Automatically reduce brightness

The idea

When watching someone working with an iBook I noticed that the brightness automatically faded to the lowest level after a few seconds of inactivity. I think that this is a simple way to save power. I wrote a c-daemon which uses the XScreenSaver extension to check whether the user is active. If he is not, it lowers the brightness to a specific level. When he is active again, the brightness is reset to the previous level.

Prerequisites

A recent kernel with IBM ACPI extensions. (You should have a file called /proc/acpi/ibm/brightness)

Installation

1. Download the brightness control daemon
2. Unpack it and chdir into the brightd directory
3. Call $ make
4. Move the brightd executable into a directory like /usr/local/bin
5. Put $ brightd -d into your ~/.Xsession (or another distro-specific startup script)
6. Change the permissions of /proc/acpi/ibm/brightness so that your user can write to that file

See the README for more detailled instructions and command line parameters.

Example installation for Gentoo linux and XFCE4

$ wget -o /dev/null -O brightd.tar.bz2 "http://pberndt.com/Programme/Linux/brightd/_download/brightd.tar.bz2?ct=raw