Granular I/O

Granular materials — clusters of small discrete particles — afford a uniquely malleable form of physical interaction, enabling intuitive shaping, splitting, and merging through natural hand gestures. Despite their rich interaction potential, granular materials remain largely unexplored as a form factor for actuated, bi-directional Tangible User Interfaces (TUIs). We present Granular I/O, an approach that employs millimeter-scale passive magnetic particle clusters, actuated by external magnetic field controllers, to enable malleable input and output interactions for granular-based actuated TUIs. We describe a comprehensive design space for malleable granular interaction, alongside a full hardware and software implementation covering particle cluster fabrication, two actuation platforms, and authoring software. We further report technical characterization and evaluation to validate the system, and demonstrate a range of applications that harness malleable I/O for interactive use.