Abstract: A method includes sensing physical proximity between a first device and a second device. At least one of the first device and the second device has transferrable data stored thereon. The method further includes monitoring whether the first device and the second device maintain physical proximity. The method further includes transferring the data between the first device and the second device while the first device and the second device maintain physical proximity.

Abstract: In a general aspect, an ornamental jewelry piece, such as a watch, a ring or a bracelet, includes a sensor package. In some aspects, a timepiece includes a timepiece body having an interior surface that defines a cavity. The timepiece includes a sensor package and a movement in the cavity. The sensor package includes a sensor that monitors the user and a battery that powers the sensor. The movement operates independent of the battery in the sensor package. In some instances, the sensor package tracks fitness data based on motion detected by the sensor and generates an output to the user based on the fitness data.