The device you are looking for is called an intervalometer. They come in all sorts of shapes, sizes, and prices. Each camera manufacturer uses a different connector as well as different connectors from the same maker, so you have to make sure you get the right one. Some cameras have one built-in (or can run hacked firmware to use one). The advantage is no external device needed. There's also software you can run on a laptop connected to the camera that will not only control the camera but also save the image directly to the computer. Lots of ways to skin the cat.

I use modified camera firmware to do this. With certain Canon camera models you can load Magic Lantern, an open source alternative firmware -- it includes intervalometer out of the box, and you can also write your own plugins and run scripts on the camera. (Separately: In general hackability is the #1 priority in deciding what gear I buy.)