Here is one memorable quote, “It is a slider, not a roller after all“. This comes from Dan Colvin, a film maker and a unicyclist that was set to build a slider that would be easy to build, even if you are not a certified maker. To meet this end, Dan removed any complicated mechanisms from his slider, eliminating wheels, pipes, metal work and leaving only a felt covered 2 by 4 and a stretch of plywood as the basic elements of the slider.
The slider is powered by a K’nex motor that pulls the felt covered 2 by 4. I must say that I was kind of skeptic about how smooth the action would be. I was surprised. It is very smooth. See for yourself in the footage below followed by a build guide. While the footage shows a small smart phone for cam, I think it would work for larger cameras too.
Following is some demo footage, followed by an instructional video