Spotlight Navigation [4, 3] is to the best of the author’s current knowledge historically the first general purpose user interface (UI) that has specifically been designed for mobile projection devices. From a user perspective, access to information through the projection device is performed by panning over a projected information space by moving the projection device as a whole, and by zooming into interesting regions using dedicated controls or specific gestures. The rendering component of Spotlight Navigation updates the projected image in real time according to the movements of the device, such that for users it appears as if they would interact on a huge virtual screen of which only the illuminated part within the projector’s light cone becomes visible. In the paper we discuss fundamental aspects that differ from traditional desktop or hand held device interaction and describe interaction techniques that have been found suitable for mobile projection. All features and techniques presented here have been implemented on a working prototype that served as a basis for evaluation and elaboration of the techniques. We also discuss the setup and implementation architecture of our prototypes in more detail, and report on previously unpublished features of the prototype device, such as specific gestures, ripples and a text selection widget.