bci2000.org BBS

Hi,

i am trying to implement a p300 speller with matlab signal processing. I want to know where the value of the last flashed row/col is stored. StimulusCode stores the value only for the period that the stimulus is presented. is there a state which stores the last stimulus code until the next stimulus is presented ? and is it accessible in matlab ?

My sample block size is 500ms. I am presenting stimulus and recording data for 500ms before presenting the next stimulus so that there is no overlap (this is just for initial stages to form a base before implementing in C and improving speed and accuracy). So i want to know the code of last flash for my signal processing in matlab. Any help will be appreciated.

Thanks.

Hi,

there is no such state variable, as it would be completely redundant. Just create a LastStimulusCode global variable on the Matlab side to hold the desired information. Then, in bci_Process(), assign the current value of StimulusCode whenever it is nonzero. This way, your LastStimulusCode variable will give you the information you need.

-Juergen