Have some 3DR Pixhawks and wondering if HexAero Here+ RTK can be used with this controller? Or is it smartest to use the HexAero Pixhawk 2.1 all the way?
The Here+ RTK will just need different connectors to get to the pixhawk 1. The safety button will have to be wired to another connector as well. Other than that, there is virtually no difference between the pixhawk and the pixhawk 2.1 regarding GPS compatibility.
You can use this http://ardupilot.org/copter/docs/common-here-plus-gps.html?highlight=here
wiring diagram to hook it up