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Jan 01, 2015, 11:18 PM
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DaddyBigas's Avatar
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Spektrum wireless module for radios without wireless trainer capability


I posted this first in one of the Taranis threads. But then I figured it might be great for those using the DX8 and other Spektrum radios without the cool wireless trainer feature that the new DX6, DX9, and DX18G2 have.

Rainy day so I spent some time in the shop. Thought I would share my project from this evening. I finally got around to building a wireless trainer module for my Taranis so I could wireless buddy box with my kids and other club members and their Spektrum radios (as well as my other Spektrum radios). It would certainly be relevant to anyone using FrSky gear, but would also be of interest to any Spektrum user that has a radio without wireless buddy box capability. I was spoiled by the DX9's wireless trainer feature and really miss not having it on my Taranis. I am sure there are some DX8 and DX7 users out there who might also want wireless trainer capability so this may be of interest to you too. But I have not yet tested with those yet although I believe the pinout is correct for them too. I can do a test tomorrow if anyone would like me to do so.

Mine is a little different than some of the ones I have seen in the past. I did not want to use the external module bay since my Spektrum module lives there permanently, plus I wanted to be able to buddy box with any of my many Spektrum models as well as my FrSky models (which is not possible if the external bay is not available). I also did not want to hack into the radio to tap power, etc. And I wanted the module to be portable to any radio.

Here it is. It is totally self contained and has an internal 200 mAh LiPo battery (swappable), a power switch, and a built in momentary bind switch. It is lightweight and just hangs from the dongle out of the back of the radio when I am using it. Total time to build is 1 to 2 hours (it took me 3 or 4 I think but that includes the design/figuring).

If anyone wants more details so they can build one themselves I would be happy to share the details here in this thread.
Last edited by DaddyBigas; Jan 02, 2015 at 02:12 AM.
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Jan 02, 2015, 12:32 AM
65 years of RC flying
Daedalus66's Avatar
Please do tell us more!
Jan 02, 2015, 12:34 AM
KC
KC
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Yes, with lots of pictures. I'd rather look at one picture than read a 1000 words.
Jan 02, 2015, 01:50 AM
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DaddyBigas's Avatar
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OK, some notes and a schematic:
  • I used an OrangeRX R615X receiver because it has CPPM out on the BATT/BIND plug. I believe Lemon also offers a receiver which outputs CPPM.
  • I have a bunch of the little 200 mAh 2S batteries that are used in planes like the UMX Beast 3D so this is the battery I chose. It is small and has plenty of power I think. The one you see in the module happens to be a Glacier battery, but it is the same as the E-flite one.
  • The momentary switch is optional and is used for binding. But if you omit it then you would need to open the unit and deal with a bind plug which would be annoying I think. You could use any switch, but I happened to have a perfectly sized momentary switch from a parted out DX6i in my parts bin. UPDATE: The bind button is not even required. I learned something from another thread just now. If you plug the trainer module into the TX and then power up the module then the RX will enter bind mode automatically. If you power up the module before plugging into the TX then it will not be in bind mode. So this means you can toggle bind mode without the switch. Nice!
  • The case is a Radio Shack battery holder part number 270-409. I basically stripped it of all parts except the included on/off switch. I also removed some of the internal plastic parts to make it basically an empty plastic box which is what I needed. I just happened to have this in my parts bin but it turned out to be perfect fit and had the on/off switch already installed. And it is easy to open and close.
  • You could substitute a FrSky, Futaba, or any other brand of receiver if you wanted to wirelessly buddy box with those brands too.
  • I have not tested binding while the unit is plugged into a transmitter's trainer port. I bind with the unit unplugged from the trainer port. Probably not necessary but I am not sure if the transmitter would be happy with the momentary switch. Spektrum receivers are put into bind mode by shorting the signal to ground and I was not sure if the transmitter's trainer port would be OK with that. Likely it is fine but I have not verified this. UPDATE: See my comment above about not really needing the bind button.
  • I can't make any guarantees on any of this so perform this mod at your own risk .

UPDATE: Based on my above updated comments regarding the bind button I am considering (just for fun) building a second one of these that is much smaller and has no bind or power switch. I have added a second schematic for this simplified version. The caveat is that while this works with the Taranis, I don't know if a Spektrum radio (DX8 or DX7 for example) will have enough resistance in the trainer port to trigger bind mode. So I am leaving the original schematic.

ADDITIONAL COMMENT: You could also force trigger bind mode in the simplified design by shorting the 2 barrel sections on the 1/8" mono plug. So there are lots of options here.
Last edited by DaddyBigas; Jan 02, 2015 at 11:40 AM.
Jan 02, 2015, 12:37 PM
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DaddyBigas's Avatar
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Spektrum wireless module for radios without wireless trainer capability


The original worked fine but I could not stand knowing there was a simpler and smaller design. Here is the new one I just built (the new one is on the left in the picture and the original is on the right). It requires no bind button or power switch. And it can be charged without taking anything apart.



If powered before plugging into the trainer port it is in normal mode and ready to go.



