Amazon announced its first smart lock that eliminates the need for a physical backup key should its rechargeable battery die while you’re away from home. While other smart locks lean on hidden USB ports or metal contacts for connecting a 9-volt battery to replenish a dead battery, the new Ring Smart Lock incorporates a more convenient charger right into its thumb-turn dial. Amazon doesn’t specify how many turns are needed but claims just “a few times” can generate enough power to…


