Using a camera as an input device is hardly a new idea -- even on a mobile device -- but most examples so far have been to enable functionality not possible on a touchscreen. As Master's student Daniel Bierwirth has shown in the video after the break, however, a phone on a camera can also be used as an alternative input method for features like scrolling or zooming, potentially allowing for easier interaction on devices with smaller screens. Bierwirth also takes the idea one step further, and sees the system eventually inc