A microphone read frequences. If sound is below, blink a led. If sound is sharpen , blink another led. That is all.
You still haven't answered our questions.
What are you getting the signal with?
- Please provide schematic
What is the format of the signal
- Oscilloscope traces would be best, or describe the signal in detail
What frequencies are you interested in?
- Is the signal a single frequency (sine wave), and what is the minimum / maximum frequency?
- Is the signal a composite signal, and you are interested in a "peak" frequency within the background noise? If so, what is the minimum / maximum frequency?
Until you provide this basic information we cannot help you.