Can the USB pot on the Smoothie board power a Raspberry Pi ?, either a series 1 or 2 (I have both)
I have use a Murata OKI-78SR-5 and I power a Pi 2 from 5V on one of the unused endstops (I'd post a link but I don't have the karma for it).
I didn't try it from the USB port because that port I use for communication to the Smoothieboard. You can not plug the Smoothie USB jack into the USB jacks on the Pi because they won't feed power back to the Pi. I could be wrong about that though, does the Pi 2 allow power feedback from the USB ports? I can't remember if I tested that.