No-WiFi robot vacuums navigate with lasers and bumpers, not an app

Robot vacuums that don’t need WiFi rely on built-in sensors — laser rangefinders and bumper sensors — to find their way around. They don’t need an internet connection or an app to track their cleaning; they just bump, map, and move. The tradeoff is you lose smart features like remote scheduling and voice control, but you also never have to deal with the vacuum losing its WiFi connection and going dumb.