Dell laptop display brightness problem

Question

I am using Dell inspiron 15 and Ubuntu 13.04. I have hot keys on my keyboard to adjust display brightness and they work fine.But the problem is, as soon as I switch on the laptop the brightness is set to 100% . I have to reduce the brightness manually. Also the brightness decreases when the battery is low, when I charge my laptop. I am looking for the following:

1. run the command "xbacklight -set 10" on booting the machine, to set the screen display brightness to 10% . How to execute this at startup?
2. How to get complete control over brightness settings? like how much brightness should be there at startup, How much brightness should be there when battery is low and how much brightness should be there during charging.
3. Is there any software/utility to sense lighting in room by using web-cam of laptop and adjust the brightness automatically. If no such thing is available, I would like to develop one. Please guide me how to start.

Answer 1

Ctrl+alt+t to open terminal and type

gnome-session-properties

a dialog box will open-up , click on add paste your command and click on ok.

this will help you to execute commands at start-up

for change to be persistent try this https://askubuntu.com/a/151665/162137

I hope it helps!

Answer 2

I think that the specific answer you are looking for on making the brightness stick at startup is to open the dash, and type 'startup' -> the program you are looking for is 'startup applications'.

Create a new startup application that looks like this:

I found this on maketecheasier.com

Answer 3

You can utilize a bash script to solve your second problem, here's the logic:

• Check battery percentage every x seconds/minutes (you can use a cron job for that)
  • If the battery is less than say 50% the script would run: xbacklight -set 70
  • If the battery is less than 10% the script would run: xbacklight -set 20

clight is a daemon that utilizes your webcam to automatically adjust your display backlight. I don't know if it's available in the official repos but it's on Github if you want to check it out.