Typically, after brain damage due to a stroke, the affected arm is weak and suffering from some of paralysis. As a result, adults with this condition are unable to move their impaired arm well during their activities of daily living. Our research is focused on understanding how best to improve the ability of the arm to move after brain damage due to a stroke. We have implemented novel robot technology designed for eventual use as a home therapy device and have used software and hardware technologies to design activities that can assess the arm ability and engage the person during therapy. We will study how the prolong use of this device with simple, functional, and engaging activities improve the arm's movement ability and sustain motivation to use the arm over repeated therapy sessions and away from supervision.