Auto Keyboard Backlight

Auto Keyboard Backlight

Auto Keyboard Backlight, published on GitHub as Auto Backlight for ThinkPad, is a free open source utility designed to remove the inconvenience of manually controlling the keyboard backlight and screen brightness on certain Lenovo ThinkPad laptops, such as the X1 Carbon, X1 Extreme and P1. These models have no automatic control for either, so the program adds it as a small system tray application that starts together with Windows.

It keeps the ThinkPad keyboard lit while you work and adjusts screen brightness to the room light using the built-in camera.

Features

The program adds two automations, and each of them can be enabled, disabled and configured from the right-click menu of its tray icon.

• Turns the keyboard backlight on whenever you use the built-in keyboard or pointing device.

• Turns the keyboard backlight off after an adjustable inactivity timeout.

• Follows the backlight level chosen with the standard Fn+Space shortcut.

• Keeps the backlight setting after sleep, wake, lid close and display on/off events.

• Estimates the ambient light level from a low-resolution snapshot of the integrated camera.

• Maps the light level to a screen brightness value through a configurable calibration curve.

• Refreshes screen brightness on a hotkey (Alt+Space by default) or on an optional timer.

Benefits

With the stock Lenovo behavior, the keyboard backlight resets after every power event, so it often stays off or on at the wrong moment. Auto Keyboard Backlight keeps it lit only while you are actually typing or using the built-in pointing device and restores your chosen level after the laptop wakes up. The screen brightness follows the room light, similar to laptops that have a real ambient light sensor.

To keep the camera activity LED from becoming a distraction, the camera is sampled only at predictable moments: after a power event, after the inactivity timeout or when you press the hotkey. The keyboard is controlled through the Lenovo/IBM power management driver (IbmPmDrv), and the camera is read through DirectShow. The frequent input events are muted when not needed, so CPU usage stays minimal.

Conclusion

Auto Keyboard Backlight is a simple way to get automatic backlight control on supported ThinkPads. It is distributed as a Windows installer that adds the program to the startup applications, and it can be removed through Add or Remove Programs. The source code is available under the Apache 2.0 license. The only release dates from 2020, and the project has not been updated since, so laptops other than the listed ThinkPad models may not work with it.