If powered after plugging into the trainer port then it enters bind mode so you can link the slave radio.
Last edited by DaddyBigas; Jan 02, 2015 at 01:41 PM.
Jan 02, 2015, 12:45 PM
65 years of RC flying
Daedalus66's Avatar
Many thanks for that. I'll give it a try with my 9XR Pro.
Jan 02, 2015, 12:59 PM
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DaddyBigas's Avatar
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You're welcome. I will likely build another one using a D4R-II so I can buddy box with other FrSky users later. But at this point there are not that many in my clubs. But I seem to convert someone at most events. I don't really mean to, but when people see all the coolness there is much interest.
Jan 02, 2015, 01:37 PM
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Dave McDonald's Avatar
This is fantastic! A great idea!

Thanks for sharing it!
Jan 02, 2015, 03:47 PM
65 years of RC flying
Daedalus66's Avatar
The great thing about doing the buddy link with Spektrum (regardless of what the Master Tx is using to control the model) is that there are so many candidates for buddy box readily available: DX4e, DX5e, Dx6i, DX7, etc.
Jan 02, 2015, 03:50 PM
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Quote:
Originally Posted by Daedalus66
The great thing about doing the buddy link with Spektrum (regardless of what the Master Tx is using to control the model) is that there are so many candidates for buddy box readily available: DX4e, DX5e, Dx6i, DX7, etc.

So true. Even the little TX that comes with the Champ (etc.) works.
Jan 02, 2015, 04:49 PM
KC
KC
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Quote:
If powered before plugging into the trainer port it is in normal mode and ready to go.

If powered after plugging into the trainer port then it enters bind mode so you can link the slave radio.
This is so cool and simple! I've been thinking about doing the wireless buddy box for awhile. This is very useful. Thanks for the info.

KC
Jan 03, 2015, 10:47 AM
Registered User

Hmmm


Quote:
Originally Posted by DaddyBigas
The original worked fine but I could not stand knowing there was a simpler and smaller design. Here is the new one I just built (the new one is on the left in the picture and the original is on the right). It requires no bind button or power switch. And it can be charged without taking anything apart.



If powered before plugging into the trainer port it is in normal mode and ready to go.



If powered after plugging into the trainer port then it enters bind mode so you can link the slave radio.
Ok this last paragraph has me scratching my head. Initially I thought the Taranis would be the Slave in this scenario. After reading this it seems the Taranis is meant to be the Master, correct?

I'm learning to fly fixed wings and friend is buddy boxing with me. He uses a DX8 TX as Master. He holds the after setting the DX8 as Master he holds the trainer button until I need assistance.

How does your wireless setup work? Would it be possible for the Taranis to be the Slave?
Jan 03, 2015, 11:20 AM
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DaddyBigas's Avatar
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Quote:
Originally Posted by hoggdoc
Ok this last paragraph has me scratching my head. Initially I thought the Taranis would be the Slave in this scenario. After reading this it seems the Taranis is meant to be the Master, correct?

I'm learning to fly fixed wings and friend is buddy boxing with me. He uses a DX8 TX as Master. He holds the after setting the DX8 as Master he holds the trainer button until I need assistance.

How does your wireless setup work? Would it be possible for the Taranis to be the Slave?
This module and thread is for when the Taranis is to be the master in a wireless setup. But this module can also be useful for wireless when the Taranis is the slave. But the module would be plugged into the master in that case. See below...

If the Taranis is to be the slave you can, of course, just use the trainer cable. But if you want to be wireless there are several scenarios:

A. If the Taranis has a Spektrum module so it can fly Spektrum receivers, and if the Spektrum master is a DX6/DX9/DX18G2 then you can wirelessly buddy box with no additional hardware.

B. If the Taranis has a Spektrum module so it can fly Spektrum receivers, but the Spektrum master is a DX8 (or other TX without wireless trainer) then you can use my module above plugged into the DX8 and wirelessly buddy box.

C. If the Taranis has no Spektrum module so it cannot fly Spektrum receivers, then the Spektrum master needs to have my module plugged in to it but instead of my module having an OrangeRX receiver in it you would put a FrSky D4R-II receiver in it. Then you can wirelessly buddy box.

Make sense?
Jan 03, 2015, 01:10 PM
Registered User
Quote:
Originally Posted by DaddyBigas
This module and thread is for when the Taranis is to be the master in a wireless setup. But this module can also be useful for wireless when the Taranis is the slave. But the module would be plugged into the master in that case. See below...

If the Taranis is to be the slave you can, of course, just use the trainer cable. But if you want to be wireless there are several scenarios:

A. If the Taranis has a Spektrum module so it can fly Spektrum receivers, and if the Spektrum master is a DX6/DX9/DX18G2 then you can wirelessly buddy box with no additional hardware.

B. If the Taranis has a Spektrum module so it can fly Spektrum receivers, but the Spektrum master is a DX8 (or other TX without wireless trainer) then you can use my module above plugged into the DX8 and wirelessly buddy box.

C. If the Taranis has no Spektrum module so it cannot fly Spektrum receivers, then the Spektrum master needs to have my module plugged in to it but instead of my module having an OrangeRX receiver in it you would put a FrSky D4R-II receiver in it. Then you can wirelessly buddy box.

Make sense?
Yep got it, makes perfect sense, thanks.

So with the buddy box has the FrSky RX in it, I bind the Taranis to it and set the Taranis as Slave?
Jan 03, 2015, 01:21 PM
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DaddyBigas's Avatar
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Correct. The slave binds to the module. And the module is plugged into the master.


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