Hello Ian,
Now the teething problems with libraries are behind me I am pleasantly surprised how quickly you can get hardware up and running with DCS_BIOS. I now have working gear lights, master caution, nose-wheel steering, missile warning light and others! I am running these from a single Arduino UNO clone but am running out of pins. Accordingly, I have connected a second working UNO clone (one from China - working after a search to find the appropriate driver). Question - I am guessing that you need a separate "connect serial port" window open and running for each Arduino board as you play DCS? My first Arduino runs on my system on Com3. The pop up window, which appears when the "connect serial port" is run, is slaved to this port. The problem is that my second Arduino is on Com4 on my PC, and I do not know how to tell the computer to "connect serial port" to this second port, Com4 rather than Com3.
Impressed with DCS BIOS and beginning to discover first hand its very real potential as I begin to get to grips with it.