I have got a little more done on my garden automation project. This shield is another part of the puzzle; others may find the ideas useful.
My goal is to control irrigation using moisture sensors. But my firmware skills are rusty, and even at my best I worked iteratively. By iterative, what I am trying to say is getting something simple working and then adding to it, while trying to keep each addition working along the way. So I need a way to upload the firmware (again and again) into an Uno in the garden while I'm at a desk with cold, dry air some distance from the water works and sun.
I put a fair amount of time into trying to make everything fit together:http://epccs.org/indexes/Board/RPUadpt/Documents/14184RSS1%20%5BEPCCS,RPUadptAssy%5D%20RPU-ADPT%203D%20ASSY.pdf
and a 3D STEP model (in zip):http://epccs.org/indexes/Board/RPUadpt/Documents/14184RSS1%20%5BEPCCS,RPUadptAssy%5D%20RPU-ADPT%203D%20ASSY.zip
My web page with more info:http://epccs.org/indexes/Board/RPUadpt
Also the board 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/RPUadpt/Design
I have not yet made the board, but another puzzle part is in place.
an image of it stacked between an Uno and latching solenoid driver shield: