Simple Taranis X9D+ Wireless Trainer Using SBUS Receiver Input

Introduction: Simple Taranis X9D+ Wireless Trainer Using SBUS Receiver Input

About: Drones & 3D Printing

The goal of this project is to connect a FrSky X-Lite transmitter to a FrSky X9D+ transmitter in a TRAINER configuration using a cheap SBUS receiver (12$). By connecting the two together in this way, it is possible for an instructor pilot using the X9D+ to pass control of one or more channels to a student pilot using the X-Lite while a switch is held. By releasing the switch at any point, the instructor can regain control of the model and recover in the event that the student pilot loses control.

Since the X9D+ does not support the FrSky wireless trainer system and the X-Lite does not have a trainer jack for connecting a trainer cable, we are going to BIND the X-Lite to an SBUS compatible receiver connected directly to the pins in the module bay of the X9D+ in order to pass channels 1 to 4 from the SLAVE radio to the MASTER radio.

Step 1: THINGS YOU NEED

  1. MASTER RADIO: FrSky X9D+ Transmitter (REQUIRED)
  2. SLAVE RADIO : ** FrSky X-Lite Transmitter
  3. SLAVE RECEIVER: ** FrSky XM or XM+ Receiver
  4. 5 Position Header

** Although I used the FrSky X-Lite transmitter and XM+ receiver as the SLAVE radio and receiver, any transmitter/receiver combination should work provided that the receiver is SBUS compatible and bound to the SLAVE transmitter. If you decide to use a different receiver, take note of the pin mapping and ensure the receiver can handle up to ~8.4V input.

Step 2: BINDING THE TRANSMITTER

* This instructable assumes that the MASTER radio (X9D+) is already bound to the RC model/drone/airplane that you plan on flying. If that is not already the case, please look up the instructions specific to your receiver (or, if the receiver in your aircraft is also a FrSky XM or XM+, follow the steps bellow for the aircraft receiver first) *

Before we do any soldering or connect anything up permanently, it is best to BIND the SLAVE receiver to the SLAVE radio since the BIND button will be difficult to access later. Follow these steps to BIND the XM+ receiver to the X-Lite transmitter:

  1. Turn on the X-Lite, create a new model called 'TRAINER', select D16 receiver and BIND (CH1-8).
  2. While holding down the BIND button on the receiver, power it up using any 5V source or using jumper wires to the VBAT and GND pins in the module bay of the X9D+.
  3. A RED flashing led indicates BIND complete, disconnect the power to the receiver
  4. Disable BIND mode on the transmitter
  5. Power up the receiver and transmitter normally, a GREEN led confirms a good connection with the transmitter

Step 3: SOLDERING THE HEADERS

One advantage of using the FrSky XM or XM+ receivers is that the solder pad spacing and order is the same as the pins in the module bay of the X9D+. This means we can solder headers to the receiver and plug it directly into the back of the X9D+ with no wiring or other circuitry required!

You will notice inside the module bay there are a total of 5 pins, pay close attention to which ones we are using and which order they are in. In order to prevent accidentally plugging the receiver into the wrong pins, we will be using a 5-position, 2.54mm spacing header that can be easily cut from one of the strips linked previously. Using pliers, remove the metal contacts from the outer 2 pins and notch the plastic of the 5th position using a hobby knife such that the LED of the receiver is still visible after soldering. Finally, solder the receiver to the center 3 of the 5 positions with the female header facing the same side as the bind button and LED as shown.

Step 4: PLUG IN THE RECEIVER

With the X9D+ turned off, plug the receiver into the module bay as shown. Before powering up the X9D+, confirm one last time that the receiver is indeed on the center 3 pins and the BIND button and LED are facing down as shown. If the receiver is on the wrong pins, you may damage it.

Step 5: ENABLE SBUS TRAINER INPUT

  1. Make sure the you have the latest OpenTX firmware (at least v2.2) installed on your X9D+
  2. Power up the X9D+
  3. Go to model setup page (MENU > [Select Model] > PAGE)
  4. Under 'Trainer Input' select MASTER/SBUS

Step 6: CONFIGURE TRAINER CHANNELS

We will be configuring the trainer channels much in the same way as described here. For more information on the different settings, please visit Sean Cull's page.

