Not sure if ultrasound stimulation of the human brain is really in the realm of hobbyists, but there is a DIY transcranial direct current stimulation scene (DIYTDCSS): https://old.reddit.com/r/tDCS/
Anyhow, he had a fairly large briefcase type device he carried everywhere with him and was trying to convince everybody to come try his 'electric brain stimulation.' Surprisingly, nobody seemed too interested in going into a hotel room with a stranger to get their brains plugged into the wall. He seemed to have zapped away all inhibitions, and common sense. Sure made for an interesting character though!
There's a bit of a correlation causation issue with understanding these studies of one. It seems quite possible that they zap away inhibitions, but equally likely that one has reduced inhibitions if one is inclined to solder things together and push them against one's skull to see what happens.