Patent ID: 8860575

Claim:
A system comprising: an apparatus comprising: a plastic substrate; a beacon circuit comprising: a transmitter module coupled to the plastic substrate; an antenna supported by the plastic substrate and coupled to the transmitter module; one or more supporting components supported by the plastic substrate; a watchdog module coupled to the transmitter module; a wireless receiver coupled to the watchdog module; a memory coupled to the watchdog module; an identification code stored in the memory; and an internal clock coupled to the watchdog module; and a power source coupled to the plastic substrate to power the transmitter module; wherein: the plastic substrate is flexible; the transmitter module is configured to alternate between: a sleep mode to conserve a charge of the power source; and an active mode for transmission of a beacon signal via the beacon circuit; the watchdog module is configured to: use the antenna to scan for a wake-up signal during the sleep mode; and enable the active mode upon receipt of the wake-up signal; the identification code is configured to define one or more sequential time ratios between receipt of two or more pulses of the wake-up signal; and the watchdog module enables the active mode when the wireless receiver receives the two or more pulses of the wake-up signal sequentially separated by the one or more sequential time ratios defined by the identification code.