# Bio-Inspired Mechano-Sensor Based on the Deformation of Slit Wake
## 3 Results and Discussion
edges of the nanoscale crack on the Au layer gradually separated, which further led to the increase in resistance (Figure 8f). The research on the FUCMSS has revealed that the initial bending degree of the PET substrate has a great influence on the sensitivity to low mechanical signals. Therefore, the bending degree of the FUCMSS was controlled by adjusting the distance from the highest point of the FUCMSS to the upper surface of the substrate. Figure 9a indicates that the heights from sample I to sample IV were 0, 0.44 mm, 0.84 mm, and 1.55 mm, respectively. A compressive force of 0.5 N was applied to the four samples, respectively. The results indicate that the resistance change in the slit-based mechano-sensor was positively correlated with the bending degree of the FUCMSS (Figure 9b). The \(\Delta R\)/\(R_{0}\) of sample IV with the maximum bending was about of 1400, while the \(\Delta R\)/\(R_{0}\) of sample I with the tiled film was three orders of magnitude smaller than sample IV. In addition, the \(\Delta R\)/\(R_{0}\) responses of the four samples under a square wave were compared; the square-wave signal input to the exciter had an amplitude of 1 V and a frequency of 0.5 Hz. Figure 9c also indicates that sample IV had the best waveform-recognition ability for dynamic mechanical signals because of its more significant resistance change. Hence, improving the bending degree of the FUCMSS distributed on the surface of the solid substrate is one of the most important ways to improve the sensitivity of the slit-based mechano-sensor to low mechanical signals. In the next study, sample IV was chosen to evaluate the performance of the slit-based mechano-sensor. In summary, for the solid substrate, the slit length and reasonable \"hollow out\" design, which influences the overall stiffness of the substrate, are important factors in determining the performance of the slit-based mechano-sensor. Additionally, for the FUCMSS covering the slit wake, the parameters (such as density, length, width, roughness of slit edges) of the slit array as well as the initial bending degree are important factors in determining the performance of the slit-based mechano-sensor. Figure 2:1 Preparation and characterization of slit-based mechano-sensor. (**a**) The slit-wake deformation and stress concentration on the slit tip with different slit lengths. (**b**) The substrate based on the optimal “hollow out” design strategy in Figure 5g. (**c**) The bio-inspired slit-based mechano-sensor. (**d**) The FUCMSS covering the slit wake in convex-bending mode. (**e**) The bending of FUCMSS with the change in slit width. (**f**) The change in nanoscale crack width with the bending of FUCMSS. To evaluate the sensing performance of the slit-based mechano-sensor, the impact-response experiment of two small particles falling on the substrate were carried out (Figure 10a). The two particles, which had masses, \(m\), of 0.0345 g and 0.3775 g, were used in the experiment. The falling height of the particles was 10 cm. It is worth noting that the mechano-sensor was placed vertically so that the direction of the impact force was perpendicular to the slit length (Figure 10a). The \(\Delta R/R_{0}\) responses of the slit-based mechano-sensor to the impact signals were compared. Figure 10b indicates that all the impacted signals caused by the above two particles were well detected. Meanwhile, there was a significant positive correlation between the \(\Delta R/R_{0}\) response and particle mass. In order to further evaluate the ability of the slit-based mechano-sensor to sense small displacement changes, the precision displacement table was used to manually apply a reciprocating displacement signal less than 10 \(\upmu\)m (Figure 10c). Figure 10d indicates that the sensor showed a strong response to the above displacement signal. The difference in the \(\Delta R/R_{0}\) peak was caused by manual operation.