A MEMS flow sensor based on fish lateral line sensing system

The artificial lateral line is a bionic sensor developed in recent years to detect physical parameters of gas and liquid flow field, which has great application prospects in underwater target detection, microfluidic velocity detection and smart skin. However, these sensors generally have only one kinocilium, resulting in inability to identify directions. Moreover, the kinocilium exposed directly in fluid shows performance of low sensitivity. This paper presents a flexible, lightweight, and sensitive piezoresistive sensor inspired by lateral line. The sensor presented comprises a cluster of micropillars arranged in stepwise distribution to detect fluid direction and a hydrogel cap to realize high-sensitive and low-speed threshold detection. The experiment of direction detection shows that the output signal in inhibitory direction of the sensor is smaller than the signal in excitatory direction and lagging behind, which can be used in orientation identification. The results show that the sensitivity of the sensor without hydrogel cap is 0.57 mV/(mm/s), while the sensor with hydrogel cap is 1.18 mV/(mm/s), which indicates that the hydrogel cap can increase the sensitivity by 107%. The sensor developed in this paper has a broad application prospect in biomedicine devices and micro-fluid equipment.