What can you tell me about telemetry and video?

I have read about this, and about this software's ability to let you use one tx to fly almost anything. I am only interested in flying my Walkera and Blade copters (both quads and hexacopters), as well as drones I build de novo.

Alas, none of my DEVO tx will run this software (DEVO 4, DEVO 7, DEVO F7), so I might be persuaded to get yet another, perhaps a DEVO 10. One concern is that, while I do not fly FPV, I like being able to glance down as see what my quad sees, and the option of recording video and storing it using my tx. Do ANY of the DEVO tx that support video feeds (DEVO F4, DEVO F12, &c.) run this software, or is it a choice between being able to fly almost anything and getting a video feed?

Finally, for the copters I build myself (quads, hexacopters and octocopters), I have a handle on motors, ESCs, FCs, but I need to know what options exist for telemetry. I have read that Deviation supports telemetry but I have yet to find the details. What hardware do I need to add to my copters, how is that hardware connected to the FC, and what rx will send all available telemetry to the tx, and what would I need on the tx to both give me an alarm of the signal is getting weak or if I am approaching LVC, and to save the data, e.g. to a microSD for later assessment? Can the recommended rx products just plug into any APM, Naze32 or MultiWii product? And then, of course, I need to know how to ensure that the deviation software handles all the telemetry properly (or if, in fact, it is so well written it already knows what telemetry data is sent by the copter and just does the right thing).

If all this is discussed thoroughly in one place, I'd appreciate seeing the URL (well, to the page, not just the site the page lives on).

Thanks

Ted

None of the Fx models currently run Deviation. Going to a separate monitor will probably provide for a better experience anyways.

Telemetry is currently available with Devo and Spektrum DSM protocols. To use either, you need the appropriate telemetry module on your model. The telemetry data is provided by the telemetry module, not your flight controller.

Devo telemetry module: bit.ly/1x405Ft
Spektrum telemetry module: bit.ly/1yBgM6M (Usually available locally)


FrSky telemetry is currently under development. The Naze32 supports limited Frsky telemetry.

The Devo12s supports limited telemetry data logging, though not to micro SD.

Thanks for this.

If you had to choose, which of the two telemetry modules would you pick, and why? They are about the same price (to within a few %), so how do they compare in terms of features and quality?

But, I notice that the Walkera module page says "This telemetry module is required for Devo compatible receivers which are not equipped with telemetry." That begs the question as to what receivers are available that DO provide comparable telemetry? On hobbyking, I have seen quite a variety of rx modules named after citrus fruit; but the number of options is bewildering and their descriptions often leave me no better informed than if I had never seen the product. Do any of them to a good job at providing useful telemetry, and would they work with a DEVO 10 or DEVO 12S?

It was my impression that the receiver had to plug into the FC, and so I assumed that any telemetry module would have to plug into the FC also and let the FC pass on that data to the receiver. Is that not correct? Is it, then, not possible for a FC to detect pending LVC and attempt to land before voltage drops too low to fly (or to compute when it must RTH in order to avoid falling from the sky before it can get home)? (My purpose in building these copters de novo is so that I can experiment with the open source software used by the FC.)

What options exist to get the telemetry data from either the rx or tx onto my computer? I want to be able to get all that data into my stats software, along with other data I'd collect from my copters, in order to properly analyze it. While I am an old hand at developing software and analyzing data, I am just beginning to learn about the hardware I need to work with.

What programming language is Deviation written in, and would it be possible for me to add code that would facilitate transferring telemetry data from a tx to a computer (or is that already possible, through, say, a USB cable)? I do know about half a dozen of the algol related languages, including C++, Perl and Java, and have been programming for dcades, but I have no experience with other languages, like Ruby or Lua (indeed, these are languages for which the only knowledge I have is that they exist).

I currently use the DSMx telemetry module, purely because nearly all of my receivers are DSMx. Features are pretty much the same. You plug the sensors into the telemetry module, and it sends the data back to your TX.


There are 2 flavours of telemetry at play here, and I think I may have misunderstood what you were after. I believe what you're after is something like the MAVLink telemetry the APM provides. You use a seperate telemetry radio to get the data from the flight controller to the ground control software. This type telemetry radio is usually listed online as the '3DR Radio'. From there you can do everything you're after with regards to logging and data analysis. There is also support for logging to onboard flash with the ArduCopter platform. There is an android app available as well.

The flight controller is able to detect LVC and attempt to land, but it does not need to send telemetry to do so. This all happens onboard. The same applies to RTH.


Deviation code is available via bitbucket here: bitbucket.org/PhracturedBlue/deviation

Actually Mike, I don't think you did misunderstand what I am looking for. You see, I am so new to dealing with this kind of hardware, I didn't know there were two kinds of telemetry. As I am completely ignorant of the hardware available to support telemetry, it is hard to know even what the right question to ask is. All I know at the moment is that telemetry data can be had, and that Deviation software includes telemetry support as one of it's features.

I guess what I really need is a source for a good introduction to what is possible and available. What sensors are available, and where; whether it is better to have a telemetry module of the sort you had recommended, or a separate telemetry radio; "optimal" options for a given budget, &c.

I will do a search for 3DR radio, to see if that turns up some decent information on what can be done at what cost.

It would be good to see a brief account of what the support for telemetry in Deviation provides. If I have to go for a separate radio in my copters, would that also be talking to a tx running Deviation, or would I somehow have to bind two tx to each copter? Or would I need to somehow make a ground station, operated by, e.g. a hobby buddy, to handle the telemetry data (and video stream in the case I have a camera installed) while I focus on flying the copter.

