Send email notification when free disk space is low

Powershell script that detects local disk drives with less free space than specified value and sends email notifications (I can't recall where I got the following script. It was probably written by a SQL Server admin).

# Get SMTP server info
$smtp=new-object Net.Mail.SmtpClient("myEmailServer.myDomain.com")

# Set thresholds in GB for C: drive and other drives
$driveCthreshold=10
$threshold=10

# Replace settings below with your e-mails
$emailFrom="serverToMinitor@myDomain.com"
$emailTo="myName@myDomain.com"

# -----------------------------------------------------------------------------

# Get server name
$hostname=Get-WMIObject Win32_ComputerSystem | Select-Object -ExpandProperty name

# Get all drives with free space less than a threshold, while excluding System Volumes
$Results = Get-WmiObject -Class Win32_Volume -Filter "SystemVolume='False' AND DriveType=3" | Where-Object {($_.FreeSpace/1GB –lt  $driveCthreshold –and $_.DriveLetter -eq "C:") –or ($_.FreeSpace/1GB –lt  $threshold –and $_.DriveLetter -ne "C:" )}

If ( ($Results | measure).Count -gt 0 ) 
{
    ForEach ($Result In $Results)
    {
        $drive = $Result.DriveLetter
        $space = $Result.FreeSpace
        $thresh = if($drive -eq 'C:'){$driveCthreshold} else {$threshold}

        # Send e-mail if the free space is less than threshold parameter 
        $smtp.Send(
           $emailFrom, 
           $emailTo, 
           # E-mail subject
           "Disk $drive on $hostname has less than $thresh GB of free space left ",
           # E-mail body 
           ("{0:N0}" -f [math]::truncate($space/1MB))+" MB"
        )
    }
}