Coding it - you have to explain more what the times are that correlate to the levels:
read 1 value(possibly analog) when it is solid positive+++++++.
and another when it is varriable+-+-+-+-+-+-+-+,--+--+--+--+ or ---++---++---++ etc.
read low or 0 if its analog when its constant neg ---------
The blinker on/off times are ages long compared to 16 MHz clock.
How long do you go before deciding it is solid positive, or negative, and can anything change outsde of those times be called variable?