bci2000.org BBS

Hi,

I'm new to the BCI2000 system and try to use Biosemi MK2 (active 2) as the source acquisition.

I have recompiled the biosemi module into the BCI2000 and try to run a demo.
The three modules I used in the BCI2000 launcher are biosemi2.exe, P3SignalProcessing.exe and StimulusPresentation.exe

Since we only have 32 channels, a modified parameter setting is as following.
However, we cannot visualize the EEG signal even when the scaling of the signal has been adjusted to 20muV.
The button of "Set Config" is pressed only once. And there is no error message returned.

Can anyone help me to solve this problem? Or send me a functional parameter file?
Whether I set correctly the sampling rate and sampleblockSize? The actual sampling rate in the hardware is 16K+, should I set the same sampling rate into the parameter file?

Thank you very much!


=========================
The major parameter settings are:
SoureCh =40
SampleBlockSize= 8
SamplingRate= 256
SourceChOffset= 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
SourceChGain= 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125 0.03125
EEGChList=1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Hi,

The Biosemi output may have a big DC offset. Perhaps this is the reason why you can't see anything. Try right-clicking on the Source display. Turn on a high-pass filter, e.g., at 1 Hz. Let us know if you still don't see anything.

Gerv

Hi Gery,

Thank you very much for your reply. I have set the filter with high pass at 0.1Hz or 1 Hz and low pass at 30 Hz.

It doesn't work.

Any other possibilities?

Hi,

Please download http://www.bci2000.org/tmp/Desktop.rar

This archive contains the latest Biosemi2 executable from SVN, which does not suffer from the "multiple Set Config" problem. This executable also has the BCI2000 high pass filter included, which means you can turn on high pass filtering at 0.1 Hz before data are saved to disk. This is advisable if you want to classify online.

This archive also has a parameter file that works for me when used together with P3SignalProcessing and P3Speller.

Let me know.

Gerv

Hi, Gery,


Yes, it works!

And the signal is in range only when the electrodes are attached to subjects or in the condition of "in bucket " test. It means the signal should be in a normal testing range to be visible in BCI2000.

Thank you so much!