Putting the OpenSprinkler and Raspberry Pi together was easy, getting them to run showed my inexperience when it comes to playing with hardware. The overall install went pretty smoothly and the documentation is good and easy to follow so I'm not going to ramble on about it for very long, but just throw up some notes.
First, my old card reader didn't want to play with any of my computers. Now, the card reader is ancient, but should have been able to work with an SD card. No joy under and available OK, so I ended up having to get a new SD/microSD only card reader.
When writing the ospi image file to the SD card using Mac OS, make sure you write to the raw device and not to the slice (in my case /dev/rdisk4 and not /dev/disk4s1), otherwise you'll end up with a non-booting OSPI and wonder why. Don't ask me how I know
Also, the OSPI image doesn't have Emacs pre-installed, so I obviously had to fix that. I mean, how would I be editing configuration files otherwise?
The hardware installation (aka screwing the controller to the wall and wiring it up) was pretty simple, to facilitate the install I had taken photos of the way the old controller was wired and use that as a guide.
The whole install went pretty smoothly and the controller has been running our sprinklers for a while now. Unfortunately the sprinkler_pi program that I really wanted to use to seems to have encountered a bug that has it trigger multiple valves at the same time; I'm planning to upgrade to the latest version and if necessary debug it a bit because I like its UI better than the default interval_program. The latter however just worked out of the box.
The only concern so far is that the CPU temperature on the Raspberry Pi seems a little high (it's usually hovering around 60-65° Celcius as it's outside in the garage. I might have to experiment with a CPU heat sink on that one.