Spektrofy your Taranis

Spektrofy your Taranis

DIY JR form factor external transmitter module with full range and full featured DSM2/DSMX modulation. Build instructions with links to everything you need to know to DIY.

I did it! 

I made my first electronic DIY electronic circuit board. This article will provide you with the information that I’ve gathered through my project of making a DSM2/DSMX JR external module for my Taranis.

Why go through all this when there is a already made DSM2/DSMX module - OrangeRX? If you are like me, I build planes for the fun of it. I love the challenge of scratch building - which is almost as fun as flying. When I ran out of model memory (10 on my Spektrum DX6i) I was really disappointed. So I started to shop around in order to upgrade my transmitter handset. After a long and extensive search, I decided on a Taranis for a multitude of reasons, mainly because I am drawn to the Open Source programming and versatility. The reviews indicated that the quality was great and a big, big plus, you can get an number of module packs to snap into the back to run any protocol that is to your liking (JR, Spektrum, Futaba, not to mention the long range modules DragonLink, EZ-UHF, etc. I was so convinced that I got one. 

I love my Taranis - but I didn’t want to buy a whole fleet of FrSky receivers to replace a all of the DSMX receivers I already have. So, I looked into getting a DSMX module. I only found OrangeRx and DIY mods. I put the OrangeRx Module on my wish list and then did some investigation - I had lots of questions about the function of the OrangeRx Module. I learned a lot from the forums including FT discussion boards (http://forum.flitetest.com/showthread.php?9788-Fr-Sky-Taranis-Chat-Questions-Answers-Share). 

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Re: T9X mod to use Flysky module, Frysky module and DSMX mod

by Daedalus66 » Sat Dec 14, 2013 3:15 pm

Yes, the Orange module works fine simply plugged into Taranis.

The drawbacks of going this way, compared to using the module from a DX4 or DX5 are:

1. The Orange module has an awkward antenna setup that sticks out the back.

2. The Orange module doesn't give Model Match or automatic shifting from one type of DSM receiver to another -- you have to do it manually.

These issues may not matter much for your use and it's certainly easy to just use the Orange module as is.

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So, the OrangeRx module is less than what I wanted to settle for… the biggest downer was stated in #2 above: You have to switch from DSM2 to DSMX on the module. In addition, and probably the biggest hassle is that OrangeRX does not support model match. I can only ask why? I don’t have a good explanation (if you can explain it, please post to the forum - I’d love to hear it). To overcome these limitations I pursued creating my own DSM2/DSMX module.

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The JR Module Box:

dmyers7 provided the files for making the JR module box and a schematic for connecting the electronic components. Big thanks to dmyers7!

http://www.thingiverse.com/thing:293608

I sent the files and my brother, Bryce, and he printed me the JR Style box which fit perfectly!

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If you don’t have access to a 3D printer - Other options for getting a case are these:

$5.95 + shipping 

http://www.jramericas.com/45067/JRPA615/?pcat=333

http://www.rcplanet.com/JR_Radio_Transmitter_Module_Case_p/jrpa615.htm

$9.95 + $8 Shipping.  

http://www.xtremepowersystems.net/proddetail.php?prod=XPS-J1CASE

$9.50 + $2 or $9 shipping. http://www.horizonhobby.com/products/integrated-case-for-jr-compatible-air-module-SPM6817

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Electronics

To get my hands on a Spektrum Tx unit, I bid on every single Spektrum DX4e and DX5e handset on ebay for months without winning the bid. I guess I wasn’t motivated to spend more that $25. Then one day I searched craigslist and snapped up one for $20.

I found several different ways to get the the electronics wired up. You don’t even need a board. The pictures and diagrams on the web provided enough information that anyone can do this, so the big “find” for me was Mouser Electronics. For a few bucks, I picked up all the parts (they do sell individual components). If you are not a DIY, then you can order a kit (board) and the parts. http://johnprikkel.blogspot.com/2014/07/jr-dsmx.html

I used this schematic with one modification - I added a LED with an inline 47 ohm resister between the 3.3v and ground so that I could tell when the unit has power.

http://www.rcgroups.com/forums/showpost.php?p=19988000&postcount=13821

http://www.rcgroups.com/forums/showthread.php?t=2086520

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Source of Electronics

Here is where I got the parts list and ordered from Mouser.

http://johnprikkel.blogspot.com/2014/07/jr-dsmx.html

Here is where someone else got theirs:

http://openrcforums.com/forum/viewtopic.php?f=25&t=541&start=150

Diode 1N4001, Radio Shack 276-1101

Resistor 4.7k-Ohm, Radio Shack 271-1124

Module case and antenna, Spektrum (SPM6817). The antenna connector matches the one on the module from the dx4e. The module fits on a 9x, no problem.

5 pin connector from Hobby King http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=29280

3.3v Ubec from Hobby King http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=17159

If you don’t want to build the power circuit, you can use a premade one.

and follow a different schematic found here. This one can be wired up without a board, just use heat shrink wrap over the two components you will need to solder together.

http://openrcforums.com/forum/viewtopic.php?f=25&t=541&start=150#p48608

Here are some pictures that I found useful.

