Bio-inspired flow sensor: mimicking the lateral line organ with an optical sensory system

In the field of biomimetics, engineers get inspired by systems of nature for the purpose of solving complex human problems. One pool of innovation is the incredible diversity of sensory systems in biology. An example is the lateral line found in all fish and permanent aquatic amphibians. Fish use this mechanoreceptive system for detection of objects, orientation in dark and muddy water, rheotaxis and schooling behaviour. The organ comprises up to several thousand mechanoreceptors called neuromasts. They are situated either on the surface of the skin (superficial neuromasts, SN) or in lateral line canals (canal neuromast, CN). So far, numerous artificial flow sensors exist mimicking the lateral line system. The majority is based on the CN principle. However, due to the canal system these sensors are limited in their field of application. Furthermore, they rarely meet all requested demands, i.e. being robust, highly sensitive, resistant to acids and economic. In this work, we tried to mimic the superficial neuromasts. We built a bio-inspired flow sensor based on optical detection principle. The sensor consists of a PDMS (Polydimethylsiloxane) light guiding fibre, housing and electronic circuit. In this work, we demonstrate the functionality of our sensor in two ways: First, we stressed the sensor with different weights and calculated the referred bending radiuses. Then, we used the sensor for detection of water flow. Furthermore, we discuss the sensitivity and robustness of the sensor. Also, we present a theoretical model to calculate the power losses due to bending.