channel. Each pair (Cyton+Dongle), must be on a unique radio channel. Both Cyton's cannot be on the same radio channel. Otherwise they will interfere with each other.

    https://docs.openbci.com/docs/01GettingStarted/01-Boards/CytonGS#5-optional-settings

  • wjcroftwjcroft Mount Shasta, CA

    Here is what you need to do. Turn off BOTH Cytons, remove BOTH dongles.

    With adhesive label tape, put the channel number you desire on each pair of Cyton+ Dongle. Number must be different between the pairs.

    NOW, only power up one pair of Cyton+Dongle at a time. Assign the channel you have chosen. Turn off Cyton, remove dongle. Now do the same for other pair. Now both Cytons should have different channels.

    Your best strategy is to use each dongle on a separate laptop. The GUI does not know how to talk to two serial ports at once.

  • ihgumilarihgumilar Auckland

    Ah I see..
    "Turn off Cyton, remove dongle" (1st dongle), so I put the first dongle back after choosing different channel for the second. Then they will have different unique channels? . Because when I tried to look at it again in GUI, both COM ports showed that they are on the same channels.

    Actually, during my experiment, I don't use GUI. I am just writing a script by using Brainflow.
    I just wanna make sure that when I am recording the data with two dongles attached to the same PC, they give me different data. Not interfering from one another. I just don't know at the moment when I am running my script whether it still gives me different or same data.

    Thanks

  • wjcroftwjcroft Mount Shasta, CA

    Please re-read my previous comment.

    You need to program EACH PAIR of Cyton+Dongle, ONE AT A TIME. With the other Cyton+Dongle unplugged and turned off.

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