revise your grammar and topic. i have trouble understanding your sentences, and i'm sure others have too. it's your best interest, not mine.
anyway. you don't need a comparator, unless you want a yes/no output.
if you want a range of values, as presented in admin's tutorial, you need an adc. An ADC, not a comparator, nor an opam.
even if you use lm358, lm324, or even a basic 741, you still need an adc to transform the voltage into a binary representation.
opamps are usually interchangable, if you replace something bad with something good (higher slew rate, more bandwidth, etc)