What is an icon to indicate something done automatically?

[Compile 'em all]

I am doing an icon for an option that when turned on, will do something automatically instead of manually. Similar to the auto brightness in the settings of the iPhone. So brightness usually is indicated with a sun or bulb, what would be autobrightness indicated with? Somehow circular refresh arrows doesn't seem right.

Would appreciate any ideas or thoughts. Thanks guys!

 

[nneufeld]

My my phone, the icon is sort of a cut in half sun. The left half is brighter with rays coming off. The other is dimmer with no rays.
It doesn't exactly suggest automation...but at least indicates a brightness change.

 

[12dylan34]

Maybe something like 3 forward (right) pointing arrows, or a version of that that works with whatever the action you're automating is?

It implies an action, as well as a repetition of that action.

Or maybe multiple arrows set to a circular path?