Frequency decoder.

[TheVig]

Gintaras,

I would like to monitor for a 25Hz tone and a 35Hz tone on the line input of a computer to use for program control.

I did a quick google search and came across this Frequency Analyzer program with source code:
http://www.relisoft.com/freeware/freq.html

Frequency Analyzer program:
http://www.relisoft.com/freq.zip

They have the source code available in C++
http://www.relisoft.com/freeware/source.zip

Could you give an example (when/if you have time):
Watches for user defined frequencies that are longer than a user defined length?

Thanks,
Jimmy Vig