We present a novel, robust, affordable and wearable, mobile gaze tracker. The tracker takes a model-based approach to tracking gaze and maps the calculated gaze on to a scene video. The system is built from standard off-the-shelf components, and is the first to our knowledge using a 3D printed frame. The system will be published as open source, and the total cost of the components for building the system is 350€. The model-based tracking provides a solution robust to changing lighting conditions and frame slippage on the head of the user.