Cybernetic steel ball roller bar

I have managed to source all parts except for the rod slider guides. Anyone got any suggestions. with regard to sourcing or using an equivalent part. Has anyone tried using the X4 instead of the Arduino?

I think it easy to make the slider guide yourself. Take any piece of material, plastic, wood or metal.
Make it approximately the rectangular block size, and drill 2 holes 3mm.
And of course 3D print. But if that isn’t available, make something out of available pieces of material.