FrSky wireless trainer system

[disco stu]

I was on the FrSky site and noticed this document there http://www.frsky-rc.com/uploadfile/201106/20110608105158691.pdf

Blurb says: FrSky V8R7SP, D8RSP and TFRSP can be used as wireless trainer systems. Please find the how-to guide with the file named “Set up FrSky as a wireless trainer system” via the following link

And in the pdf there is a cable that links trainer port to a reciever.

It also says at the end of the document that V8R7SP can be used as well.

I"m trying to figure out if you have to use something futaba fassst compatable, or if you can get away with normal FrSky on your JR, Turnigy etc

Anyone use it or got an idea?

[kaptain_zero]

A quick look at the documentation indicates that this is all about using an FrSky receiver to replace the trainer cable connection. The documentation states that the "Student radio" *MUST* be faast compatible. The teachers radio does not have to be faast compatible, and it is the teachers radio that controls the model. You will need to use a FrSky TFRSP Futaba FASST compatible receiver connected to the "teachers radio" with the trainer cable and a FrSky TFRSP TX module installed in the "Student radio".

In other words, instead of having the cable link the student/teacher radios directly, you would use the FrSky TX/RX bits to make that link "wireless". Seems like an awful lot of work just to avoid the umbilical cord to me.......

Regards

Christian

[disco stu]

I spent ages reading through it all, and that was what they said at the top using futaba radio and also with fassst Rx on trainers radio. Its just that down the bottom of that document they had written that you could also use other recievers that were of normal FrSky format:

﹡FrSky V8R7SP and D8RSP can be used to set up wireless trainer systems too, along with respective
FrSky compatible modules. The module of the student’s radio needs to be replaced by respective FrSky
module, with the same set up procedures above.
Below is the compatibility chart:
Receiver Respective compatible module
V8R7SP Non-telemetry module: V8FT, V8JT, V8HT
Telemetry module in V8 mode: DFT, DJT, DHT, DHT-U
D8RSP Telemetry module in two way mode: DFT, DJT, DHT, DHT-U

Not sure what happened to the link in the first post, but try these

http://www.frsky-rc.com/uploadfile/2011 ... 158691.pdf
http://www.frsky-rc.com/download.asp?id=23

[disco stu]

I worded it a bit stupidly in first post also, saying using JR instead of faast, I meant normal FrSky instead of the faast compatable one. Edited, along with the dodgy link

[disco stu]

Should add my reasoning. I agree that its a lot of stuffing around for nothing that much better, but I'm keen to DLG with my son on a buddy box. Doesn't take much imagination to see that we both can't hold a Tx joined via buddy cable and launch as well, so when I saw this I thought it would be brilliant for what I want to do

[kaptain_zero]

Well, the way I read the requirements of the student's radio is that it must be able to *take* a FAAST module (as in compatible, it does not state that it must be a Futaba radio). The radio will not be equipped with a FAAST module, it would be the FrSky TFRSP module mentioned and the receiver would also be a FrSky of one of the models mentioned, and that receiver would be connected to the Trainer's radio via the buddy cord plug.

[disco stu]

Seems to be the PPM data stream that it needs, looking at those recievers.

Keen to have a play with it at least, just need to find a way to make that cord that it wants

[Shotglass]

It's quite simple really and I was feeling rather pleased with myself when I came up with the idea only to find that Frsky had the same idea a couple of weeks later.

Anyway the basic idea is that what gets sent through a trainer cable is the PPM frame you can see on this graphic both on the top and bottom (the two red graphs):



So any receiver that outputs a PPM frame can be used to do this.
As far as Frskys portfolio goes that would be either this one:
http://www.frsky-rc.com/ShowProducts.asp?id=48
or this one:
http://www.frsky-rc.com/ShowProducts.asp?id=80

To wire it all up what you do is you take either of those two receivers and wire a trainer cable to the signal and ground pins (ie. the yellow and black cable on a servo) of the PPM output (eg. channel 8 on the first receiver i linked to).
Then all thats left to do is plug that trainer cable into the teacher port of the teacher radio and provide it with power, preferably an external 5V battery so you dont suck the teacher radio's battery dry.

For the student radio you need one thats equiped with either an Frsky transmitter module (for the V8R7-SP) or a Futaba transmitter module (for the TFRSP).

The last step is to bind the student radio with the receiver thats plugged into the teacher radio and it should work as if youre connected via cable.


From our experience with it thus far (about 2h of flying I'd guess) it works very well and is a lot more comfortable than having to watch out not to get caught up in the cable.

[disco stu]

Thanks Shotglass, thats really helpful. Good to know I was starting to understand it correctly also. I can't see the images you posted as my work blocks everything, but will go over this again when I get home.

Will it matter if I get the PPM wires the wrong way around trying to figure out the correct way to do it/or do you know what will need to go where for JR trainer cable?

I'm really keen on getting this going, will make it really easy to teach using DLG.

[Shotglass]

Will it matter if I get the PPM wires the wrong way around trying to figure out the correct way to do it/or do you know what will need to go where for JR trainer cable?

Not really no, thanks to Murpyh's law I've soldered trainer wires on the wrong way round plenty of times before without incident.
It might case some unexpected servo behaviour if you get the polarity wrong so make sure to either unplug the motor or try with a receiver and servo youve got lying around.
JR is 3.5mm mono right? No idea which is which really (or whether or not JR radios expect positive or negative PPM inputs for that matter) but since there's only two ways to wire it up trial and error wont become too annoying.