I ordered a Shutter Precision hub, and it should be arriving soon. Then I can rebuild my front wheel and wire up the headlight/taillight that are already here.

In theory, it should be easy enough to have a switch, allowing me to direct where I want the power from my hub to go. Then, I could charge my phone during the day when I don't need the headlight. Has anybody actually done that? I bet there are DIY kits for just that sort of thing, if I knew where to look.