DIY G scale DCC: new products to make it simpler

[notofthiscenturyTim]

Thought I'd share my experience with DCC on a budget. I've only been doing G scale for a couple months and I've found it's quite tricky to create a diy DCC command station cheaply.
For smaller scales it is very straightforward to build one running open-source DCC-EX software. All you need is a smartphone app, an Arduino board with on-board wifi, a "motor shield" board for track power and an old laptop power supply. Well under £50, less if you already have an old laptop power supply kicking around.
The challenge with G scale seems to be that the higher voltage and amperage requirements necessitate different boards, soldering and jumper wires.
I think this is about to change. Last weekend I built an Arduino-based DCC command station using a new "Powershield" board which delivers 5a @22v. It's developed by Hans Tanner who runs the Internet of Toy Trains youtube channel.
The board slots straight into the Arduino and it's working brilliantly. I also really like the fact that you can plug an external USB volume knob into to the phone and use it as a hardware throttle.
The Powershield board costs $35 but stock has been quite limited and you have to reckon with postage costs if you're outside the US.
The second really exciting development is that the DCC-EX project are releasing an officially supported motor shield which delivers 5a @ 22v and which will be widely available. It's a simple install, just slotting into an Arduino with no jumper wires or soldering needed. Price is £35 or $35. I've got one on preorder and will report back on it once it arrives. Details here:

DCC-EX Releases 5A EX-MotorShield8874 — DCC-EX Model Railroading documentation

DCC-EX is a team of dedicated enthusiasts producing, easy to use, affordable, do-it-yourself, open source, DCC solutions to allow you to run your complete model railroad layout.

dcc-ex.com

 

[Software Tools]

That's a whole other set of jargon to learn, on top of the standard DCC jargon! It may be interesting but how it actually works with existing commercial DCC kit is not exactly clear....

 

[notofthiscenturyTim]

So motor-only decoders with tons of features are cheap. This is a cheaper decoder, with fewer features, larger size, and less current capability and will not tolerate the NMRA max voltages.

You can buy an NCE system at 2 amps and add a $50 booster for under $200 total including the very nice hammerhead throttle.

You can add JMRI and cell phone support for very cheap.

No offense, but there are already better solutions for very little more money.

Greg

Hi Greg,

You appear to have misunderstood. It's not a decoder, it generates the DCC track signal up to 24v, 5a. NMRA Max is 24v?

There is still a difference between under $200 and well under $100 for a G scale DCC system for those of us on a budget. I.E. $200 is double $100. NCE is also more expensive outside the USA. Personally I'd rather have that $100 to spend on rolling stock or track.

Does adding JMRI to the NCE setup you mention involve using a computer if you want cellphone support? This is a stand alone solution which just needs mains power. That appeals to me as I have small temporary layouts outside and it minimises set up time and wiring. Horses for courses.

It also supports JMRI out of the box if you want by plugging it into a computer with its USB port.

I would be interested in that $50 booster for a different project. Do you have a link to the model reference please?

 

[notofthiscenturyTim]

That's a whole other set of jargon to learn, on top of the standard DCC jargon! It may be interesting but how it actually works with existing commercial DCC kit is not exactly clear....

I'll attempt a de-jargon!
This is a way to build a complete G scale DCC system controller using three things: a 24v power supply, an Arduino circuit board commonly used in electronics projects and a circuit board to generate the DCC signal for the track.

To assemble it you stack one board on top of the other using the built-in sockets. Takes under 30 seconds, no wires or soldering needed. You then plug the board stack into a computer using the USB port and run a programme which loads the DCC software onto the boards. This is a one off and you never need to connect to a computer again.

To run trains you just connect the mains power supply and the track to the stack and control them over WiFi using the free Engine Driver app. The most similar commercial product on the market is probably the Roco z21 system. Hope that helps!

In terms of compatibility with existing commercial DCC kit, it is fully compliant with NMRA standards so it will run loco and accessory decoders and anything else NMRA-compliant like any other DCC controller. It also supports JMRI, RocRail and the wiThrottle protocol for wireless throttle control.

