apparently the projected keyboard uses another laser to track your fingers in relation to the projected keys. The darned thing actaully knows where the keys are, not just where they would be if the pen is "placed so the emmiter is 3 inches above a flat, clean, nonreflective surface at an angle between 85 and 95 degrees. The darned thing sees the keys and your fingers! You can project the keyboard on the dog and it still works! I read a thing about it.