Hi,
You're talking about psychotronic weapons and so on. Beware difference between plausible theories undermined with propaganda and tin-foil hat theories meant to distract from fact.
Build something at home of dubious likelihood of being attainable with current technology that security forces can't make work and some have given up spending money on the research, allegedly? Dream on...
We'd all be enslaved, mindless, borg-like, unthinking creatures if any such tools weren't still long into the future of being workable and effective.
At best, a directed high-pitched whine in the inner ear is possibly feasible, with a team of engineers and big money.
Make one at home? Dream on... I have a time machine that works and a free energy machine I'm working on, if you're interested.