This is how I did it
You don't have to sleep/wake it.
Go into settings and set the brightness to the level you desire every time you change rooms/lighting. The next time you return to a similar room/lighting, it will automatically adjust to what you previously set.
So just to clarify
1. I went into a dark room, set the slider where I wanted for that room, in this case low setting.
2. Closed settings turned off phone ( not power off) just click the power button to turn off screen.
3 went into a bright lighted room, turned on phone,( push home button) go to brightness settings and slide the adjustment to a brighter setting for the lighted room.
4 get out of settings.
5 turn off screen and it will remember those settings. Add more for different lighting conditions.
Now when I go back into the dark room the screen is dim. :)
Lupe, your first description of the process is not the way it performs, but the step by step is correct. You cannot set the brightness you want in any setting and have it return to the same setting when you return. Only thing you can do is to set it to the darkest conditions you expect to be in as it will not go lower than what you set it too, only up and back down to it.
Auto brightness feature has NEVER worked correctly on ANY iPhone model to date! This is very simple folks and doesn't take a rocket scientist to figure out, the screen is suppose to AUTOMATICALLY dim or brighten (when you have "auto brightness" enabled) depending on the lighing conditions your phone is in, you shouldn't have to make "ajustments" to make it work right! This is one feature that RIM and Android have been perfect at, "it just works!"
Apple come on already, 7 years and you still can't get it to work properly?
As with most of my experiences with iPhone 3gS, 4, and 5, Ive realized the phone is really is like a handheld PC. The fix for many solutions does not require much voodoo exercises. For many issues you can simply close out apps by double tapping the "home" button, the multitasking view showing last used/running apps should appear, then tap & hold an app until the "–" symbol appears to the top left of the all the apps, close those that you dont need, then press & hold the "i/o" button up top, when "slide to power off" appears, simultaneously press & hold the "home" button and hold until the phone cycles off and on and the Apple logo appears. This is the Hard Reboot. Ive used this for countless issues, like freeze ups and wifi connectivity difficulties. Good luck