Take pipeline input and beep when the input changes. It will optionally stop when the change occurs.

BeepOnChange.ps1

 function BeepOnChange {
<#
.Synopsis
   Take pipeline input and beep when the input changes.
   It will optionally stop when the change occurs.
.PARAMETER Skip
   Number of lines to not consider for comparison. If you're piping
   a long running command like ping /t, you want it to skip the 
   header of the command. Combine ping with the StopOnChange switch
   for it to alert when a network connection comes back up and ping
   no longer reports "Request timed out."
.EXAMPLE
    & ping 192.168.1.1 | BeepOnChange -Skip 2 -StopOnChange
#>
    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline=$true,Position=0)]
        $InputObject,
        [int]$Skip=0,
        [switch]$StopOnChange
    )
    begin {
        $line = ""
        $iter = 0
        $changed = $false
    }
    process {
        $InputObject | foreach { 
            if ($iter -ge $Skip) {
                if ($line -notlike $_ -and $iter -ne 0) {
                    $changed = $true
                }
            }
            $line = $_
            $iter++
            $_
            
            if ($changed) { 
                [Console]::Beep()
                if ($StopOnChange) {
                    continue
                }
                $changed = $false
            }
        }
    }
}