My Digitrax/Smail switch motor journey (critiques welcome/needed)

SDVike Aug 1, 2021

  1. SDVike

    SDVike TrainBoard Member

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    I have decided to start a thread related to my use of SMAIL switch motors on my layout. I've found almost no information on people using them online. There are 5 or 6 videos on Youtube related to them that go beyond the very basic parts. Not a single one of them show install with a control panel. Thats not surprising considering they are designed to be controlled from a DCC controller. I'm not sure why I want a push button control panel so bad when it will add a ton of work to my wiring. I guess, I'm hoping that it will make it easier for my kids to use.

    I thought about posting this under my build thread, but I really want help from those who have done this before. I think it will be helpful for those looking for information on the SMAIL motors. I am doing all this based on Youtube videos and Criterion documentation. I'm also learning DCC and Digitrax at the same time. I'm sure I will make errors so please critique and warn me of errors.

    So I think I will start with the Electrical Diagram related to the SMAIL motors. At some point I will get to the Digitrax side of the adventure, but I feel I need to lock in the SMAILs first.

    As you can see, I will have 2 wiring busses. One will be the DCC feed for the Smail motors. The other will be the track bus. By having two separate busses, I don't need to worry about a short on the track causing the switch motors to stop working (assuming i have two boosters).

    If you have used a TORTOISE, some of this will be familiar. SMAIL motors are pretty much the same except, the power comes from the DCC track instead of a constant power source. They include a DCC decoder allowing you to control them from a DCC handset (or JMRI). They have the same 8 connectors as a TORTOISE. 1 & 8 are for the DCC power. 2, 3, 4 are one DTP switch and 5, 6, 7 are another. Finally, there are 3 connectors that allow you to control the SNAIL using push buttons in a panel.

    My diagram shows me using one of the internal DPT switches (2-4) to electrify the frogs of my turnouts. DPT 5-7 will switch the LEDs on the control panel. I will use Kadee push buttons on the control panel. I haven't decided on LEDs (suggestions welcomed).

    When I started back into the hobby, I got over aggressive buying wire. I ended up with a 100' feet of 14 ga solid wire in Red and White. If I hadn't cut off 3 feet from each wire, I would have returned it as it was really expensive. It will be my buss wires. For each SMAIL motor, I will wire up all the connections to the motor at my workbench using 18 ga Thermostat wire. It is also solid. Its the cheapest I could find at my local HD.

    The extensions from the Terminal Strip to the control panel will use the same 18/7 solid thermostat wire. In the control panel, it will connect to another terminal strip. At that point, I will connect to the LEDs, Push buttons and power source using stranded wire so it can flex without breaking.

    So now, I need to order a bunch of Terminal strips, wire up 17 SMAIL motors, create a layout on my control panel, settle on power district, and hook up my Digitrax base. Looking at this, I'll probably be done by Christmas.

    And finally, I added a picture of my first buss line in.

    [​IMG]
    [​IMG]
     
  2. SDVike

    SDVike TrainBoard Member

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    In all the DCC videos I watch they talk about breaking down the layout into power districts. This is for trouble shooting reasons. I'm not sure what size to make the power districts. I'm thinking it makes sense to make the branch line (green) one district. Do I make the rest a district or should I break out the yard (yellow/brown)? Eventually the red main will be extended.

    FYI, I'm thinking of making the blue track a programing track, although I am also thinking of making the lowest yellow track a programing track.


    Screen Shot 2021-07-31 at 8.57.32 PM.png
     
  3. BigJake

    BigJake TrainBoard Member

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    With DCC, power districts are used for different reasons.

    1. reversing sections (each fed by an auto-reversing switch or booster).
    2. current-based occupancy detection for automated trackside signals, automated control of trains, etc.
    3. limit maximum current to any given section of track to levels that won't damage equipment if a short develops (generally on fairly large layouts with lots of locomotives running). This current limit is also related to scale (larger scale equipment both draws more current and can generally withstand more current in a shorting situation without damage than smaller scales.) For example, it's probably a good idea to limit N scale power districts to ~3A or so. This could mean just using ~3A circuit breakers to drive separate districts off the same booster/command station.
    4. programming locomotives vs running trains (or just being able to leave other locos on the layout while programming one loco on the designated programming track)
    I look at your layout, and as it stands now, #1 & #3 do not apply. #2 may apply when you add on to it, but then the additional track can be in it's own power district(s), separate from what you need for the present layout.