There is also a LocoNet interface board available for $15 to communicate with LocoNet devices though that's not something I've looked into as I have no existing LocoNet DCC kit.

 

[notofthiscenturyTim]

I addressed both the decoders and command station, I did not mean to call it a decoder, my mistake, was typing too fast.

Your command station cost is a small part of your DCC expenditure, compared to decoders in locos... 100 or 200 dollars makes no difference in the big picture.

There's tons of options out there...

Portable NCE System

Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers

elmassian.com

NCE PowerCab

Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers

elmassian.com

WifiTrax

Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers

elmassian.com

just a VERY limited accounting of inexpensive, flexible systems with PROVEN capabilities on many decoders, and by many users.

All the things you asked for and more are available....

Greg

Thanks for the link.

I still fear you've misunderstood, there are no decoders or any mention of decoders in my post. It's all about the components to make a command station aka DCC Controller. I think you may have read "motor shield" as "loco decoder".

A motor shield is a board which stacks on top of an Arduino and can generate a signal to run a motor for any application. In DCC-EX it's the part of the command station used to generate the DCC track signal which is then read by the decoders.

It would be great if there were also loco decoders available based on an open source electronics platform like Arduino, but thus far it hasn't been possible or economical because of the degree of miniaturisation required and the different shapes, sizes and power requirements for different locos. So there's no alternative to commercial products for them as far as I'm aware.

There are projects for Arduino-based accessory and function decoders but that's not something I've looked into as my layouts are temporary and all the points/switches are manual.

I've been using DCC-EX with H0 for several years and it has been rock solid so it's entirely proven for my purposes. G scale has always been possible using DCC-EX but until recently has required additional components and wiring.

The thing which has now changed is that there is a much straightforward solution for G Scale's higher power requirements in the form of the new boards. This makes it as easy to create a DCC-EX command station as it has been for smaller scales.

You're welcome to keep using NCE and other commercial products as they clearly suit your preferences and budget. Mine are different and I'm completely happy with DCC-EX. Horses for courses.

I also prefer open source products in general so that's another plus for DCC-EX from my point of view.

 

[Software Tools]

In terms of compatibility with existing commercial DCC kit, it is fully compliant with NMRA standards so it will run loco and accessory decoders and anything else NMRA-compliant like any other DCC controller.

Thanks, that's a start. In terms of working with "existing commercial DCC kit", the sort of information I'm interested in includes (but is not limited to) topics such as....​

​

* How is the changing of CVs on a DCC loco or accessory decoder performed with a DCC-EX "command station"? Is that done via an app on a USB attached mobile device, or by some other method?​

​

* When it comes to programming a loco decoder, is that done on a dedicated programming track, or via using "programming on main"?​

​

* How many "handset equivalent" devices can be connected to a DCC-EX "command station", and how would they be connected?​

​

etc.​

 

[notofthiscenturyTim]

Thanks, that's a start. In terms of working with "existing commercial DCC kit", the sort of information I'm interested in includes (but is not limited to) topics such as....​

​

* How is the changing of CVs on a DCC loco or accessory decoder performed with a DCC-EX "command station"? Is that done via an app on a USB attached mobile device, or by some other method?​

​

* When it comes to programming a loco decoder, is that done on a dedicated programming track, or via using "programming on main"?​

​

* How many "handset equivalent" devices can be connected to a DCC-EX "command station", and how would they be connected?​

​

etc.​

The command station has terminals to connect a programming track and a main track. It supports read and write of CVs on the programming track and write using Programming on Main.

You can programme decoder CVs either using the phone app "EX-Toolbox" connected via WiFi or JMRI Decoder Pro on a computer connected via USB. It supports 10,239 DCC addresses.

You can create a roster on the computer with names for each loco's functions 0-28 and upload it to the command station. The names of the functions are then displayed on the buttons in the app rather than just numbers. I like this feature as I don't have to memorise 29 functions. You can also add a photo of each loco.

Using the EX-Toolbox app you can also test and fine-tune servos and sensors and measure track current.

