Abstract: Articles of footwear and other devices include modules, e.g., for sensing physical and/or physiological characteristics associated with use of the footwear or other devices. Such devices include: (a) a housing, optionally an asymmetrical housing, for receiving an electronic module; (b) release mechanisms for removably mounting the module in the housing; and/or (c) activation/authentication systems for selectively activating the module. Additionally, methods of making articles of footwear or other structures that include such housings, electronic modules, release systems, activation systems, authentication systems, etc. are described. Performance sensing systems and methods of using the above devices for sensing performance characteristics also are described.