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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Perhaps in the future with the new telemetry system that is planned for OpenTX 2.1 that might be possible.

Although I'm installing MinimOSD on my Hexa (and banging my head on the wall with it) most of the time I fly without FPV. Although I also have telemetry on my phone via either Bluetooth or via the 3DR radio I opted to pursue this project. 

There are also efforts on the ArduPilot side to have native telemetry reporting to FrSky, but the data is even more limited to what we currently have. Also there have been discussions on replacing the MinimOSD with a better solution. Currently I have both telemetry ports occupied with 4 devices (3DR Radio+MinimOSD and 3DR Bluetooth+Teensy) and they all live together well.

The biggest challenge so far has been the small amount of data available on the FrSky telemetry that really constrains what we can do.

Oh, and I won't even mention the limited resources we have for running scripts on the radio......I have hit several of them several times :), and not only me, ask Wolke and Christian :) :)

Solved at RCGroups :)

Hi Guys,

I have this mod on my Walkera x350Pro and get the data, flight modes, etc to the Taranis great

However, I have been playing around with a second Taranis, re created the model, and it seems like some of the switches are already coded for some functions, and I would like to change it.

For example, I want to set up one of the switches on the right for simple and super simple modes, however whenever I flick the switch I get a voice 'mid rates selected, low rates selected, etc)

These sound files are not allocated (by me) to any switch, so I am assuming they are 'programed' in one of the LUA scripts.

Is this so? if so, which one? and what do I look for?



Thank you Louis. Taranis has firmware 2.0.13, the Pixhawk has Arducopter 3.2. 

Both Tx and RX connected. I've tried Teensy alone on Telemtery 1 or 2 and togheter with 3DR Radio but doean't work. Work the voltage, the current, the arming, the height but not the roll and modes....

I've defined the mode on the script and the announcement about mode selected is correct, but not the actual mode on the Pixhawk, The telemetry scrren always diplasy Stabilize, bliking if not armed and still if armed. But always Stabilize, also when in the Mission Planner i see Alt Hold or other.....

Thank you for your effort and support.


I have another Teensy around and will program it with the same imo as the one I have on my Hexa to see if anything weird happens. At the moment I'm fighting with a damn chinese knockoff of the MinimOSD.

Can you reflash the Teensy ?

Yes. I've reflashed many times but i will try again.

Thank you


On the standard Taranis telemetry screens please check the Fuel value, because the Flight Mode number is encapsulated on that value.

Also check if the other values are being reported correctly. The script just uses these values and present them in a different way.

Cell ( Voltage of Cell=Cells/(Number of cells). [V])
Cells ( Voltage from LiPo [V] )
A2 ( HDOP value * 25 - 8 bit resolution)
A3 ( Roll angle from -Pi to +Pi radians, converted to a value between 0 and 1024)
A4 ( Pitch angle from -Pi/2 to +Pi/2 radians, converted to a value between 0 and 1024)
Alt ( Altitude from baro. [m] )
GAlt ( Altitude from GPS [m])
HDG ( Compass heading [deg]) v
Rpm ( Throttle when ARMED [%] *100 + % battery remaining as reported by Mavlink)
VSpd ( Vertical speed [m/s] )
Speed ( Ground speed from GPS, [km/h] )
T1 ( GPS status = ap_sat_visible*10) + ap_fixtype )
T2 ( Armed Status and Mavlink Messages :- 16 bit value: bit 1: armed - bit 2-5: severity +1 (0 means no message - bit 6-15: number representing a specific text)
Vfas ( same as Cells )
Longitud ( Longitud )
Latitud ( Latitud )

Fuel ( Current Flight Mode reported by Mavlink )

AccX ( X Axis average vibration m/s?)
AccY ( Y Axis average vibration m/s?)
AccZ ( Z Axis average vibration m/s?)

ALso see if the script changed the A values


I've reflashed the Teeensy with your files. Checked the firmware versione of the Taranis and is 2.0.13. The script changed value A. From the Teensy and Pixhawk i can read well the value of HDOP, HDG, Voltage and Altitude, but i can't read Fuel A3 and A4.

Tried also with brand new model, same attitude.

I've installed Arducopter 3.2.

I've tried also with an old APM 2.5, but still the same.

I've an headhache. I know i'm asking you a lot, but i can't find alone the solution...


Hi. I've soldered a new Teensy 3.1 and flashed with your sketch. Now FUEL work and after changed the mode on the script, when i change mode on the Pixhawk i can see the confirmation on the radio. Still doesn't work A4 and A5, so no roll, but now the value isn't 180 but 1; but the important thing is the mode confirmation.

Thank you for your help.

Now i have to find how change the timer to display only the motor time and not the mode time.


Glad you managed to work out.

That issue with the A registers still puzzles me.

Please note that you have several timers. One for each flight mode (on the top line) and one for time the vehicle is armed (I assume that armed corresponds to motor on).

Yes, I'll keep my eye out for developments - considering all the amazing stuff that has appeared in the past 2-3 years there's no telling what we can expect next!

Is this Taranis only? I have a 9XR Pro, and with an XJT module installed I'd think the values would at least be available.

Does this work with the 9XR Pro?  If not, what would it take?

hi peter,

i am not sure if it make sense to have an hud display on taranis, because if you fly fpv you need a hud on your goggles or on your fpv monitor.

imo, this teensy project is really usefully to monitor important data on your taranis including an acoustic warning system because audio output on taranis. for example voltage,  consumed power, orientation and so on. also this data on taranis is an redundant information if you for example out of range with your fpv video system. and at least if you use this teensy converter, there is no need to use other frsky sensors. for example, i have create a mod which also measured cell voltage with the teensy(A0-A5) ports. so at least you can set-up a system with less electronic elements to reduce complexity and increase safety operation.

BUT i agree completely that there is a major technical hurdle to integrate this converter into your system when someone is not familiar with micro-controllers, electronic basics and software development.

the pro with such projects is, that people are able to create systems as they like. also you are complete independent from closed source and closed electronics which mostly restrict usability.

and the biggest pro:), people are able to learn all the needed skills because everything is well documented. the arduino and teensy project contains everything you need to learn microcontroller development including basic electronics and soldering. opentx has an excellent documentation including an opentx-lua reference handbook. lua is also extremely well documented. :-).


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