Patient description: The patient is a 24-year-old man who has had type 1 diabetes for 11 years. He presents to the emergency room with hyperglycemia and concern for possible diabetic ketoacidosis after not taking his insulin for 3 days. The patient reports that he is currently homeless and has lost his supply of insulin, syringes, glucometer, and glucose testing supplies. The patient states that at the time of his initial diagnosis with type 1 diabetes he was hospitalized with a glucose value >1000 mg/dL. At the time, he was experiencing polyuria, polydipsia, and polyphagia. He reports that he has been on insulin since the time of his diagnosis, and he has never been prescribed oral agents for diabetes management. Most recently, he has been using insulin glargine 55 units once daily, and insulin aspart sliding scale 3 times daily. The patient has had previous episodes of diabetic ketoacidosis, for which he was hospitalized. With this episode of hyperglycemia, he is not experiencing any nausea, vomiting, or abdominal discomfort, and he appears well. His lab studies showed: A1c: 11.3% Creatinine: 0.9 mg/dL with eGFR >60 mL/min Aspartate aminotransferase (AST): 17 U/L Alanine aminotransferase (ALT): 14 U/L Beta-hydroxybutyrate: 0.1 mmol/L Bicarbonate: 25 mEq/L Anion

Clinical trial eligibility criteria: eligible ages (years): 15.0-45.0,  Type 1 Diabetes Clinical diagnosis of type 1 diabetes and using daily insulin therapy for at least one year and an insulin infusion pump for at least 6 months The diagnosis of type 1 diabetes is based on the investigator's judgment; C peptide level and antibody determinations are not required Age 15.0 to <46.0 years HbA1c <10.0% Measured with DCA2000 or equivalent device for assessing HbA1c measurements performed as part of usual clinical care within 2 weeks prior to obtaining informed consent for participation in the trial may be used Uninterrupted internet access while study system is being used overnight and for upload of study data in the morning Living with a significant other or family member ("companion") committed to participating in all study activities, and being present and available to provide assistance when the system is being used at night An understanding of and willingness to follow the protocol and sign the informed consent  Diabetic ketoacidosis in the past 3 months Hypoglycemic seizure or loss of consciousness in the past 6 months History of seizure disorder (except for hypoglycemic seizure) History of any heart disease including coronary artery disease, heart failure, or arrhythmias Cystic fibrosis Current use of oral/inhaled glucocorticoids, beta-blockers or other medications, which in the judgment of the investigator would be a contraindication to participation in the study History of ongoing renal disease (other than microalbuminuria). Creatinine level must have been obtained within the last year if subject has diabetes of >10 years duration. If creatinine is >1.5 mg/dL (132 µmol/L), the subject is excluded Medical or psychiatric condition that in the judgment of the investigator might interfere with the completion of the protocol such as Inpatient psychiatric treatment in the past 6 months Uncontrolled adrenal disorder