Today, wearable computing is being recognized as an interesting research and product area by a number of commercial entities, small and large. This has not always been the case, however, and as such, academic researchers have needed to "roll their own" hardware in order to obtain experimental results. Wearable hardware development at Carnegie Mellon has taken place at a number of points in the design spectrum, from "customer"-driven systems integration based on a task specification, to fully-exploratory systems designed in-house from a clean slate. This section contains information on the hardware systems deployed by the Group, as well as background material on the academic projects surrounding the machines themselves.