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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I feel very incompetent as I have not managed to get this working with my PixHawk. 

I have data going into and coming out of the Teensy3.1 to the SPort but only get A1 data at the Taranis transmitter (upgraded to version 2940 firmware). I get no other data.

Is there something else I need to setup - I am still using the radio telemetry link to Mission Planner on the laptop and that connects and works ok. 

Any help appreciated. 


A footnote to my PixHawk question. I am using the Telem2 connection to the Teensy and am wondering if that has the same data as Telem1 ?


Great, will keep an eye that!

Your sure that you are connected to SPort and not SBus??


Yes I am using the SBus for the receiver output to the pixhawk. 

I suspect the 'wrong' data is coming from the telem2 port but I don't know what data it is!


I am using a pixhawk on telemetry port 2 and it just works.  I had the same issue at first until I realized you have to configure the telemetry screens on the Taranis to show all the other stuff.  By default it only shows a1.  Have you done that?

Yes I have configured all three screens on the Taranis.

Is the data from telem2 the same as telem1?

Can you confirm the led on the teensy blinks at a slow rate all the time? 


If the LED blinks slowly then the Teensy tries to connect to Mavlink.

When connected and receiving from MavLink the LED shall be steady on.

If not check to see that you have Rx,Tx connected the right way..

Teensy Pin9 ---> Pixhawk Pin2

Teensy Pin10 ---> Pixhawk Pin3

Teensy GND ---> Pixhawk Pin6

Hi Rolph,

Just wanted to thank you very much for this !

Special thanks also to Francis for the battery voltage detection, it works like a charm.

I'm a total newbie, yet I got my Teensy and my telemetry working perfectly.

This is really great stuff and I hope it can get copied over the the wiki or at least get some more exposition because it's just the perfect complement for any Taranis users out there.



Have you definitely got it connected to the smart port on the receiver and not the sbus? You get A1 without the Teensy.

Got a small problem with the initialization routine.

If i connect Teensy alone to APM telemetry port (RX, TX and GND) I receive no data at all on my Taranis (LED is on, flickering)

If however i connect Teensy in parallel with the 3DR radio (obviously only RX and GND) data starts showing on Taranis AS SOON as 3DR Radio has made a connection to APMPlanner (LED again on, flickering)

It seems to me that 3DR Radio is successful in requesting data streams from APM, but Teensy on its own is not. Any idea where the problem lies ?

Thanks in advance

There could be a problem with the signal levels from Teensy because it is 3,3V on TX output and the APM is 5V or even higher depending on the voltage you supply the APM with.

All inputs to the Teensy is 5V tolerant but it can only drive up to 3.3V.  You can try to use a level converter or lower the voltage to  the APM a little.

My APM is working with Teensy without a problem with a voltage supply from the 3DR Power module of 4,9V measured at the IO pins, the threshold level on ATMega2560 is ~3V @ 5.5V or ~2.8V @ 5V Vcc.

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