BillyBot is designed for the RoboGuts™ circuit board ... an Arduino can't fit to do the same work, but the RoboGuts™ circuit board crams much more functionality into the same space!
The fastest and cheapest way to get all my .STL files FREE is to donate $5 to help fund school materials ... once I have $3,500 I'll convert all these files to FREE downloads. https://www.gofundme.com/roboguts-kits-lessons
These are the files to 3D print a BillyBot robot ... designed for the RoboGuts™ S.T.E.A.M. education program for schools is a RoboGuts™ circuit board, lessons and 3D printed parts http://www.R2Pv1.com/
No an Arduino is too big to fit inside this and also fit all the wiring and piggyback boards needed to make a real BillyBot ... this is why I had to design the RoboGuts™ circuit board ... a perfect fit with all the needed components to make a talking singing (in any language) and dancing RoboToons Robot Theater Productions character.
3D Printed BillyBot and his Adaptive Abilities
3D Printed BillyBot Singing "This is America"
3D Printed BillyBot Sings "Electronic"