“Personal Sunrise” is a dawn simulator for Android devices. It helps to wake up more easily in the morning, as your body prepares for wakeup due to the increasing light.
Multiple lights can be used and separately configured (In the Settings, choose “all” options at the
right top, then there are Hue options available for both Dawn and Dusk simulation)
Wikipedia says “Dawn simulation is a technique originally developed to help treat seasonal affective disorder, but can be used as a soundless alarm clock to wake up the body naturally. Typically, the treatment involves timing lights in the bedroom to come on gradually, over a period of 30 minutes to 2 hours, before awakening.”