This $200 AI Will End Tennis Club Screaming Matches

Players suffer complete meltdowns as they hurl insults. Postmatch beers can undo some of the damage, but the shame and resentment linger for days. More civilized times may lie ahead. French inventor Grégoire Gentil has designed a $200 GoPro-size device that can be fastened to any net post and detect whether balls are in or out with surprising accuracy. It's called, reasonably enough, the In/Out.