It is easy to take a Raspberry Pi and treat it like a cheap Linux PC or server. Running an ad blocker or a VPN gateway is simple and doesn’t require any real interfacing. However, it is a big leap to actually use the Pi to control something and a good example can go a long way to helping you develop your own projects. [Joeseph Luccisano] posted a tutorial with just that aim. The goal: build a low-cost lawn watering system.
It is an interesting project since it has hardware and software components, of course. But it also has a hydraulic part, so you have to deal with all three domains coming together.
Of course, your yard will be different, so some of the design will change if you decide to implement this yourself. However, there is plenty of information about how he placed the zones and why he made the choices he did. That should be a good basis for your own design.
It looks like the software section of the tutorial is a work in progress. But the basic idea is to create an HTTP server using Flask for Python and exposing a basic Web API. An iPhone app called Curler creates a good-looking use interface to call the API. We think you could do the same basic thing with HTTP Request Shortcuts, on Android, or any of many other similar apps.