Applications in breath monitoring. (a) The presented device is composed of two PI films to encapsulate the gold patterns and a medical tape is used to attach the device to human skin. Sensor-2 and Sensor-3 locate at two sides of the Heater/Sensor-1 (Hot-Film type), which is the only device to be heated up by the external power [89]. (b) The breath velocity vs. time, measured by using Heater/Sensor-1 during the continuous exhaling and inhaling process [89]. (c) The continuous wavelet transforming results, to show the frequency and magnitude parameters of apnea, hypopnea, and polypnea [89]. (d) Schematic of Morse code [59]. (e) Schematic diagram of a quadriplegic aphasia to communicate with the help of the presented sensor [59].