Reads input from Dymo S100 Digital USB Postal Scale
http://www.dymo.com/en-US/s100lb-digital-usb-shipping-scale
Raw data format:
=> [0] Unknown 3
=> [1] Stability (2 when at 0, 3 when getting stable, 4 when stable, 5 when negative, 6 when too much weight)
=> [2] Mode (lbs = 12, kg = 3)
=> [3] Scale factor
=> [4-5] 16 bit weight
$ irb -r ./lib/scale.rb
> scale = Scale.new