fig4

Figure 4. (A) A wide-bandwidth nanocomposite-sensor integrated smart mask for tracking multiphase respiratory activities^[23]; (B) A smart ultrathin pressure sensor-based face mask for breath monitoring^[28]; (C) An electronic tattoo for sensing multiple signals^[43]; (D) Epidermal electronics for respiration monitoring^[67]; (E) A wearable cardiac ultrasound imager^[91].