Fascinating and I like how cheap it can be made - those ultrasonic emitters are right of a HC-SR04 by looks of it and those are cheap as (got half dozen for £1

Fascinating and I like how cheap it can be made - those ultrasonic emitters are right of a HC-SR04 by looks of it and those are cheap as (got half dozen for £1 each few months back). I did start a project to jam gopro's (audio and visual recording) - was combination of IRDA emitters and resonance inducing the housing - but this is less niche and focused. My design was to use a hat with sensor emitters attached. Though canned progress after friend asked if it could disable a police body-cam, of which I said no and yet it probably would and morally weighed up the pro's and con's and canned that.