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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Joy,  Disregard the last post.  My APM 2.6 board is now out putting Telemetry once I hooked the battery up to the power module and connected to the APM.

Now my only problem is "Batt" is showing 7.9 volts and is static.  "Cels" is showing "0" and so is "Cell".  I don't have the other side of the power module hooked to anything now.  Would this be the reason why I would  not be showing battery data.  It seems like it still should be registering Battery Voltage and cell voltage.

Thanks again,


Hello everyone,

thank you very much for this work.
I buy a teensy 3.1 module and I own a radio pixhawk + 3DR Radio (TELEM 1) with a receiver and a X8R taranis.
if I understand correctly, you must:
_Flasher The teensy 3.1 with MavLink_FrSkySPort_1.3.zip
_Cabler In this way on the Port TELEM2
Teensy Pin 9 ---> Pin 2 Pixhawk
Teensy Pin 10 ---> Pixhawk Pin 3
Teensy G ---> Pixhawk Pin 6
Teensy PIN 1 ---> S.Port Signal
Teensy Vusb ---> S.Port V +
Teensy GND ---> Gnd S.Port
_to end must be configured paramettres telemetry on taranis.

I think the new firmware of taranis is not compatible? There he has a solution for this problem?
it seems to me as seeing the S.Port is supplied with 3.3Volt not otherwise must supply the teensy?

thank you again for this project


It's irrelevant the firmware on the Taranis, because the received telemetry "comes" in FrSky SPort format.

The newer Taranis firmware 2.0x adds the possibility of "building" custom telemetry screens via scripting which gives a great possibility for building even better solutions around the Taranis and APM/Teensy.


Don't worry about the powering of the Teensy with your components. It "just" works.

I have the 3DR Radio on telemetry port 1 and the Teensy on telemetry port 2 on my PixHawk running APM 3.1.5 and no problems.

thank you
it remains only to test me all once the teensy received;)

I can so my updater taranis in 2.0 no problem ^ ^

I am having the same problem I see the pin numbers but have not been able to find a doc that maps out the telemetry port on the APM.  Which is pin 1 the outside pin (closest to the edge of the APM or the inside pin?


here is the equipment has arrived!
I read the code a bit, and I myself noticed that the voltage per cell is indicated for a 4S battery. can we change parameter is simply?
I never compiled the arduino, I am interested in any information!
thank you

oops, I see vien line 209 "MavLink_FrSkySPort.ino" file there is an automatic selection of the number of cells as a function of voltage.

remains to test it all;)

As of now and with the 1.3 version linked at the first post the parameters available on the FrSky telemetry are these:

teensy 2 frsky
Cell           ( Voltage of Cell=Cells/Nr of Cells - Automatically calculated - Assumes Battery at least 80% charge. [V] ) 
Cells         ( Voltage from LiPo [V] )
A2            ( Analog voltage from input A0 on Teensy 3.1 )
Alt            ( Altitude from baro.  [m] )
GAlt          ( Altitude from GPS   [m])
HDG        ( Compass heading  [deg])
Rpm        ( Throttle when ARMED [%] )
AccX        ( AccX m/s ? )
AccY        ( AccY m/s ? )
AccZ        ( AccZ m/s ? )
VSpd       ( Vertical speed [m/s] )-Vario
Speed      ( Ground speed from GPS,  [km/h] )
T1            ( GPS status = ap_sat_visible*10) + ap_fixtype )
T2           ( ARMED=1, DISARMED=0 )
Vfas          ( same as Cells )
Longitud     ( Longitud )
Latitud ( Latitud )
Dist          ( Will be calculated by FrSky Taranis as the distance from first received lat/long = Home Position
Fuel ( Flight Mode )

( current )

There are more FrSky telemetry values but are not being dealt with 1.3 version

Batt Transmitter Voltage
Cnsp mAh
Power watts 
Tmr1 Model timer 1
Tmr2 Model Timer 2
SWR measure of transmitter antenna quality. Reading below 51 is normal.
RSSI Received Signal Strength Indication

excelent !

unsurprisingly everything works flawlessly;)
thank you all for this project

It took while but I finally found docs showing the Inner pin (farthest from edge of APM) on the telemetry port is #1. I have everything wired up i believe correctly now. I have successfully downloaded the code into the teensy3.1.  But when I power up my quad the following occurs.

1. X8R bind light goes green

2. Teensy 3.1 Led blinks slowly for approx 10 seconds and then goes solid orange.

3. Taranis gets basic voltage telemetry from my X8R receiver on A1 

4. Nothing on A2.

What am I missing?

Thank you.

Just wondering if I can use a Arduino Nano instead?  And will the code work with my FrSky D8R-II Plus? These questions came up after I changed the Turnigy 9XR to Er9X software today, so I had to start Googleling for solutions :)

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