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...

Views: 310279


Reply to This

Replies to This Discussion

Rolf, I am wondering if this is supposed to be functional with the FLD-02. I still get both RSSI, and the A1 voltage as without the Teensy plugged in, but I also get the altitude now too. Every other value is 0. The LED on my Teensy goes solid after APM is powered. I have a DHT-U DIY hack module installed in a Futaba T7CHP with FLD-02, and a Bluetooth TTL-RS232 installed in my Tx. On my cellphone I get the voltage and both RSSI, but selecting hub channels shows no valid data (everything is -1). Confirmed 3D gps fix in mission planner, and good MavLink data.

FYI, moving the APM up/down changes the altitude. I have tried both your original sketch, and also modified as I thought there were some errors in your example for HDOP after I got compile errors.

uint16_t  ap_HDOP = 0;


case 19:

APM 2.6 @ 2.78b

Futaba T7CHP w/DHT-U, FLD-02


Hey , I get the same error, however I followed the above instructions to the point. what was wrong with your setup? 


Awesome work on this!

I am on the Trannis wait list, hope to have it soon. I am converting my fleet over to the X series receivers along with the trannis upgrade. I already have telemetry from my copter over the old "hub" protocol and was looking to modernize with s.bus and found this awesome thread.

I am the guy working on the "mavboard" project (original post here: http://diydrones.com/profiles/blogs/sneak-peak-at-mavboard-progress). I am finally getting around to actually doing a production run and putting a bunch up for sale on indegogo in the next couple weeks. I would love to offer your software on it as well, so it supports both the old and new telemetry modes of the FrSky system. I was wondering if you wanted to work together to get a version of your code working on my mavboard hardware? I can send you some free boards. Should be a simple port (Im assuming just mapping the s.bus tx pin to be the same pin wired to my FrSky connector).

I now see the teensy3 is not based on the atmega chip so it will take a little extra work, but it should be possible. I found the ATMega hardware UART cannot do inverted mode, but the SoftSerial as of 1.0 is much more reliable, and most importantly, can do inverted signaling. 

Your code is much simpler than the code to emulate the old hub protocol, so I am excited we should be able to get this going on the mavboard pretty easily.

Also, the new version of my board has 2 extra digital and 2 extra analog pins broken out as pins on the edge, in addition to the RC connector (that will connect to the s.bus port), so if one wanted to attach sensors and devices and have that data feed back over the s.bus telemetry, it should be pretty easy. 

This is awesome, great work.

I've just ordered a Teensy 3.1, can't wait to try it.

Rolf, another working unit! 

Thank you, and if have time, please integrate flight mode info in the prog! 

Thank you again! 

p.s. is there any progress on teensy onboard s.bus to ppm conversion, it would be really cool, less wires, less mess less points of failure! 

p.p.s. there is this project: http://www.wedontneednasa.com/2014/01/using-audio-channel-for-air-t...

and since we already have teensy on board we could theoretically do something similar but much simpler, those FSK modems are 2400 baud and we receive mavlink at much higher rate. so we just need to extract GPS info with Alt and send it to the FSK modem at 2400baud. on the ground we could use this guy's code on another teensy to run a tracker. 

Hi Artem,

I'm working on the S.Bus to PPM converter but I have to be sure that the ppm output is not hanging up, cause then all will blame me for craching.  ;-))

I'm also rewriting the code for the MavLink to S.Port.

Regarding the FSK modem i will be back....


btw, I found some 4800 baud FFSK modems which should work too, looking at the video of the tracker in action you can clearly see the tracker delay to react when the copter moves fast and close, even though I think a lot of this delay comes from actually converting mavlink into the LTM (they guy's own creation). if we pick GPS/alt data only and skip the rest it should be much faster, but it would be a good idea to pump all the data necessary to run minim OSD on the ground, so in the event of video loss we would still have the horizon, alt and home direction info.  OSD on the ground opens up a lot of possibilities! 

FYI   Make sure you have the units on your taranis set to metric.  Had mine on imperial and got a lot of crazy readings.  Working great!  Thanks again Rolf.

This is great stuff. Thank you.

I will be ordering a teensy and will connect it on the telemetry2 port of Pixhawk (telemetry1 port in use for 3DR radio and MinmOSD)

Hello Rolf,

can you help me?

I want to query the failsafe state.
In fact, I would like to query a "Battery Failsafe" and then turn on a LED.


I'm not sure that there is a Mavlink message with the failsafe info from APM (maybe some can help on this)


Reply to Discussion


Season Two of the Trust Time Trial (T3) Contest 
A list of all T3 contests is here. The current round, the Vertical Horizontal one, is here

© 2020   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service