My monitor's power button is broken - how do I black out the display without unplugging it?

Question

Occasionally, I leave my computer turned on all night with some program running. If the computer logged off or sleep, the program is stopped. The monitor light is bright enough to disturb my sleep. My monitor power button is broken. I have to pull out the monitor power cable to turn it off.

I've tried to reduce all the contrast and color to 0. But, it is still not enough. How to make my monitor completely black without make it sleep or logged off and keep the program running? My monitor is
HP ZDisplay.

Notes:

• The program I running is auto move the mouse cursor (something like mouse recorder).
• I do not want to cover my monitor with some blanket or other thing.

Answer 1

Since you're having issues with the other answers so far:

• "it prevent my program from running"
• "I think it's not force turn off the display. I've just test it"
• "the main problem is how to keep my program running with black screen. Most third party program stopped my program from running."

You're saying pretty clearly that your mystery program is just not going to co-operate with a software solution. You're just going to have to "think outside the desktop" & tackle the real problem:

Fix the power button.

You might get lucky and it's just dirty (like a remote control), or you say "it's missing the button to press" so just replace it with any similar shaped object, wood, plastic, a marble, tape it in & press away.

Or at least do the next best thing:

Install another power switch inline on the monitor's power cord

Use an inline lamp switch / inline rocker switch:

They're quite easy to install, just carefully strip the wire & attach according to the specific switch, there shouldn't even be any soldering or shrink tubing required. They usually only switch the "hot" wire, and of course unplug the wire first! Better search for how to install an inline rocker switch to see some videos too.

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Oops, I just read the "I don't want to cover the monitor" line, after typing the next part... Well, give it a second thought, it's probably the easiest solution. Just put some cloth over the monitor & cover it up. It shouldn't be hot enough to start a fire or anything hazardous (if it is that's a separate problem), so buy a cover or use a shirt or a cardboard box, basically anything opaque.

If you're concerned about extra heat from covering it completely wearing away at the remaining life of your monitor, then don't cover it up completely. You really only need to block the screen side, so lean a piece of cardboard up against the screen, or optionally use paperclip "hooks" to hold/hang it, and let the other 5 sides breathe free:

A nearly-finished DIY screen cover, just bend to fit.

Answer 2

I recommend getting a power strip and installing it within reach of your foot or hand. Not sure where you live but I can buy one for about $2 - $3.

This way you can plug the monitor into this switch and power it on/off whenever you need.

IMPORTANT - for daisy-chaining

Make sure to get a simple power strip and NOT a surge protection device or else you will have the potential to create a fire hazard. As long as your house's circuit breaker maintains complete control of your circuit then it should be relatively safe to plug in nothing more than a monitor via daisy-chaining.

Answer 3

Try changing the input of your monitor to a source with no video eg: vga. Most modern monitors have multiple inputs and you can manually select the one you want. Then, it will tell you there is no source and then go to sleep.

Answer 4

Just turn off the monitor.

Seriously! Assuming your other power settings don't shut down the PC (set it to never go to sleep), your task should still be running in the background. My system's also set to turn the monitors off automatically after 10 minutes

You might also be able to use a third party tool to turn off the monitor in software - nircmd comes to mind - with a simple command like "nircmd monitor async_off" doing what you need.

Answer 5

Since the power switch is broken (how do you turn it on, anyway?) you can use a separate switch. Rather than splicing the power cable as someone else suggested, it would be easier to use one of these:

These are great for any device that does not have a built-in power switch (increasingly rare anymore) or the switch is broken.

You can also buy cables that have switches inline. You are better off purchasing a cable made for the purpose rather than splicing your own. The pre-made cable will have proper strain relief, water resistance, and all of the components and splices will be rated for the current expected from that type of cable.

Answer 6

Are you able to turn your monitor around? Turning it to face the wall shouldn't introduce any overheating issues.

Alternatively, have you looked into wearing an eye mask for sleeping? I use these when I'm camping since the tent rarely provides sufficient darkness during early morning in Summer to let me sleep.

Answer 7

Cover the monitor's power light with masking tape (or with more opaque tape if you want it fully blacked out). I use masking tape on some of the brighter lights on my tower case (e.g. the stupid blue LEDs for HD activity. What was wrong with red LEDs? Nice sleep-friendly color, and still easy to see).

Turn off the monitor's backlight with the DPMS "off" powersaving state. Activate it with
sleep 1 && xset dpms force off (Linux or any other OS using an X11 display server) or
wizmo monoff (Windows). The sleep is so you can release the enter key before the command runs, otherwise the key-release would wake up your the screen again. (IIRC, wizmo sleeps first).

Moving the mouse or pressing a key will bring your computer out of powersaving screensaver mode. You may want to turn your mouse upside down to make sure it doesn't detect movement if your desk is jiggled (or depending on your mouse, even if it isn't).

This might not work in your case, where your program involves simulated mouse movements. IDK if it's possible to disable mouse wakeup and only leave keyboard. wizmo shake=0 only works for it's built-in animated screensavers, not for triggering Windows' built-in monitor powersaving mode.

