So I'm building a manned aircraft/multicopter, using an Arduino-enabled set of joysticks for input. They're working fine and I can see them on QGC.

My only issue is that my ESCs aren't recognizing that they're plugged into a FC. I've calibrated all sensors, added an external compass, etc. Everything seems fine with the VOXL. I'm getting a flaking alternating blue and green light though. If I arm the VOXL through the joysticks, it works, and I get a steady green for a few seconds, flying which time the ESCs still don't see the FC. But then it goes back to flashing blue and green.

Not sure where to look. Guessing it's something simple but I'm out of ideas?

Anyone have a thought or similar experience? Thanks