Computer controlled help.

Chrisms Jul 2, 2008

  1. Chrisms

    Chrisms TrainBoard Member

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    Hi guys,
    I'm new to this whole deal, but I've got a decent background working with robotics, and i program computers + web sites. so I'm not totally lost. But I'm a bit lost here.
    I'm looking to segregate my tracks electrically, in a way that I can control which section of track is on, off,speed, and direction. My ultimate goal, is to hook this up to a computer via a serial port through something along the lines of a basic stamp (except not, because i hate PBasic, and I don't think basic stamps do PWM out... i may be wrong i hate working with parallex stuff) And be able to have sensors (most likely IR, but i might even go RFID just for the sake of learning RFID) along the track know when a train passes it, signalling which section of track the train is now in, and being able to "map" where trains are in the program, and keep track of the train through the track via programming that i'll do.

    The question is, has anyone tried anything like this before? And also, i'd need to know waht kind of current actualy flows on the rails, what voltage and amperage the trains need to run normally. Also, if anyone knows of any (multiple names for this) PWM controllers/speed controolers/motor controllers/drivers That would work in this application that would be awesome.

    I'm not sure if i made sense to anyone but myself, if i didn't, let me know i'll try explaining it differently!

    thanks a ton!
     
  2. rray

    rray Staff Member

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    Have you thought of using DCC, because it sounds like you are trying to re-invent DCC.

    I am a Z Scale modeler, and have 2 computer controlled modular layouts. I use NCE, and connect my PC to the controller with the RS232. I use the free Panel Pro/Decoder Pro to run the layout and control speed, direction, sound, turnouts, and more.

    There are also block detectors, and transponding so you can detect the location of trains on your layout. the RFID sounds cool for the rolling stock, but you would need several readers placed around the layout.
     
  3. dstuard

    dstuard TrainBoard Member

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    Unless you want to do a roll-your-own system, Digital Command Control (DCC) is what you want to look into. This has evolved over the last 15-20 yeards or so and is pretty much standardized now. Some of the technical stuff is in the NMRA standards and RPs (http://www.nmra.org/standards/sandrp/consist.html) . Appropriate sections of S9 and RP9 should be of particular interest.

    As to computer interface and control, there are a variety of approaches, depending on which system you use. Digitrax, IMHO offers the most flexible approach (http://www.digitrax.com), employing a robust peer-to-peer network (LocoNet) to connect the main components. Third party vendors also support LocoNet as well as connection to a computer (via a LocoBuffer-USB from RR cir-kits (http://rr-cirkits.com/) or the Digitrax PR3) running packages such as the JMRI suite (http://jmri.sourceforge.net/)(freeware) or RR&Co (http://www.freiwald.com/) ($$$). Other systems offered by Lenz (http://www.ncedcc.com/), NCE (http://www.ncedcc.com/), etc. are also good and are NMRA compliant at the track interface.

    If you're a techie, the above links will give you enough to chew on for a good while. If you're not, it will fry your brain.

    If you want to step back a little, here are some DCC turorials:

    http://tonystrains.com/tonystips/dccprimer/index.htm

    http://litchfieldstation.com/lobby/u_university.htm

    http://www.siliconvalleylines.org/dcc/presentations.html

    http://www.wiringfordcc.com/wirefordcc_toc.htm

    Buuuttt.....If you want to go deeper, I can give you a few more refs as well.

    Welcome to the hobby(?)
     
  4. Locomotion

    Locomotion TrainBoard Member

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  5. Lownen

    Lownen TrainBoard Member

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    I'd have to agree that, unless you're trying to re-invent the wheel, Digitrax is the way to go. Yes, there are other DCC systems, some more user-friendly. But Digitrax not only offers block detection, they have actual transponding... so you can know not only what block a train is in, but which train is in it. Digitrax transponding is pricey, but probably not a lot compared to the R&D you'd be getting into. The main questions are, what is your time worth? and is the development what is enjoyable to you or is running the trains what you want to do.

    Best!
     
  6. Chrisms

    Chrisms TrainBoard Member

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    I was considering them already:) great minds think alike eh?

    secondly: whoa. wait, you're blowing my mind here, you're telling me that these "decoders" go in the locomotives and control each one individually? I'm going to have to read up on this before i ask any more questions i suppose. haha, unless you guys want a few "noob" questions... i'd still have to come up with a way to "track" a train i suppose.it doesn't look like DCC offers any sort of ability to know exactly where on the tracks the train is? or have i just not read enough yet.
    i'll go back to reading, this is very cool, it seems i've been beaten to the punch by the system! (speaking of the system ,does DCC interface with a computer in real time well?)
     
  7. dstuard

    dstuard TrainBoard Member

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    Decoders can even go in Z scale locos and have amazing features. Here's one example: http://www.digitrax.com/prd_mobdec_dz143.php

    Digitrax transponding can locate a specific train (actually, a decoder) in a specific detection block. Any finer resolution would require Time Domain Reflectometry (good luck!).

