Always on display on S5 with app.
This is the app called "Always on Amoled", it is in Beta but i works really well. I use it as my night clock with my phonestand when my phone is charging. You can use it on the go but it is for the moment quite battery consuming. (maybe this is do to the rom i use...)
Link to playstore: https://play.google.com/store/apps/de...