In order to make our piezoelectric generator, we are going to need a plastic base. I have provided the links to my tinker cad files below. Feel free to customize them to suit your needs/foot measurements. The piezo element holes are strategically placed so that they line up with the large indents on my shoe's insole, which indicate the areas of most pressure. These files are based off of my foot, which is a size US 9.5. Although my heel piece fit perfectly, my toe piece required a good bit of sanding in order to get it to fit properly.