Graynomad:
reprograming the stock chip
I'd buy a $20 programmer like this
http://www.pololu.com/catalog/product/1300
from Pololu or someone (there are a few around) and make up a 6-way to 5-way cable.
Rob
I might end up doing that but there's no reason why I can't use an Arduino for this project unless the manufacturer has burned the fuses to disable reprogramming.