    For #4 (programming track district), I would select a programming track with as few connections to the rest of the layout as possible, and one that is unlikely to have more than one loco on it at a time. IOW, I would not want to use a track that is normally used to store multiple locomotives as my programming track, since I would have to move them all off the PT to use it for programming. However, if you have current based occupancy detection, including freight cars, cabeese, etc. then you need to clear them off the PT too before programming a loco on it, or they will interfere with programming. So I would use a simple spur (or just the tail end of one) that is not likely to have many locos or cars occupying it.

    Second, depending on the decoder, a loco can "walk" quite a distance if it uses its motor to create the current pulses for acknowledging programming commands. Some decoders alternate direction of the motor for each response, so the loco does not go very far while responding to multiple programming commands. So, to protect all the other locos elsewhere on the layout if it walks too far, you need a "dead track" between your programming track and the rest of the layout, that is unpowered when you are in programming mode, but powered when you are in operating mode. NCE sells an automated switch that handles that for you. The dead track needs to be at least as long as your longest loco (including the tender if it is wired to pick up power for the loco). Otherwise, you can put a stout pin or small nail in a hole between the rails, on the programming side of the boundary with the rest of the layout, to stop a responding locomotive from walking onto the normal part of the layout.

    In the end, lots of folks recommend having a completely separate programming track, not on the layout. It can be fastened to a small board that you put on your workbench when you want to program a locomotive. You can also use a treadmill for a programming track. If you have a separate system for programming anyway (lots of folks use a SPROG and JMRI* for this), then you can keep your layout DCC system intact while programming.

    Note that not all "programming" needs to be done in service (broadcast) mode, on a programming track. Using Ops-mode programming (aka "programming on the main") for things like speed matching locos, etc. allows you to test your speed matching over your layout, grades, curves, with loads, etc. Tweaking momentum settings, etc. is also often done on the layout.

    *No matter how you arrange your programming track, I STRONGLY recommend using (free) JMRI Decoder Pro software for programming decoders. It really makes the whole process so much easier to do and understand. It breaks out individual bits/fields of multipurpose registers, with on-screen descriptions for each item. It also stores a copy of your decoder's register settings, so you can restore them if you got confused, or had to replace a decoder. It can read and/or restore the entire decoder in one step. You will need a computer interface (usually USB) for your DCC system to allow the computer (windows, mac or linux) running JMRI to communicate with the DCC system.
     
  4. SDVike

    SDVike TrainBoard Member

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    Thanks. This really helps a lot. Especially the programming track. I’m thinking maybe I just add a track to my workbench that is connected through LocNet to my layout and a computer.

    The only issue is there is an isle between my workbench and the layout. I plan on placing a monitor and PC at the workbench anyway. It will give me the JMRI capability. Figuring out the connection to the loconet and DCC power will just another part of the fun.


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  5. SDVike

    SDVike TrainBoard Member

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    So I wired up my first Smail motor to a terminal strip. A couple lessons learned.

    1. Pay attention to which way you solder the screw connectors on. Can you see the error in the first pic?

    2. I think I cut my wires too long. The terminal strip is going to be a long way from the switch or the wires will hang too low.

    3. There is no way I could consistently repeat this without my wiring diagram.

    4. Installing a switch motor in a hole under your layout sucks. I could barely get my screwdriver to drive in the set screw. I need to plan ahead on future motor installs as I may not be able to tighten that screw once installed.

    Hopefully I get the DCC system up and powered this weekend so I can test my busses and motor setup.

