Fig. 4: Design, construction, and application of an integrated flexible wireless sensing system.

a Photographs of the integrated system on a morphing aircraft including printed sensors, wire connections, and a LoRa module. b Block diagram of the wireless sensing system. Low dropout regulator (LDO), Serial Wire Debug (SWD), input/output (I/O), ANT antenna, digital signal processing (DSP), integrated circuits (IC). c Relative change in resistance of the sensing system when the aircraft is under normal morphing for various configurations at −20 °C. The right panel shows the photographs of the aircraft under morphing and the corresponding morphing angle. d Time-frequency domain spectrum and the PSD spectrum of the sensing system under normal morphing. e Relative change in resistance and the calculated PSD values of the sensing system under various morphing angles from 180° to 90°. f Resistance signals obtained by the printed sensor when the aircraft morphs from configuration one to several other conditions, and the corresponding time-frequency analysis diagram. Arrows indicate the timing of the morphing. g Relative change in resistance of the sensing system under vibration with a frequency of about 1 Hz, and a high-temperature environment of 200 °C for >3 h. Insets show the captured vibrational signals at 40 min and 180 min. h Photographs of the wireless sensing system for aircraft status monitoring at a high-temperature smoky environment, and 2 km long-distance data transmission to a computer screen showing the morphing configuration.