From: Justin Richards <justin.richards@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Thu, 8 Oct 2020 05:06:21 -0700
Subject: Re: [EE] Looking for technique to record audio after level exceeds
	some value
Thread-Topic: [EE] Looking for technique to record audio after level exceeds
	some value
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How far apart are the ignition events,

VLC has worked well to quickly and cheaply get audio from one place to
another via a network where it can be saved to file and/or monitored as
required.

I used VLC to stream UHF radio whenever it was keyed so it could be
monitored locally and 100kms away at a remote site.

VLC is handy as it works on many platforms and is somewhat uniform to
configure.

It is currently being used to reliably stream 4 radio stations
(received via satellite) to VLC running on RPi's, Windows and Linux based
PC's.



On Wed, Oct 7, 2020 at 3:19 AM Dwayne Reid <dwayner@planet.eon.net> wrote:

> Good day to all.
>
> I have a peculiar problem and I am hoping there is an off-the-shelf
> solution.
>
> It is approaching winter in Canada, which means that heating season
> is about to be on us.  One of the roof-top HVAC boxes on our building
> appears to have a gas ignition problem.  I hear explosions both quiet
> and loud when the heater turns on.
>
> This is obviously a gas ignition problem and we have called the
> service people a couple of times to get this fixed before the heat
> exchanger becomes damaged.  Specifically, what I think is that the
> fuel gas (Natural Gas) is accumulating in some area away from the
> ignitor, reaching some level higher than the Lower Explosive Level,
> then some traces of the fuel reaching the ignitor.
>
> But the service people can't see any problem and they are questioning
> whether I am just imagining the problem.
>
> What I would like to do is to set up one of my spare Android devices
> with the microphone in the heating duct.  But I need some way to have
> the device record just of few seconds BEFORE the explosion occurs as
> well as a few seconds AFTER the explosion occurs.
>
> Kind of like how pre-trigger works with a DSO.
>
> I've been looking but have not yet found an app that does this.  I'm
> hoping that someone here might have a suggestion.
>
> Note that I'm not married to the idea of using an Android device -
> just that's what I have handy.  I could also set up a laptop or
> netbook running Windows or DOS if I can find an appropriate application.
>
> I do have a fair amount of audio equipment here - mixers, preamps of
> various types, microphones ranging from really inexpensive to stupid
> expensive, audio recorders of various types.
>
> Problem is that none of the audio recorders that I have (DAT, SD-card
> based, Compact Flash based, etc) have the capability to continuously
> record a buffer, then capture several seconds before and after the
> loud sound occurs.
>
> Individual files with time stamps would also be desirable.
>
> IBM compatible Shareware or paid Android app is just fine.
>
> Suggestions gratefully accepted.
>
> dwayne
>
> --
> Dwayne Reid   <dwayner@planet.eon.net>
> Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
> 780-489-3199 voice   780-487-6397 fax   888-489-3199 Toll Free
> www.trinity-electronics.com
> Custom Electronics Design and Manufacturing
>
> --
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