autoBright

Mobile devices actively control their display brightness by adjusting to ambient light levels.
For a desktop setting there are (expensive) monitors that have integrated ambient light sensors.
Even cheap monitors can be controlled via DDC from any operating system.

This project combines a microcontroller based USB HID ambient light sensor with python based DDC control on Windows.

 Ambient Light ☀️/🪟/☁️/💡
        ↓    ↓    ↓
[ Light Sensor (1250 lux) ]
        ↓   USB   ↓
    [ PC / autoBright ]
        ↓ DDC/CI  ↓
   [ Monitor (72%) 🖥️ ]

For Linux there is also a well documented project with the same approach: xythobuz/AutoBrightness

Overview

To adjuist the monitor brightness main.py uses:

• Windows Sensor API (LightSensor) for lux input via winsdk
• Windows DXVA2 DDC/CI APIs for monitor brightness output via ctypes
• a system tray icon with manual offset controls via pystray

Further development/integration:

• add the USB HID light sensor function to TwinkleTray or similar software.

Dependencies

Dependencies for main.py:

• python 3.12
• winsdk
• pystray
• Pillow

Install required packages:

pip install pystray pillow winsdk

Autostart on Windows

Win+R, shell:startup, create shortcut with python3.12.exe "path\to\autoBright\main.py" (if path variables are set correctly)

Hardware

Reading ambient brightness is done with an USB-C ATtiny85 and a I2C BH1750 (GY-302/GY-30) brightness sensor. See MatejKocourek/spark-als. The folder housing includes a 3D printable enclosure.