You wake up in a dark room. Should you get up? It is impossible to tell. You need to turn around and reach for your phone to check the time - this wakes you up even more.
Horolux turns the display of your phone, tablet or computer into a digital sun - it gradually lights up when the morning approaches. If you wake up at any point of the night, the amount of light in the room will allow you to instantly tell if you can keep on sleeping. https://blog.vanousek.com/horolux/