    [​IMG]
    [​IMG]
    [​IMG]


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  6. BigJake

    BigJake TrainBoard Member

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    I'd just get a SPROG II to run the programming/test track, they are tailor-made for that. And you'd have no wires from your bench across to your layout (until you decide to use JMRI on your layout, anyway)

    For running JMRI on your layout, I'd probably put a Raspberry Pi under the layout to run JMRI for it, and VNC into the R-Pi (like a remote desktop) from your computer via WiFi. Look, Ma; no wires!
     
  7. BigJake

    BigJake TrainBoard Member

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    duplicate removed...
     
    Last edited: Aug 4, 2021
  8. Sumner

    Sumner TrainBoard Member

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    An option but going with DCC++EX (Arduino & Motorshield) and R-Pi (or spare computer) would cost far less and works great...

    https://dcc-ex.com/

    Sumner
     
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  9. BigJake

    BigJake TrainBoard Member

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    A couple of questions:
    1. Will DCC++EX (either on Mega+WiFi board or Mega/Arduino board w/WiFi shield) connect to an existing WiFi network, or must it operate as a hotspot?
    2. Can DCC++EX connect to JMRI on another computer over WiFi?
      • He's trying to avoid wires from layout to computer on workbench.
     
  10. Sumner

    Sumner TrainBoard Member

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    Fred is probably the one who should address this or look at the info here...

    https://dcc-ex.com/throttles/index.html

    DCC++EX is and has been for a while really developing fast with a lot of nice features and I'm behind on where they actually are today. I'm not running a recent version of it or Todd's image file on the Pi. I did recently get the WiFi shield to try out at some point. With it DCC++EX is acting as the hot spot as for as I know and you don't need to be running JMRI to connect.

    I don't see where there is a provision to connect to a WiFi network but might be wrong. The same seems to be pretty much the same with JMRI running on the Pi, which is what I use. I don't know if Steve has that blocked it on the Pi for some reason or not but I can't seem to get my Pi connected to my house WiFi (which I haven't needed/wanted to do). I can connect another Pi that I use as a chartplotter on a boat to a network without a problem so wonder if it is something in Steve's image file. There are ways to connect to the Pi remotely though. You don't need a Pi thought to use DCC++EX.

    I know that he has the following, all of which I don't fully understand and he does mentioned plugging into existing network:

    • AutoIdentify of attached hardware (Locobuffer-USB, PR3, SPROG, LENZ USB, NCE Serial, NCE USB (Note 1), DCC++, EasyDCC Serial, MERG USB, MRC Prodigy)
    • Autostart of JMRI PanelPro with WiThrottle and Web Server. (enabling DecoderPro)
    • Creates network access point for device connection, or can be plugged into existing network
    • You can upload roster files and icons via the JMRI web server.
    • Web server extensions for restart/shutdown of the RPi, viewing the session.log, viewing JMRI tables, and more.
    • Access to GUI desktop via attached monitor or remotely via VNC client
    • Support for defining GPIO Pins as JMRI Sensors and Turnouts
    • Latest Raspbian Buster image
    • Secure file access via SCP or Windows file share.
    I personally haven't had a need to connect to an existing WiFi network in using it.

    Hopefully Fred will see this and maybe give us an update on where they are at this point and where they hope to go,

    Sumner
     
  11. BigJake

    BigJake TrainBoard Member

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    Steve Todd's R-Pi image is the basis of the image that comes from SPROG for Pi SPROG products, so I am familiar with it. It can be configured either way (hot spot, or connect to existing WiFi network). IIRC, it involves commenting out 3 lines in a config file, and removing a module from the system, or the reverse, to switch between the two modes.

    Connecting to an existing WiFi network removes the need to switch smartphones (to run throttle apps),to a different WiFi than than they are normally on. On a Pi, that also means not having to switch a laptop to the R-Pi's hot spot to VNC into it to run Decoder Pro (the Pi can run Panel Pro headlessly for most purposes). Also, keeping Raspberry Pi OS up to date is easier with an internet connection.
     
  12. SDVike

    SDVike TrainBoard Member

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    Wow, you guys have gotten way ahead of me. I’m still running buss wires and trying to get my first switch wired to the panel. Lol.


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  13. BigJake

    BigJake TrainBoard Member

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    Some dogs sit down and chew on a bone, some dogs run away with it!
     
