Hi all,

I just bought an FrSky Taranis for my quad copter and needed to get the Mavlink data up on the Taranis LCD telemetry display. So here is my solution using a Teensy3.1 as a converter between MavLink and the S.Port on FrSky X8R.

See attached file below...

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OK, your explanation accepted! Most of the forums I visit indicate my loocale, S. of France, but not here on DIYD. Actually, I find only the occasional U.S. company has reasonable international shipping, and many Asian sources offer free shipping. And for some lucky reason, French customs only appear to be on duty when the supervisor makes his monthly check up. So 90%+ of my hobby purchases are from the East, and make it through with no additional tax or duty. Even HobbyKing is a good source for me, for light weight stuff.

From your analysis, it definitely seems the 3.1 is the one to try, looking forward to implementing your excellent system!

The 3.1 is the only one that will work for this specific project. There are some issues with inverting signals that the other Teensy boards can't do so it really needs to be the 3.1. It's a pretty simple project as well and is fairly straightforward if you have selected out the posts in the thread that look important. That's what I did.

Just saw this commit on the ardupilot github repo:

Frsky on PX4 Telem 2

Wonder if native S.Port is next...

At the moment is only DBus FrSky.

There is the problem of physical signaling between a "typical" serial connection as present on the PixHawk and APM and the SPort on X series receivers.

There is an existing implementation of FrSky telemetry on the PixHawk firmware here: http://pixhawk.org/peripherals/telemetry/frsky?s[]=frsky

I didn't pay much attention to the current commits, but I wouldn't be surprised to see a migration of the existing PixHawk code to ArduPilot.

With the push of dropping DBus telemetry for the newer SPort I don't see the point of insisting but.....

I got the teensy3.1 programmed and connected up, results;

Fuel = OK
Vspd (but bouncing all over)
T1 mostly working but sometimes displays wrong info compared to MP, like displays 199 when I have 9 sat and 3D lock.
T2 = OK
ALT = -13 (why negitive value?)

Not working:
Galt = 0
HDG = 0
Lat = 0
Long = 0
Current = 0

Taranis FW is R2751 date 9-1-2013

Do I need to update Taranis FW to latest openTx, or openTx 2.0 or any other suggestions?

My Teensy 3.1 arrived today and I was sniffing around on the PJRC site and saw this: Looks like your "teensy"

They claim it won't work with the loader, etc.  My controller and receiver (for my Alien 560 quad) should be here in a week or so.  That's the build I'll try this on.  In the mean time, I'm looking at other Teensy projects to see if another one could sequence LEDs or something else entertaining.  I'd like to have some clue how it works beyond just putting wires in the right places and loading a program.

S-port is not easy on a non dedicated hardware as S-port is based on polling and the pixhawk need to answer as fast as possible. D-port was trivial compare to it (and thanks to the existing job done with the px4 driver).

But yes , I have something working on the bench but .. badly working

And D-port it still widely used.

I'm using the Teensy now and with this code it was working fine with previous OpenTX versions. I'm still looking for a cause of why, since OpenTX 2.05, that "broke" all the Voltage options and reporting on the radio. I believe that some polling addresses might have changed but not sure.

I've also changed some values that were being collected - like AccXYZ for some thing more useful IMHO like pitch, roll, yaw angles.

The scripting on the radio allows us to do some interesting things if we have the right data coming from the telemetry.

something like this would be a nice to have :)

I believe that one of the hurdles connecting the PixHawk to the X line of receivers was an electrical one ?

Does anyone have the 2.0.5 version of OpenTX w/ haptic or know where I can find it? 

Very nice but is it also possible to use the 3DR Telemetrie set with this way? egen APM->teensy->3DR antenna or would it not work because of some data  traffic?

So, was there a result to this? I want to upgrade to 2.0.8 but have held off because I hadn't hear a solution. If it's as simple as changing a couple of ID's in the code, I just need to know which ones to change.


You can connect multiple devices to the apm telem port but only one will be connected to the tx, rx, power and ground. The rest with only have rx, power and ground.

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