PX4/Firmware — pull request #97 by sjwilks (2012-12-07 21:28:35+00:00)
Title: Add new safety switch LED blink sequence when both FMU and IO are armed

If both the FMU and the IO board are armed then the secure switch will
blink two times quickly then a pause followed by two quick blinks and
so on.

Here is a video of the new mode in operation: http://www.youtube.com/watch?v=v3TY77wbeYw