## 2 Materials and Methods
### Finite Element Analyses  
A Finite Elements Analysis (FEA) was performed by using ANSYS 2018 commercial software. It was applied to the last version of the casing prototype (Figure 7). The mesh of the CAD model was made by using solid tetrahedral elements according to the Voronoi-Delaunay algorithm with 16 Jacobian points per element. A selective set of mesh controls resulted in a finer mesh at the threads and thinner parts. Figure 7 shows the assembly mesh (Figure 7a) and load distributions (Figure 7b,c). Any possibility of penetration between the surfaces in contact was excluded to better simulate the mechanical behavior of the pedometer subjected to the possible load configurations. The overall mesh counted a total of 16,458 nodes and 11,112 tetrahedral elements  
Figure 6: Pedometer with reinforced casing, top cap thread and mainboard housed in the cap. Figure 7: (**a**) Assembly mesh; (**b**) impulsive force application; (**c**) distributed force application (Reproduced from [24] with permission from Springer Nature Switzerland AG). for the top cap, 23,606 nodes and 12,262 tetrahedral elements for the inner case, and 16,111 nodes and 8079 tetrahedral elements, respectively. Boundary conditions were applied as fixed constraints along the generatrix of the external cylindrical part of the pedometer to simulate the anchor system to the cow leg. Two load configurations were analyzed:  
* An impulsive force of 3000 N acting on the side opposite the constraints, to simulate an accidental impact, i.e., against a fence post, a cow kick, or a cow tipping by other cows [25]. The application area of the impulsive force was assumed to be circular with a radius of 25 mm (Figure 7b). * A force distributed on the upper surface of the cap equal to 1.75 MPa, to simulate a possible laying of the animal above the leg. This value came from considering a maximum value of half of the weight of an adult Friesian cow and should not exceed 300 kg [26] (Figure 7c). Figures 8 and 9 show elastic strains and the maximum values of von Mises stress under both load conditions. The values of maximum equivalent stresses, evaluated according to the von Mises criterion, were found to be equal to 42.11 MPa in the impulsive force configuration and 54.63 MPa in the distributed force configuration, respectively. Both values are sufficiently lower than the yield tensile strength of the material considered (\(\sigma_{y}\) = 62.5 MPa). In addition, the elastic strains found in both conditions (1.68 mm and 0.64 mm) fall within the elastic range of the material. Indeed, the worst value, found in the application area of the impulsive force where the overall thickness of the resistant material is 6 mm = 3 + 3 mm (Table 1), corresponds to an elongation of 27.9%, which is lower than the elongation at yield (\(\xi_{y}\) = 50-70%). This is a confirmation that, even in extreme conditions, the design proposed for the casing of the pedometer prototype proves adequate mechanical resistance. A set of seven modified prototypes, ready to be tested in the barn, has been proposed (Figure 10). The printing of these two versions of the prototype casing was carried out by a 3D PRUSA i3 MK3s FDM printer using a new thermo-plastic organic compound made of polyamide 66 reinforced with organic hemp fibers (hereinafter SDS Nylon), which was developed by one of the authors in previous studies. Despite these changes, problems of interruption of the signal continued to occur, mainly due to disconnections between the mainboard and the battery. To deal with the problem, while maintaining the pseudo-cylindrical shape of the casing, as it conforms to animal welfare, a double-casing geometry was adopted, as shown in Figures 11 and 12. The activity related to this new design was carried out thanks to the funding of CowTech, a project financed by the European Union within the P.O. FESR SICILIA 2014/2020 (CUP: G69J18001020007).