Problems with JR XP652 - Loss off Signal

[JeffP]

I have built two different serial interfaces from the links on this site.
When I connect the interface to the PC the signal is seen and I am able to calibrate the transmitter, but after 5 seconds the signal is lost. If I unplug the lead and plug it back in the signal is seen again for another 5 seconds.
Have you any suggestions for a solution.

[bsergeev]

Wow! That's exactly what I get with JR 622!
I tried to play with the resistor values--nothing changed!
At the same time, the first interface (the first diagram at French site) works great for Futaba. I tried to make a parallel cable for Futaba and it was jittery as h*ll (I tried several different circuits). Serial worked great for Futaba but not for JR, which usually works fine with parallel cable.
Strange situation! It would help if Herr Moeller disclose the pieces of code, which read setial and parallel ports.
I'm going to buy an oscilloscope and measure the trainer signals of different brands of transmitters (I'll post the results as soon as I get them), but without knowledge of FMS port reading algotithms, my data will have little use.

[Steve Lewin]

By poking round with a 'scope I found that the trainer signal from JR (652 and old Max 6) actually floats with respect to ground. The others all have nice fixed amplitude from 0V to about 6V.

I got the published serial i/f working reliably by adding a transistor and capacitively coupling the signal in. Circuit available if you need it.

Steve

[JeffP]

Steve

This sounds very interesting unfortunately I am not very good with electronics but I can follow a circuit diagram, so if you have one that will be great.

Thanks Jeff

[Steve Lewin]

I've uploaded the modified circuit to [url=http://members.tripod.co.uk/SteveLewin/index.html

I'm]http://members.tripod.co.uk/SteveLewin/index.html

I'm[/url] sure it could be simplified but at least this one seems to work. I don't use JR myself but it's been tried with an XP652 and an old Max6 so far. If you use it with a different model of Tx please let me know so I can add it to the list.

Steve

[JeffP]

Steve

Thanks for your reply the circuit works fine, and I am now able to use FMS.

I do have another question, if you can help, the controls seem a bit jittery when calibrating, is this due to the JR or FMS?

Having put a scope on the output from the interface, I do not get a stream of pulses as I would expect. The first pulse seems to have a very large amplitude with the following pulses very much reduced, is this a characteristic of the JR buddy connection? or is this causing the unstable controls.

Thanks again for your help.

[Steve Lewin]

Hi Jeff,

I'm glad it works for you. I've never managed to get rid of all the jitter in the signal though I've built a few different interfaces, serial and parallel, for Futaba/Hitec and JR. A good screened cable helps and the serial i/f seems a little better than the parallel but it always jitters.

Mine is now not too bad but you can't really fly hands off even if you can get the models in trim. I'm sort of hoping that it's something to do with the way FMS reads the i/f and that it will be fixed sometime soon. But who knows ? At the price we paid for FMS I'm certainly not going to complain

Steve

[domador]

fue el unico que me funcionó en JR!

good luck!

[Deimos]

Hi Guys,

I'm using FMS 2.0b6 and a JR-452 controller via the serial port. I can't seem to get the interface working at all and I'm not sure why, although FMS runs like a dream.

I could be missing it, but the RTS and DTR lines don't seem to even flicker when I start FMS (and RTS/pin7 needs to be set to provide +'ve power the interface). All appears OK if I run up Hyperterminal.

Also, FMS isn't displaying the Transmitter option in the Controller menu for me, only Keyboard and Joystick. Since I've seen a screenshot of 2.0b5 displaying the Transmitter option, I tried running it to see if I got the same result - unfortunately it doesn't run on my system.

I guess I have two questions for you:
1. Is the Transmitter option supposed to appear in 2.0b6 (and all of the time)?
2. Do you have your new circuit available on another web site? (Freebox.com seems to have killed its webhosting services.)

Thanks for any help you can provide,

Anthony.

[Steve Lewin]

What operating system ? The transmitter option doesn't work in Win NT or 2000.

What circuit are you using ? My modified one (from the Tripod site) or something else ?

Steve