On Sun, Feb 19, 2012 at 07:33:30PM +0100, Renato wrote: > On Sun, 19 Feb 2012 17:53:37 +0000 > Fons Adriaensen <fons@xxxxxxxxxxxxxx> 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. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
