SendPushoverDiskNotification.ps1

# Alert whenever the free space on disk falls below the following factor
# .20 = 20 %
# .10 = 10 %
$alarmThreshold  = ".20"

$pushoverUrl     = "https://api.pushover.net/1/messages.json"
$pushoverToken   = ""
$pushoverUserKey = ""

foreach ($disk in (Get-WmiObject -Class Win32_LogicalDisk | Where {$_.DriveType -eq 3})) {
    # Calculate the percent free
    $percentFree = $disk.FreeSpace/$disk.Size

    if ($percentFree -lt $alarmThreshold) {
        # The disk has less free space than the threshold, trigger the alarm
        [int]$freeSpaceGb = $disk.FreeSpace/1GB
        $params = @{
            "token" = $pushoverToken
            "user" = $pushoverUserKey
            "title" = "$($env:COMPUTERNAME) $($disk.DeviceID) low free space!"
            "message" = "$($env:COMPUTERNAME) <b>$($disk.DeviceID)</b> has only $freeSpaceGb GB free space. This is below the configured threshold."
            }
        Invoke-WebRequest -Uri $pushoverUrl -Method POST -Body $params
    }
}