Skip to main content

Control OSX Screen Brightness from Ubuntu 14.04 (on a USB stick!)

After trawling here and there and trying lots of different things, for me this works on my late 2012 21″ iMac with an ACPI card.

It’s best to put the script into a file, make sure the file is discoverable on PATH.

All details are in the folder: 
/sys/class/backlight/acpi_video0
which on my machine looks like this:
ubuntu@ubuntu:~/mc2$ cd /sys/class/backlight/acpi_video0
ubuntu@ubuntu:/sys/class/backlight/acpi_video0$ ls -l
total 0
-r--r--r-- 1 root root 4096 Oct 7 08:29 actual_brightness
-rw-r--r-- 1 root root 4096 Oct 7 08:29 bl_power
-rw-r--r-- 1 root root 4096 Oct 7 08:28 brightness
lrwxrwxrwx 1 root root 0 Oct 7 08:29 device -> ../../../0000:01:00.0
-r--r--r-- 1 root root 4096 Oct 7 08:03 max_brightness
drwxr-xr-x 2 root root 0 Oct 7 08:29 power
lrwxrwxrwx 1 root root 0 Oct 7 08:29 subsystem -> ../../../../../../class/backlight
-r--r--r-- 1 root root 4096 Oct 7 08:03 type
-rw-r--r-- 1 root root 4096 Oct 7 08:03 uevent
WARNING: If you use values higher than the maximum allowed for your card you *MAY* cause damage. The limit on my machine is 15 as indicated in the file
echo $1 | sudo tee /sys/class/backlight/acpi_video0/max_brightness
There are more exhaustive solutions out there including one I saw that didn’t work first time for me that limits the value but for me, being a hacker, I only needed a one liner. YMMV.

 DISCLAIMER: If you damage your machine, that’s your fault not mine!!!
Labels:

Comments

Post a Comment

Popular posts from this blog

PHP and Lisp: multiple-value-bind (MVB)

This is another article in my attempts to find new ways of looking at PHP and making it less of a chore to type in all that code. As much as I love PHP I hate wasting keystrokes. More typing is more errors is more grief. Being an off and on user of Lisp, although not as much as I used to, one of the things that I always liked in Lisp was the ability to be able to return multiple values from a function at once using (values) and then marry that with (multiple-value-bind) to create convenient named bindings for whatever you were about to do. I recently found myself wanting to return a couple of values from a helper function and I just didn't want to go to the trouble of having to type all those character required to create an array with keys for the two values and then I remembered MVB and a little light went on in my head! If somebody else has already done this then I apologise up front but it was new to me and I haven't seen it anywhere else so this could be a first! ...
Post a Comment
Read more

Handling multipart/form-data with NanoHTTPD

I am in the process of reviving an old project from 2014 that I never finished because of other work commitments. In that time, bitrot has set in, the Android API has moved on and all in all, the home-brewed HTTP server I wrote using SocketServer and the org.apache libraries had to go! I looked around, found a couple of contenders and after much time decided to go with NanoHTTPD because it is lean, small and fits in exactly two files. The main server is in one file `NanoHTTPD.java`and there is another file called `ServerRunner.java` which manages instances of running servers. The others The other project I looked at is this one:  https://github.com/koush/AndroidAsync which led me a merry dance and I just couldn't figure out how get the POST data I had uploaded. I spent a few days really digging at it with Wire Shark too to make sure the data was going up. It was. Whatever... I had used it via a gradle dependency entry but I dropped it and went back to NanoHTTPD. For m...
Post a Comment
Read more

Cross platform development with Scheme

Just a quick note about something I recently found whilst trying not to buy MOCL… http://www.lambdanative.org/ LambdaNative is developed and maintained by the Pediatric Anethesia Research Team (PART) and the Electical and Computer Engineering in Medicine (ECEM) group at the University of British Columbia (UBC). I have spent a week or two evaluating it and accidentally contributed a pull request that got merged and one that didn’t and I have to say that, for what it offers, it is awesomely good. Having personally spent many hours with it now, I do not yet think it is ready for mainstream development for a few reasons. I don’t mean that it a bad way either. What I mean is that the language, Scheme, is not really that widely known and as such it probably won’t break out into the public arena any time yet. That’s a real shame because I think that they have achieved an amazing thing; total abstraction of the underlying platform with a really powerful, underestimated language. ...
1 comment
Read more