1. A system, comprising: one or more sensors to detect movement of a mobile object; and a processor coupled to the one or more sensors and a wireless transceiver to classify sequences of movements of the mobile object into groups of similar postures represented by a model and to apply the model to identify an activity of the mobile object, wherein the processor identifies each elemental motion of a sequence of elemental motions of the mobile object, and identifies the activity of the mobile object by matching the sequence of identified elemental motions with one or more stored sequences of elemental motions, wherein each stored sequence of elemental motions corresponds with an activity.