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To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Wed, 7 Oct 2020 04:42:00 -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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> Many of the cheap dashcams have sound and record on a loop
> so you could have video and audio?

That was my thought too. If it could be mounted so the thump of the
'explosion' triggered the crash detector then the clip would not get
overwritten if left recording.

Would make an interesting court exhibit if there was a major 'bang'
resulting in emergency services callout, especially after multiple
complaints to the HVAC engineers :)

On Tue, 6 Oct 2020 at 23:50, Clint Jay <cjaysharp@gmail.com> wrote:
>
> Many of the cheap dashcams have sound and record on a loop so you could
> have video and audio?
>
> On Tue, 6 Oct 2020, 20:19 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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