Control external monitors on Windows
How to use a free app to control the brightness for all monitors
A small open source tool called Twinkle Tray brings the settings for adjusting the screen brightness of connected display devices to the system tray of Windows 11 and Windows 10. The free app offers extensive setting options for professionals and can either be downloaded from the Microsoft Store or Github.
Using Twinkle Tray makes adjusting the brightness on each monitor as simple as possible, as your PC now becomes the command center to define all brightness values on all monitors.
Twinkle Tray uses the Display Data Channel/Command Interface (DDC/CI) to control the display device. In addition to DDC/CI, Twinkle Tray also uses WMI monitoring software to communicate with the connected image output device.
DDC/CI is a common serial port that enables bidirectional communication, effectively creating a Plug-and-Play functionality. Please note you may need to enable this feature in the monitor’s settings. For more information, simply check out the Readme-file of the project (also linked in the addendum at the end of the page).
The documentation is currently vague on the specific advantages of also supporting WMI, but I assume that its implementation allows for more monitors to work correctly.
Works with different display technologies
The open source tool is also designed for operation with multiple display devices, whether monitors or OLED TVs, and integrates itself discreetly, unobtrusively and coherently into the system tray of Windows 11 and Windows 10.