Hedders on Nostr: Can I ask the Fedi hive mind for some advice on a slightly weird topic please? ...

Can I ask the Fedi hive mind for some advice on a slightly weird topic please? Firstborn (17 going on 18, very autistic, quite introverted) likes to hide in their room a lot, which is at the other end of the house from the living room, kitchen etc. They also wear noise-cancelling headphones a lot. Calling them for dinner currently involves a lot of yelling and knocking hard on doors. Over lunch today, they floated the idea of a light or sign in their room we could turn on to summon them. "Like the Batsign," to quote. I guess I could do it with a simple light-up message board and a smart plug, but any more creative suggestions would be most welcome!