- Sample audio signal
- Extract breathing sounds from it
- Determine rate of breathing (or time since last breath)
Breaths are likely to be about 1Hz, but the sound is actually much higher frequency – maybe a few hundred Hz, so I think I am looking for the variation of amplitude of the ~200Hz signal.
How to process this?
Sound card samples at 8 kHz, so we should be able to capture signals at up to 4 kHz, so this is fine – the challenge will be how much data we have to handle.
Go for collecting 1 second of data = 8000 samples, and doing a FFT