For portability, the unit is desired to be small, battery operated, ease of operation, and hang-able by it own cables without long term damage, and low cost. To help meet the goals the unit includes a display to indicate the relative stepper position since the unit was turned on. The will be powered from either NiMH or Li-ion batteries. Whichever I have that fits in my on-hand inventory. To keep size and cost low, the enclosure will be from a re-purposed wall charger.