interfacing microphone to MCU to detect two tones

[bugmenot]

Hi

I need a simple circuit to interface a microphone with an MCU. I would like to detect just two tones (2khz and 2.5khz).

At first I thought that I could simply use an ADC connected directly to the MCU as in here
8051 microcontroller hardware interfacing tutorials -adc dac 0808 0804
However apparently this wont work since the microphone gives AC output.

Can anyone please kindly indicate how the circuit should be. Sorry but I am only a hobbyist and have only an amateur electronics background, so please try to be as specific as possible (indicating which components should be used clearly)

Thanks

 

[colin55]

The connection between mic and PIC chip in my project used a simple common emitter stage.
I opened the gate for a short period of time and read the value in timer 0