Is there anyway to connect a HIGH/LOW wire between two Pixhawks such that one can read whether the other is sending a high or low? And if so, which ports would it use? Also, would it be possible to read this voltage in a python script? I have seen that the Main Aux Out ports where a servo would typically be connected can be configured via Mission Planner to be a GPIO but I can't really find anyone using it as an input; I've only seen it used as an output for an LED or something similar.
The context to this question is, I am trying to fly two Quadcopters linked together in a master/slave configuration (master releases slave) and need the slave to know when it is disconnected from the master so that the python script can move on accordingly. Currently, both vehicles are using Pixhawk flight controllers. I have purposed that I attach a signal wire between the vehicles that pulls apart when the physical linkage mechanism unlatches.
Note: I realize that when the signal wire is disconnected, the signal will not go low, but will be floating around. I have taken this into consideration and plan on designing some sort of circuit that grounds it out if the signal wire is disconnected.
Thanks in advance for any help anyone can provide!