Guiding Light is a navigation-based application that provides directions by projecting them onto physical spaces both indoors and outdoors. It enables a user to get relevant spatial information by using a mini projector in a cell phone. The core metaphor involved in this design is that of a flashlight which reveals objects in and information about the space it illuminates. For indoor navigation, Guiding Light uses a combination of e-compass, accelerometer, proximity sensors, and tags to place information appropriately. In contrast to existing heads-up displays that push information into the user's field of view, Guiding Light works on a pull principle, relying entirely on users' requests and control of information.