  1. Turn on both radios
  2. On the X9D+, navigate to the TRAINER menu (long press MENU until RADIO SETUP appears then press PAGE 3x)
  3. If everything has been done correctly up until now, when you move the sticks on the X-Lite the values at the bottom of this page should change accordingly, if everything works, configure the channels in pass-through mode (:=), adjust the scaling as required and go to the next step.

Troubleshooting: (values not reacting to SLAVE stick input):

  1. Verify the receiver is powered and bound to the X-Lite (GREEN LED).
  2. Verify channels 1 to 4 on the X-Lite are mapped to the sticks using the CHANNEL MONITOR page on the X-Lite.
  3. Verify the receiver is connected to the center 3 pins of the module bay in the correct order.
  4. Verify trainer mode on the X9D+ is set to SBUS-MASTER

Step 7: CONFIGURE HANDOVER SWITCH

Now we will assign a special function to a switch on the MASTER radio so that it will hand over control to the SLAVE radio while pressed. Navigate to the SPECIAL FUNCTIONS page on the X9D+ by pressing MENU > PAGE (x9) and configure your switch of choice as shown.

Step 8: FINAL CONFIRMATION

With everything configured you should now be able to open the CHANNEL MONITOR page on the X9D+ and see the channel values change when the sticks are moved. When the previously assigned switch is held down however, the channel values should change according the sticks of the SLAVE radio instead.

Step 9: BONUS POINTS - 3D PRINTED ENCLOSURE

Although the receiver and its antennas fit just fine behind the module bay cover on the X9D+, it is possible to take this project one step further with a 3D printed enclosure that snaps right into the module bay and makes it even easier to swap in and out as needed.

See the enclosure that I designed here! All that is required is (6x) M2x8 flat head screws for the cover which can be found here. The enclosure fits snugly around the headers and the lid holds the receiver module in place.

Enjoy your new trainer system with a friend!

4 People Made This Project!

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26 Discussions

0
stlucia2
stlucia2

Question 12 hours ago on Step 6

I'm trying to build this project using a Taranis X9D+ 2019 with EU LBT v2 firmware as Master, and a Taranis X9D+ with EU LBT v1 firmware as Slave. I have a FrSky XM receiver which is bound to my Slave transmitter, showing a solid green LED. I have plugged it into the module bay pins of the Master Tx as per your diagram and, with all screens configured as per your descriptions and pictures, I get power to the receiver (a red light) when I switch the Master Tx on, then a bind (green light) when I switch the Slave Tx on. So something's working!

But after verifying that the Slave sticks are working correctly in its channel monitor I still get no response in the Master channel monitor -- either before or after I've configured SH to activate trainer mode. All is correct as per your final checklist, so I'm beginning to wonder if the pin next to the Batt pin in the module bay is in fact an SBus pin, for there's several diagrams on the internet that show it as a 6v pin.

More likely I've missed something very simple. Any ideas please? I've already checked the pin in question with my DVM and it's showing 0.0v, so it's not a 6v pin.

0
tdevos
tdevos

2 months ago

would this work on a Jumper T16 pro too?

0
Vector3D
Vector3D

Reply 2 months ago

If you were to flash the Jumper T16 pro with the latest version of OpenTX and double check the pins in the module bay are the same as the Taranis then it should work no problem. I personally have never tried but can't think of another reason that it wouldn't work. Good luck!

0
tdevos
tdevos

Reply 2 months ago

I can't find nowhere the bay pin put of the Jumper T16. But if accepts the Frsky DJT / R9 and Crossfire modules soI guess it will be same pin out of the Taranis.

0
tdevos
tdevos

Reply 2 months ago

hmm, story ends. There is no MASTER/SBUS option in the latest openTX firmware for T16. Only /BLUETOOTH /JACK /MULTI.

0
jims1234
jims1234

Question 10 months ago on Introduction

Vector3D,
As I mention below I got this to work in two Taranis Q7XS radios and it's working very reliably. .. but I wonder if it will also work with a TARANIS Master radio that can support TRAINER: MASTER SBUS mode, But with a non-Taranis Student Radio perhaps even non FrSky Type Student Radio if that Radio can Bind with the XM or XM+ Receiver? I think that is may .. do you agree?

