9X receiver update possibilities

[Irish Steve]

OK, here we go.

There's massive activity on the transmitter side, but there seems to be a distinct silence on receivers. which is interesting.

Is this because there's no need for a better or larger or more capable receiver, or is it that we don't know enough about the protocol and what's going on in the receivers?

Reason I ask is that I was looking at the site of the receiver chip makers, and it seems that they also make a number of other chips that will both transmit and receive, and some of them are up to 4 times faster in terms of data throughput in comparison to the chip being used in the receiver at the moment.

I would be the first to admit that right now, I don't know enough about the protocols that are being used on the 9X, or if it's appropriate to look at alternatives to the present and working protocol.

What I am aware of is that I have users that are looking to implement things like landing lights, nav lights, rudder logo lights, and other things that need a digital channel, and that if nothing else, that could be done by using one of the analog channels as a multiplexed digital channel, but that seems to me to be a poor way to do it, but I don't know enough about the protocol and packet structure that's used to transmit the information at present.

So I guess the questions start with,

Is there an interest / need for a faster/better receiver?

Can the present protocol cope with additional channels or options, at both ends, and is it needed?

If there is interest in going down these roads, what other areas or options should be looked at?

I'm very much aware that this could open up a whole can of worms, in terms of possibly raising expectations that may be unrealistic in terms of timescales and capabilities, and that the alternatives out there may not be as capable as I think they are, but at the same time, there are areas that I think could benefit from upgrades, if the chips are capable of handling the requirement, and this includes things like failsafes, which are not ideally managed at the moment.

So, am I asking this too soon, or expecting too much, or am I maybe even just anticipating changes that are about to happen with the 9XR from Hobbyking, I get the distinct impression that Hobbyking are not just taking it in house, but are also maybe making some fundamental changes, which may incluse using the new chips, which could open up all sorts of possibilities.

It will be interesting to see where this thread goes, it could get interesting.

It's also possible that I'm straying into areas that are at present restricted by NDA limits, and I'm well aware of the implications of that, if I'm straying into shark infested custard or other minefields, let me know by PM, and I'll deal with it accordingly.

Let the fun begin

[Kilrah]

Frsky equipment is cheap, works very well, already has telemetry downlink... which is why it's a very popular upgrade for the 9x.
It does all you need except digital uplink at this point, but it supposedly should come soon enough. So not sure it's worth reinventing the wheel...


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[Irish Steve]

OK, fair comment, maybe then what's needed is a "what it can do" guide for the different firmwares and modules combo's, as it's getting VERY hard to try and keep up with what's going on with all the variations. In a thread on RC Gropups, I've just seen mention of using cascaded receivers with ER9x, which is a step in the right direction, ideally, an add on board for digital outputs would make it easier than having to use servo based switches, which are heavier and more complex.

In some respects, the 9X family is becoming a victim of it's own success, in that it can do so much, the threads about it are now too long and complex to keep up with.

Early days for this, let's see where it goes. I will be very interested to see what some of the developers might add to this

[cre8tiveleo]

... the 9X family is becoming a victim of it's own success, in that it can do so much...

Good, someone else thinks this too. People are becoming sheeple.

[Kilrah]

Now that I am back home, I can elaborate a little

I have mentioned a few times in other threads that one thing that the 9x was lacking at this point was a proper RF link, tailored to work with it (no more old-school PPM between the radio and module, but a low-latency, bidirectional data protocol), allowing more flexibility.

However after some thinking there are actually quite few scenarios that would benefit from it... And as I mentioned, frsky gear already has most of the characteristics we would want. While the ground is solid (fast over the air protocol, efficient downlink) they currently lack the uplink and digital protocol between radio and module, but the latter is on the way (see this thread), and there have been talks of them potentially supporting the former in the future as well. So with the improvements we should be getting, everything would be there. And while they are a little slow in implementing them, I doubt we'd finish before them if we had to start all over from a blank sheet. And that doesn't include all the work that would be implied by producing, selling and supporting custom TX/RX modules in the long run, which would start getting quite a bit beyond the hobby open source work...

[Irish Steve]

Now that I am back home, I can elaborate a little ..

That's very thought provoking indeed, I have to admit to having been very surprised that the links seem to still be effectively analog based, given the massive numbers of off the shelf chips that are now available and being used for things like Wireless Internet, mobile phones and the like, I would have expected to see that concept being used in model radio, in that there are so many options which are much easier and more reliable using digital. That said, the concept of having multiple digital switching channels is going to make waves, as none of the receivers we have at the moment have the connect capability for that at the moment. It's not going to be hard, especially if the switching is done at the zero volt level, as that will reduce the complexities of the card or module. Equally, things like digital switching only need to be sent to the receiver if they have changed, which could make the sending a lot easier, and it's rare that they need to be updated with the speed that servos need.

I've just posted a "help, what do I need" in another section, as I know I'm going to have to get involved more, but it's a case of knowing what's needed to be effective, and that's far from clear right now. Didn't realise your link was to the PXX thread, I read that last night, and got a severe dose of brain ache, that's a HEAVY thread

Longer term, with FPV, telemetry, and by that I'm also thinking about the possibilities of GPS location feedback, autopilot, stabilisation and other things, as well as all the lighting and related systems, there's huge potential. Not all of it is relevant to hobby interest, some of it is more RPV related, but the same concepts will apply to all of them.

Living dangerously, if RPV takes off like I think it will, we could also see a scenario where the regulators may well start looking for something like a sub set of mode C transponders, which will be a whole new and very different can of worms to deal with, but it may happen.

Not all of the ideas I have are model related, there are ideas in my head that might help disabled modellers, but that's for the future, the first thing to do is get comfortable with the present hardware and software. Then, who knows, there's some incredible talent out there in this open source movement.

Thanks for the thoughts.

Steve

[Kilrah]

RF links are now digital-based since we got into the 2.4GHz band. However the first 2.4GHz links for R/C only came out about 5 years ago! So we're still in (albeit coming close to the end of) the transition period where 2.4GHz TX modules were simply upgrades to existing radio designs, and thus had to take the good old standard PPM signal as an input. Radios were working in different bands depending on countries (35, 36, 40, 41, 50, 72MHz...), and thus were often module-based (either internal or externally replaceable, but still modular) so a single base unit could be combined with the module that was suitable for each zone. The first 2.4GHz offerings were simply modules you fitted on your radio, or that manufacturers fitted in existing designs in place of the MHz one.

Now most new radios are "native 2.4GHz", and have done away with the PPM signal between the radio and the TX module. However on the other side you usually still have standard servo signals between receiver and servo, and a separate, digital downlink "network" of sensors that differs with each manufacturer.
There's still some way to go until we find a single digital communication between the receiver, servos and other components. Futaba is the only one with their S-Bus to go in that direction at the moment.

[jhsa]

Not the only one.. frsky is doing it as well..

[Kilrah]

?

[jhsa]

http://www.frsky-rc.com/ShowProducts.asp?id=136

João

[Kilrah]

Yep, it's a "Futaba compatible" receiver, meant to be used with a Futaba radio, and that puts out the Futaba protocol. They don't do it for their own gear.

[jhsa]

well, we'll have to keep our fingers crossed that they'll do it.. maybe if we ask nicely..