Clones, maybe - maybe not

For your very first Arduino I would recommend a genuine UNO.  Once you have that working well then try clones.  For permanent installations I use NANOs or ProMinis.

I have an assortment of 2 dozen or so Arduinos, including UNOs, NANOs, ProMinis and Megas.  In the beginning I ordered the cheapest clones through eBay.  Some did not work.  My last purchase was a package of 5 NANO clones from Amazon seller Keywish and I was very pleased.  Cost a little more than the cheapest on eBay.  I have also had good luck with clones purchased through BangGood and AliExpress.

One area where I have been disappointed is with UNOs.  My recommendation is only buy the UNOs with the main chip in a socket.

Avoid UNOs with...

Dear Michael,

Avoid the pain I felt, avoid any UNO listed as having a "CH340" USB-SERIAL interface.
While OK for standalone projects, the cheaper CH340 (and variant) USB-Serial equipped boards cannot handle the high BAUD communication rates demanded by DCC++ applications.

Result? DCC++/JMRI operation was unstable, control intermittently lost, and runaway-locos abounded :-( 
(If there is _ANY_ percievable delay in response/tally between pressing the "Track Power ON/OFF" button on your SmartDevice/Throttle, and the Status LEDs on your DCC++ Motor Shield,

and/or the Track-Power button icon shows YELLOW instead of either Green or Red,

then SUSPECT the Arduino USB-Serial chip speed/behaviour!)

As a spotting feature of a (BAD) "CH340" interface,
if the UNO has a SMD DIL chip (rectangle, pins only down the long sides, see below)
directly behind the USB socket, DO NOT PURCHASE. 

If the chip directly behind the USB socket is a tiny square thing with almost-invisible pins on all 4 sides, (commonly listed in eBay auctions as a having "ATmega 16u2", see below) then it's most likely OK.

The "socketed main Atmel processor" is being replaced on _genuine_ UNOs with smaller square equivalents in current (Q1 2019) "R3" UNOs,
(IE "R3" UNOs are the ones typically called-for-use in DCC++ missions) 

Whether the main CPU is socketed or not =/= the presence of a (GOOD) Atmel 16u2 or (BAD) CH340 USB-Serial interface chip.

FWIW, the minimum cost on ebay.com.au of a _China_source_ 16u2-equipped UNO is approx AUD$8.50,

for a "Aussie source" 16u2-equipped unit the cost goes up to Min AUD$12.50...

Happy Modelling,
Aim to Improve,
Prof Klyzlr

PS for those playing along with Steve Todd's RTR "Raspberry Pi 3B / DCC++" image,
if the RPi JMRI instance does _not_ auto-detect your UNO as a "DCC++ interface"
(most likely stubbornly reports it as a "Digitrax", no matter what you do),

Then it's very-likely that you've got a CH340-equipped (IE BAD) UNO...
(Go get a 16u2-equipped UNO for the DCC++ rig,
and quarantine the CH340-unit to standalone duties, such as one of Dr Geoff B's animation projects...)

genuine UNOs have Arduino logo

I believe this  listing for a real Arduino Uno.   It has the infinity sign Arduino logo on it.  Others just say Uno.   I have some cheap compatibles that have parts (LEDs) in backwards and regulator that don't work

good luck.  i'd be glad to help

DCC ++

I'm thinking the first application I'm going to try is DCC ++ I want to evaluate it as a low cost control solution for my bedroom sized layout which has only two locos at present and will probably have a maximum of three. My next project will most likely be along the lines of my DIY "steam look" throttle thread. I appreciate the tips so far and if anyone can think of anything else I might need to know, please post. BTW, my wife and I have Amazon Prime so I do tend to shop there a lot but it's not a requirement Arduino items come from there. I do shop E-bay as well and the unit posted by gregc above looks attractive.

My next project will most

have you considered how your "steam look" throttle is going to communicate with the loco?

if you expect to communicate with a DCC decoder, then you need a throttle that can communicate with the command station.

@gregc

That's probably beyond the scope of what i'm going to do. One reason I branched off and started a separate thread from the steam proto throttle discussion was that I felt things there were going beyond what I was wanting to do and they also would be well beyond my means. I've been a ham radio op since I was 15 and have a build rather than buy mentality anyway which makes it surprising I haven't already hopped on the Arduino train.

I feel the deadrail and/or RC control avenue with two way telemetry is the ultimate way to accomplish everything Mark wants but the reception to that idea was tepid at best. Probably because so much of that is still experimental, especially in the smaller scales. I envision locos with controlled battery capacity where operators really would have to make "water stops"! The water sight glass would be reading battery capacity. Also varying battery capacity between road engines and switchers but that's a whole other thread.