    ...and no, you haven't read enough yet...nobody has! :tb-tongue:

    DCC can interface real time. With Digitrax it's via a LocoNet-to-USB interface and appropriate computer software. See my previous post.

    read, read, read......:tb-wacky:
     
  8. Chrisms

    Chrisms TrainBoard Member

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    god, this stuff.. is exactly what i was trying to do on my own... only, mine would have been a lot less..... kosher. haha.

    thanks a bunch guys! this is all very helpful!
     
  9. Lownen

    Lownen TrainBoard Member

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    Here's my non-technical overview of DCC. At the bottom of the page is a link to a good technical article.

    An Overview of Digital Command Control (DCC)

    By the way, the new DZ125 is smaller than the DZ143. There may be some slightly smaller decoders available from Europe. I haven't checked lately.

    Best!
     
  10. Chrisms

    Chrisms TrainBoard Member

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    alright, thanks for that info guys:) i've read up quite a bit. but all of this is.. lacking in my book... I'm curious, what exactly do these decoders do? is there some sort of PWM (pulse width modulation) going across the tracks, with a start bit that lets the decoder know who the instruction is meant for, then say 6 bits of instruction, then a stop bit?

    but also, my *main* reason behind wanting to do this was to create sections of track, and know if a train was occupying that section of track. I've seen things that say they can "detect" trains, but it seems a bit expensive, to detect one section of track it looks like it would be $100, dividing that up into 10 sections and it's a grand, just for segmenting your track? Is that an accurate estimate of cost? I'm looking to segment the track, know where a train is (which segmant it's in) know when it leaves (and if the last car leaves as well, this way if i have a derailment i know) and send all this data to a computer, which would re-route other trains around the derailment/not cause any crashes.
    is DCC really a viable option for that? I'm finding it hard to find info on detection and computer interfacing, any tutorials on those anyone knows about? thanks guys!
     
  11. mfm_37

    mfm_37 TrainBoard Member

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    I think you need to read a little deeper in the product manuals. e.g.Digitrax BDL168 will get you 16 detection sections for $150 msrp. Street price would be lower yet. Still less than $10 per section at full retail.
    We use Team Digital DBD22's on our NTRAK layout. About $8 per section.
     
  12. Chrisms

    Chrisms TrainBoard Member

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    haha, i'm embarrassed now... I did look at that too, i forget why i wrote that off as not being what i needed... thanks, i feel really dumb now, haha. I thought for some reason that was only used for signals...

    anyone up to being able to explain how this all works from a technical standpoint? i'm dying to know.. My friend who goes to Cornell and works for Lockhead can't even figure it out... We've been stumped! haha.
     
  13. Phil Olmsted

    Phil Olmsted TrainBoard Member

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  14. Chrisms

    Chrisms TrainBoard Member

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    ahhh that's exactly what i was looking for! sort of what i figured, but whoa, the decoders have an internal power supply (capacitor). they're getting small.. wow.

    thanks for all the help! i'll be going to the local hobby shop probably Monday (since i think they're closed tomorrow and today for the 4th such stuff)
    now i can go in knowing what i need and not be a *total* idiot:)
     
  15. Lownen

    Lownen TrainBoard Member

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    A DCC decoder has much more than just a power supply in it. I've written a brief technical overview of what decoders actually do on my About.com site. I hope this is helpful.

    How a DCC Decoder Works

    Best!
     
    Last edited by a moderator: Jul 6, 2008
  16. L Lee Davis

    L Lee Davis TrainBoard Member

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    It does sound like your trying to reinevnt the wheel, I go along with most others that DCC is what your looking for. Now if you want trains and computers have a look see at Zimo www.zimo.com They are not cheap but they will do just about everything you stated you want a layout to do. HUL, STP, Rail-Com, and Cann Buss are some of the platforsm and software upon which they are built. Their decoders are fawless, smooth as silk and slow speed that's hard to beat. Other systems will do it too although not as seamless. I would caution you to have a close look at all the systems out there and pick which one works best for you.
     
  17. russmc

    russmc TrainBoard Member

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    zimo.com is a different site, the one you want is: ZIMO, model railway control with future

    WOW those are VERY cool. If they fit in N gauge I might consider them!

    Actually I'm rolling my own radio system for my G scale locomotives and turnouts. I'm going to use battery power with auto charging while on powered sections of track. Just something I've always wanted to do. I have a few train engineers and they are fine but my design uses 434 MHz radio so shorter antenna and ~100 yard range with 8 different channels each having 255 receiver IDs. 256th ID is the reserved broadcast all-stop address. Not that I'll ever have that many receivers.

    I built the radio systems for another use and they worked so well I had to prototype one for use in my trains. Once I make the first receiver boards and work out any electrical noise issues I'll try to post a picture or two.
     

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