Hello Lukas,
exciting use case, even if it’s sad that you need solutions for it at all. Have you made any further progress here? If not, here’s a first idea I’d like to try:
Existing socket(s) with a smart plug (such as this one: https://iot.zenner.shop/en/nke-WATTECO-Smart-Plug-LoRaWAN-Radio-Socket-p-170791) to the radio-controlled socket convert and connect and control “signal light” and “siren” to it. As a result, they do not necessarily have to support LoRawAN and it may be a little easier to find suitable devices for it or one that can do both. Then store appropriate rules via the RuleEngine in the B.One Middleware, which sends a downlink to the radio-controlled socket with the appropriate command when it is opened (possibly simply power on when opening and power off when closing).
How does that sound to you? Like I said, I’d just give it a try. Let’s see what comes out of it in the end 🙂
Best regards
Michael