Screen Brightness By Battery

A lightweight Windows application that automatically adjusts your screen brightness based on your device's power state (battery or AC power) and prevents sleep mode when an external monitor is connected.

Features

• Automatic Brightness Control: Adjusts screen brightness automatically when switching between battery and AC power.
• Smart Sleep Prevention: Optionally prevents your device from entering sleep mode when an external monitor is connected.
• System Tray Integration: Runs silently in the system tray for easy access to settings.
• Adaptive Brightness Support: Supports Windows adaptive brightness feature.
• Auto-start Option: Can be set to start automatically with Windows.
• Simple Configuration: Uses an easy-to-edit INI file for settings.

How It Works

Brightness Control

The application automatically detects when your device switches between battery power and AC power, then adjusts the screen brightness according to your preferences:

• When running on battery power: Sets brightness to a lower value to save energy
• When plugged into AC power: Sets brightness to a higher value for better visibility
• Supports adaptive brightness setting ("auto" mode)

Sleep Prevention

When enabled, the application will:

• Detect when an external monitor is connected
• Prevent the system from entering sleep mode while the external monitor remains connected
• Allow normal sleep behavior when the external monitor is disconnected

Settings

The application stores your preferences in a settings.ini file with the following sections:

[Brightness] Section

• Enabled: Whether the brightness control feature is enabled ("on" or "off")
• Battery: Brightness level when on battery power (0-100 or "auto")
• AC: Brightness level when on AC power (0-100 or "auto")

[Sleep] Section

• Enabled: Whether to prevent sleep mode when external monitor is connected ("on" or "off")

System Requirements

• Windows 10/11 (10.0.17763.0 or higher)
• Compatible with x64 and ARM64 architectures

Installation

1. Download and run installer of the latest release from the Releases page
2. Run Screen Brightness By Battery from start menu
3. The application will appear in your system tray

Usage

• Right-click the system tray icon to access settings
• Select "Screen Brightness by Battery: Enabled/Disabled" to toggle the brightness control feature
• Select "Prevent Sleep (External Monitor): Enabled/Disabled" to toggle the sleep prevention feature
• Select "Open Settings File" to manually edit your configuration
• Select "Add to Startup Process" to make the application start with Windows

Building from Source

This project uses:

• .NET 9.0
• Windows App SDK
• WinUI 3
• Target Windows version 10.0.22621.0 (minimum 10.0.17763.0)

Requirements

• Visual Studio 2022 or newer
• Windows App SDK development tools
• .NET 9.0 SDK

Build Steps

1. Clone the repository
2. Open ScreenBrightnessByBattery.sln in Visual Studio
3. Build the solution for your target architecture (x64 or ARM64)

License

This project is licensed under the MIT License - see the LICENSE.txt file for details.

Author

이호원 (Howon Lee) a.k.a hoyo321 or kck4156, airtaxi