I’d like an alert when a person appears after no person there for a certain time. For example, if there is no-one in the room for an hour (or 5 minutes so it needs a setting I can adjust), I’d like an alert when someone returns. But not continuous alerts while they are there. Also, if no person for > X minutes, one alert.
Example application: Get an alert when someone comes into the kitchen for the first time that day so I can go and assist.