The next step in decoding DCC has arrived!

Available from now: the Arcomora DCCNext DCC decoder!

What is it:

A single pcb that combines an Arduino and the existing Arcomora DCC/Power shield.
It is a DIY kit that you have to solder yourself.

It contains:

  • Internal power supply. Input: 9-16V  AC or DC
  • Input for DCC with led indicator  and decoder circuit
  • ATMEGA328P processor
  • 16 Outputs or inputs for controlling accessories and servo’s.
  • Outputs with Dupont pins (for servo’s) or screw terminals
  • Separate 5V input for servo’s
  • Additional 5V output for testing purposes (no servo’s)
  • Can also be powered by external 5V.
  • Status led
  • Power led
  • Servo power led
  • Reset switch

To keep the price low there is no USB interface on the board.
But an external USB interface(CH340) is also available.
It can be used for multiple DCCNext decoders.
So you need only one!
That saves money.

You can also use a FTDI interface if you already have it. But take care of the order of the connection pins!

Also available is a housing box for a more  protected mounting.



  • You can create your Arduino sketches for processing  a  DCC signal and upload them to the DCCNext.
  • Upload the Mardec 5.0 sketch for use as multipurpose DCC decoder for accessories and servo’s.
  • Upload the  ArSigDec sketch for use as signal decoder.

The board has three power options:

  • Internal. Circuit powered by internal power
  • Servo. Circuit powered by the 5V on the terminal for servo power
  • External. Circuit powered by the 5V terminal


You can make a reservation for:

The DCCNext decoder DIY kit. Contains the pcb and all components. Price: €7,90

The USB-Serial interface including a cable.
Price: €2,95

Type: CH340

A box with text stickers. Price: €4,30

Or a combi-set of all three parts. Price €14,20

You can also order a completely build DCCNext with interface and box.
The print is already soldered and tested. You only need to solder the screw terminals and Dupont pins if not specified. In the Remarks field of the order page you can specify which ports requires Dupont pins for servo’s.
Just connect to your PC and upload Mardec or Arsigdec or your own sketch.
Price only €24,95

Click here to go to the reservation page

21 thoughts on “DCCNext”

  1. Hello Nico,
    In the dutch “Montage handleiding DCCNext” i see a LED between pin 3 and 4 of the 6N137. In all other schematics i know of there is a 1N4148 in that place. Is the LED indeed functioning the same as the 1N4148? Futhermore is the 220 pF capacitor placed between pin 2 and 3 of the 6N137. In the DDC circuit shown on page 7 of arsigdecmanualdb.pdf there is a 100 nF capacitor between pin 8 and GND. Can you explan the different choice to me?. Can I build the DCC circuit part as shown in the DDDNEXT diagram als a saperate single board as well?
    Thnks in advance for responing.
    Greetings, Chris de Groot

    1. Hi Chris,

      Yes the led functions the same as a 1N4148, so don’t worry.
      Do you really think that I would sell it if it doesn’t work?
      The 220pF capacitor also occurs on other schema’s of the DCC circuit.
      Capacitor C4 of the DCCNext functions as the 100nF on the DCC/Powershield.


      1. Hello Nico,
        Thank you for your answer. Ofcourse I know it works, but I am not that experienced in electronics. I just wondered, and liked to know.

  2. hello Nico

    I have built 2 dcc next decoders.
    one configured as a mardec, the other as arsigdec
    They both work fine, without any problems at all
    Thank you

  3. Hi
    Concerning the CH340 module. Do you use the DTR and the CTS signals on the board or are the just unconnected?

    1. Hi Tomas,

      As you can see in the schema of the assembly manual (download from download page!) the CTS is not used and the DTR is connected.


      1. Hi Nico
        Thank You for your help. I didn’t see, there were a schematics included in the assembly manual. But the pinout int the schematics doesn’t comply with the pinout on the assembly. RX/TX is placed different.
        In the schematics, it is: GND, RX, TX, +5V, NC, DTR.
        In the assembly drawing, it is: GND, CTS (NC), +5V, TX, RX, DTR

        I suppose the assembly is the correct one?


        1. Hi Tomas,

          You are right.
          I fixed the manual already a few weeks ago. But apperently I forgot to upload it.
          Done now.


  4. Hi Tomas,

    The file was replaced indeed. May be your browser picked it from the cache
    Clear cache and try again.
    You can order the CH340 interface by me or buy it at Aliexpress.
    Search for: CH340 micro USB


  5. Great – Much better now 🙂
    I found the board at Ali’s at $1.20 🙂


  6. Hello Nico, this is a very interesting development. My layout currently has over 70 servo operated turnouts using hard wired control panels feeding into servo interface boards. It works fine, except for a lot of wire. I’m currently expanding with another 20 turnouts and DCCNext has the potential to be useful. I use the NCE DCC system.
    Just to clarify, I understand this board is essentially a multi channel accessory decoder. Using it to operate a turnout, please confirm I would need to generate a DCC accessory command from either the throttle, or a PC running JMRI or similar, or an encoder such as a Cobalt Alpha.


  7. Hi Darryl,

    Yes, the DCCNext requires indeed a real DCC command as specified in the NMRA specifications.
    However accessories and servo’s can also be controlled by a switch connected to a port that is set as an input.


  8. Hi Nico,
    Am I right in thinking that a servo can only be operated one way by a switch connected to a port that is set as an input. I say this as on page 6 of the Mardec manual under Input Commands you say, “Nothing happens when the pin is made ‘high’ again”.
    Thanks, Ted

    1. Hi Ted,

      That applies only to Mardec versions prior to version 5.
      To rotate the servo back again the input must be made low a second time.
      But Mardec 5 offers more options. Look in the manual:
      An input can be activated in three ways.
      1) By lowering the input. Nothing happens when the entrance becomes high again. (type D)
      2) By making the entrance high. Nothing happens when the entrance becomes low again. (type U)
      3) By making the input low or high. The accessory or servo “follows” the input signal as if it is controlled by DCC. (type L)
      With this option, for example, a switch can also be converted by means of a switch.

      With options 1 and 2, an input acts as a momentary switch.
      With option 3, an input acts as a changeover switch. Just like a DCC command.
      The activation method is requested when configuring a port as input.

      Download the latest version of the manual!


  9. hallo
    is het mogelijk om elke poort te configureren als in of output?
    dus is het mogelijk om ze door elkaar te gebruiken.
    Jan Hendriks

    1. Hallo Jan,

      Ja, je kunt met Mardec van iedere poort een input of output maken.


  10. Dag Nico,

    Wat is de reden dat de DCC Next zijn instellingen kwijt raakt. Dat is mij deze week al twee keer overkomen. Ik heb de gegevens natuurlijk wel bij de hand maar het wel weer een aardig klusje om al de instellingen voor de servo’s opnieuw in te voeren.

    Gr. Jan

  11. Hallo Jan,

    Geen idee waarom dat kan. Probleem niet eerder gehoord. Het lijkt erop dat het EEPROM niet helemaal goed (meer) is. Heb je dit vanaf het begin of is het pas na een tijdje fout gegaan? Heb je nog een andere DCCNext? Verwissel dan eens de processoren.
    Is de voeding helemaal in orde? Geen spanningspieken of zo bij inschakelen?


    1. Hallo Nico, goed idee om de processoren te verwisselen, ik heb nog een DCCNext liggen.
      Voor zover ik weet zijn er geen spanningspieken.
      De andere Mardec en de Arloco functioneren prima en houden de instellingen vast.

      Wanneer jij nog niet eerder van dit probleem hebt gehoord zal het een toevalstreffer zijn.

      bedankt voor je reactie,

      mvg Jan

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