The risk of hypoglycemia in individuals with type 1 diabetes increases considerably during exercise. As a result, many patients with type 1 diabetes experience fear of and reluctance to pursue physical activity, in order to avoid the discomforting symptoms associated with hypoglycemia. The bi-hormonal artificial pancreas, a device used for automatic delivery of insulin and glucagon subcutaneously to subjects with type 1 diabetes, is paving the way to revolutionize the management of this disease. The investigator's group has recently completed a study of the bi-hormonal artificial pancreas system during exercise, suggesting reduced hypoglycemia around the exercise period. In order to prepare for a future home study, the ability to detect, grade, and classify physical activity so as to appropriately adjust system parameters is vital in helping to prevent exercise induced hypoglycemia in the home setting.