Megado Loom Dobby SystemsChoose the dobby style you prefer for your Megado: a mechanical dobby (comes with 20 program bars) or our Computer Dobby 2. 0. The mechanical dobby comes with 20 program bars. Set up your treadling sequence with pins in the bar's holes, numbered to match the shafts. The pins control shaft movement as you weave your design. The Computer Dobby has universal voltage compatibility and attaches directly to the loom castle. Set up your WIF on another