Hi Chris,
Seems like I'm very late to the party. Just started with Arduinos a few weeks ago, and am building a vario sensor based on the OpenXSensor page.
Do you have any of the PCB boards left? Don't worry if not.
Was there anything in the magazine article that you've not covered here. I've tried to get hold of a back issue, but there doens't seem to be any available.
Many thanks.
David