On Fri, 29 Nov 2002, arm pdlist wrote:
No comes que question. I have a small mic that i connected to my laptop. I can get the signal in PD. But how can i detect the bpm of a signal that is coming from adc~ object? I'm just touching on the mic to simulate the heart beat, but would be possible to detect some kind of bpm of the signal? If so, what do i have to do? Can you give some links where i can get some more info on what i should do?
My first idea would be to try a Fourier transform but with very low frequencies. When trying this on music you may have some preprocessing to do to ensure that you actually get a spectrum for the beat instead of just for the hearable tones, but for a heartbeat you have true low frequencies that could appear directly in an "ordinary" frequency spectrum as long as that spectrum is done in the proper range of frequency (say 0.1-10 Hz instead of the normal 20-20000 Hz).
I haven't tried it myself though.
Mathieu Bouchard http://artengine.ca/matju