[Automator] Using an ls command and then getting the finder items?

Question

So i want to make an automator app that looks for all external hard drives and then ejects them. Unfortunatly to my experimentation you cant use the finder actions to search in the root directory so i simply added a shell script with
ls /Volumes
which works.
then i have a Filter finder items so it doesnt try to eject the Macintosh HD
then i have eject Disk.
The problem lies in that the shell script does not spit out finder items to the filter so the filter throws a warning because it isnt supplied the required data.
My question is, how do i get the shell script to pass down finder items to the filter so everything else runs through smoothly?
EDIT: i have python installed if that helps for simplicity i also know a small bit of C
Thanks
Tom Copcutt

Answer 1

Where did he say that? He only stated that he wanted to avoid ejecting the HD, which isn't possible in any case.
If avoiding .dmg is the issue, one way would be to hard code the possible disk names by using a list like this:
Replace the example volume names with your own volume names inside the curly brackets below;
Names must be quoted and comma separated as shown.
Spaces in names ARE allowed. You can name as many or as few volumes as you wish.
set gDiskList to {"External1 500GB", "Time Machine HD", "External2 HD", "External3 45GB"}
repeat with i in gDiskList
          set i to quoted form of i
      try
                    do shell script "diskutil umount " & i
          end try
end repeat