I am currently building a S-BUS to PPM encoder. I got the basic code working and tested on APM2 and KK2 board. (not in flight but looks good on radio calibration page)
I am wondering it it better to keep the signal chain in digital form rather than going from S-BUS(digital) to PPM (analog) then on the APM, PPM (analog) back to digital (APM) then PWM (analog) out to esc /servos.
I think it might be possible to code a S-BUS to i2c convertor and make Arducopter read the value off the i2c bus.
Hope to get some comments here before I send the board out, I did make provision for i2c on the PCB but will take it out to save space if it is not feasible.
Also is anyone is already working on 1?