foo.ps1

# https://docs.microsoft.com/en-us/dotnet/api/system.windows.forms.sendkeys

[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing") 
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")

while (1) {
  $duration = Get-Random -Minimum 10 -Maximum 60
  Write-Output "Waiting $duration seconds ...";
  Start-Sleep -Seconds $duration

  $inputs = ('w', 'a', 's', 'd', ' ');
  $input = $inputs[(Get-Random -Maximum $inputs.Length) - 1]
  Write-Output "Sending $input ...";

  [System.Windows.Forms.SendKeys]::SendWait($input);
}