DataHub

Lab Streaming Layer

Developer(s)	Christian Kothe; Chadwick Boulay.
Development status	-in development-
Written in	C, C++, Python, Java, C#, MATLAB
Operating system	Windows, Linux, MacOS, Android, iOS
Type	Data collection
License	Open source
Website	LSL webpage

Resources

DataHub

Downloads
Viewer & Streamer
Manuals
Documentation LSL Validation Supported Devices and Tools
Templates
Example Scripts

The DataHub Makes use of the lab streaming layer. The lab streaming layer (LSL) is a system for the unified collection of measurement time series in research experiments that handles both the networking, time-synchronization, (near-) real-time access as well as optionally the centralized collection, viewing and disk recording of the data.

Installation

Our support for LSL is mainly done in python. Download python here: Please choose a 64 bit version.. Run the installer and make sure to add Python to the file path (it's an option in the installer). Open a command prompt, start with upgrading the pip installer by typing:
c:>python -m pip install --upgrade pip
Then:
c:>pip install pylsl

more info: cross platform pylsl

Versions

Pylsl version 1.16.2 is installed on our Lab Computers. Open a command and type the following to find the version used:

c:>python
>>> import pylsl
>>> print(pylsl.__version__)

Usage

Python

Example demonstrating how to send LSL stream and marker data:

#!/usr/bin/env python3.10
# -*- coding: utf-8 -*-

import time
import random
import keyboard
from pylsl import StreamInfo, StreamOutlet

from pylsl import local_clock

# --- Setup Marker Stream ---
print("Setting up marker stream...")
marker_info = StreamInfo(
    name="MarkerStream",
    type="Markers",
    channel_count=1,
    nominal_srate=0,  # Irregular sampling
    channel_format="string",
    source_id="MarkerSource"
)
marker_outlet = StreamOutlet(marker_info, chunk_size=1)

# --- Setup Data Stream ---
print("Setting up data stream...")
data_info = StreamInfo(
    name="TestStream",
    type="TestData",
    channel_count=4,
    nominal_srate=100,
    channel_format="float32",
    source_id="TestStream_Source"
)

channels = data_info.desc().append_child("channels")
for name in ["A", "B", "C", "D"]:
    chan = channels.append_child("channel")
    chan.append_child_value("name", name)
    chan.append_child_value("unit", "unitless")
    chan.append_child_value("type", "TestData")

data_outlet = StreamOutlet(data_info, chunk_size=1)

# --- Start Streaming ---
print("Start streaming... Press 'q' to stop.")
marker_outlet.push_sample(["Start"])

while not keyboard.is_pressed('q'):
    random_numbers = [random.randint(1, 2) for _ in range(4)]
    data_outlet.push_sample(random_numbers)
    time.sleep(0.01)

marker_outlet.push_sample(["Stop"])
print("Streaming stopped.")

Matlab

Please, read the instructions on the GitHub labstreaminglayer website (https://github.com/labstreaminglayer/liblsl-Matlab) on how to prepare Matlab to work with LSL. You can either use the latest release for your Matlab version, or if that doesn't workout well, build it from the source files. Make sure to add the liblsl-Matlab folder to your path recursively to make it available to your own scripts.

A short example for sending lsl streaming data:

%% instantiate the library
disp('Loading library...');
lib = lsl_loadlib();

% make a new stream outlet
disp('Creating a new streaminfo...');
info = lsl_streaminfo(lib,'BioSemi','EEG',8,100,'cf_float32','sdfwerr32432');

disp('Opening an outlet...');
outlet = lsl_outlet(info);

% send data into the outlet, sample by sample
disp('Now transmitting data...');
while true
    outlet.push_sample(randn(8,1));
    pause(0.01);
end

A short example for receiving lsl streaming data:

%% instantiate the library
disp('Loading the library...');
lib = lsl_loadlib();

% resolve a stream...
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
    % get data from the inlet
    [vec,ts] = inlet.pull_sample();
    % and display it
    fprintf('%.2f\t',vec);
    fprintf('%.5f\n',ts);
end