@mhoye depending on how much effort and parts one wants to piece together, there are z-wave smoke detectors (eg, First Alert). Can setup something with OpenHAB/HomeAssistant to send a message on event. Combine with jmp.chat for SMS. That's at least 3 layers deep, though. Someone else may have a more direct path
@keverets That reminds me, I need to get my DSL connection on battery backup.