Lamplighter groups, bireversible automata and rational series over finite rings

We realize lamplighter groups $A\wr \mathbb{Z}$, with $A$ a finite abelian group, as automaton groups via affine transformations of power series rings with coefficients in a finite commutative ring. Our methods can realize $A\wr \mathbb Z$asabireversibleautomatongroupifandonlyifthe$2$-Sylow subgroup of $A$ has no multiplicity one summands in its expression as a direct sum of cyclic groups of order a power of $2$.