Hello. yes built in. but can this sensor be used separately as a trigger in scenarios with other devices? Well of course not. Does this sensor detect light sensitivity in lux? Of course not. So what’s the use of it??? A separate street device is required and there are no other alternatives and options!!! I don’t understand at all how it turned out that this basic device may not be in a smart home??? I don’t understand what’s the problem with creating it??? If you don’t want to create sonoff, then just make support for similar devices in ewelink. After all, there is already a practice where when support for some Sonoff devices comes out, then literally within a month other manufacturers release similar devices with ewelink support. A striking example is presence sensors.