Calise Sets The Screen Backlight Based On Ambient Brightness

Calise (Camera Light Sensor) is an application that uses your computer's camera as a light sensor for obtaining the ambient brightness and then calculates and sets the correct backlight according to an user defined scale.
Calise features:

• command line, GUI (with tray icon) interfaces and daemon mode
• profiles support
• DBus service optimized with automatic dawn/sunset recognition and weather information by using latitude and longitude.

More info on Calise cam be found at its official website.

Install and set up Calise

Ubuntu 12.10, 12.04, 11.10, 11.04 and 10.10 users can install Calise from the main WebUpd8 PPA:

sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt-get update
sudo apt-get install calise

Note: I've only tested it in Ubuntu 12.04 because it can't be tested in VirtualBox.

After the installation completes, you must start the Calise calibration process (but before you do, read the "Important" note below) using the following command:

calise --calibrate

Important: before proceeding with step 3, you have to give write permissions to the file used for step 2 (the sysfs backlight path) using the following command:

sudo chmod 666 INTERFACE

Where "INTERFACE" is the file you've selected under step 2 (example: /sys/class/backlight/acpi_video1/brightness).

Then, continue with the remaining calibration steps.

Once you're done, you can run Calise from the menu / Dash. If you prefer to use the command line interface or the daemon mode, use the following commands to see the available options:

calise --help #command line interface
calised --help #daemon mode

Arch Linux users can install Calise via AUR.

Download Calise for other Linux distributions via SourceForge.