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Here is my build.

Crack the case of the Spektrum DX4e (I’ve read that this Tx unit is the same as used in the DX5e and DX6i). Remove the 5 screws from the circuit board. Desolder the Tx unit from the front side of the board. I used some desoldering ribbon wick and it came right out. I’ve read that the leftover DX4e unit can be used as slave or simulator… we’ll see about that later.

I had a leftover piece of electronic stripboard that I cut to fit the box. It fit real nicely along with the Tx unit. I soldered the electronics to the board based on the schematic above. Before plugging them into my Taranis or Tx module, I performed the smoke test on the voltage regulator by hooking it up to an external power supply and volt meter. No smoke and 3.3 volts! We’re in business.

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Final Assembly

I lined the inside of the box with aluminum foil as a RF shield. I covered the foil with clear electric barrier to prevent any shorts

Final assembly was hooking up the wires to the Tx pins, connecting the antenna, screwing the back onto the box and snapping the module into the Taranis. I turned on the external Tx and the light came on - no smoke either.

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Testing.

Will this DSMX module allow more that 10 model memory? This was one of the questions that was raised on the FT forums, by me, to which I didn’t get an answer. My hypothesis is that the Tx chip doesn’t remember which model to bind, but it is a part of the memory based in the handset programming. 

Binding a DSM2/DSMX Rx to the Taranis

On the model setup menu, about 3/4 the way down there are settings for Internal RF and External RF. 

Set the Internal RF Mode to OFF and the External RF Mode to DSM2 DSMX. When the Mode is changed from PPM to any other mode, the line below appears to set the Rx number, [Bind] and [Range]. To bind the Rx, put the cursor of the Taranis on [Bind], insert the binding plug into the Rx, give it power, and pres "ENT" on the Taranis. After a few seconds, the Rx is bound and the binding plug can be removed. A complete and excellent training for setting up the Taranis can be found here: http://open-txu.org/ - See more at: http://flitetest.com/articles/spektrofy-your-taranis#sthash.DoYWF0Ib.dpuf

To test this, I bound two mini OrangeRx receivers (the only unused 2 I have) to channels 11 and 12 (I had already setup 10 models on channels 1 - 10). With both receivers connected to power, I was able to switch from one to the other by selecting the model number on the Taranis.

Here I show the two receivers, both on yet only one is active and this is dependent on the model selection of the Taranis handset. Perfect - now I can have up to 60 model memory between FrSky or DSM2/DSMX receivers. That should keep me in business for a few decades. 

All in all - This modification cost $20 for the Tx (plus $6 for the gas to pick it up), the box was free - but lets say I paid $10 for a commercial molded one, electronics were $10, but I got enough to build 3 units, the time spent was 3 hours. Round it out at $50 for the project… 

Was it worth it - You betcha!  All the function of the Taranis to my DSMX models without manual switching DSM2 to DSMX, 60 model memory - I just have to smile.

Adding Style:

And just for fun… I created a Spektrum sticker and stuck it to the module.

My unsolicited advice for someone entering the hobby on purchasing a transmitter. If I knew then what I know now… When I started into the hobby a few years ago, I researched all the different kinds of transmitters, Specktrum, JR, Futaba and Gruapner. Admittedly, the Taranis (or HK Orange Tx) was not yet on the market, but I determined the DSMX modulation had the features I needed for the type of models I would be flying. Here is where some people will start to argue about your model not being compromised for an unreliable cheap $10 receiver. When you get into the models costing several hundreds of dollars and a year to build, then admittedly, the cost of the receiver becomes far less important. I have used OrangeRx receivers for the FT models and have never had a failure yet. So, if someone asked me how to start into the hobby with economics in mind, I would advise them to look on ebay and get a used Spektrum or HK OrangeRx 6 channel receiver. This will get you into the hobby with 10 model memory. If you are still flying and crashing less after a year or two, and you need more features, more channels - the Taranis is the logical choice. It offers limitless features with all the knobs, buttons and switches you will need, 16 channels out (you can bind two receivers), and an open source program that allows for customization. Even without learning any programming, the radio offers the pilot all the convenience of selecting which channels do what.

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Resources:

Simple complete blog on making DSMX module with lots of pictures.

How to modify your 9x to the DSM protocol

Here are some links to the sites I frequently visited to make this module:

• 9x Full Mod DSM2/X

• T9X mod to use Flysky module, Frysky module and DSMX module

• DIY Spek DSM2 / DSMX JR Module - For my Taranis

• Spektrum module for Taranis

• JR-DSMX - A Spektrum DSMX compatible JR Module for OpenTX or ER9X

• Taranis and DSM2 mods

• Beaten to death: Serial DSM Module

• SPEKTRUM DSM2 MODULE FROM HP6DSM

• Taranis Spektrum RF Module Hack

• How to build a true Spektrum DSMX module for Taranis

A complete and excellent tutorial to learn the functions of the Taranis can be found here:

http://open-txu.org/

HilldaFlyer February 2015