Instructables user yonderknight writes:

I’ve always wanted to make time lapse videos, but I don’t have a camera with an intervalometer feature built in. In fact, I don’t think very many cameras come with such a feature (especially not SLR cameras). So what do you want to do if you want to make time-lapse videos? You can buy a commercial intervalometer (yeah, right). You can check out some instructables and make one yourself out of electronic components, but what if you don’t have the time/skills necessary to build one? You just want something quick and cheap. Well, you can actually use a common TI graphing calculator (I don’t know of any high school student without one of these) and hook it up to any camera with a remote shutter release socket. It’s quite easy, and depending on your camera can require no electronic work at all.

Turn a TI Graphing Calculator into an Intervalometer and Create Time Lapse Videos – Link.