Information Technology Reference
In-Depth Information
Fig. 3.3
A basic P300 composer interface. In the
above
image, the note-letter D3 is flashing. If
the user is attending to D3 at that moment, there should be an increase in amplitude detectable in
the averaged signal after each complete trial run. Note that although this display shows 5 octaves
in the key of C, there are no restrictions in terms of which note-pitch values and controls can be
represented
In this way, different types of user interactions can be explored quite easily
without making changes to the underlying speller paradigm. All that is required is
that each individual element in the grid be connected up to a synthesiser note or rest
in a sequence, or to a user-interaction event, for example: play, stop, delete etc.
Through these types of approaches, the standard P300 speller approach can be used
to make a reasonably featured composition tool.
3.4.1 MusEEGk
—
The P300 Sequencer
An expansion of this approach is detailed in Yee Chieh (Denise) Chew
'
s paper
“
, presented as work in progress at
CHI 2011 (Chew and Caspary
2011
). She describes a similar system but where
P300 detection is used to indicate notes in a continuously looping sequence. This is
particularly usable in the context of electronic music, and not unlike conventional
approaches to loop-based electronic music composition and performance.
One of the useful adaptations apparent with this technique is the way in which the
system becomes programmable whilst producing sound
MusEEGk: A Brain Computer Musical Interface
”
that is to say, it allows a
user to specify and play back a looping sequence, and then to iterate through it
indicating any changes they wish to make whilst it continues to play. This mitigates
—
