An interactive core for use in making electronic cards has rear and front adhesive layers which surround a stiffening spacer which has an interior opening in which electronic components (e.g., a PCB, battery and display) are located along with thermosetting polymeric material. A battery contained within the interior opening can be activated from an off state to an on state via use of an initialization antenna which can also be configured to allow a CPU to be customized for personal use.