move-if-idle.ps1

<#
.DESCRIPTION
Moves the mouse cursor 1 pixel to the right and then back if the user hasn't
touched the computer in a bit

.PARAM CheckInterval
Interval between checks for idle-ness, in seconds. Default: 9.75 minutes

.PARAM MaxIdleTime
Maximum time since last input to trigger a mouse move, in seconds. Default: 9
minutes.
#>
[CmdletBinding()]
Param(
	[Float]$CheckInterval=585,
	[Float]$MaxIdleTime=540
)

# garbage from SO https://stackoverflow.com/a/15846912/5719760
Add-Type @'
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace PInvoke.Win32 {

    public static class UserInput {

        [DllImport("user32.dll", SetLastError=false)]
        private static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);

        [StructLayout(LayoutKind.Sequential)]
        private struct LASTINPUTINFO {
            public uint cbSize;
            public int dwTime;
        }

        public static DateTime LastInput {
            get {
                DateTime bootTime = DateTime.UtcNow.AddMilliseconds(-Environment.TickCount);
                DateTime lastInput = bootTime.AddMilliseconds(LastInputTicks);
                return lastInput;
            }
        }

        public static TimeSpan IdleTime {
            get {
                return DateTime.UtcNow.Subtract(LastInput);
            }
        }

        public static int LastInputTicks {
            get {
                LASTINPUTINFO lii = new LASTINPUTINFO();
                lii.cbSize = (uint)Marshal.SizeOf(typeof(LASTINPUTINFO));
                GetLastInputInfo(ref lii);
                return lii.dwTime;
            }
        }
    }
}
'@

Add-Type -AssemblyName System.Windows.Forms

# general idea from https://gist.github.com/MatthewSteeples/ce7114b4d3488fc49b6a
# you could also use something like:
# [System.Windows.Forms.SendKeys]::SendWait("{NUMLOCK}{NUMLOCK}")
# to "type" numlock twice
function MoveCursor {
	[CmdletBinding()]
	Param(
		[int]$dx=0,
		[int]$dy=0
	)

	Process {
		$pos = [System.Windows.Forms.Cursor]::Position
		[System.Windows.Forms.Cursor]::Position =
			[System.Drawing.Point]::new(
				$pos.X + $dx,
				$pos.Y + $dy
			)
	}
}

Write-Verbose "Assemblies loaded, checking idleness"

while($True) {
	$time = [PInvoke.Win32.UserInput]::IdleTime
	Write-Verbose "$($time.Seconds) seconds since last user input"
	If($time.Seconds -gt $MaxIdleTime) {
		# no movement in <X> amount of time
		# NOTE: i'm not sure if this mouse movement is too fast to
		# actually register as input; might have to put a `sleep 1` in
		# the middle
		Write-Verbose "Moving mouse to prevent sleep"
		MoveCursor 1
		MoveCursor -1
	}
	sleep $CheckInterval
}