Using Naza X2 port to control servo ?

[qtluong]

I am trying to control a servo (for camera trigger) using the left (IOC) switch on the stock phantom 2 remote. I would like the servo to be activated whenever the switch is moved from the top position to the bottom position. I know this is possible, because it is demonstrated in this video at the 00:24 mark https://www.youtube.com/watch?v=vXTujIVNRQU

I have connected a Y-splitter to the X2 port, however I found that the signal which is sent by the switch is not a standard servo signal. Does anybody know how to convert it into a servo signal to make it work ?

BTW, I am aware that the F2 port will activate a servo controlled by the bottom lever, but I am already using it to control the pitch.

 

[ElGuano]

It's a digital D-BUS/S-BUS signal. The problem is that every single control from the TX is being encoded and sent serially through X2, not just the IOC switch. So if you wanted to tap into the stock RX, you'd have to capture and unpack the payload for the entire control system. Which I'm sure can and already has been done multiple times, but it's not like a traditional RX setup where you have separate leads to each of A/E/T/R/U/X1/X2 etc. and you can just monitor pins individually.

 

[OI Photography]

DroneExpert is known for using creative (but useful) non-standard arrangements. I'm guessing they pulled that off with a S-Bus-to-PWM converter but I have no idea which they used or how they set it up.

 

[qtluong]

Thanks for the insight. The Naza manual stated "S-bus compatible", but I wasn't sure. It also explains that DroneExpert are able to control channel seven for tilt from X2 as well.

Do you think it might be possible to extract the relevant signal by tinkering with a S-Bus decoder & channel changer ?

Or would it be simpler to use a different RX and TX ?

 

[ElGuano]

I may be thinking about this wrong but the easiest way may be to just replace the stock rx with a 3rd party FASST-compatible rx with individual channel pins that will bind to the stock tx, and you can hook up your shutter servo directly to the rx, bypassing the Naza completely?

 

[OI Photography]

Yeah I think ElGuano is right about it being easier using an aftermarket receiver that will bind with the Phantom's stock controller...I'd forgotten that some Futaba models should work that way.

That would be the easiest way once you know which receivers you can use, or you could just swap out the controller too.

I wouldn't mess with converting the S-Bus signal unless those other options won't work for you for some reason.

 

[qtluong]

Thanks again for the ideas. Indeed those S-Bus decoders are quite heavy. Is there any particular RX that you'd recommend for this use ?