I am sure this is a simple problem, just curious on other with a different approach. Curious if anyone has tackled the way to use ALL motion senors in the house to see if there is motion and trigger an alarm.
i.e. When I am away, if any motion is detected in the house I was to notify me. Issue is we add and remove motion sensors from time to time, what is the best approach so this automation just keep working even if I add or remove one or two?
Create a binary sensor group containing all your motion sensors. Detection on any of the sensors will turn the group on - that change of state can be used to trigger an automation to send a notification.
You just need to add sensors to this group and your automation will continue to work.