January 25, 2015

Controlling your monitor’s brightness from your computer

I usually have to work more than eight hours a day on my computer. Especially in winter when the sun sets early, I often would have to dim the brightness of my monitor in the evening. But because most monitor on screen menus are hard to use, I almost never do that, because I am too lazy. But if I don’t I sometimes get a headache. So I thought, it must be possible to somehow control the brightness of my monitor without using the crappy menu. And it turns out that this is actually possible. Many monitors support DDC, which should in theory allow you to adjust their brightness. For Linux, there is DDCcontrol, which worked perfectly for my Dell UltraSharp U2412M, altough it does not offically support this monitor.

Unfortunately, DDCcontrol is not in the Ubuntu package repositories. However, on my Ubuntu 14.04 I was able to use the packages from ddccontrol, gddccontrol and libddccontrol0 from 15.04. Additionally, I had to install ddccontrol-db from 10.04. However, keep in mind that using packages from different Ubuntu versions could in theory break your whole system. So be careful, I am not responsible if kittens die.

After that, I had to install i2c-tools and add my user to the i2c group: sudo apt install i2c-tools && sudo gpasswd -a nico i2c

Then, ensure that the i2c-dev module is loaded on boot by adding it to /etc/modules.

After rebooting your machine, you should be able to use gddccontrol to adjust monitor parameters. On the shell, I was able to adjust the brightness using the following command: ddccontrol -r 0x10 -w “$your_brightness_value” dev:/dev/i2c-7 Keep in mind that the command most likely looks different, depending on your machine and your monitor.

That’s it! Now I can adjust the brightness of my monitor more conveniently!

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