You're more hardware than I, but would there be away to grab a different pin
(mini breakout exposes more than Arduino - so is there a way to expose an extra pin)
that you could use to run through a swtich -
<power from board> to <switch via extra GPIO> to <power on shield>
throwing GPIO triggers the switch to power shield on/off?
Just to follow up here. I believe most of the shields that I use, get their power directly from the +5v pin that comes in. Many of them have their own voltage regulator that converts the +5v to which ever voltages that they need.
It is also my belief that the +5v that goes to the +5v of the shield comes directly from the voltage regulator maybe through some other discrete components and not under any control of the processor, so this may be hard to change without modifying the board.
One option would be to take the bottom shield, and bend out the +5v pin such that it does not go into the socket. Then use a jumper wire that I could then go to some relay, that I could control by any IO pin, that would turn on when power is attached, which then routes power to the shield. But it would be nice if this could be done internally.
I think you are right. Edison has bee my first non pc hardware, from everything I have seen the shield power pins are direct. Lots of shields coming with a power button/switch on the shield - but not programmable. Of all the code I have seen so far (lots and lots and .. ) I haven't run across anything yet for controlling the power pins through code. It was the only thing I could think of was to create-a-switch. Hope your holidays were wonderful.