look at ne567 ICi have no idea, but would a analog in work?
Would Goertzel's algorithm work for you?
I want to know if certain frequency or frequencies are present in the input.
2. look whatever "pop-up" in sampling pull - FFT.For second variant, more details necessary, in order to be sure that arduino "capable" for a mission: sampling rate, freq. selectivity / resolution (Q) of the filter?