This is one of the simplest, yet most effective things I have implemented in our home automation. It may solve a simple, yet very real problem for those with young children out there. This one is more psychological than technical.
Our son is 3, hence has no idea what time it is whenever he wakes up in the morning. That means he will get out of bed at 2am, 4am, 5am, whatever. Not awesome for parents : )
All we did is have his Hue lamp by his bedside glow a dull green at 6am, so in that way he can clearly see that it is now OK for him to get out of bed. So simple, yet it works sooo well. He will just look at it, understand that it is time or not time to get out.
It may not work for all of you, but for us it it’s great! 6am for weekdays, 7am for weekends. Simple and effective!