I work on Rover and Copter projects who work with Pixhawk and Dropix.
I search a simple solution for add different sensors for execute commands.
Use a rain sensor for activate Hold command on my Rover and eventually Land for Copter.
Use a crepuscular sensor for start Auto mission.
Use a voltage sensor for a return to launch with Rover
The idea is to have inputs available on Pixhawk and when a voltage input it work like a Boolean and execute an action.
I don’t know if my explanation is understable.
If there is a developer that can help me. I work on several projects with Pixhawk. I can give a little remuneration.