The two simple ways are:1) Emulate a PS/2 keyboard. If Dance dance whatever works with a keyboard then you need no special program on the computer side to read the Arduino input.2) Emulate a USB keyboard. Same as above.
but those work with leonardo... i have just a uno r3
That's not correct. And if that's the level of attention you're going to give to answers posted to your questions then you should not bother posting questions at all.