New experimental feature
Here is possible to add devices that aren't detected, like devices under an Areca controller, that needs a specific command to access to S.M.A.R.T. data.
To add a new device click on "Add" button and put a little description (example: /dev/areca2) of device and the command to access to this device (example: -d areca,2 /dev/arcmsr0).
Note that you need to restart HDD Guardian to make this setting work.