yabd

Yet another brightness daemon

This is a simple (~200 lines of python) daemon that sets the brightness of the screen depending on ambient brightness. It was developed for my framework laptop on wayland / sway, but it should work with any system that

1. uses systemd/dbus (with systemd-logind)
2. has an ambient light sensor compatible with iio-sensor-proxy

Features:

• Set brightness depending on ambient brightness sensor
• dim screen with a dbus command (for use with swayidle or similar)
• optionally ramps brightness up and down smoothly
• Uses dbus interfaces systemd-logind (8) (to set brightness) and iio-sensor-proxy. This means it should be compatible with any window system / wayland / tty (though I have only tested it on sway).

Installation

This needs python3.10 or newer. It also needs iio-sensor-proxy to be installed, as well as pygobject and dbus-python

Arch linux

There is a PKGBUILD in the etc folder. You can install it with makepkg -si.

$ cd etc
$ makepkg -si

With Pip

First install python3.10 or newer and iio-sensor-proxy through your package manager.

Then use pip to install yabd and its python dependencies:

$ pip install git+https://github.com/tbrugere/yabd.git

it will get installed in $site-packages/yabd.py

Optionally also install the systemd service file:

$ cp etc/yabd-installed-with-pip.service  ~/.config/systemd/user/yabd.service

Usage

systemd

The easiest way to use this is to use the provided systemd service file. To start the service once

$ systemctl --user start yabd

To start the service on login

$ systemctl --user enable yabd

To modify the options, edit the service file using

$ systemctl --user edit yabd

and modify the command line options in the [Service] section. The command line options are described below.

Command line

$ yabd --help
usage: yabd [-h] [--max-brightness MAX_BRIGHTNESS] [--min-brightness MIN_BRIGHTNESS]
            [--max-ambient-brightness MAX_AMBIENT_BRIGHTNESS] [--device DEVICE]
            [--subsystem SUBSYSTEM]
            [--change-to-get-control-back CHANGE_TO_GET_CONTROL_BACK]
            [--ramp | --no-ramp] [-v]

options:
  -h, --help            show this help message and exit
  --max-brightness MAX_BRIGHTNESS
                        max selectable brightness in percent (default: 100.0)
  --min-brightness MIN_BRIGHTNESS
                        min selectable brightness in percent (default: 5.0)
  --max-ambient-brightness MAX_AMBIENT_BRIGHTNESS
                        ambient brightness (in lumen) corresponding to the max
                        (default: 500.0)
  --device DEVICE       device to control (default intel_backlight)
  --subsystem SUBSYSTEM
                        subsystem to control (default backlight)
  --change-to-get-control-back CHANGE_TO_GET_CONTROL_BACK
                        how much the ambient brightness has to change to get control
                        back (default 100.0 lumen). If the screen brightness is changed
                        by another application, this daemon stops controlling it
                        temporarily. but if the ambient brightness changes more than
                        this amount, it takes control back. set to 0 to disable this
                        behaviour
  --ramp, --no-ramp     ramp brightness changes (default True) (default: True)
  -v, --verbose         enable logging

Dimming the screen

Dimming / undimming the screen can be done with via re.bruge.yabd dbus interface.

$ gdbus call --session -d re.bruge.yabd -o /re/bruge/yabd -m re.bruge.yabd.dim
$ gdbus call --session -d re.bruge.yabd -o /re/bruge/yabd -m re.bruge.yabd.undim

For example, here is my swayidle config:

timeout 200 'gdbus call --session -d re.bruge.yabd -o /re/bruge/yabd -m re.bruge.yabd.dim' resume 'gdbus call --session -d re.bruge.yabd -o /re/bruge/yabd -m re.bruge.yabd.undim'
timeout 300 'swaymsg "output * dpms off"' resume 'swaymsg "output * dpms on"'
timeout 600 swaylock resume 'swaymsg "output * dpms on"'
before-sleep swaylock
lock swaylock