It's not on AWS but runs on a local raspberry pi, but my doorbell signals via MQTT that someone ringed. This makes my security camera take a picture and sends a

It's not on AWS but runs on a local raspberry pi, but my doorbell signals via MQTT that someone ringed. This makes my security camera take a picture and sends a push notification to a custom made iOS app which shows who's in front of the door on my apple watch. If I'm logged in my home wifi, I can even open the door with a button directly from this notification. I would argue that I'm not the only one who finds that useful.