A system includes a thin-film battery and an activity-activated switch. In
some embodiments, the system is placed on a substrate with an adhesive
backing. In some embodiments, the substrate is flexible. Also formed on
the substrate is an electrical circuit that includes electronics. The
activity-activated switch places the thin-film battery in electrical
communication with the circuit and electronics. The battery and the
circuit are formed on the substrate and may be comprised of one or a
plurality of deposited layers.