The Balance Toolkit: Democratizing Balance-Based Interaction Through Open-Source Software for Repurposed Wii Balance Boards

Balance-based interaction offers unexplored design space for games, rehabilitation, and accessible play, but remains confined to proprietary platforms. The Wii Balance Board (WBB) is an inexpensive balance board that correlates highly with research-grade equipment (r=0.99). However, existing software prevents developers from exploring balance mechanics due to platform limitations, complex Bluetooth pairing protocols, and a lack of real-time integration. We present The Balance Toolkit, an open-source framework that enables balance-based player-computer interaction using repurposed consumer hardware. Co-designed with experts (N=26), we provide cross-platform connectivity across Windows, macOS, Linux, Android, dual-board support, game engine integration, LSL and TCP integration, and six posturography activity templates. First-use testing with 5 experts achieved mean SUS usability scores of 77.0 (SD=8.2). By democratizing access to 42 million manufactured boards, we enable community innovation at the intersection of play and health.