Presumably anything that covers the Windows desktop with a black window will stop your program from working, unless it passes through mouse clicks. But backlight-on is not the same as dark, and is a waste of power.

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Alternate Option 1: Run your program inside a VM, so the Windows that's directly connected to the actual monitor isn't seeing virtual mouse movements, only the OS inside the VM.

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Option 2: Put your monitor on a separate power bar with its own switch.

(Or buy a power bar with switches for every outlet, but make sure you label the switch well and don't plug the monitor in next to your computer or anything else it would be annoying to accidentally power-cycle.)

Answer 8

nircmd has a "put the monitor to sleep" option.

I put this in a shortcut in my PATH:

nircmd.exe cmdwait 100 monitor off

Answer 9

Just unplug the monitor at the wall! Or, if it's receiving power from the PC, unplug it at the PC.

The question has now been edited to add "without unplugging the monitor". As far as I can see, that's only because the plug is in an inconvenient location. In that case, just use an extension lead to move the plug to a more accessible location.

Alternatively as @brichins points out, some monitors allow you to unplug the power and/or data cable at the monitor end.

Answer 10

Couple other options I hadn't seen mentioned (As of the time of posting this):

• KVM Switch? Switch the Monitor to alternative/empty input.

• If your software doesn't "Sleep" because of a mouse macro (can't sleep if mouse is moving)... maybe you could virtualize the software? Move it into a VMWare PC? Program runs in a VM and your main OS can then go to sleep?

• Do you have multiple inputs? Use a keyboard shortcut to switch output location? (You might have to plug something into the other port long enough to say "Yes, this is a valid option")

• Anti-Glare/Privacy Filters - they block light from angles and are typically used in office environments where you don't want people to see your stuff. But they should lessen the light and alleviate the light "noise" thats keeping you up at night.

Answer 11

Try enabling presentation mode

Hopefully, pressing Win+P will let you throw your display to a non-existent projector and turn your main display off.

Answer 12

Here is a Windows PowerShell script that I researched several years ago - I got some help from folks on a forum - I don't remember which one.

Incidentally, the main reason I use it is to reset my graphics card. I use 4 screens and for some reason my primary screen occasionally reverts to low res and I can not get to the reboot button. I found that when the monitor wakes up it restores to the proper res.

Copy the text below into a file name like monitor_off.ps1. If you edit your file associations, you can execute it by double clicking the file. Or as pointed out by "Davidw" below, right click and select run with Powershell.

# Windows PowerShell - Turn display off by calling WindowsAPI.
# Jan Zumwalt - rev 2017.12.05
# Moving the mouse or pressing a keyboard key reactivates the screen.
# works with multi-screen systems too.


# SendMessage(HWND_BROADCAST,WM_SYSCOMMAND, SC_MONITORPOWER, POWER_OFF)
# HWND_BROADCAST  0xffff
# WM_SYSCOMMAND   0x0112
# SC_MONITORPOWER 0xf170
# POWER_OFF       0x0002

Add-Type -TypeDefinition '
using System;
using System.Runtime.InteropServices;

namespace Utilities {
   public static class Display
   {
      [DllImport("user32.dll", CharSet = CharSet.Auto)]
      private static extern IntPtr SendMessage(
         IntPtr hWnd,
         UInt32 Msg,
         IntPtr wParam,
         IntPtr lParam
      );

      public static void PowerOff ()
      {
         SendMessage(
            (IntPtr)0xffff, // HWND_BROADCAST
            0x0112,         // WM_SYSCOMMAND
            (IntPtr)0xf170, // SC_MONITORPOWER
            (IntPtr)0x0002  // POWER_OFF
         );
      }
   }
}
'

[Utilities.Display]::PowerOff()

Answer 13

There are a few good answers here. I black out all the LED lights on my system so it does not disturb sleep. I have all my monitors plugged into a power strip and when I turn that strip off all the monitors turn off. Any software I run will continue to run when the power strip and monitors are off.

Any modern OS or app should not be dependent on a physical monitor being on, and should work headless. If that isn't the case with this particular piece of software, then you will need another solution to whatever that software is doing.

Answer 14

I have a similar problem, as sometimes I have to leave the computer on to let the weekly backup complete, and I have the external hard drive plugged into one of the ports on the monitor, so if I turn the whole monitor off, it turns off the USB ports, so here's my solution for Windows 7:

In Control Panel, go to Power Options and click on "Chose when to turn off the Display" Set the "Turn off the Display" option to 1 minute and set "Put the Computer to Sleep" option to never.

You can save this setting as a Power plan by clicking on "Create a Power Plan" on the Power Options page.

At the next page, set the name for your power plan:

Set the above options for your power plan:

Set the power plan:

Answer 15

While there are many tools that can turn off your monitor or even windows is able to set it to sleep (which is definetely the recommended way here) there is one simple solution I would like to propose:

Just create a black powerpoint presentation and open it as a fullscreen presentation ;-)

Answer 16

Simply create/download a black image and open it full screen while your program runs on the background. Simple and no hardware changes needed.