Originally Posted by ElecManEXE
Greivous uses them. Though I don't know if its programming or the fact that he has human parts that actually allows it. If nothing else they could probably design droid-only lightsabers that use the droid's power supply rather than "the Force".
Grirevous wasn't a droid, he was an actual alien species but has robotic life support systems due to an injury and Count Dooku taught him how to use a lightsaber.