Here are a few diagrams to illustrate what I've done (I like diagrams!). The following is a block diagram of the "standard" tricopter:
And here is the same thing with the new "transmission" block:
Concretely, I've basically replaced these simple and effective pieces of equipment:
And this (on the receiving end):
Funnily enough, it's possible to connect an RC-transmitter to the laptop via USB. It will be perceived as a gaming device... Yes I realize how silly it all is :) !
Strapping all this on the tricopter was a bit lousy (the USB cable takes so much space and weight!)
But here's a successful 5-second test flight :)
The overall control felt a bit sluggish... It might be the extra weight or more likely the whole system introduces latency. Anyway I need to make some more tests!