USB OTG (On the go)
Galaxy R supports USB OTG (On the go). You just need a OTG cable.
You can also use a Nokia Usb OTG (On The Go) Cable.
You can get the Nokia Usb OTG Cable for less then 2 euro on Ebay and Amazon.
The Samsung Usb OTG Cable costs much more.
The Nokia Usb OTG Cable just has one disadvantage, it has a "micro usb type A" connector.
The Samsung connector is "micro usb type B" .
But the difference between "micro usb type A" and "micro usb type B" is just that type A is not rounded, type B is rounded.
So you have to "round" the Nokia type A with a File tool http://en.wikipedia.org/wiki/File_(tool)
, transforming it into a type B.
It works, I have done it.