Question about BCI2000 2D cursor task with Field trip buffer

[krinsk2011]

Hi, I'm a college student currently working on the BCI2000 2D cursor task with Field trip buffer.

To moves cursors all directions (up, down, left, and right), I followed the description from the wiki that
event_up = event;
event_up.value = 1;
event_down = event;
event_down.value = -1;
event_null = event;
event_null.value = 0;
(see http://www.bci2000.org/wiki/index.php/P ... rip_buffer)

Currently, my cursor moves right and left (x-axis) with matlab coding of
event_right.value=1,
event_left.value =-1.

While I'm trying to move my cursor on y-axis(since I'm aiming for 2D control), I couldn't figure out how I should write the script for up & down movements.
Does anyone know how to do it?

Thanks.

[mellinger]

Hi,

Code: Select all

event.type = 'Signal';
event.sample = 1;
event.offset = 0;
event.duration = 1;
event.value = [ deltaX deltaY ];

should work if you set deltaX and deltaY to the desired change in position.

HTH,
Juergen

[krinsk2011]

Hi, Juergen

I tried the method you posted, but the BCI2000 operator had an error that:

%----------------------------------------------------

8/21/2012 3:03:23 PM - FieldTripBufferFilter::Process: Number of entries in Signal event must match the total number of entries in the FTInitialOutput matrix.

%----------------------------------------------------

I googled it, but had no clue what it means.
Can you give me an advice for it?

Thanks
Kirnsk2011

[mellinger]

Ah, right. You need to resize the FTInitialOutput matrix parameter to have two rows, and one column, and each entry set to 0.

Best,
Juergen