Joe's project: lowbat

lowbat - lightweight low battery notifier

1 Why lowbat?

I've been using minimalist OS installations for work, personnal computing and playing video games for a while now. I used Arch Linux, I still use Gentoo Linux - which is by far my favorite Linux distribution - as a desktop OS, and now I am using FreeBSD on my workstation.

Those operating systems and distributions basically come with a kernel, coreutils, a shell and that's pretty much it. Everything else has to be installed manually. I love this philosophy, the simplicity behind it and the fact that you know exactly what's on your system at any moment.

As window managers, I used dwm for a while, and I am now using bspwm. They are ultra-fast, very lightweight and do not bring extra bloatware to my systems. I do not use a status bar as well, I like my applications to use the full screen space available.

A big problem for me with this setup for me was that they do not come with some kind of warning or notification system, like fancier desktop environments would, when my laptop battery is low. That also was before I started using Emacs, discovering the battery level indicator in the modeline. Ultimatly the frustration was too important when the computer kept shutting down in the middle of important work too many time. Then I decided to create lowbat to cure this issue.

2 History of lowbat

It started as a very short dash shell (get dash here) script that was working fine but I wanted to experiment a little bit with this. It turned into a C++ program, which is still the case for the GNU/Linux version. Switching to FreeBSD, I exerimented again by turning it into an x64 assembly program, following the Intel syntax. In that way lowbat is even more lightweight and consumes less battery power. These days, I am rewriting it in the AT&T syntax.

3 How it works

3.1 libnotify lowbat

The principle of lowbat is rather simple. When it's running in the background, it checks every 4 minutes whether your battery is above 15%. If that is the case, it sleeps for another 4 minutes. When your battery runs bellow 15%, lowbat checks your battery level every 20 seconds as well as sending you a notification using libnotify. You can display live notifications on your desktop using dunst for example, as well as many other I'm sure.

lowbat-01.jpg

Figure 1: A notification generated by lowbat, displayed by dunst

3.2 espeak lowbat

lowbat also has an option to send a custom voice message to the use using espeak. Very handy if you are not in front of your computer or if you want to bring joy to this dramatic event.

3.3 unknown lowbat

Sadly, I wasn't able to test lowbat on machines with more that one battery. My call is that it will only warn you for the first battery, but I can't be sure. Try it and tell me!