I use a keyboard that is not available in a wireless or bluetooth version, but connects to the computer via USB. Is there any way to make this keyboard wireless? In other words, is there something small I can plug the keyboard wire into that will broadcast the signal wirelessly to be picked up by something plugged directly into the computer?
You could try with something like this. If I get it correctly, it comes with power injector. Still, you'd need to connect the injector to power and that means wires.
I can't find any battery powered injectors at the moment, but you could always make one yourself. Still, it's going to be complicated and it's going to be a hack.
Unfortunately, as far as I can see, there's no elegant solution to this problem.