Too bad there isn’t some mechanical device that allows a person to defend themselves from attackers at a distance that also negates differences in size, athleticism, and even numbers.
Hmmm... Let me think. Where would a person get such a “device”? :)
Perhaps this might be what you’re looking for. Via Wiki
Usage and deployment[edit]
An NYPD officer stands ready with the LRAD 500X at an Occupy Wall Street protest on November 17, 2011 near the city hall
Extremely high-power sound waves can disrupt or destroy the eardrums of a target and cause severe pain or disorientation. This is usually sufficient to incapacitate a person. Less powerful sound waves can cause humans to experience nausea or discomfort. The use of these frequencies to incapacitate persons has occurred both in counter-terrorist and crowd control settings.
The possibility of a device that produces frequency that causes vibration of the eyeballs — and therefore distortion of vision — was apparently confirmed by the work of engineer Vic Tandy[1][2] while attempting to demystify a “haunting” in his laboratory in Coventry. This “spook” was characterised by a feeling of unease and vague glimpses of a grey apparition. Some detective work implicated a newly installed extractor fan that, Tandy found, was generating infrasound of 18.9 Hz, 0.3 Hz, and 9 Hz.