HELP with EOG based Morse Decoder

Oh yeah I should have been more specific, I just wanted to illustrate roughly what I was doing but yes I would have to be exact with the dots and dashes to represent the correct letters. Ok, so attached is an output image from the circuit onto the oscilloscope. The negative peaks indicate a left eye movement and the positive peak (highest peak on the plot) indicate a right eye movement. I know arduino can't read in negative values so I do need to add a potentiometer to remove the offset but assuming the offset will be removed (because I know how to do this) any ideas on how to proceed with the coding? Thanks.

test1___.png