I found that lot of people discovered this new feature of the wr703n flashed under openwrt : It is able to stream an USB webcam (soon a Gopro using an easycap) and also to make a bridge between a serial interface (USB according to CDC driver or 3.3V TTL).
Here is the tutorial (3 parts + 1 part unbricking ;) ) on Openpilot Forum : http://forums.openpilot.org/blog/52-fertitos-blog/
So I started a TUTORIAL to help those that would like to add this feature on theyre drone and start developping new sensors :
I'ld like to work on a laser line avoidance system using the webcam :
If you have question... ;)