0
Vector3D
Vector3D

Reply 10 months ago

It should work, so long as as the master is a Taranis and the receiver is either the xm or xm+ (or another SBUS receiver).

0
jims1234
jims1234

Tip 10 months ago on Step 9

Here’s something worth noting if you have trouble binding a new FrSky Receiver , or if you get a “No bottom pin response” error while flashing new firmware to a new Receiver via Tasanis SPort , you may want to try it again with this module temporarily removed. I found out this module can conflict due to a loading issue on the internal Module bay Pins unless you pull it out before doing these things..

0
Vector3D
Vector3D

Reply 11 months ago

Excellent! Happy flying!

0
jims1234
jims1234

Tip 11 months ago

One of the recommendations made in this project is to download and install the latest firmware.. I have that im my Radios but wasn't sure about the XM+ Rx itself . So I downloaded the .zip from FrSky of the three variants in the non -EU LBT version of FCC approved code and picled the middle one with Telemetry and 8 Channels.. But i QUICKLY found that trying to use the same pin outs as shown in this project with a 7XS radio Pin outs needed for flashing the Receiver do NOT match the 9D+ pins in this project doc at all.. I did however find a good RCDIY.com video on YT with the X7 pin outs needed and was able to easily jumper them to the three female module pins and write the new firmware.. but if you try to use the pin outs that are almost unreadable in the .pdf ( the one showing a TELEM Pin as the bottom of the 5 pins .. you will never get it to flash using these X9D+ pin outs .. What actually DOES work to Flash an XM+ in a 7X bay is to jumper the Square Yellow SBUS Pin across to the BOTTOM of the 5 JR Module bay pins, Then jumper the middle V BATT RED pin to the second pin up in the module bay, and then Jumper the GND Black / top active pin of the Receiver across to the third Pin up from the lower right of the module bay and the .frx file "Write to External Module" process will then work properly..

Once done Writing firmware, it's time to BIND the newly programmed Rx to the MASTER Radio and to do that I used a 6dvc Rx battery and the RED and Black BATT and GND pins (only) jumpered to teh XM+ with the FS BUTTON held just before applying battery power.. That bound the Rx on an open Channel in D16 with 8 bit telemtry.

The final step is to remove the jumpers and insert the Wireless Link module and its 5pin header as designed in this project on the 5 male pins in the bay with the top module header (inactive) pin that is notched above the LED in the TOP X7 bay pin position. The three active pins SBUS. VBATT and GND follow and the last inactive Pin of the header plugs into the bottom (labled as TLEM pin on the .pdf) of the 5 bay male pins.. If you did it right and have the Rx bound properly.. the LED will stop flashing as you Power up the Slave Tx and select the the Student/SLAVE TRAINER Model.. teh XM+ should go to steady Green and stay green.

To see this I drilled a little 1/4 in hole in the bay cover and wrapped the antenna leads one CW and the other CCW to fit them all under it. Have Fun with your Student..

BTW: I don't recommend setting the Passthru rates at 100% for most students and planes or Quads this is far too aggressive as they will tend to over compensate .. I'd use 50% to start, and consider not passing the Throttle on a typical glider anyway at more than 30% .. Be sure to CAL the sticks and the Slave to trainer compensation CAL: too or the bias will cause a attitude shift as you switch to Trainer mode each time.. Have Fun.. JimS

0
jims1234
jims1234

Question 11 months ago on Step 2

Hello Vector3D
I'm committed getting this trainer function set up for the grandkids.. and to doing this project and have all the parts, but before I start i want to ask a couple questions.. 1.) How reliable is this set up? I'm asking cause I invested a lot of time and $$ in getting two Taranis Q7XS Radios with the internal BT Wireless training capability built in each.. only to find that after setting it up and checking everything pre-flight and doing the CAL steps and making sure all 4 control surfaces were Ok when switched to student control .. then mid-flight I get a "Student Connection Lost alert" and the student standing near me no longer could control anything in "student SH selected state" .. So here's my question 1...

1.) How many times have you flown this trainer config and is it 100% reliable so far?

