LumiWatch: On-Arm Projected Graphics and Touch Input

Compact, worn computers with projected, on-skin touch interfaces have been a long-standing yet elusive goal, largely written off as science fiction. Such devices offer the potential to mitigate the significant human input/output bottleneck inherent in worn devices with small screens. In this work, we present the first fully functional and self-contained projection smartwatch implementation, containing the requisite compute, power, projection and touch-sensing capabilities. Our watch offers roughly 40 sq. cm of interactive surface area – more than five times that of a typical smartwatch display. We demonstrate continuous 2D finger tracking with interactive, rectified graphics, transforming the arm into a touchscreen. We discuss our hardware and software implementation, as well as evaluation results regarding touch accuracy and projection visibility.