This is a USB charger for mobile devices that snaps into a Makita LXT-type battery pack. It's based on the very useful Makita battery clip by joeynovak. Using a simple off the shelf USB/voltage regulator circuit board and some scrap sheet metal, this is a useful addition to the workshop or jobsite.
1) Print with support enabled.
2) Drill/ream out screw hole bosses to match the screws you'll use.
3) Buy item 144860 from DX.com, or a voltage regulator of your choice. Install onto bosses using screws or glue in place.
4) Bend a 1mm thick piece of scrap sheet metal tabs to fit into slots.
5) Solder/crimp/bolt on wiring onto sheet metal tabs, run wire to voltage regulator.
6) Attach tabs to slot using adhesive of your choice (I used a thick ABS/acetone sludge).
7) Screw the two printed parts together.
The regulator I linked to is supposed to be able to pump out 3A through the USB port, so it should charge just about anything.