Really, really simple:
DPDT switch routing the control signal (blu) from either the Spektrum or HK receiver going to the DJI controller. The returns (blk) are all tied together and the second side of the switch applies power (red) to the HK rx when in P2.
So, if I'm flying solo (P1) I have control of the tilt function only (8ch Spektrum rx and all channels used up) while DJI also influences gyro stabilization of the gimbal.
When cameraman is operating the camera (P2), tilt control is shifted to his TX (HK) and DJI still influences gyro stabilization of the gimbal. The HK rx then also controls the REC and ZOOM functions of the RC Shutter.
Have not actually got the HK 4-ch tx in my hands yet, but I figure I will be converting the "rudder" channel to a simple toggle sw (three fixed resistors should do the trick) to control the camera REC function (ON or OFF).
"throttle" channel will control gimbal TILT and "elevator" channel will operate the ZOOM ........should make for an intuitive setup