I think I've been talking about throttles rather than handset equivalents. One throttle controls one loco. The command station's default limit is 50 throttles running simultaneously. That can be increased but needs additional configuration. Each device running the Engine Driver app can control six loco throttles.

Depending on their design you can connect throttles over:
Direct connection using a USB cable
2 wires to an Arduino serial port
Ethernet
WiFi
Bluetooth
Remote connection (VNC, MQTT, etc.)

For those who prefer a physical dial/knob for speed control you just plug a USB volume control knob into the phone. You can also use Bluetooth gamepad with the phone as controllers though I haven't tried that.

I get the impression that most people use cellphones for standard loco and accessory control over WiFi and JMRI on a computer for really complex tasks.

DCC-EX has some other features for the more advanced user which I don't need but might be of interest.

- Controlling points and signals using a module based on the PCA9685 chip (under $10) and generic servo motors and LEDs
- Integrated train automation for continuous running and for switching. It can run sequences based on locos, sensors, points etc. A particularly neat-sounding feature is "Drive-Away". This allows you to use a section of track to identify a locomotive's address and then drive it onto the main layout. It does this by starting an electrically isolated section of track as programming track, reading the loco address, then switching the section to main track and driving the loco onto the main layout.
- Integrated turntable controller to control turntables and traversers based on generic motors, stepper drivers and sensors.

Hope that provides some more info.

There's as series of articles on the DCC-EX site which provide a “big picture” view of how to put all the DCC-EX capabilities and use it with the various different supported hardware components and automation sequences.

The Big Picture — DCC-EX Model Railroading documentation

These "big picture" pages provide a view of how to put all the DCC-EX capabilities to use. [DCC-EX is a team of dedicated enthusiasts producing, easy to use, affordable, do-it-yourself, open source, DCC solutions to allow you to run your complete model railroad layout.]

dcc-ex.com

 

[Software Tools]

Hope that provides some more info.

Thank you, that is indeed very useful information.

 

[gn13565]

Hi All,

I got the board in the UK a few weeks ago. Works a treat on my test track. Not stressed it yet though.

It's available for back order from these guys.

DCC-EX Motor Shield - CMMME

Overview The EX-Motorshield8874 is a pin compatible with the original Arduino Motor Shield Rev3 but provides significantly improved electrical performance for driving higher loads, and improved usability. The EX-Motorshield8874 is based on two DRV8874 H-bridge motor drivers with integrated...

chesterfield-models.co.uk

Cheers

Greg

 

[notofthiscenturyTim]

Hi All,

I got the board in the UK a few weeks ago. Works a treat on my test track. Not stressed it yet though.

It's available for back order from these guys.

DCC-EX Motor Shield - CMMME

Overview The EX-Motorshield8874 is a pin compatible with the original Arduino Motor Shield Rev3 but provides significantly improved electrical performance for driving higher loads, and improved usability. The EX-Motorshield8874 is based on two DRV8874 H-bridge motor drivers with integrated...

chesterfield-models.co.uk

Cheers

Greg

Thanks for the update. That sounds promising. What are you using for train control out of interest? I'd be interested to hear how the stress testing goes.

I'm still waiting for my board. It looks like they've been very popular and I was a bit slow off the mark ordering.

Tim

 

[Big Trak]

Hi All,

I got the board in the UK a few weeks ago. Works a treat on my test track. Not stressed it yet though.

It's available for back order from these guys.

DCC-EX Motor Shield - CMMME

Overview The EX-Motorshield8874 is a pin compatible with the original Arduino Motor Shield Rev3 but provides significantly improved electrical performance for driving higher loads, and improved usability. The EX-Motorshield8874 is based on two DRV8874 H-bridge motor drivers with integrated...

chesterfield-models.co.uk

Cheers

Greg

Could this be used with the LGB 50015/16 serial/parallel controllers or Lokmaus controllers?

 

[notofthiscenturyTim]

Could this be used with the LGB 50015/16 serial/parallel controllers or Lokmaus controllers?

No unfortunately not. There is a way to add connectivity to LocoNet devices but not LGB MTS or X-bus/XpressNet devices.