Turn off display in Windows on command

Question

Is there a way to turn off the display in Windows (7), preferably without using additional software?

Powershell script works fine, but leaves command-line window after turning on the display.

Answer 1

A couple more options:

• Turn Off LCD - just place the executable on your desktop
• NirCmd - you'll need to copy nircmd.exe to your Windows system directory, or add its location to the PATH environment variable. Then just run nircmd monitor off from the command line. More information at the link.

Answer 2

On a laptop you can use the keyboard shortcut combination of Fn+F7 (F7 might differ depending on the laptop model) and for a desktop you can always use the power button.

Do you need any other specifications such as wake up on mouse movement or something else?

You can always create a shortcut and assign a keyboard shortcut to a black screensaver, use this path:

%systemroot%\system32\scrnsave.scr /s

This will not turn off you screen but make it completely black

Answer 3

You can use WinAPI call SendMessage(HWND_BROADCAST, WM_SYSCOMMAND, SC_MONITORPOWER, 2) where HWND_BROADCAST = 0xFFFF, WM_SYSCOMMAND = 0x0112 and SC_MONITORPOWER = 0xF170. The 2 means the display is being shut off.

There are several ways to make the call:

• Separate executable. You can fire it through a script, command line, Run window, shortcut (*.lnk), etc. Note that shortcuts can be invoked using a keyboard shortcut. The executable may be written in C or C++, or via P/Invoke in .NET languages (C# or PowerShell), or in many other languages that have a foreign language interface (e.g. JNI in Java).

• AutoHotkey script. For a non-programmer, this way is probably simpler. Making customizations still requires some scripting. This script turns monitor off on Win + M:

  #m::
  Sleep 1000
  SendMessage, 0x112, 0xF170, 2,, Program Manager
  return
  

Note the timeout before the SendMessage call in the AutoHotkey script. It gives the user a chance to release keys (in case their release would wake up the monitor again). Do not forget about it even when making the call from a script in another language.

For more info, see the documentation of SendMessage function, WM_SYSCOMMAND message and AutoHotkey SendMessage. It might be of interest that since Windows 8, using the same method to turn monitor on does not work, but there is a work-around.

Answer 4

Powershell one-liner would be:

(Add-Type -MemberDefinition "[DllImport(""user32.dll"")]`npublic static extern int SendMessage(int hWnd, int hMsg, int wParam, int lParam);" -Name "Win32SendMessage" -Namespace Win32Functions -PassThru)::SendMessage(0xffff, 0x0112, 0xF170, 2)

Answer 5

As one-liner for instance using Win+R:

powershell -command $obj = Add-Type -MemberDefinition '[DllImport(""""user32.dll"""")] public static extern int SendMessage(int hWnd, int hMsg, int wParam, int lParam);' -Name fn -Namespace ns -PassThru; $obj::SendMessage(0xffff, 0x0112, 0xF170, 2)

It's not possible to put in a shortcut .lnk file unfortunately because the line is too long, I run it with Flow Launcher and my Favorites Plugin, this supports long command lines.

https://github.com/stax76/Flow.Launcher.Plugin.Favorites

Answer 6

Based on Ujjwal Singh's answer, here is a Python script to do so.

First install pywin32 module, if you haven't already.

$ python -m pip install pywin32

Here is the script:

from win32api import SendMessage
SendMessage(
    # https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-sendmessage?redirectedfrom=MSDN#parameters
    0xFFFF,  # HWND_BROADCAST
    # https://docs.microsoft.com/en-us/windows/win32/menurc/wm-syscommand
    0x0112,  # WM_SYSCOMMAND
    0xF170,  # SC_MONITORPOWER
    2,  # the display is being shut off
)

Or if you prefer a one-liner to run directly from command prompt:

$ python -c "import win32api; win32api.SendMessage(0xFFFF, 0x0112, 0xF170, 2)"