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  • DCC Decoder Shield for Arduino

DCC Decoder Shield for Arduino



The ARD-DCCSHIELD is an optoisolated interface shield for connecting an Arduino (as a decoder) to a model railroad DCC control system.  The board has provisions for sending a DCC ACK pulse, connecting I2C accessories and general purpose I/O lines, as well as optionally powering the Arduino from DCC power and providing up to 400mA of 5VDC to connected circuitry.  The board is designed to be compatible with various DCC decoder libraries and Arduino boards.  We typically use Alex Shepherd's excellent NmraDcc library.

Note:  The board implements the functionality necessary for being a decoder.  It does not implement the ability to generate DCC signals (ie, act as a command station).


  • DCC interface for Arduino
  • Support DCC ACK pulse
  • I2C port and general purpose I/O lines
  • Can be powered from DCC power
  • Provides 5V, 400mA auxiliary power
  • Compatible with various DCC decoder libraries


2.7"(L) x 2.1"(W)


The complete gEDA design files are available on GitHub.


Hardware Reference

Note: Arduino is a registered trademark of Arduino AG.

  • $30.00

  • 11 in stock

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Application Notes

High Current DCC Accessory Decoder

One of our customers was trying to build an accessory decoder using our I2C-RELAY16 to drive a bank of relays for high current loads, and they were having a bit of trouble.  So, I thought I’d sit down and work through the issues tonight, as I’ve always thought having an accessory decoder with isolated, high current relay outputs might be nice. 

[See image gallery at www.iascaled.com]

Controlling an SDX-1 with DCC

This is very much a “because I could” project, so keep that in mind…  I built the SDX-1 soon after it appeared in Model Railroader in 1991.   It served its purpose, both on my home layout and at several NTrak layouts with which I was involved.  However, it has sat dormant for many years.  A few months ago, I started to wonder what it would take to DCC enable it (it was originally intended to be used with DC throttles). So, with an Arduino and a little code, I now have a sound system that can make an N-scale diesel shake the room (literally!).

Keep in mind that the sound on the recording doesn’t do justice to the low frequency components. It’s much better to hear (and feel) in person.  And yes, there are many other ways (maybe even more practical) to do this.  This, however, was intended more as a fun application and test of the DCC Arduino Decoder Shield than any practical application.

As for the equipment seen in the video, from left to right, there is the SDX-1, an Arduino + DCC shield, a very crude level-shifting PWM DAC (i.e. a single transistor), and the Lenz DCC base station. The SDX-1 is driving the speaker itself (out of view below, sitting on the floor).


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