A pre-fabricated sensor assembly for an interactive object including an object substrate is provided. The pre-fabricated sensor assembly includes a touch sensor comprising a plurality of flexible sensing elements, a first electronics module comprising sensing circuitry in electrical communication with the plurality of flexible sensing elements, a communication interface comprising a first end portion coupled to the first electronics module and comprising a second end portion, a receptacle coupled to the second end portion of the communication interface, and one or more flexible retaining layers that define a housing for a first portion of the pre-fabricated sensor assembly. The first portion of the pre-fabricated sensor assembly can include at least a portion of each of the plurality of flexible sensing elements.