Contributions:OpenBCISource

OpenBCISource

Function

The OpenBCISource filter acquires data from a OpenBCI wireless (Bluetooth) Arduino. The OpenBCI is a low-cost, high-quality biosensing hardware for brain computer interfacing. This arduino compatible biosensing board provides high resolution imaging and recording of EMG, ECG, and EEG signals. This device has been used by researchers, makers, and hobbyists in over 60+ countries as brain computer interfaces to power machines and map brain activity. OpenBCI allows anyone interested in biosensing and neurofeedback to purchase high quality equipment at affordable prices.

More information on OpenBCI can be found at: [1]

OpenBCI Hardware

Either up to 8 referential EEG/ExG channels (with either passive or active electrodes) or up to 16 EEG/ExG referential channels in daisy mode can be inputs. There are built-in 3-axis acceleration sensor with 3 separate channels (x, y, z).

More on hardware can be found at: [2].

Installation

No software needs to be installed. Just plug in the bluetooth dangle.

Parameters:OpenBCISource

Parameters common to all source modules are described under User Reference:DataIOFilter. In addition, the OpenBCISource provides the following parameters:

SourceCh

The total number of channels: EEG + Acc.

SampleBlockSize

Samples per channel per digitized block. Together with the sampling rate, this parameter determines how often per second data are collected, processed, and feedback is updated. For example, at 500 Hz sampling and a SampleBlockSize of 20, the system (e.g., source signal display, signal processing, and stimulus presentation) will be updated 25 times per second.

For OpenBCI Cyton the sampling rate is 250Hz and it sends data to buffer every half second. So the suggest value for sample bock size is 125.

SamplingRate

The sample rate of the system. All data is either acquired at 250Hz In case you are experiencing problems by higher sampling rates (e.g., data loss, jerky display, etc.), increase the SampleBlockSize so that you are updating the system less frequently (usually, updating the system 20-30 times per second is sufficient for most applications), and increase Visualize->VisualizeSourceDecimation. This parameter will decrease the number of samples per second that are actually drawn in the Source display.

SourceChGain

Gain for each channel.

SourceChOffset

Offset for each channel.

ChannelNames

Names of each channel.

AcquisitionMode

Data acquisition mode, it can be:

• inactive - no recording
• analog signal acquisition - standard recording mode
• test signal - a test signal, same on all channels

Parameters:LiveAmp

EegChList

List of indexes of EEG channels used. For example, you can write index in any order, like: 21, 3, 5, 6, 7, 8 (the order of channels does not matter). That means that only 6 EEG physical channels will be recorder: 3,5,6,7,8 and 21. Channels may not be listed twice.

BipolarChannels

Checking this option the last 8 of 32 channels will be bipolar. When user wants to record bipolar channel, he/she must put appropriate indexes in the 'EegCHList' (indexes between 25 and 32).

AuxChList

List of indexes of AUX channels. For example, if there are 6 AUX available, you can put 1, 2, 5, 6. That mans that only 4 AUX channel will be recorder, with indexes 1,2, 5 and 6.

ACCList

List of indexes of Acc (acceleration sensor) channels. There are 3 Acc channels, with indexes 1(x), 2(y) and 3(z).

TriggerChList

List of indexes of trigger channels. There is one analog and 8 digital channels. The order of indexes can be used in the same manner as EEG and AUX channel indexes.

See also

User Reference:Filters, Contributions:ADCs