Detection of a specific sound

[alister]

On Mon, 02 Nov 2015 20:49:03 -0700, Michael Torrie wrote:

> On 10/25/2015 06:17 PM, Montana Burr wrote:
>> I'm looking for a library that will allow Python to listen for the
>> shriek of a smoke alarm. Once it detects this shriek, it is to notify
>> someone. Ideally, specificity can be adjusted for the user's
>> environment. For example, I expect to need moderate specificity as I
>> live in a quiet neighborhood, but an apartment dweller might need more.
>> 
>> I'm thinking of recording a smoke alarm and having the program try to
>> find the recorded sound in the stream from the microphone.
>> 
>> Any help is greatly appreciated!
> 
> At this point, from what you say, your problem is not a python one. It's
> a more general problem that you have to tackle.  In other words how are
> you going to identify this one sound amongst background noise?  Once you
> know that, then you can apply Python to the problem.
> 
> I suggest you spend some time exploring how you would actually go about
> recognizing a particular sound algorithmically.  Relevant tops of
> research include: digital signal processing and fourier analysis.
> 
> A quick google search reveals some info that may point you in the right
> direction:
> 
> https://blog.adafruit.com/2015/01/12/think-dsp-introduction-to-signal-
processing-using-python/
> http://samcarcagno.altervista.org/blog/basic-sound-processing-python/
> 
> I know very little about the subject, but if it were me, my naive
> approach would be to do fourier analysis on the sound you are trying to
> identify to pick out the sound's fingerprint (certain component
> waveforms that stand out), and then do the same analysis on your audio
> stream, looking for this footprint.

Personally I would forget trying to analyse sound & see if there is any 
way to get an input signal direct from the alarm (even if that is as 
crude as taking a tap from the siren feed wires) 

This application sounds far to critical for anything else.



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