Head tracking signal input from USB port

Hi all, Have been using a Walkera 10 with Deviation for over a year now. It works so well and is absolutely great!
For my long range FPV project I am using the DCS trainer port on the transmitter to out put PPM control signal for my external long range radio transmitter (openpilot OPLM), so that port is already used.
Lots of people have this setup.
Now, most Goggles do have Head tracking functionality sending PPM - so how to get that signal in to the Deviation? The USB port is the only I/O left on the transmitter.

Any plans to support PPM Goggle Head tracking input using the USB port?
Any other solution to this situation?

Thanks a lot Deviation team
karla

Not that I know of. Doing ppm over USB seems a bit silly. Especially with the world moving from ppm to serial line protocols. But I don't do fpv, much less long range. So do other txs do ppm over USB?

Can you go the other way? Use usbhid to get the control signal to your transmitter, and the use the DSC port for head tracking input?

Haha, yes maybe its silly However the result would not be silly at all, it would be awesome!.
No, other txs have either some slot where you can change the radio frequency (by connecting external radio unit) or a dedicated port for Tracker input. A popular long radio radio, Dragonlink, describes how they can hook up and take the signal from most common txs on the market. PPM from trainer port works on all txs.
Since Walkera txs do not have this option on any model I am aware of, I will have to move away from walkera and Deviation. But I am sooo pleased with how it works so I will try to find a work around.
I was not aware of any movement away from PPM.
I think doing it the other way, USB out to external radio (OPLM), would work as fine. The OPML just expects to get PPM in. I can solder a special cable with usb in one end and a connector on the other.

So any idea How to send the output signal to the USB port rather than to the DCS trainer port on the Walkera? Seems must be done by developer with great insight and skill, I would have no idea.

Come to think of it, that USB-out solution could also supply power to the external radio of 4.5v. That a hazel today for everyone to fix with step-down gadgets from 12 to 4.5v.

Has been asked before second ppm....

Best I can offer www.rcgroups.com/forums/showthread.php?t=1677559
Open source!

This is a great idea! And the DIY tracker seems like a fun project.

It seems to me the problem is that you want two separate PPM streams, one in from the tracker and one out to the long range radio. If that's the case, I don't see a direct solution in the current software. But the alternative output could be a to a receiver, right? Have you considered rigging your external radio using a ppm receiver? Configure a DSMX Orange x20 receiver and connect PPM to the long range radio. The use the Devo to talk to the Orange. Your head tracker then fits in the DSC port.

I love the PPM receiver on my quad, it's just one connector from the RX to the FC. And I have a little Arduino-based box with my extra switches and pots that goes into the DSC port on my TX. This all works nicely.

I wonder if there might be some additional latency in the approach? Anyway, just my .02 cents.

Deal57's solution of using an OrangeRx Rx with PPM output is probably the easiest. Certainly the only one that won't require hardware and software mods to your Tx. LemonRx also has some options there. If your OPLM can accept S.BUS (the most popular of the serial options), then there are OrangeRx Rx's that do that as well. If you have a CC2500 installed, the FrSky D4R-ii is a great choice, but probably not worth installing the module to use.

You can get power from the USB port even if you don't get signal with it. I recall seeing a hack for a USB simulator PPM cable that wired it into an OrangeRx receiver so they didn't have to drag a cable across the room, complete with powering the Rx from the USB port.

The problem with PPM is that once you get past 6 channels, having a frame long enough to guarantee you won't lose sync means having a frame long enough to cause latency noticeable to some people. The serial line solutions don't have that problem, and work reliably with 16 or more channels with a latency that's 20% of the latency of even a six channel PPM frame.

Hey mwm, Deal57 and SadSack, thanks a lot for great leads!
I will try all of them. Will feed back in a week or two.
karla

Seems the Walkera USB port is not designed to output 4.5v rather it can be powered up. So I can't power an external trx with it.