I have found some time to work on my garden automation project. This shield is only one part of the puzzle, but others may find the ideas useful.
My goal is to control latching irrigation solenoids, and monitor a flow meter during watering. Then when not watering I want to monitor humidity sensors (humidity changes frequency output). The schematic: http://epccs.org/indexes/Board/RPUShldGP/Documents/RPUShldGP,Schematic.pdf
My web page with some more info: http://epccs.org/indexes/Board/RPUShldGP/
Also the files are in Eagle (CC) BY-SA if you want to download them, just look for the zip link. https://epccs.org/hg/epccs/Board/file/tip/RPUShldGP/Design
I have not had the boards made yet, I want to find errors first (thanks for any help with that).
I better put a disclaimer about my web site. I have had it for many years (over 15 I think), and much of the stuff on it is just abandoned tinkering, so I hope that serves as enough warning.