Bonjour,
I was not familiar with Arduino's either, but it is pretty simple to get LED's working with it using DCS BIOS in my L-39C pit build.
Helios supports the Phidgett's and I think another called an EOS setup for outputs, at least for the Ka-50 and A-10.
Ikarus can work with Arcaze cards. I would have used these if I could get them in the US.