Write a Program Which Recognizes a Sound and Performs Action

Question

I would like to write a program which is capable of storing a sound pattern, such as a train whistle, horn (beep beep)...listening for the sound via the microphone...and the

Answer 1

If you're listening for a particular recording of a horn or a train whistle, that the program knows about beforehand, then it is likely that if the sounds are sufficiently distinctive, you will be able to detect and distinguish between them reliably.

Classifying a new sound that the program hasn't heard before (as sounding like a horn, or like a train whistle, etc.) is a much harder problem.

In either case, sound identification algorithms will generally look at the frequency spectrum of recorded sound (see Miky D's link on digital sound processing), and perform some pattern recognition on this data, rather than on the recorded waveform itself.

As for language and third-party libraries, go for something which allows you to get at the recorded audio data with a minimum of fuss. Java seems good in this respect (see also the Java machine learning algorithm WEKA). While there are programs/libraries around for speech and music analysis, I don't know of one designed for arbitrary sounds, so you may end up having to write the analysis algorithm yourself.