A free program for Android, by Michael Diener – Software e.K..

If you’re one of those people who spends too much time on their phone, this app is for you! It shows you how your screen time looks in real-time and gives you a reminder when you’re about to use the phone for too long. The idea of seeing yourself staring into the phone (or alternatively someone else staring) as a reminder that your mind leaked is effective at reducing your screen time.

You can also set the time for the reminder, so it shows up at the right moment. And there are no ads or analytics, it relies on generosity alone.

The data is safe, will only be stored locally, and never be shared with anybody.

The developer is an independent developer and the creator of this app (and others).