A handy DC to USB assembled circuit that we use to make our Altoids USB chargers. You can use it too. Takes DC power from as low as 2V and bumps it up to the 5V USB needs.
- Apple Products (except for the iPad 2 & 3, and the iPhone 3GS)
- Garmin GPS
- Android Phones
- Arduino and Arduino Clones
- To be honest, most anything that charges with USB