A highly sensitive underwater hair-like sensor with design of spiral resonant sensing base

Biological hair-like mechanoreceptor is one of the optimal forms of perceiving the water flow disturbances with high sensitivity and robustness, which has inspired many fascinating underwater bioinspired hair-like flow sensors. However, few of these sensors focused on the mechanics-guided design methods to enhance the sensitivity of the sensor. Here, this study proposes a highly sensitive underwater hair-like sensor with a spiral resonant sensing base, which is to design the sensing base as a spiral structure with the resonance effect. The resonant frequency of the sensor could be customized according to the characteristics of flow disturbances, thereby achieving high sensitivity in frequency range near the resonant frequency for flow perception. The sensitivity of the designed sensor to vibration velocity of dipole (underwater vibration source) could be improved by around 4 times as compared to that of the sensor without spiral structure. Moreover, the designed sensor keeps high output reliability and strong robustness even when the signal to noise ratio of input signals is -20 dB, demonstrating the potential to extract required information in complex water environments. The study opens a promising pathway for designing hair-like sensors with high sensitivity and strong output reliability.