Smoke detectors all over Germany: You should consider that

The smart smoke detector:

We recommend smoke detectors that can be networked with each other, because smoke detectors can also have helpful features.So-called "smart smoke detectors" with WLAN function (here at Amazon) offer the opportunity to access the battery level via your smartphone.

A smoke detector connected to a smart home system can also act as an alarm provider, who trigger the warning system (e.g. broken doorbell).The biggest advantage of smart smoke detectors is the possibility of networking: the smoke detectors can be connected to other smoke detectors.Due to the networking, these smoke detectors warn even before the poisonous smoke makes possible escape routes impassable.You can find more information about WLAN smoke detectors in this article.

A representative of this "luxury smoke alarm" comes from the manufacturer Nest (viewed here at Amazon).This can also be combined with other smart home devices from Nest-but also cheaper smoke detectors offer the function to network with others, but then they have to do without WLAN and thus the app control, since they only directly via radioConnect together.