I like to build a device that recognizes certain audio frequencies. The usecase is as follows:
My daughter is diabetic and weares an Insulin pump. If the blood sugar is out of range the pump plays an alarm beep. At fast decreasing sugar values it plays a three tone melody.
I tried to use a standard Baby Monitor to transfer alarms to my bed room but baby monitors do not hear that frequencies at all. So I need to solder something.
My basic question is: can I connect a microphone to the analog Input and separate the beep frequency from all the other noise by software in the espruino or shoud I connect an external ADC? At a later stage I like to recognize three tone melodies to separate different alarms.
Does this work at all?