P300 flashing sequence modification

[chantrip]

Dear all

I've tried P300-speller with xDAWN using row-column (RC) flashing and everything works fine (so far). I'd like to know how to modify the flashing sequence such that only specified letters are flashed. For example, from P300-speller, instead of the row 'A B C D E F' flashing, how to modify them such that the letters 'A Z O 3 7 Y' flash?

Thank you very much for your help and support

-Jim

[lbonnet]

Hi Jim,

If you want to specify the flashing sequence, just modify the LUA stimulator box named Target Letter Generation.
One setting is the word to spell. Default value is empty, so 10 letters are randomly chosen at startup.

Laurent-

[chantrip]

Thanks Laurent for a quick response. However, what I want to modify is how the alphabets flash, not the output sequence. In the conventional P300 scheme, alphabets are flashed in a row/column scenario e.g. every alphabet in the row 'A B C D E F' flash simultaneously. Can I modify the flash such that only specified alphabets are flashed simultaneously e.g. the alphabet 'A E I O U' flash simultaneously?

Thank you very much for your kind help

-Jim

[chantrip]

I found this link viewtopic.php?f=3&t=329 and not sure if this is the one that I want. However, is there any tutorial or read-me file to explain the programming structure in the file 'ovpCBoxAlgorithmP300SpellerVisualisation.cpp'?

Thank you very much

-Jim