On: Trouble sleeping? Maybe it's your iPad

[samdk]

There's an open-source alternative, Redshift, that does something similar: http://jonls.dk/redshift/

There's a fork of Redshfit, RedshiftGUI, which gives you a GUI if you want one: http://www.mao-yu.com/projects/redshiftgui/

I don't use either, but I've seen the former recommended, and the latter came up a few times while I was searching around to remember what its name was.