Does anybody know of cheap/easy methods of causing a lot of pain but with no damage to the skin? One example is the wartenburg wheel, but you can only put so much pressure before it breaks skin.
Microwaves and electricity (but only at the right frequencies) may selectively excite nerve endings without doing much actual damage to the tissue around them. A pain ray is probably not cheap/easy (the military research is expensive), but there ought to be guidelines for zappers