The present disclosure enables apparatus and methods for tracking medications and/or product units via smart-packaging concepts. Embodiments include sensors that monitor the state of a blister-card package having an unpatterned lidding film by measuring the impedance of each dispensing region of the lidding film that defines a portion of a blister. In some embodiments, the impedance is measured via a plurality of contact points arranged on opposite sides of each dispensing region, where the contact points are resistively or capacitively coupled with the lidding film. In some embodiments, the impedance map of a measurement region on the blister card is derived via electrical impedance tomography or electrical resistance tomography, where the measurement region includes a plurality of dispensing regions.