my macbook pro's screen brightness randomly fluctuates when on battery power

The macbook pro has a sensor hidden in the speakers that is light sensitive. if the room your in is no lighted well, the screen will dim a lil (to prevent eye strain in the dark) and the keyboard will get brighter so you can see what your typing. if the room is well lighted, the keyboard will go very dim and or turn off to save battery and simply because u dont need a lighted keyboard in broad daylight (u kno what i mean). try it yourself, put you hands over the speakers (im not sure which one exactly im pretty sure its the left one. but just cover both and you will see.

 

I notice this happens when I'm normally typing. When I go to rest my hand over the speaker grill, the display brightness fluctuates. It's extremely annoying.

 

You can turn it off in system preferences...

 

Mine fluctuates depending on what is on the screen. If it's a white screen it'll darken slightly, darker screens increases brightness, etc. I thought it was my eyes at first. Turning the ambient sensor off in System Preferences stops this, but I don't mind it.

 

Thanks Guys.. I just bought my MacBook Pro not long ago and i thought there was something wrong with the screen. Thanks for the clarification.

 

Haha I thought my mac was effed up. Glad I found this site!

/newbsauce

 

True for the previous generation MacBookPros

The newest MBs, MBPs have their sensor next to the iSight camera. (just an fyi - for those who think there is something wrong when they try to place their hands over their speakers and try to change the ambient light )

 

The actual setting changes on my MPB. I like to keep the keyboard at 3 bars when it's needed but sometimes it will go up to 10 or even turn off without me changing the settings.

 

Those of you who are experiencing fluctuations in brightness on screen/ keyboard changing from being illuminated to not:

Are you sitting with your back to the strongest source of light?

If so, do you lean over to varying degress?

Well, the sensor will pick up the slightest fluctuation in light brightness and it could be that your head or shoulders or hands or a combination of these are blocking out enough light to make the keypad light up/screen dim etc.

Try changing your position and seeing what happens.

 

I just turn off automatic brightness and set it to what I need manually.