This experiment uses a disk that accelerates down a slope very slowly. Thanks to Mark Schober for creating an example of this using electrical conduit as rails, a CD as a disk and a steel rod as an axle. Here simple meter sticks are used with a paper disk. As the disk picks up speed very slowly, you can use a single sensor to make time measurements, pointing it upward when moving it to a new location, and pointing it in the path of the disk to capture the time.
Thanks to Brendan Walsh for creating this demo.