Building your own motorised camera gimbal or slider seem to be the in thing at the moment. In fact, I built one myself recently (that’s for another post, though). This one, though, from Michael Klements at The DIY Life is pretty cool and incorporates a slider with a motorised pan axis so that it can track a subject as it moves from one end of the rail to the other.
It’s a total DIY project with a bunch of off-the-shelf parts and 3D printed components that Michael has designed himself. And while he doesn’t appear to have released the project under an open-source license, he has made the STL files and the source code available to download so that you can have a go at building your own.