Search found 7 matches

by dmedine
Sun Feb 13, 2022 10:03 pm
Forum: BioSemi Hardware
Topic: what is going on with the raw trigger data?
Replies: 2
Views: 1710

Re: what is going on with the raw trigger data?

That makes sense. Thanks for pointing me to the FAQ. Somehow I couldn't find the documentation for this.
by dmedine
Thu Feb 10, 2022 2:41 am
Forum: BioSemi Hardware
Topic: what is going on with the raw trigger data?
Replies: 2
Views: 1710

what is going on with the raw trigger data?

Why does the raw trigger data look like this: raw_trigger_data.png Close up showing expected shape of trigger with unexpected trigger values (and one of the intermittent huge negative spikes): closeup.png I would expect an integer value corresponding to the actual active pins on the parallel port co...
by dmedine
Mon Dec 20, 2021 11:08 pm
Forum: BioSemi Hardware
Topic: correct way to wire a GSR sensor test?
Replies: 4
Views: 2686

Re: correct way to wire a GSR sensor test?

Cool. Thank you for the very detailed explanation. This now makes perfect sense. Typically I couple electrodes for things like this by putting them in globs of electrolytic gel. Obviously whatever electrolytic material is used to couple the electrode leads will not have infinite admittance and this ...
by dmedine
Sat Dec 18, 2021 5:21 am
Forum: BioSemi Hardware
Topic: correct way to wire a GSR sensor test?
Replies: 4
Views: 2686

Re: correct way to wire a GSR sensor test?

Thank you for the swift response. Unfortunately, I don't quite understand. What is meant by 'Connect the GSR and DRL electrodes to one of the GSR electrodes (no resistor needed)'. Did you mean connect CMS/DRL to on of the GSR electrodes? I get the rheostat between the GSR electrodes bit.
by dmedine
Fri Dec 17, 2021 3:27 am
Forum: BioSemi Hardware
Topic: correct way to wire a GSR sensor test?
Replies: 4
Views: 2686

correct way to wire a GSR sensor test?

I wish to test the BioSemi GSR sensor with a potentiometer. If I understand correctly, the way to do it is to use the pot as a rheostat (i.e. leave the center terminal disconnected) and attach the GSR electrodes to the outer terminals of the pot. What I don't understand is how to connect the CMS/DRL...
by dmedine
Fri Nov 19, 2021 3:10 am
Forum: BioSemi Software (LabVIEW programming)
Topic: single vs double precsion in GSR preprocessing?
Replies: 0
Views: 2490

single vs double precsion in GSR preprocessing?

I am trying to implement a C++ routine to do online GSR processing that will produce identical output as does ActiveView. I noticed a numerical issue and I am not sure the right thing to do. The preprocessing pipeline, among other things, downsamples the raw data from the GSR Aux channels. This mean...
by dmedine
Wed Sep 29, 2021 3:21 am
Forum: BioSemi Software (LabVIEW programming)
Topic: Correct way to index AUX channels?
Replies: 1
Views: 2616

Correct way to index AUX channels?

I am writing a data acquisition client in C/C++ and I am a bit confused on this point. Here: https://www.biosemi.com/faq/make_own_acquisition_software.htm (at the table on the bottom) the aux channel count appears to be 16 (after EEG and Ex), but here: https://www.biosemi.com/faq/adjust_samplerate.h...