We've greatly benefitted from the Open-Source community, especially with APM/Pixhawk and Mission Planner. Part of keeping this community together and advancing is to share our experiences and solutions. To be honest, I haven't had much time to do this but I'm doing my best to help. Today, I'd like to share with you our solution to triggering a camera via a wired remote shutter release cable WITHOUT needing third party hardware. I hope this little guide is useful to some of you!
A special thanks to all the developers involved with Ardupilot and Mission Planner.
Micro Aerial Projects L.L.C.