Student trainer mode

Post by **Kilrah** » Thu Jun 07, 2012 5:41 am

I used to crimp servo plugs long ago, when we were paying $5 for a simple servo extension...
Now we have 10 for $2 at HK I don't bother, and cut an extension in 2 if I need just one plug. If it's to lengthen a servo cable I've always cut the servo's wire and soldered wire inbetween, reusing the original plug.

Post by **ShowMaster** » Thu Jun 07, 2012 7:24 am

About inexpensive cables, soldering, and shrink tubing.
To each his own. I just like to keep my connections just as short or long as needed and as custom looking as possable. Many are solder chalanged from what I fix for free at my club field. I also make custom smaller diameter servo extensions for the mini plane flyers. I wouldn't want to wast time soldering those up from extensions. Just cut the bulk wire to length, or cut down one end of an extension and in 3 or 6 fast crimps a custom cable is ready to go.
Black electricians tape is cheaper than shrink tubing, I see a lot of that also. Duct tape is being used more and more for repairs and holding motors on planes as well.
I just like to raise the bar a little with my electronic projects. If you solder well, have the extra time and it works for you than it's all good.
In my case, one $30 tool for a lifetime works for me and I was asked to post more info BTW.
SM

Post by **Crucial** » Thu Jun 07, 2012 3:27 pm

SM that is the same crimper I have. It works good but I have to be careful as sometimes the crimp breaks the tabs when crimping. I bought mine at some other website though.

In reading Kilrah's post I don't think he was criticizing your post. Just posting a different opinion.

Post by **ShowMaster** » Thu Jun 07, 2012 9:50 pm

All's good! I may have misunderstood and only wanted to post the bennifets.
It was never meant to get so far off topic and that's ending now. We all want to help and sometimes it gets messed up in trying to help. If I'm guilty of that I'm sorry.

SM

oiseau · Post by **oiseau** » Sat Jun 09, 2012 3:54 pm

I got my hands on the dx5e... plug and play! except that the channel order is TAER, almost cost me a finger!

Ufdah · Post by **Ufdah** » Fri Jun 15, 2012 3:51 am

I'm trying to set up a DX5E as slave to my ER9x and I'm not having any luck. Oiseau could you give some details about how you got this set up? Mono or stereo cable? What are the power switch positions on each trainer? Did you have to do any mods to get it going?

Post by **Kilrah** » Fri Jun 15, 2012 8:27 pm

He uses the Spektrum TX as master. This way, no problem.
With the 9x as master, no way without HW mod (a buffer in the cable) as Spektrum radios put out a signal that is too weak.

kaos · Post by **kaos** » Fri Jun 15, 2012 9:05 pm

What kind of buffer? can you be more specific?

Post by **Kilrah** » Fri Jun 15, 2012 9:16 pm

There have been several threads about that lately.... don't have a link though, maybe a little search...

Ufdah · Post by **Ufdah** » Sun Jun 17, 2012 4:40 am

oiseau wrote:Ah, new replies, thanks for the additional information, let me know if this is what you mean.

oiseau, thank you for putting this thread together! I used your schematic from Ghost in my trainer cable and it works! I didn't have two 1K resistors so I used a 680 on the 9x side and it worked just fine. I actually didn't have a NPN either but I found a tiny surface mount transistor driving the speaker on my Hobby Zone Champ transmitter and was actually able to fit both resistors and the transistor inside the 1/8" plug on the end of my cable. It looks super clean since there is no external circuit board and I didn't have to mod the transmitter.

It's pretty great, I was able to remove the transmitter module from my DX5E and put it inside my 9x and now I can use either FlySky or DSM2/X then I took the DX5E body and turned it into a slave box since it doesn't transmit any more. No waste!

Ufdah · Post by **Ufdah** » Mon Jun 18, 2012 3:43 pm

Went out and used the DX5E as a slave to my ER9x yesterday and it worked flawlessly! Thanks so much, I was able to introduce two friends to the hobby.

Post by **ShowMaster** » Mon Jun 18, 2012 5:17 pm

Wiki!
SM

oiseau · Post by **oiseau** » Wed Jun 20, 2012 10:57 pm

Ufdah wrote:
oiseau wrote:Ah, new replies, thanks for the additional information, let me know if this is what you mean.

oiseau, thank you for putting this thread together! I used your schematic from Ghost in my trainer cable and it works! I didn't have two 1K resistors so I used a 680 on the 9x side and it worked just fine. I actually didn't have a NPN either but I found a tiny surface mount transistor driving the speaker on my Hobby Zone Champ transmitter and was actually able to fit both resistors and the transistor inside the 1/8" plug on the end of my cable. It looks super clean since there is no external circuit board and I didn't have to mod the transmitter.

