[LAU] iPad and Linux audio

S. Massy lists at wolfdream.ca
Mon Feb 20 03:50:10 UTC 2012


On Sun, Feb 19, 2012 at 07:33:30PM +0100, Renato wrote:
> On Sun, 19 Feb 2012 17:53:37 +0000
> Fons Adriaensen <fons at linuxaudio.org> wrote:
> 
> > On Sun, Feb 19, 2012 at 04:11:55PM +0100, Renato wrote:
> >  
> > > I'd like to understand how the sensors work, but his site doesn't
> > > seem to go much in depth on this... it says the sensors register
> > > the sounds of the undercutaneous muscles. But are those even in the
> > > audio frequency realm? And how would you capture them, with a piezo
> > > contact mic?
> > 
> > There was a paper on this at LAC 2011, see the proceedings.
> > <http://lac.linuxaudio.org/2011/?page=download>
> > 
> 
> again, thanks Fons. For the lazy, the actual sensor device is described
> at page 160 (170 of the pdf) of the proceedings pdf [1]. It's basically
> an electret condenser microphone, kept in place by a silicon case that
> should also filter out external noise. So he's (knowingly) leaving out
> part of the spectrum, since as he describes earlier in the article
> muscle sounds are in the 4-45hz range and those mics go down to only
> about 20.
> 
> I must say I'm quite surprised to learn muscles make loud enough
> sounds to be used this way... and this project of his looks freaking
> cool IMO.
Wouldn't the sound of blood flow cause significant interference?

Cheers,
S.M.


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