Optimization Of Bio-inspired Hair Sensor Arrays

Crickets use a pair of hairy appendages on their abdomen called cerci, each of which contains numerous mechano-receptive filiform hairs (Fig. 1). These sensitive hairs can respond even to the slightest air movements, down to 0.03 mm/s, generated by the approaching predators and initiating an escape mechanism in the crickets [1]. Bio-mimicking the cricket cerci, arrays of artificial hair sensors have been successfully fabricated using advanced MEMS techniques [2] (Fig. 2). Each artificial sensor consists of a SU-8 hair mounted on a suspended nitride membrane with two chromium electrodes on top, which form differential capacitors with the conductive silicon substrate (Fig. 3). Air flows on the sensors induce a hair deflection resulting in a membrane-tilt which is capacitively measured.