EEG Pulse Duration with Onsetsignal

[Nate]

Yes it's ridiculous.  It's even more ridiculous that our lab paid for
one...but we don't really have a dedicated tech staff.  (Have you seen
how much the electrode caps cost?! I would be willing to quit my job
and sit at home and make them myself for that price.)

Thanks for the help on the pin placement- I'll check this out.  If
anything it is a good lesson in parallel port communication.



On Nov 16, 4:41 pm, David McFarlane <mcfar... at msu.edu> wrote:
> Wow, BioSemi wants $100 for a simple 25-pin D-sub to 37-pin D-sub
> cable?  I could build one from parts for a lot less than that, and
> then I would know exactly what it does.  But anyway...  I would just
> work on the 25-pin connector on the E-Prime end (and in fact I would
> add a straight-through 25-pin cable just to make my work
> easier).  That pinout remains the same for Presentation and EP.  Then
> yes, your negative lead goes to ground (pin 25; you can Google to get
> several pinout diagrams, pay attention to gender).  Then you have to
> know how to translate decimal to binary, and be aware that we count
> bits from low to high.  The value 9 comes to binary 00001001, which
> means that it would raise a signal on pins 2 and 5.  So put the
> positive lead of the meter on either of these (you will of course try
> both those pins plus a few others just to complete the exercise and
> to see if I really know what I am talking about).  If you then still
> wanted to see how the signal makes it through the BioSemi cable, then
> it looks like you put leads from pin 37 to pins 1 or 4 at the end of
> the BioSemi cable.
>
> Sorry, I can't help at all with the Brain Vision issues.
>
> -- David McFarlane, Profesional Faultfinder
>
>
>
> >This is indeed VERY helpful.  If I was to measure the duration of the
> >pulse (the trigger sent is actually '9') using a voltmeter, I would
> >then connect the negative wire to the incoming PCI-DIO cable ground
> >hole (which one is this?) and the positive lead would then connect
> >to...hmm the chart below does not show 9....
>
> >This shows the pin mapping for this, but there is an error on the page
> >and I also can't tell which chart is actually for eprime.
> >http://www.biosemi.com/faq/presentation.htm
>
> >Onto the other method/explanation: in this example then, I do not have
> >a prerelease for this particular slide, so the pulse duration is
> >probably1500ms.  Other triggers/slides are of different durations and
> >are hopefully not relevant....
>
> >However, now comes the potential problem of analysis in Brain Vision
> >analyzer, though I am not sure this is the correct forum for this (but
> >then again, I have not found a BV forum anywhere).  Anyways, if anyone
> >is familiar with this, I would really appreciate some input, as I am
> >kind of lost:
>
> >I have been told that the triggers/markers (or only the one marker of
> >interest?) need to be moved based on the length of the pulse.    So
> >in  this example the 5 (or 9 in my instance) marker would need to be
> >moved with an offset of 1500 ms. Anyone know if this is true?

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