A printed circuit board (PCB) assembly includes a first PCB and a second PCB disposed substantially parallel and opposite to each other, such that a second side of the first PCB is opposite to a first side of the second PCB; wherein the second PCB has a first set of side connectors on its first side and a second set of side connectors on its second side, configured for both electrical power supply to and signal communication with the second PCB; the second PCB both electrically and mechanically connected to the second side of the first PCB via a first elastomeric connector; and the second PCB electrically connected to the first PCB via its second set of side connectors and a flexible electrical connector that is electrically connected to the second set of side connectors and the first PCB.