Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail From: Dennis Lee Bieber Newsgroups: comp.lang.python Subject: Re: Detection of a specific sound Date: Tue, 03 Nov 2015 09:03:14 -0500 Organization: IISS Elusive Unicorn Lines: 34 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news.uni-berlin.de V1k6g1qVH/C9mSRzKMUxPwm0WSXiUGj1W4BDA2dZc3Uw== Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.042 X-Spam-Evidence: '*H*': 0.92; '*S*': 0.00; '(even': 0.05; 'responding': 0.07; 'falls': 0.09; 'message-id:@4ax.com': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'alarm': 0.16; 'received:80.91.229.3': 0.16; 'received:io': 0.16; 'received:plane.gmane.org': 0.16; 'received:psf.io': 0.16; 'sorts': 0.16; 'url:home': 0.18; 'input': 0.18; '2015': 0.20; 'liability': 0.20; '(the': 0.22; 'trying': 0.22; 'header:X -Complaints-To:1': 0.26; '+0000': 0.27; 'monitored': 0.27; 'detector': 0.29; "i'm": 0.30; "i'd": 0.31; 'supposed': 0.31; 'anyone': 0.32; 'tue,': 0.34; 'that,': 0.34; 'gives': 0.35; 'could': 0.35; 'feed': 0.35; 'nov': 0.35; 'something': 0.35; 'expected': 0.35; 'but': 0.36; 'too': 0.36; 'needed': 0.36; 'there': 0.36; 'to:addr:python-list': 0.36; 'subject:: ': 0.37; 'received:org': 0.37; 'beyond': 0.37; 'signature': 0.37; 'charset :us-ascii': 0.37; 'anything': 0.38; 'application': 0.39; 'to:addr:python.org': 0.40; 'forget': 0.60; 'close': 0.61; 'digital': 0.63; 'fire': 0.63; 'monitoring': 0.64; 'between': 0.65; 'else.': 0.66; 'direct': 0.68; 'risk': 0.68; 'sound': 0.72; 'sounds': 0.76; '(utc),': 0.84; 'circuit': 0.84; 'wiring': 0.84; 'concluded': 0.91; 'dennis': 0.91; 'received:108': 0.93 X-Injected-Via-Gmane: http://gmane.org/ X-Gmane-NNTP-Posting-Host: adsl-108-68-178-61.dsl.klmzmi.sbcglobal.net X-Newsreader: Forte Agent 6.00/32.1186 X-No-Archive: YES X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com comp.lang.python:98155 On Tue, 3 Nov 2015 08:50:34 +0000 (UTC), alister declaimed the following: >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. A direct line is what I'd recommend too -- but I'm going to be paranoid today: If a fire did occur, and the inspectors find traces of wiring going into what was supposed to be a stand-alone detector there is a risk that it will be concluded that the detector had been tampered with and may not have been functional... And that could lead to all sorts of liability problems. I don't know if anyone makes a model that falls between (common) stand-alone and full monitored (tied to burglar alarm system with a service provider responding to triggers). Something of a monitored type (hence designed to be wired to central panel) but without the outside monitoring agency. Barring that... if the detectors are all close in pitch, a PLL circuit fed from the microphone, using the "locked" signal to indicate when the alarm is chirping -- gives a simple on/off digital signal for the computer (the computer may be needed to ensure the chirps are at an expected rate and not stray whistles). Beyond that, FFT to look for spectral signature of chirps. -- Wulfraed Dennis Lee Bieber AF6VN wlfraed@ix.netcom.com HTTP://wlfraed.home.netcom.com/