Disclosed herein are methods and systems for detecting information related to a drug reservoir (320, 1000, 1002, 1006, 1008). According to one example disclosed herein, a method includes a detector feature (100, 500, 600, 700, 904) determining an electrical property related to a coded material (120, 502, 606, 708, 900) for a drug reservoir (320, 1000, 1002, 1006, 1008), wherein the coded material (120, 502, 606, 708, 900) comprises at least one circuit (122, 400, 800, 802, 804a-e, 902, 906, 908). The at least one circuit (122, 400, 800, 802, 804a-e, 902, 906, 908) may be printed onto the drug reservoir (320, 1000, 1002, 1006, 1008). The method further includes determining information related to the drug reservoir (320, 1000, 1002, 1006, 1008) based at least on the determined electrical property.