using LSL to send both data and stimulus

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HA3
Posts: 21
Joined: Sun Nov 23, 2014 5:32 am

using LSL to send both data and stimulus

Post by HA3 »

I've try to send both data and stimulus on LSL export box in openViBE, but I can't understand how to recieve the stimulus, I have write a matlab code, which is shown below to recieve the data and the stimulus, but it's recieve the data and additional row, which is always has the value zero. for example if I have 4 channels I will receive (444 4445 4446 1478 0) where the first four values is the values of channels and the last one always has the value zero.

I expect the last value or the additional row is the stimulus value, but why it's always has the value zero! I have applied many stimulus by the keyboard stimulus but it's still give me zero ! could you help me to know how to recieve the stimulus?

Code: Select all

disp(Loading the library...');
lib = lsl_loadlib();
disp('Resolving an EEG stream...');
result = {}; 

while isempty(result)
    result = lsl_resolve_byprop(lib,'type','EEG'); end

% create a new inlet
disp('Opening an inlet...');
inlet = lsl_inlet(result{1});

disp('Now receiving data...');
while true
    [vec] = inlet.pull_sample();
    disp('new data : ')
    fprintf('%.2f\t\n',vec);
    % Ex : vec  = [9987 4452 1147 7777 0] 
end

jtlindgren
Posts: 778
Joined: Tue Dec 04, 2012 3:53 pm
Location: INRIA Rennes, FRANCE

Re: using LSL to send both data and stimulus

Post by jtlindgren »

Hello,

if I understand correctly, the LSL Export box you're talking about (in 1.0 its called 'LSL Export (Gipsa)') is supposed to append the stimuli as a number in the last column, with 0 meaning there is no stimulation at the time corresponding to that sample.

In 1.0, you can also try the other LSL Export box which encodes stimulations in a separate integer stream.


Happy hacking,
Jussi

jtlindgren
Posts: 778
Joined: Tue Dec 04, 2012 3:53 pm
Location: INRIA Rennes, FRANCE

Re: using LSL to send both data and stimulus

Post by jtlindgren »

Btw, I've posted a brief documentation about using LabStreamingLayer in OpenViBE 1.0.0 here,

http://openvibe.inria.fr/how-to-use-lab ... -openvibe/


Cheers,
Jussi

faturita
Posts: 8
Joined: Fri Jun 08, 2018 3:15 pm

Re: using LSL to send both data and stimulus

Post by faturita »

We have the same exact issue when the "Stimulator Input" for "LSL Export (Gipsa)" is connected to the "Stimulator Output" of the Acquisition Server.
The only way to fix it was to connect it to a different Stimulator output.

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