Stroke causes damage to the brain, often resulting in weakness or paralysis on one side of the body. Everyday objects such as smartphones can play an im-portant role after a stroke facilitating participation in daily activities. However, commercial smartphones can be challenging to use, and people with stroke of-ten adjust their behavior to minimize the affected arm and hand use. This study explores how an object attached to a smartphone could evoke behavior change and contribute to the initiation of use of the affected arm. As part of a design workshop, different ideas were envisioned to promote the use initiation of the affected side of the body. Two high-fidelity smartphone accessories were devel-oped and tested with four people with chronic, mild stroke impairments based on the results. The initiation of use observed during the formative usability test seems to be evoked by the learned behavior patterns rather than the design prototypes.