Signal not centred in live-streaming through time series widget
Hi everyone,
I have a problem with my Ganglion boards: actually I have home made cables connected to the board's pins through a PCB receptacle. Unfortunately, this cable has to be replaced (thus removed from the PCB receptacle) according to the different cables needed.
The problem is then that, over 5 Ganglion boards in my possession, only in 1 (the only one with a fixed cable that is never replaced), do not show any more the EEG signal in the live-streaming through the time series widget. What I mean with this, is that the signal is visible and clean with the biggest vert scale but not in the smallest one (I actually use a customized one at 500uV).
To check that is not a cable problem, I connect the board without anything attached, and the problem is still there: the signal is not centred. I also try to clean/polish the pins, but the problem persists.
I will be very grateful if someone of you can help me to fix this problem.
(I am running the OpenBCI GUI From The Processing IDE with a customized script that has always worked on a Windows computer)
Comments
Micaela, hi.
Can you clarify, I am having difficulty interpreting your situation. So you have 5 Ganglions there, how many are working normally, and how many exhibit the large signal offset (on the order of hundreds of microvolts?) When did you purchase these Ganglions?
Why are you using "home made cables connected to the board's pins through a PCB receptacle"? What function does the PCB perform? Could the circuit on the PCB be affecting your Ganglion signal? What actual electrodes are you using, what metal type, with paste, gel, or dry?
Note that you cannot mix electrode metal types. For example gold, tin, silver. Doing so will create a 'galvanic' battery affect which will result in a substantial DC offset to the received signal.
Regards, William