It's pretty great, I was able to remove the transmitter module from my DX5E and put it inside my 9x and now I can use either FlySky or DSM2/X then I took the DX5E body and turned it into a slave box since it doesn't transmit any more. No waste!

Good to know that it works, I will have to make one myself

frviana · Post by **frviana** » Sat Apr 13, 2013 10:19 pm

Could someone be kind enough to post a picture of the cable assembly? Im not great in reading the electronic diagram... for me looks like the resistors are in series on a single wire from this diagram.
I'm trying to have my 9X as Master and my DX7 as slave. Running Frsky on the 9X.

Any help would be great.

Thank you

Post by **jhsa** » Sun Apr 14, 2013 12:29 pm

Maybe it helps

frviana · Post by **frviana** » Tue Apr 16, 2013 12:00 am

Thank you... It did help... Will build it now and will post the results. Thank you.

Sent from my SGH-I747M using Tapatalk 2

Post by **ShowMaster** » Wed Apr 24, 2013 6:19 pm

I built this circuit up today and so far not so good. I'm using a dx7 as the trainer and tried several 9x builds as the master and one sky Ver c board.
The 9x does put 5v on the collector but the dx7 is putting out a ppm signal that's at zero and goes negative from there 2-3 volts. The NPN is never turned on to drive the collector.
I ran out of time and will try again with scope pictures later.
It's been asked before and this circuit has always been the answer but I'm not sure anyone's ever actually posted that it works for them with a JR, Spektrum or any other newer tx ppm out into a 9x that's the master?
I would like to see this sorted out since the 9x wants to see a much higher ppm in than most TXs put out these days. I wonder what the new Frsky tx wants as a ppm trainer input?
SM

Sent from my iPod touch using Tapatalk.

Post by **MikeB** » Wed Apr 24, 2013 9:25 pm

Try swapping the two wires from the DX7 to give a positive signal. The two transmitters dont really share a ground signal.

Mike.

ReSt · Post by **ReSt** » Wed Apr 24, 2013 9:37 pm

Or use a capacitor in series with the basis resistor

Reinhard

Post by **MikeB** » Wed Apr 24, 2013 9:52 pm

If you use a capacitor, you may need a diode across the base-emitter junction of the transistor to provide a symmetric charge/discharge path for the capacitor.

Mike.

Post by **ShowMaster** » Wed Apr 24, 2013 11:09 pm

Thanks guys, I'll try all the suggestions.

Sent from my iPod touch using Tapatalk.

Post by **ShowMaster** » Wed Apr 24, 2013 11:33 pm

I didn't try my JR pcm10 as a trainer yet. Does anyone have a clue what the ppm output circuits look like for JR or Spektrum?

FYI I did find another ppm interface circuit to try. It seems to address the cap coupled ppm output.
Maybe the input circuits cold be used?
The 9x seems to supply and use a 5v rail.

: ImageUploadedByTapatalk1366845380.808327.jpg (23.01 KiB) Viewed 15356 times

Redrawn

: ImageUploadedByTapatalk1366845443.782190.jpg (27.2 KiB) Viewed 15356 times

SM

Sent from my iPod touch using Tapatalk.

Post by **ShowMaster** » Sat May 04, 2013 8:52 pm

gohsthb wrote:That circuit is meant to go in the trainer cord. So you would need to at least have to cut an existing trainer cord. The collector of Q1 would be wired to the end of the mono plug. And ground would be hooked to the other part. On the other side of things the end of the mono plug would get connected to R2.
Now that I have thought about it a little more I think 1 more resistor should be added on the collector side. This is just to save the hardware, should the 9x try to output 5V on the trainer port and the student tx try to pull the line low at the same time. That condition would cause a short through the transistor, the extra 1k resistor would limit that current.
-Gohst

Just to keep this topic and discussion going I'm replying to your post but it's meant for anyone trying to solve this.
I tried the 1 transistor circuit and a few other configurations and I still can't get the Spektrum or JR ppm out converted to 5 v ptp to drive the 9x ppm in.
I'm sure there is a cap involved in the ppm out that's not allowing the converter to reference to ground.
I've also read that the newer TXs use some open collector circuit and may also be through a cap.
A goggle search unfortunately as expected doesn't find a Spektrum or JR ppm output circuit diagram so I can't see what's actually going on. I probably can open up my dx7 and try to reverse engineer the ppm out circuit but I'm hoping to avoid that.
Someone must have worked this out and can post a circuit they personally have used, I'm counting on it.
It doesn't have to be powered by the TXs, even using a battery in a small inline circuit box is ok with me.
I have the parts for a wireless trainer setup and may personally go that route in the end but solving this will benefit everyone.
I'm not sure about the latency of a wireless setup?
Also any mod internally made to the 9x defeats the concept of being a universal external trainer cable.
Thanks and I can't wait for the person with a working verified circuit it to be a hero and save the day!