2.) Its going to be a bit complicated for me to do this not because the project is difficult, but I still fly several legacy non FrSKY planes that currently require external PPM JR Modules or a 4 In 1 DIY module until they’re upgraded to ACCESS X series as well as fly new X series G-RX8 and RX6 in them which are bound to the master radio’s internal RF section in ACCST mode ...so it would Be simpler for me if i could leave those JR modules and the matching models in place .. and put this new XR+ Rx module into the opposite ( my former Slave) radio .... But i doubt this could work with the Tx with the new XM+ Rx mounted in its bay functioning as the Slave radio right?

I will try to do this progect anyway, and move my Ext JRModules as needed into the slave radio, and copy and rebind all my legacy models into what you are showing a the slave radio until I get time and $$ to upgrade them to ACCeSS if possible . But I’ll keep using my X series receivers in INT D16 along with the new XM+ in the Master Radio’s bay.

3. is there anything that would preclude using ACCeSS Tx and Rxs protocol within the MASTER in the future with this XM+ setup only passing thru the slave’s analog 4ch data?

4. whats non intuitive about all this is normally in a "wired" trainer config, or the internal FrSky Bluetooth config the slave has BOTH the EXT PPM JR module and the INTERNAL RF sections turned OFF while the master is set to do all the RF transmission ...in this case however we are using an external SBUS signal in the MAster tho apparently it’s new XM+ rX never transmits RF like it can to send Telemetry

Fun Stuff..
JimS

0
Vector3D
Vector3D

Reply 11 months ago

Hey Jim,

I will try to answer as best I can based on what I understand you are trying to do.
1) I have only flown this setup a handful of times and the trainer link has always been reliable (RSSI close to 100).
2) The MASTER radio can NOT have a JR module already in place for this system to work. To my knowledge only one device can be connected to the JR module bay at a time (either the 4 in 1 Transmitter module connected to your models as you described OR an SBUS receiver acting as a trainer input device to your MASTER radio) I also have not tried using an analog protocol (PPM) input, I have only tried using a digital one (SBUS).
3) If your MASTER has an INTERNAL RF capable of binding to your model and the JR Module bay is free, I see no reason why this trainer link shouldn't work regardless of the protocol you use (see answer above with regards to analog link).
4) The idea is the same, in a normal wired trainer setup the other items are greyed out because you can only output to one device at a time, in this setup the link to the MASTER IS the internal RF (and external RF would be greyed out, so still only 1 device). Please note that the model is receiving control signals directly from the MASTER radio only and is unaffected by the SLAVE radio in any way except that the OpenTX software will *MODIFY* the channel values of the first 4 channels that it is sending to the model IF it is receiving a valid input on the SBUS pin of the module bay AND the selected button is being held down. If the trainer link fails or the button isn't held the model will behave exactly as it would with no trainer link.

Hope this answers your questions, any feedback is more than welcome if you decide to take on this project.

James

0
jims1234
jims1234

Reply 11 months ago

James,
excellent.. understand all.. been busy but this weekend I shud be able to try getting the firmware updates and giving it a go. Very glad it seems like it should be as reliable as a typical radio link at short range.. the built in BT I can’t trust it.. so this seems promising thanks .. JimS

0
FabienG10
FabienG10

1 year ago

Great tuto. Are you ready to share the link to the enclosure?

0
Vector3D
Vector3D

Reply 12 months ago

Sorry for the delay in answering you. I have now uploaded the enclosure. Cheers!

0
skotte
skotte

1 year ago

I am struggling to find the option of Master/SBUS? Its not in any firmware I have tried from 2.2.1 and up to 2.2.3?
How does this get enabled?

0
Vector3D
Vector3D

Reply 1 year ago

From the model selection page simply press page once. You should then see the option to configure timers, etc. Scroll to the bottom (after the receiver BND options) and you should see a trainer option.

Hope this helps!

0
ssombra
ssombra

1 year ago

Great tutorial! Is it possible to use the Q X7 instead of the X9D+? would the pinout in the bay be the same? thanks

0
Vector3D
Vector3D

Reply 1 year ago

My understanding is that the JR module pinout is standard across most if not all radios. Provided the QX7 is flashed with recent firmware there shouldn't be any problem connecting it up exactly the same.