DCC++ Hardware - Motor Shields

KE4NYV Jan 25, 2016

  1. zephyr9900

    zephyr9900 TrainBoard Member

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    Thank you, mikegillow. I hadn't noticed that chart (though I had seen the photo below it of the enclosure with no openings other than connector access!) I will plan on a small fan and see if I can add some ducting or something to keep its noise down.

    Randy
     
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  2. DougL

    DougL TrainBoard Member

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    What type of heat sink would I use for the Arduino motor shied?
    The physical format of the DEEK closely matches the official motor shield.

    The last few images at that site show the enclosure he designed and used. I am surprised it does not permit for heat sinks or a fan.

    One suggestion if anyone adds a fan: Use some filtration media before or after the fan, a square of air conditioning filter will help. I opened my tower pc and it had good-sized dust bunnies from ambient dust and the fur of our several dogs.
     
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  3. David Bodnar

    David Bodnar TrainBoard Member

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    Gents - heat sinks and fans should be considered if you are going to be running larger engines (HO or larger) or many locos. If you are only running small scales and one loco you can get away without them.

    If you are expecting to run at the limits of the standard motor shield I would suggest switching to the 43 amp H-Bridge - then all heat issues go away.

    As to adding heat sinks to the motor shield, I did add some using small heat sinks and double sided thermal tape. The photo below shows one I added to the 43 amp unit - I used it because I had removed the large heat sink that came on it.

    dave

    [​IMG]
     
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  4. DougL

    DougL TrainBoard Member

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    That makes things simpler. I will run the standard motor shield with HO. If anything pops I will go to the higher capacity.

    Currently (pun intended) I am learning the whole setup from JMRI to the base station to installing decoders. The Arduino knows more than I do.
     
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  5. DougL

    DougL TrainBoard Member

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    Everything is connected and booted up. No output from the Arduino motor shield. I know it is nearly impossible to troubleshoot physical devices on a forum. Maybe someone can offer insights.

    Setup:
    • Arduino mega clone with correct USB drivers (tested)
    • Deek Robot motor shield
    • connection cut so power does not go to the Ard
    • 16V DC into the motor shield
    • DCC++ loaded into the base station.
    • conncet arduino to 'puter with USB, port com3 recognized
    • JMRI 4.3.4 because 4.2.n might not play well with DCC++
    • JMRI booted, set for DCC++

    Multimeter reads a few millivolts from motor shield output

    What should I be reading at the motor shield outputs?
    What tests can I run?
    Is there an order for connecting things, like power first or USB first?
     
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  6. UK Steve

    UK Steve TrainBoard Member

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    Hi DougL,

    Try some simple debugging using the arduino IDE serial monitor. Don't connect JMRI at this stage. Sending <s> will return (or not) some status info.
    <1> should turn the track power ON, indicated by the 4 LED's near the output on the motor shield and a <p1> response from Base Station.
    Once you got these basics to work, you can then move onto something like JMRI.

    Steve.
     
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  7. mikegillow

    mikegillow TrainBoard Member

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  8. DougL

    DougL TrainBoard Member

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    thanks, just what I hoped for. testing and diagnostics procedures before adding a large programs on top of it.
     
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  9. Transitguard

    Transitguard New Member

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    Has anyone tried using DCC++ with a seeed motor shield? I'm having trouble getting mine to work at all.
     
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  10. Scott Eric Catalano

    Scott Eric Catalano TrainBoard Member

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    Not sure about Seeds....I use Pololu worked like a charm
     
  11. lnxlnx

    lnxlnx TrainBoard Member

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  12. crusader27529

    crusader27529 TrainBoard Member

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    I'm late to the party, and I've no idea what the 8 inputs are used on your design, but there are a few things that might make sense for you to consider.

    I'd like to be able to do 2 specific things with your design.....I'd like to be able to parallel the outputs (and inputs obviously) to increase the current capability of the design, and secondly, I'd like to be able to stack multiple boards to allow for several power districts.

    It'd be great if that could be done just by using jumpers.....

    Your thoughts???
     
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  13. hoyden

    hoyden TrainBoard Supporter

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    To follow up, I was successful using the Seed with DCC++. My goal was to verify DCC++ would drive two motor shields and the two drivers on the Seed could be wired in parallel. My next experiment will be to connect the Seed parallel outtput in parallel with the first motor shield.

    Besides some pin remapping the problem using the Seed alone is that it requires an inverted signal from the first shield.
     
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  14. Gregg

    Gregg TrainBoard Member

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    Out-of-the-box, the SEEED shield will unfortunately not work with the standard DCC++ code. This is because the SEEED motor shield has the control lines for the directions of the outputs wired directly to the shield pins. On the Arduino and Pololu versions of the shield, the shield pins pass through some additional logic chips before connecting to the H-bridge chip's control lines. There are two "fixes" for this. The first is to add a simple inverting circuit to one of the shield pins, though this requires bending the pin out of the way so you can interrupt the direct connection (see @hoyden's response above). The second is to modify the DCC++ code to create an inverted signal through a separate interrupt instead of using the micro controllers built-in PWM timers. I believe one of the TrainBoard members did this a while back but it is not part of the main code base.

    It's unfortunate that the SEEED shield does not copy the logic of the Arduino or Pololu since it is usually available at Radio Shack (assuming you can still find a Radio Shack).

    -Gregg
     
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  15. KE4NYV

    KE4NYV TrainBoard Member

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    Sorry! I have been away from this project for a while working on some contract work I took on around Christmas time. So here is the current status...

    I have gone through four board revisions of this design and I am still running into current control issues. I have no idea what is wrong because at this point I have an exact clone of even cheap Chicom boards and I still have the same problem. Basically I have to really fudge the numbers in DCC++ to get the board to output anything. Plus, it doesn't take much current draw to have DCC++ just kill all power. It's not making much sense. I want to keep working on this because I think it's a perfect fit ie. no jumpers, no cutting traces, no modifying to work with our application. Plus, I added on the additional I/O for future expansion. When I get back from Pittsburgh next week, I'm going to sit down and really go over this again. I know it has to be somthing stupid that I am overlooking.

    Part of my problem is I have so many electronics, trains AND woodworking projects going at once that I keep losing focus. I'll get back on it and update the forum soon!
     
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  16. Scott Eric Catalano

    Scott Eric Catalano TrainBoard Member

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    How long are you in pittsburgh for? I am north of pittsburgh....zelienople to be exact!
     
  17. David Bodnar

    David Bodnar TrainBoard Member

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    Small world, I am south of the city in Mt. Lebanon

    dave
     
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  18. Scott Eric Catalano

    Scott Eric Catalano TrainBoard Member

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    well then! I started my railroad career on the URR....I operate on a few model railroads in the area. The well known B&O of the late Don Casseler.
     
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  19. David Bodnar

    David Bodnar TrainBoard Member

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    I belong to the South Hills Model Railroad club and the Pittsburgh Garden Railway Society - I am sure our paths have crossed at shows & such.
    I'll keep an eye out for you!
    dave
     
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  20. Scott Eric Catalano

    Scott Eric Catalano TrainBoard Member

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    yes I am sure it has at one time or another!
     

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