November 6, 2025
Let there be light (and drama)
Show HN: Auto-Adjust Keyboard and LCD Brightness via Ambient Light Sensor[Linux]
New Linux tool auto-dims your keys—commenters yell “we already had this”
TLDR: A new Linux tool auto-adjusts keyboard brightness using the laptop’s light sensor, with screen support planned. Commenters say GNOME and iio-sensor-proxy already do this, sparking a debate over reinventing the wheel versus fixing what GNOME doesn’t: smarter, less blinding keyboards that could actually save eyes and battery.
A new Linux project swoops in promising auto-adjusting keyboard backlight (with plans for screen brightness next), and the crowd instantly splits into teams. One camp cheers, “Finally, the keyboard gets some love!” while the veterans roll their eyes and point to iio-sensor-proxy, a long-standing sensor tool that feeds data to desktop systems like GNOME. The most upvoted mood? Been-there-done-that—but also, GNOME’s auto-brightness “hasn’t exactly been great,” so maybe a focused, keyboard-only fix could actually be better.
Drama sparks around the install instructions: running as a root-level service with systemctl has the “not another daemon” crowd clutching pearls, while pragmatists shrug and say, “If it works, it works.” Someone flexes with the classic monitor-sensor command, the Linux equivalent of “pics or it didn’t happen.” Others riff on memes: “My laptop at midnight—lighthouse mode,” and “If this saves my eyes, take my makefile.”
Jargon gets translated: ambient light sensors are tiny parts that tell your laptop how bright the room is; this tool reads them and tweaks your keyboard glow automatically. Config lives in /etc/als-led-backlight.conf for tuning sensitivity, and there’s a “later” promise to handle the screen backlight too. Verdict from the comments: it’s either reinventing the wheel—or reinventing it but rounder. And on Linux, that’s enough to spark a full-on brightness debate.
Key Points
- •als-led-backlight auto-adjusts keyboard backlight using a laptop’s Ambient Light Sensor on Linux.
- •Future plan includes integrating automatic LCD backlight (screen brightness) control.
- •Requirements include Linux, gcc, and make; build with the make command.
- •It can be installed as a system service with make install and managed via systemctl.
- •Configuration is read from /etc/als-led-backlight.conf, allowing adjustment of a base reading threshold; uninstall via make uninstall.