The overall objective of this project is to sequentially test, validate, obtain regulatory approval for, and deploy at home, a closed-loop Control-to-Range (CTR) system for optimal blood glucose (BG) regulation in people with type 1 diabetes. The CTR system is comprised of two algorithmic layers: a Safety Supervision Module (SSM) and Insulin on Board Tracking and Safety Module (ITSM), and an automated Range Correction Module (RCM). Both modules will receive continuous glucose monitoring (CGM) and insulin delivery data. The SSM and ITSM will monitor the safety of the subject's continuous subcutaneous insulin infusion pump (CSII) to prevent hypoglycemia. The RCM will be responsible for optimizing BG control and mitigating postprandial hyperglycemic excursions through series of insulin boluses. To run CTR, we will use our wearable artificial pancreas platform, known as DiAs (Diabetes Assistant), which consists of a smart phone running CTR and connected to standard insulin delivery and CGM devices.