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  14. SDVike

    SDVike TrainBoard Member

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    My mainline and accessories busses are installed. I’ve added terminal strips to the control panel. I’ve also ran power from the DC power pack to a DPTS. I just need to hook up the DCC power to the DPTS and I can switch back and forth.

    A couple mistakes
    1. The DPTS I bought from Home Depot is too big. Or my control panel is not deep enough. I’ll order some switches online. I’m not sure if I need to extend the panel somehow.

    2. The way I mounted the hinges, doesn’t create a good pivot for the wires. If I rebuild the box, I can solve this.

    3. I’m starting to think 14 ga stranded may be too big for the flexible power connectors. I only have 1 switch wired and it’s filled that side. Any suggestions for alternates? It will get better if I cut the wires to the correct length.

    4. I drilled the holes in the back of the panel wrong because I forgot terminal strips for the power. I had enough for all my switches. I had to add to more to cover power.

    The next step is to wire in the DCC power. After that I will add a single Smail motor and set of Smails connected to a crossover. Once both setups are tested and work, I will probably rebuild the panel slightly for better wire management. Then it’s the install of another 14 Smail motors, wiring them to the control panel, and install of leds. Thinking about all that makes me tired. And a little geeked out.

    Oh, and I really need to come up with a wire labeling system before it gets too much to memorize.

    [​IMG]
    [​IMG]


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  15. SDVike

    SDVike TrainBoard Member

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    I though I would add some questions here that aren’t buried in my last post

    1. My main power bus is 14ga solid copper. In areas that the wire needs to flex (control panel door and drawer) can I use 16ga stranded?

    2. Can anyone recommend a good smaller DTPS? I’m slightly nervous ordering a bunch online since it’s really hard to know how big they are.

    3. Same question, only for LEDs. I need red and green LEDs for the control panel. They need to be bright enough to see but not blind.

    4. I also would like to find a good narrow tape that would work to make track lines on a panel. Any recommendations?

    Thanks for all help in advance.


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  16. Sumner

    Sumner TrainBoard Member

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    [​IMG]

    I've gotten a number of the ones shown above in different configurations. Only had problems with a couple. You can find them all over the place, Amazon, eBay and other places. Just test them before you use them.

    [​IMG]

    I've used them in the servo controller shown above and ( HERE ) and...

    [​IMG]

    ... for switch panels,

    Sumner
     
  17. SDVike

    SDVike TrainBoard Member

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    Thanks

    I looked those up on Amazon. I ended up ordering something really similar. Thanks for the heads up. One thing I noticed is I already messed up my panel by drilling a bigger hole for the oversized DPDT switch that I won’t be using.

    I’m also still stuck on what wire to use in the panel. My busses are 14 gauge solid which won’t work as a connection to a movable panel. I connected 14 gauge stranded and it’s just too thick. I’m thinking of changing to 16 gauge stranded for the panel wiring.

    I’ve found that I am glad I ran two separate busses for the track and for my Smail switch motors. Because I did that, I can switch off the track buss and edit the CVs on the switch motors without worrying about messing up my one DCC engine.


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  18. SDVike

    SDVike TrainBoard Member

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    I forgot to mention, I need to get a 3D printer. I like what you’ve done. I have a very nice one at work but I don’t want to cross that line of using it for personal use. I keep coming up with uses for one but I need to stop spending money on trains right now so it will be a Christmas present this year or next.


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  19. Sumner

    Sumner TrainBoard Member

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    Others might agree or disagree but for those short runs in the panel and if it was just track power and/or other power I'll bet 18 gauge would be just fine. I wouldn't hesitate using 16 at all.

    When I wired some panels for out boat where the amperage was quite a bit higher than on the railroad I put in terminal strips. I wired heavier wires for the runs to the lights, pumps and other items from one side of the terminal strip and used smaller gauge wire off the other side to and from the panel switches.

    On the hole problem maybe cut a disc out of styrene with a smaller interior hole for the new switch and the outer circumference could cover the hole and a little bit more. If it works I'd then glue it to the panel.

    Sumner
     
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