There is definitely a steeo learning curve, with tons of option to look into. I'd recommend picking a platform, and starting there.

The Ardupilot project is a great place to look. A lot of the concepts apply to other platforms as well. Here's a bit of an overview:

copter.ardupilot.com/wiki/mission-planning-and-analysis/
copter.ardupilot.com/wiki/common-using-t...ry-with-apm-and-px4/

The 3DR radio connects your APM to a ground station; A laptop or tablet running the Mission Planner software. They're quite cheap, on the order of $40 for the pair.


Horizon has a video tutorial series on using the DSMX telemetry module with their transmitters:

The Devo10, 7e, 6s, 8s and 12s all do telemetry, and should work with any DSM or Walkera telemetry radio. The DSM telemetry modules will work with pretty much any DSM-capable Rx, even if it doesn't have a "data" port. That just sends radio information to the Telemetry module to send back to the transmitter (I've done this). However, as of 4.0.1, the DSM telemetry code in Deviation doesn't seem to work very well (maybe mikemacwillie can provide more information): I couldn't get altimeter or GPS data back from it. There are some DSM telemetry fixes available for the nightly builds, but I haven't tried them with those sensors.

I personally have used the DSM ones, because the third party radio gear - OrangeRx from HobbyKing and LemonRx - is smaller, lighter and less expensive. However, I'm moving to FrSky because the receivers have telemetry built in, which is even better. Spektrum is behind the curve on this one.

For getting the data into your computer, the only option I know of for Tx-based telemetry is logging it to the internal flash in the Tx, and then loading it back later.

Another option to look at (I know that's not what you wanted to hear) is the Eagle Tree line of sensors. They can log to an onboard memory, so you don't need radios on both ends. They have widgets for adding custom sensors, and you can get a radio system to transmit data to the ground. I suspect they have a computer interface of some kind for the ground station, but haven't really looked for one. It's really good kit, but costs like it as well.

Thanks.

If I got a DEVO 10, does it take a microSD or have a USB port, to allow these log files to be transferred from the tx to the computer, after the flight?

Can you tell me more about these FrSky rx products, and what telemetry is built in?

I suppose I have to get various sensors also. Can you tell me about which ones will provide data on capacity remaining in the battery, what current the motors are drawing, motor temperatures, and what the copter is actually doing? I suppose all these sensors just plug into the Frksy rx or telemetry module.

Ummm, why would I not want to hear about the Eagle tree sensors? i did not even know they existed.

Thanks

Ted

All of the Tx's that deviation supports have a USB port. That's how you install software upgrades, like deviation. You can also boot them in USB disk mode to read/write files on the flash.

FrSky built-in telemetry is similar to the DSM telemetry: the telemetry radio gives you radio strength information, and voltage it's getting (i.e. the 5 volt servo voltage). You then need to add sensors for various things, mostly of interest to rc model pilots: flight battery voltage, altimeters, RPM sensors, and GPS data.

The FrSky Rx's have an A/D converter - or two - that can be used to measure an arbitrary analog voltage. But they are 0-3.3 volts, so may need a "sensor" consisting of a voltage divider. I bought the "flight battery sensor" for this, and it's basically a voltage divider array with multiple inputs for different battery sizes. It also has an input for a single sensor, though not all sensors work with it. If you want more than that, or some of the other sensors, you'll need a sensor hub.

The DSM Rx's don't have a telemetry radio. Instead, you have to buy one externally, and plug that in. It gets radio signal data from the Rx, and has plugs for multiple sensors. The plugs do have supported sensor types, and are undocumented - so there's no generic A/D sensor, though you could use the flight battery voltage sensor for that.

My primary usage is flight battery voltage, so the FrSky stuff is a major win. Next for me is an altimeter (aka a variometer), and there's one that will work without the hub, so again - major win for me.

There's a great wiki page on the FrSky telemetry hardware .

That also covers the Rx's, which can be an important issue. Multirotor control boards often accept CPPM or SBus, which means you can get all the channels on one cable, which makes the wiring simpler. And in some cases, you get more channels. The D4R-II is a 4-channel FrSky Rx, but you get 8 channels via CPPM. I've not been able to find a similar DSM Rx.

Only 6CH, but working with CPPM and DSMX on Bind/Bat header.
Failsave is CH3. Fixed ID.
> Orange RX615X >DSM2/DSMX

...and it rebinds with Devo/Deviation the same time the bootscreen appears
on the Devo. Not that slow as shown sometimes with the Spektrum tx.

I've got one of the older 6-channel orange Rx receivers, as well as some Spektrum low-end ones. I've never noticed that deviation binds a lot slower, but I'm used to all of them binding pretty much on power on once they're bound with the id info.

But the FrSky D4R-II is a much nicer package than the OrangeRx ones. Using CPPM gets you 8 channels, even though it only has 4 servo outputs. Since the number of channels is a pure software function, this makes a lot of since. The only limit is how many full-on channels will fit in the packet time. This actually pisses me off about proprietary radios - they charge more for more channels? When it should require nothing more than changing a constant and rebuilding the firmware to increase it?

Also, the OrangeRx Rx has no telemetry built in. It will work with the Spektrum telemetry modules, and presumably the LemonRx ones. But OrangeRx doesn't see to make Telemetry modules, and the LemonRx ones cost about the same as the Spektrum ones.