I believe this is the “1.0” version of the Raspberry Pi 4 lawn sprinkler controller. I decided to put a fuse in after I burned up my first power supply with a badly designed ground circuit. Of course this can be used as a general purpose controller even capable of switching higher voltages, with a few modifications. Will be running it live on my sprinklers in the next few days. Will post a link when I put the code and parts list out on GitHub.