Set-KeyboardDelay.ps1

param(
    [int]$Delay = 0
)
$Win32 = Add-Type -Name WinAPICall -Namespace SystemParametersInfo -PassThru -MemberDefinition @'
[DllImport("user32.dll", EntryPoint = "SystemParametersInfo")]
public static extern bool SystemParametersInfo(uint uiAction, uint uiParam, uint pvParam, uint fWinIni);
'@
if($Win32::SystemParametersInfo(0x17,$delay,$null,0)) {
    Write-Host "Keyboard delay changed to: $delay"
} else {
    Write-Host "There was an error while changing the keyboard delay."
}