Meeting Abstract

P3-127    Design and Fabrication of a Low-cost, 3D printed Underwater Force Plate Gamel, KM*; Pinti, SG; Astley, HC; University of Akron; University of Akron; University of Akron kmg205@uakron.edu https://kmg205.wixsite.com/adaptevolvethrive/about-me?fbclid=IwAR0WNuItEA0006k9NiNd4GvNkHnymdXBAbET_anCgHOvmGEjmi792lCH3Pc

Fully submerged aquatic walking was an evolutionary predecessor to terrestrial locomotion and the invasion of land. However, the substrate reactions forces of this evolutionarily important mode of locomotion are largely unknown. To overcome this limitation, we designed a low-cost force plate sensitive enough to detect ground reaction forces from animals interacting with the bottom substrata using 3D printed parts and commercial electronics. Custom-designed 3D printed shear beam load cells were equipped with strain gauges in a Wheatstone bridge configuration. The strain gauges were powered and amplified using an INA125 amplifier in a custom-designed circuit board, from which we recorded the output using a NIDAQ system and various programing platforms (Python, Matlab, IGOR wavemetrics; scripts freely available on github). This system was capable of detecting forces as low as 1 mN in all three axes (fore-aft, lateral, and vertical), with a maximum force of over 1 N. This system provides a low-cost design that can easily be adapted for different geometries and sensitivities, and which can be easily deployed. Trials of underwater walking in axolotls showed clear patterns of substrate forces with high signal-to-noise and low drift suitable for biomechanical analysis (see talk by same authors). In addition to two versions used in our lab, we have deployed two more, including a system at Friday Harbor Labs, and have gathered substrate reaction forces from several fish (Rock prickleback, Skates). Additionally, preliminary data shows evidence of collecting wake forces from swimming species moving above the instrumented substrate. This system offers a versatile force plate for different types of scientific questions for underwater force detection and for labs with smaller budgets.