How to change the brightness on iPhone (using private APIs)

I want to make an app similar to SBSettings (a quick settings application on Cydia) becaus开发者_开发百科e developers can't jailbreak their devices. Can someone tell me how to change the screen brightness? It doesnt need to be approved by Apple, so it can use private APIs if needed. Any help would be appreciated.

You can use [[UIScreen mainScreen] setBrightness:0.1] in iOS 5.0