At last year's Google I/O developer conference, the company introduced Project Gameface, a hands-free gaming "mouse" that allows users to control a computer's cursor with movements of their head and facial gestures. This year, Google has announced that it has open-sourced more code for Project Gameface, allowing developers to build Android applications that can use the technology. The tool relies on the phone's front camera to track facial expressions and head movements, which can be used to control a virtual cursor. A user could smile to "select" items onscreen, for instance, or raise their left eyebrow to go back to the home screen on an Android phone. In addition, users can set thresholds or gesture sizes for each expression, so that they can control how prominent their expressions should be to trigger a specific mouse action.