Hum…I am going to have to look at this more closely to see if I can do this with my radioshack scale. The problem is the scales do not have a built in display, and need to be plugged into a computer to work. Problem there is the software maybe only for a given OS (windows 98 for example) and once you upgrade, guess what, software stops working. I wonder if there is a cheaper route to do this since using all the arduino shields and such can be a bit pricy.
http://hackedgadgets.com/2013/09/13/hacked-stamps-com-scale-displays-weight/
original post