My "relatively" qualifier does a lot of work... relative to projects like rebuilding transmissions or doing hobby robotics, I think adding a few bluetooth/wifi

My "relatively" qualifier does a lot of work... relative to projects like rebuilding transmissions or doing hobby robotics, I think adding a few bluetooth/wifi enabled sensors and a bit of logic to toggle a light is pretty simple. And yeah, that's what I mean by doing your own design engineering... are you actually going to solve for that "once in a year" case? Or do you just use a switch to toggle to "normal mode" for when you want to take that long bath? I don't have any kind of platonic ideal for what a "smart bathroom" might be, I just like thinking through the design/engineering possibilities.