Attached is a pic of the install I did Sunday at my new home. I used a Raspberry Pi 2 Model B with some heatsinks and a SanDisk Class 4 4GB Micro SD card I had laying around that does the job just fine. I ordered a pretty decent WiFi module as well with the external antenna for range that you can see poking out the right side.
I opted to use Minibian instead of Raspbian for the OS to shed the extra weight of the GUI and default packages. Result is a much faster boot and lower system resource usage. Be forewarned, you will need to install some packages as well as manually extend the SD card’s partition before OSPi will work properly if anyone decides to go that route. I’m using Dan-in-CAs github repo for the OS software as I prefer the flexibility of a scripted language versus compiled C++. Currently runs my 7-Zone system effortlessly.
For people wondering, this is an outdoor unit located in Orlando, FL. It’s currently 96 degrees out and the Pi is sitting around 60-62 degrees Celsius or ~140 degrees Fahrenheit which is well within its operating range. I doubt I will have a problem with heat but I added the heat sinks to be sure.
Only issue I had was with the wireless rain sensor I have. I ended up removing it in favor of the Wunderground based rain detection instead. Basically, I have an Irritrol wireless rain sensor. Since it requires 24VAC for the receiver, I was hesitant to start splicing wires off the 24VAC transformer as it would be one more thing to disconnect if I had to bring the OSPi and transformer inside for debugging. The Orbit 57899 this replaced had 24VAC dedicated terminals for this purpose. Might not be a bad thing to add to future versions of the OpenSprinkler board as more people are using wireless systems these days instead of running cables to the roof of their house for a mechanical sensor.