Smartphone App for Stroke Survivors with Arm Challenges

Inclusion Criteria: * Stroke survivor (ischemic or hemorrhagic), \>12 months post stroke, at the time of consent * Aged between 18 and 80 * Ability to extend ≥ 10° at the metacarpophalangeal joint and one of the interphalangeal joints of each finger, ≥ 10° extension or abduction of the thumb, and ≥ 20° extension of the wrist from a fully flexed starting position. * Demonstrating more affected arm nonuse, defined as a MAL-AoU score of \</= 4.5. * Actively uses at least one smartphone app. * Strong beliefs towards being in control of their recovery, indicated by a score of ≤ 10 points on the Internal Recovery Locus of Control (I-RLOC) Scale. * Participants must be able to read, write, and understand English at a level sufficient to comprehend study materials and provide informed consent. Exclusion Criteria: * Cognitive impairments that may affect the ability to understand and follow instructions (score \< 24 in the Mini Mental State Examination) * Difficulties comprehending numbers, dyslexia, severe aphasia, or other neurological conditions that prohibit the use of smartphones for safety reasons. * Undergoing other types of motor therapy during the study period. * Previous participation in constraint-induced movement therapy. * Currently participating in or has participated in the past 3 months in any experimental rehabilitation or drug studies. * Use of botulinum toxin for motor disability ≤ 3 months before treatment. * Significant changes in pharmacological or treatment plans during the study period that may affect upper-limb use. * Major medical problems that could interfere with participation. * History of a disabling stroke (i.e., need more than minimum assistance to perform ADLs). * Legally blind status. * Uncontrolled seizures. * Inability to don/doff sensors independently or with the assistance of a caregiver. * Implantable medical devices that do not comply with the ISO 14117:2012 and/or ANSI/AAMI PC69 standards for electromagnetic compatibility. Subjects will be asked to provide their medical device record card, and non-compliant devices will result in exclusion from the study.