Just had a funny thought...
If Harry wanted to work around computers, he'd probably need a circle for any long period. And the circle would probably have to be made out of the same things a computers to allow him to use keyboards and stuff. So what's a computer made of? Silicon, plastic and copper wiring. Of course, he'd have to find a way to use it without any hands...
"Harry, is that-"
"It's my portable murphionic field dampening device. Very sophisticated."
"It looks like a hula hoop with some wires taped on."