When we started our Smart Home, we were looking for a reliable trigger to set the home into night mode. I came up with the idea embodied in the smart app below. It will monitor the power consumption on a power meter switch, e.g. the SmartThings Smart Outlet. When the power goes to zero in a user selected time window, it will run the user selected routine (previously known as “hello home” phrase).
We’ve been using it since last year and it works great for us. The night stand light is always the last thing to be turned off before we go to sleep. This will trigger the app to “Say Goodnight” to ST. That, in turn, will run all the automated tasks you have associated with the routine. In our case it will turn off all the lights and set the thermostat temperatures cooler.