MAVLink and Arduino: step by step

[ppoirier]

I think you may be interested to that:

Basic Obstacle Stop System-Build Log and firmware

Hi everybody, I will post here the process for building and setting up a simple and inexpensive obstacle stop system. The base concept is to put a "sensing " box between the RC receiver and the flight control board of the flying machine, so no mods on the arducopter firmware are required. The sensing box will act as an override on the pilot controls whenever an obstacle comes within the rangefinders predetermined “distance_threshold” (see the meaning of this parameter in the attached GitHub …

In the example above it is sending control directly to RCIn but you could add RC override through Mavlink.