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Offline walter__  
#1 Posted : 22 July 2014 18:12:42(UTC)
walter__

Belgium   
Joined: 30/12/2013(UTC)
Posts: 19
Location: Antwerp
Hi All,

We were working on a DIY locdecoder, which works rather nice, but only with MM2 commands.
They were used to do a low cost upgrade for old locs.. see our example rejuvenating an oldie
Recently we adapted the software to be used with the basic MFX commands, like speed and functions.
In order to add the feedback for programming and other extended communications, we would like to know if someone already did some research on the RDS topic, as it must be possible to do it software with minor external components.

Also should someone be interested in the progress we made, questions are welcome.

thanks,
Walter


thanks 1 user liked this useful post by walter__
Offline perz  
#2 Posted : 22 July 2014 23:33:34(UTC)
perz

Sweden   
Joined: 12/01/2002(UTC)
Posts: 2,578
Location: Sweden
I have made some experiments with picking up the feedback from a section supplied from a non-mfx-capable booster and retransmit it on the directly MS1-supplied section. See my article on my homepage: http://www.persmodelrailroad.com/mfx_boost.html. The feedback modulates the current consumption with approximately 130 mA, while the MS1 can detect variations down to approximately 13 mA. For a simple ping there is only the RDS carrier, and no data content, so that should be simple. I have not digged into the more complicated real data responses, but some hints can be found in Rainer Müller's description of the mfx protocol:

http://www.alice-dsl.net/mue473/mfxmenue.htm

Edited by user 03 August 2014 23:08:28(UTC)  | Reason: Not specified

thanks 2 users liked this useful post by perz
Offline walter__  
#3 Posted : 23 July 2014 13:33:50(UTC)
walter__

Belgium   
Joined: 30/12/2013(UTC)
Posts: 19
Location: Antwerp
@perz we exchanged some info a few month ago, after seeing your site I was already convinced that using a transformer was better than a resistor.
I took an interference suppressor coil from an old PC power supply and removed a coil counting the loops, then added a 1.5 mm² as primary.
Result is a 1 to 25 transformer which gave good signal.

trafo 1 to 25
For now I used a simple passive RC filter, but I ordered some RDS chips to further examine the signals after filtering 52.632 KHz

the final goal is to implement some encoder software with filter and modulator in the locdecoder ThumpUp

more info later
walter__ attached the following image(s):
trafo.jpg
thanks 1 user liked this useful post by walter__
Offline kiwiAlan  
#4 Posted : 03 August 2014 21:01:32(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 8,067
Location: ENGLAND, Didcot


I am unable to reach this web site. Has it moved elsewhere?



Offline perz  
#5 Posted : 03 August 2014 23:12:50(UTC)
perz

Sweden   
Joined: 12/01/2002(UTC)
Posts: 2,578
Location: Sweden
Originally Posted by: kiwiAlan Go to Quoted Post


I am unable to reach this web site. Has it moved elsewhere?





Sorry, http://www.persmodelrailroad.net is down for the moment due to change of ISP. But all the content is also available at http://www.persmodelrailroad.com. I have edited my previous post.
Offline kiwiAlan  
#6 Posted : 05 August 2014 18:34:56(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 8,067
Location: ENGLAND, Didcot
Originally Posted by: perz Go to Quoted Post
Originally Posted by: kiwiAlan Go to Quoted Post


I am unable to reach this web site. Has it moved elsewhere?





Sorry, http://www.persmodelrailroad.net is down for the moment due to change of ISP. But all the content is also available at http://www.persmodelrailroad.com. I have edited my previous post.


Ah, OK. Unfortunately that one doesn't have the mfx booster on it.

Thanks

Alan
Offline Moritz-BR365  
#7 Posted : 05 August 2014 23:35:15(UTC)
Moritz-BR365

Germany   
Joined: 02/04/2013(UTC)
Posts: 682
Originally Posted by: walter__ Go to Quoted Post
Hi All,

We were working on a DIY locdecoder, which works rather nice, but only with MM2 commands.
They were used to do a low cost upgrade for old locs.. see our example rejuvenating an oldie
Recently we adapted the software to be used with the basic MFX commands, like speed and functions.
In order to add the feedback for programming and other extended communications, we would like to know if someone already did some research on the RDS topic, as it must be possible to do it software with minor external components.

Also should someone be interested in the progress we made, questions are welcome.

thanks,
Walter

Hello Walter,
a great project to have such a basic decoder to reuse old AC motor locos without converting the motor to a DC motor! I would be interested in testing one...

Moritz
Offline walter__  
#8 Posted : 12 August 2014 21:16:29(UTC)
walter__

Belgium   
Joined: 30/12/2013(UTC)
Posts: 19
Location: Antwerp
Originally Posted by: Moritz-BR365 Go to Quoted Post
Originally Posted by: walter__ Go to Quoted Post
Hi All,

We were working on a DIY locdecoder, which works rather nice, but only with MM2 commands.
They were used to do a low cost upgrade for old locs.. see our example rejuvenating an oldie
Recently we adapted the software to be used with the basic MFX commands, like speed and functions.
In order to add the feedback for programming and other extended communications, we would like to know if someone already did some research on the RDS topic, as it must be possible to do it software with minor external components.

Also should someone be interested in the progress we made, questions are welcome.

thanks,
Walter

Hello Walter,
a great project to have such a basic decoder to reuse old AC motor locos without converting the motor to a DC motor! I would be interested in testing one...

Moritz


Hi Moritz,

With adding the MFX software we came into timing limits, to keep things stable we are moving from AtTiny4323@8MHz (internal) to AtMega88@16MHz (Xtal) also to accommodate the RDS feature later on..
While waiting for some chips to arrive from China, to do final testing, I expect the new PCB layout to be ready for fabrication just before our vacation, so it can be assembled and tested immediately after..
The timing on this is start October, if you like I can provide you one by then for beta-testing.. will keep you informed meanwhile

Walter
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