NOVELTY - A tag apparatus (102) has substrate, conductive structure formed on the substrate and detection circuit. The conductive structure comprises a layer of redox-active polymer film having terminal (T1) and terminal (T2) configured to receive electrical signal. The layer of redox-active polymer is configured to conduct electrical current generated by mobile ions and mobile electrons with respect to the electrical signal, and detection circuit operatively coupled to conductive structure and configured to detect electrical current flowing through conductive structure.    USE - Tag apparatus e.g. active tag apparatus used for detecting a change in the physical environment of the conductive structure and generating an identification signal (all claimed). Used for primary and secondary fastening system in consumer and automotive electronics.    ADVANTAGE - The tag apparatus has excellent flexibility and is manufactured by economical process.    DETAILED DESCRIPTION - A tag apparatus has substrate, conductive structure formed on the substrate and detection circuit. The conductive structure comprises a layer of redox-active polymer film having mobile ions and mobile electrons, terminal (T1) and terminal (T2) configured to receive an electrical signal. The layer of redox-active polymer is configured to conduct an electrical current generated by the mobile ions and the mobile electrons with respect to the electrical signal, and detection circuit operatively coupled to the conductive structure and configured to detect the electrical current flowing through the conductive structure. INDEPENDENT CLAIMS are included for the following:    (1) active tag apparatus;    (2) method for detecting a change in the physical environment of the conductive structure;    (3) method for generating an identification signal;    (4) manufacture of tag apparatus; and    (5) manufacture of active tag apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic illustration of a tag device having conductive polymers.    Tag apparatus (102)    Anode layer (110)    Cathode layer (120)    Single electrolyte layer (130)    Adhesive layer (150)    Protective layer (160)