I’m considering using an electret microphone and pre-amp to detect brief tone bursts. An Arduino UNO sketch would use the pre-amp’s output as its input to A0. The two tone bursts would be approximately 1kHZ and last about 200ms each, separated by a gap of 100-500ms. (They result from the press of a button.)
I’m fairly confident about getting an output in quiet conditions. But is it feasible to ensure that the program reacts only to a narrow range of frequency, say 900 - 1100 Hz, to avoid unwanted triggering?
Or is 16 MHz too slow for my idea to be practical please? A brief test showed that a loop doing nothing but serial print millis() took about 1ms.