@christian: I am glad to hear that you got my firmware working! I just now realized you were using nano to refer to the NS1 and not an Arduino Nano. Sorry for the confusion. Remember that the firmware has extra features like an extra audio rate square wave oscillator as well as a lofi noise source; it is not just an LFO. 🙂
It sounds like you will be having a lot of fun with your two NS1 synths! If you happen to use Reaktor, check out my free set of modular blocks.