a) Schematic diagram of ant crawling on the sensing film surface. b) Monitoring the ant crawling movement induced weak strains. The inset is the ant crawling field test picture. c) The setup of microphone application. d) Frequency response characteristics of this flexible microfiber sensor. e) The frequency spectrum of the recorded CR change induced by the broadcasted music. The inset is the related CR time-varying waveform. f) Mechanism of frequency division multiplexing based on this proposed strain sensor. g) Simultaneously monitoring and demodulating the arterial pulse and human voice signals by this proposed sensor fixed on the wrist.