Fig. 5: Waveforms of lung and heart sounds monitored on a healthy volunteer.

a, b Lung sound waveform detected by our sound sensor (a) and by a commercial high-end electric stethoscope (b). c, d Heart sound signal recorded by our sensor (c) and by commercial stethoscopy (d). The volunteer was a 29-year-old healthy male (#1), and sound signals were recorded during a resting respiratory function