AutoBrightness

AutoBrightness

Simple solution to measure ambient room lighting conditions with an AtTiny85 based USB lux sensor and set external display backlight intensity accordingly via DDC/CI.

See this blog post for details.

Sensor

Uses a Digispark Rev. 3 clone with a GY-302 BH1750 breakout board connected to the I2C bus.

Quick Start

Check out the repo and required submodules.

git clone https://git.xythobuz.de/thomas/AutoBrightness.git
cd AutoBrightness
git submodule update --init

Build the firmware and upload it.

make -C sensor upload

Prepare udev rules for our new device.

sudo cp sensor/49-autobrightness.rules /etc/udev/rules.d/49-autobrightness.rules
sudo udevadm control --reload-rules
sudo udevadm trigger

Client

Uses KWin scripting to get the active window from the KDE window manager. This is used to pause adjustments while a fullscreen window is focused (eg. while gaming). Also sends status updates to a local InfluxDB.

Run the command-line version with systemd automatically (modify paths in the commands and file accordingly):

mkdir -p ~/.config/systemd/user
ln -s /home/thomas/Projekte/AutoBrightness/client/autobrightness.service ~/.config/systemd/user
systemctl --user daemon-reload
systemctl --user enable --now autobrightness

Or alternatively modify the paths in the AutoBrightness.desktop file and copy it to ~/.local/share/applications for a graphical version that you can easily auto-start on boot in eg. the KDE settings menu.

Quick Start

Install dependencies and run the systray client:

yay -S python-pyusb python-pystray python-pillow python-cairosvg
./client/tray.py

Or for just the command-line version:

yay -S python-pyusb
./client/brightness.py

License

The firmware of this project is licensed as GPLv3. A copy of the license can be found in COPYING.

It uses V-USB and is based on their example code.

Also includes the I2C Master implementation from the Atmel AVR310 AppNote.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

See <http://www.gnu.org/licenses/>.