In one embodiment, a surface is navigated by 1) using a first light sensor, mounted to a navigation device, to detect light reflected from a surface, and 2) using outputs of the first light sensor, over time, to determine relative movement of the navigation device with respect to the surface. While using the first light sensor, it is determined whether the outputs of the first light sensor, over time, are indicating movement of the navigation device with respect to the surface. If not, 1) a second light sensor that is mounted to the navigation device, and of a different type than the first light sensor, is used to detect light reflected from the surface, and 2) outputs of the second light sensor, over time, are used to determine relative movement of the navigation device with respect to the surface.