While they may not fast charge, many of the devices will trickle charge - simply because the original USB 2.0 spec didn't require high amperage. In fact, 2.0 spec allowed for a max of 5 'unit loads' with a unit load of 100 mA (5x 100 mA = 0.5A). Putting out more than that was against spec unless the port was specifically marked as a 'charging port' per the Battery Charging specification (you may have noticed USB ports with battery icons next to them).

It wasn't until USB 3.0 that the limits were increased. Additionally the Battery Charging spec was re-written to increase limits for charging ports.

If you can plug your device into any single USB jack on a computer (not just ones with a battery icon next to them) and it will charge, it will likely charge with this project.