When using a S900 with Lightbridge and Wookong M the landing gear cannot be configured to be automatically lowered during a failsafe event. I have used mixing on my transmitter to partially get around this so that the landing gear is lowered when Failsafe (return to home) is triggered intentionally. However, this does not deploy the landing gear when the failsafe is automatically engaged during a control link loss.
I am hoping that I can achieve this by intercepting the D-bus (S.bus) link between the Lightbridge and the WKM. However, I cannot work out how the Lightbridge notifies the WKM of a failsafe situation in the case of a control link error. Using an S.bus decoder, I can see that during a control link failure, the Lightbridge uses a "hold" failsafe, with the output on channels 1-7 (equivilent to A,E,T,R,U,X2 and X3) all remaining the same. Despite this, the Wookong assistant software shows the Flight Control mode move to "Failsafe". I do not think that the Canbus is used for this, because the Wookong assistant still goes to failsafe during a control link event even when the Canbus is not connected to the lightbridge (via the GCU).

So, how does the lightbridge send the failsafe command to the Wookong in the case of a control link failure?

DJI, hopefully you will not mind releasing this information because it is not to develop a third party alternative to a DJI system, but rather to fill an important capability gap in a currently supported hardware configuration.

Many thanks,

Guy

It seems that S.bus can send failsafe information in two ways. There is a "frame lost" byte and a "failsafe activated" byte in the data stream (http://developer.mbed.org/users/ ... controlled-by-mbed/).

I wondering the Lightbridge sends one or both of these, and the Wookong M recognises one or both of these?