use Win32::OLE;

$phidget = Win32::OLE->new("Phidget21COM.PhidgetTextLCD");
$phidget->Invoke("Open", -1);

(check/wait loop here for "IsAttached")

$serial = $phidget->{SerialNumber};

$phidget->{"Backlight"} = 1;
$phidget->{"CursorBlink"} = 0;