New DCC++ HAT!!!

DCUTTTING Apr 8, 2017

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  1. DCUTTTING

    DCUTTTING TrainBoard Member

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    The DCC++ HAT is here!!! I'll be offering boards with all the SMD's reflowed in a few weeks.

    [​IMG]

    Features:

    - 5 Amps on both main and programming track, with 6A peak current (I designed a huge heat sink into both the top and bottom copper layers). A lot of members of the DCC++ FB group have expressed interest in this feature because of the current 2A limitation of the L298.

    - ATmega328P running at 8mHz 3.3V (8mHz because I didn't want to have to level shift 5V for the Pi). This will act as the DCC++ side of things because I don't want to have to port all of the code to the Rpi. The Rpi in this case will either serve as the JMRI controller in most cases.

    - EEPROM chip that stores info about the HAT as specified by the Rpi foundation HAT Spec. It will allow the Rpi to detect the presence of the shield and verify that it is the correct one.

    - Communicates with Rpi over Serial (UART). Basically the USB interface from before, but without all of the USB bits that make USB boards expensive.

    - Programming requires external ICSP programmer (you can use your arduino). Programming directly from the Rpi would have been challenging and risky, with different voltages and connected hardware.

    - 100% compatible with existing DCC++ Code, as it uses the same pins and microcontroller

    If you have any questions or suggestions, I'd love to hear them below.
     
  2. Travis Farmer

    Travis Farmer TrainBoard Member

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    I like my version better ;) yours lacks the wire clutter ;)
    [​IMG]

    (just joking around)

    great idea, making a solid solution, and kind of sets a standard, for RPI users.

    ~Travis
     
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  3. crusader27529

    crusader27529 TrainBoard Member

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  4. DCUTTTING

    DCUTTTING TrainBoard Member

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    Should cost $50 for an assembled, programmed, tested board. The headers will be included in a separate bag for you to solder on, but that's just the ICSP header, the Rpi Header, and the three screw terminals.
     
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  5. Keith Ledbetter

    Keith Ledbetter TrainBoard Member

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    Price seems reasonable to me. under $100 (including the pi) for a sprog like device with more power, 2 tracks, etc. I'd be in just to get rid of rats nest (mine is even worse then Travis :))
     
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  6. Jean-Eric

    Jean-Eric TrainBoard Member

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    I am interested!!


    Envoyé de mon iPhone en utilisant Tapatalk
     
  7. DaPenguin

    DaPenguin New Member

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    Question;
    What is the possibility of replacing the track or both outputs with dead rail transmitters
    TCC:}
     
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  8. Keith Ledbetter

    Keith Ledbetter TrainBoard Member

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    David, I'm pretty pumped about this and think could be a really slick package that capable of running all but huge layouts in a compact, clean package complete with JMRI!
     
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  9. Mdwildcat04

    Mdwildcat04 TrainBoard Member

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    I'm not 100% sure, but I don't see any current sensing. Is that the case?
     
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  10. crusader27529

    crusader27529 TrainBoard Member

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    Wouldn't make much sense to include the program track stuff without current sense.....

    PLUS, the current sense implementation doesn't need any external components, depending on what motor driver chip(s) are used in the design.

    I'd GUESS that current sensing is implemented.
     
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  11. Mdwildcat04

    Mdwildcat04 TrainBoard Member

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    agreed.

    I couldn't code my way out of a paper bag, but looking at the forked code, it lists A0 and A1 as current sense, so that is a good omen.
     
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  12. DCUTTTING

    DCUTTTING TrainBoard Member

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    The current sensing is implemented on the board. I'll need to do some testing just to make sure that all is well. The github repository that I made has all of the schematics and board files in it now.

    You could do it, it's really up to you.

    I finished up the board yesterday, and here's the results:

    [​IMG]

    I should get all of the manuals and code done in the next month.
     
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  13. Scott Eric Catalano

    Scott Eric Catalano TrainBoard Member

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    Would this board be able to be attached to an arduino or is this just a Pi only shield?
     
  14. Xmtrman

    Xmtrman TrainBoard Member

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    A Hat is Pi only.

    The connector arrangement and pin-outs are different for a Pi hat compared to an Arduino shield.
     
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  15. Scott Eric Catalano

    Scott Eric Catalano TrainBoard Member

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    Would be cool to have an Arduino version....I think someone on this board was going to make one...not sure if they finished it or not
     
  16. crusader27529

    crusader27529 TrainBoard Member

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    That doesn't make sense, becaue the primary purpose of this setup is to have the Raspberry PI function as the JMRI system, and the Arduino is nowhere powerful enough to do that, even if the code was compatible, whick it's not.
     
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  17. Keith Ledbetter

    Keith Ledbetter TrainBoard Member

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    Yes agreed that is the huge advantage with the PI but if someone made a motor shield with dual motor drivers that would drive 5A constant as a shield and had jumpers for the uno/ mega setup it would be a worthy effort as well. Or even shipped with the DCC++ software preloaded and shield with these large amount motor drivers on top there would be a market for it. Again not hard to do yourself but a compact all in one setup would be pretty nice with ardunio as well.
     
  18. DCUTTTING

    DCUTTTING TrainBoard Member

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    Keith et. all, this board is the Arduino, Raspberry Pi, and motor driver all included on one board. The Arduino microcontroller is connected to the Raspberry Pi UART (Serial) and it uses the DCC++ code.
     
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  19. Keith Ledbetter

    Keith Ledbetter TrainBoard Member

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    Got it. Makes total sense. Basically you are just using the pi for power and it's serial connection. So basically stand alone dcc++ basestation plus motor driver all in one that hooks onto the pi as a plug and play jmri/serial interface and for power.

    Theoretically couldn't the hat have a USB port then that is used as its serial port and power and then you hook up through PC to jmri?

    You could have a config variable for stand alone or pi. This of course coming from a guy who has no idea how hard/easy that would be to do.

    Super slick looking by the way. Looks really good!
     
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  20. lnxlnx

    lnxlnx TrainBoard Member

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    @Keith Ledbetter
    Sorry but the PI is running JMRI. The PI is running the Linux operating system which is different to the microcontroller systems like an Arduino. The PI is a fully functioning PC in its own right. So there is no need for a PC.
     
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