Seems to be working fine for me. I took an unknown motor that I bought from a surplus store and first got it hooked up on the Arduino. I guessed based on the color of the wires in the connector that they put the coils on opposite sides of the center tap wires in the middle. I counted the number of poles by hand just feeling the cogging of the magnets (I was off by a factor of 2 here but was easily adjusted). Wired it up and it worked great.
Then I transferred the wiring to the Spark Core Shield Shield so I didn’t have to worry about a wiring mishap. I just needed to figure out which outputs of the Core were routed to the standard Arduino pinouts. For this I looked at the schematic for the Shield Shield. I really wish this info was on the back of the Shield Shield itself @mohit
See it in action!
https://vine.co/u/1038681799087321088
Source code:
https://github.com/technobly/Spark-Stepper