SM

Sent from my iPod touch using Tapatalk.

Post by **MikeB** » Sat May 04, 2013 10:08 pm

Just having a brainstorm on this, I wonder if the following will work:

: Trainer1.png (2.49 KiB) Viewed 15320 times

It attempts to bias the transistor from the (internal) 5V supply, allowing a low level, capacitively coupled signal to switch it on and off.
Some of the resistor values may need adjusting.

I'll try it myself when time permits, but it looks like decent flying weather tomorrow!

Mike.

Post by **ShowMaster** » Sat May 04, 2013 10:41 pm

What bothers me Mike it that the 1 transistor circuit posted on previously has some saying it worked with their JR or Spektrum. I know the internal 9x added to the 4066 circuit posted several yeas ago works for me but I not anything external. I'm just trying to pin down weather I'm messing up or what?
Please try both yours and the other posted circuit if you get a chance.
I'll try yours right after I button up my megasound moded tx now that it's working. I have some wiring to clean up.
This trainer circuit should be so simple.
I haven't tried a JR with my 9xr yet? Too bad HK didn't post the schematics for a "open FW tx" they produced.
I'll test it with my 9x, pcm10, a dx7, a older Futaba, and a lower end newer JR first chance.
SM

Sent from my iPod touch using Tapatalk.

leonalee · Post by **leonalee** » Sun Jun 28, 2015 5:43 pm

Crucial wrote:Oiseau, here is a link with different electrical symbols and their descriptions

http://www.rapidtables.com/electric/ele ... ymbols.htm

one more resource which helps you with more information, all symbols along with how it will helpful, hope this information helps.

http://www.electronicshub.org/symbols/

Post by **ShowMaster** » Wed May 04, 2016 8:55 pm

I'm finally working on getting a JR S400 trainer tx to output a usable ppm level. Old discussions around on JR so I hope this one is active.
Mike came up with a circuit some time ago for the 9x. The trouble is not all tx's have a collector voltage source. I'm thinking I'll just buffer the S400 opm out. This tx will never be used as a master again on 72 MHz.
The current pulse train is what I'll call going negative 1.5v ptp, too low for most tx's trainer inputs. I'm going to make sure it works with a original DX7 as these are still used as club trainers, why this tx was purchased original but never worked. It should work with a Taranis and other tx's if buffered to 5v ptp.
I'm in the process of tracing the S400 Ppm out circuit. I've found a good 5 volt reg buss I can use.
For MikeB or anyone reading this, I'm thinking of using Mikes circuit as a start.

The added cap is to remove the DC component from the base transistor input.
Mikes earlier post
"There is a pull-up resistor on the trainer input of the 9X, which is why the circuit doesn't need one or power.
The cap on the input centres the input signal, by removing the DC level, at the base voltage of the transistor.

Mike."

I'll know the answer to my next questions when I build it, but I'm brainstorming now.
Since this circuit will be installed in the S400, I'll use the internal 5v on the collector.
Now here's my questions.
Will adding the cap on the input, prevent the output from being inverted from the input, or will I want to use 2 NPN's to invert again?
Will I want to cap couple the output to the master tx for protection from any masters power buss?
I am surprised that the S400 doesn't have posts on solving it's low ppm out? A search only found those asking for one or referencing to using it on a JR. Not having access to a JR comparable tx, I have no idea of what it's ppm trainer input circuit is?
Hopefully this will result in a fix others can use.
I haven't figured out how the S400's master/trainer circuit works yet. If I do, maybe I'll try and preserve it, not just a trainer.

Daedalus66 · Post by **Daedalus66** » Thu May 05, 2016 12:09 pm

Thanks for sharing your efforts. I suggest pursuing the simplest solution that will convert the S400 to a viable buddy box for use with Spektrum, Er9x/ErSky9x and OpenTX transmitters. I can't imagine anyone at this point wanting to use the S400 as a master transmitter!

Post by **ShowMaster** » Thu May 05, 2016 2:49 pm

I made some progress. I used 2 2n7000 fets to buffer and keep the polarity. I've found a good 5v source and ground on the S400 board along with a Ppm source.
I have a first attempt 5v ptp from 1.5v ptp Ppm signal.now.
It look good on the scope.
Now I'm not sure how to couple it's output to my dx7 and other tx's?
Use a resistor, cap, or maybe a diode?
I'm concerned about the possibility of mixing student with master trainer port voltages if there are any?
I'm using basically Mikes circuit but with 2 cascaded fets and 8k drain resistors to keep the polarity correct (collector on his circuit). I just grabbed parts I had handy.
I'm thinking on the output coupling next and then try it.

Daedalus66 · Post by **Daedalus66** » Thu May 05, 2016 4:31 pm

I'm watching with interest but can only offer moral support!

openrcforums