Harry actually needs a less brutal version of Thorn Manacles, which allow him to dial back his powers to protect tech when required, something no more than a diabetic blood test finger prick, rather than the savage bite. Rotate, prick, powers off, rotate again powers back on.
Harry would of course get it accidentally jammed on. During a fight.
However this would be very useful for Young wizards to attend normal schools without killing their computers and phones. Harry could go to a normal cinema. Or hospital.