Suck

while true do
  turtle.suck()
  if turtle.getItemCount(1) > 0 then

    if not turtle.dropDown() then
      term.clear()
      term.setCursorPos(1,1)
      term.write("waiting for space...")
      sleep(10)
    end
  else
    term.clear()
    term.setCursorPos(1,1)
    term.write("Waiting for item...")
    sleep(10)
  end
end