I wouldn't bother with old 8-bit Arduinos MCUs

Instead head directly to ESP32 land because that's where it's at now, and where it's going to be for the little while. Dev. boards cost ~$15 but the processing power is magnitude better than any 8-bit MCU original Arduinos (UNO, MEGA etc) are based on. Plus you get plenty of Flash storage with WiFi and Bluetooth built-in.

You can program ESP32 using an Arduino IDE, if you are familiar with it, and there's lots of sketches to get you started. Otherwise, many people use (also free) PlatformIO IDE which has excellent support for ESP32 and supports additional libraries for almost anything imaginable.

Also, DCC++ has been ported to ESP32 thanks to the great work by atanisoft:  https://github.com/atanisoft/DCCppESP32/tree/development This work is ongoing and if you follow the git you can see improvements and fixes done all the time. Absolutely no reason to use the original, and now obsolete, DCC++ project.

I've been using ESP32 with OpenMRN to build LCC (OpenLCB) nodes for my railroad. Again, atanisoft (Mike) has done all the work of bringing OpenMRN to Arduino ESP32, and I can't say enough praises for him.

@Michael re: Your Original Question

Hi Michael,

First, I will state precisely where I've bought batches of Arduinos I am using for my 2019 clinics.

Uno Boards:  $5.88
UNO R3 ATMEGA16U2 Development Board With USB https://www.ebay.com/itm/361870287636
/> or on Amazon  $6.09
Arduino UNO R3 MEGA328P ATMEGA16U2 Development Board + USB Cable
https://www.amazon.com/Ikevan-MEGA328P-ATMEGA16U2-Development-Compatible/dp/B07BHKYTJ2/ref=sr_1_2?s=electronics&ie=UTF8&qid=1550190534&sr=1-2&keywords=arduino+uno+board

Mega2560   $11.69 QTY 4+    $13.75 QTY 1
ZYLtech MEGA 2560 R3 Board Atmega16u2/Atmega2560
https://www.ebay.com/itm/323191680958
/> or on Amazon   $14.99
MEGA 25https://www.amazon.com/Elegoo-EL-CB-003-ATmega2560-ATMEGA16U2-Arduino/dp/B01H4ZLZLQ/ref=sr_1_fkmr0_1?s=electronics&ie=UTF8&qid=1550190655&sr=1-1-fkmr0&keywords=ZYLtech+MEGA+2560+R3+Board+Atmega16u2%2FAtmega256060 R3 Board ATmega2560 ATMEGA16U2 + USB Cable for Arduino

Pro Mini   $2.20
Pro Mini Enhancement 3.3V or 5V adjustable 16MHz MEGA328P
https://www.ebay.com/itm/230795578198

Pro Mini USB/Programming Cable   $17.95
FTDI Serial TTL-232 USB Cable
https://www.adafruit.com/product/70
/> or on Amazon
Adafruit FTDI Serial TTL-232 USB Cable [ADA70] $18.32
https://www.amazon.com/Adafruit-Serial-TTL-232-Cable-ADA70/dp/B00SK8LK1W

Prof K gave you some good advice. On either an Uno board or a Mega2560 look for a little square IC like these:  and  

  which is a CH340G USB driver substitute.

'Hope this helps. Have fun! 

DIY "steam look" throttle

so why don't you just build a "steam look" throttle using the electronics of a DCC cab? 

it's just looks, right?

so why don't you just build a

Right now I don't have a DCC cab to get the electronics from. I have a Digitrax Zephyr DCS-51 that I'm about to sell for whatever it will bring because I've become disenchanted with it as well as that company. I'm really not interested in another commercial system right now and I'm more intent on a DIY approach these days. One that goes back to my ham radio/electronics experimenter roots. I like the options that JMRI and things like DCC++ as well as Geoff's throttle give me. I can get as little or as much involved in it as I need on my own timetable and budget. I'm early retired and have a lot more time to play with things, but unfortunately a lot less money.

 I think i'm leaning towards

I think i'm leaning towards getting a couple of ESP32's. Seems to be the best bang for the buck.

ESP32 DCC ++ question

So is there an actual video somewhere that shows how to integrate the ESP32 board with the motor shield like the ones showing the Uno or Mega being plugged together with the shield? I ask because I'm seeing what appear to be different ESP32 boards. The one Geoff recommends for his SMA 30 WIFI throttle doesn't appear to have "headers" (?) on it and it's unclear to me how it would plug together with the motor shield. I was going to buy a pair of those, one for the throttle, one for DCC ++ base but I want to be sure on what I'm doing before I order anything.

@ Michael

The size and shape of the ESP32 is different than the Pololu so a couple of options come to mind.  You could hard wire them together, or you could get a blank circuit board, solder headers on the ESP32 and Pololu, then put sockets on the circuit board and solder your wiring to the circuit board, kinda like your own motherboard.  That would make them easily removable/replaceable. (my choice)

And I know from your previous posts that you are up to the soldering.

ESP32 DCC++ System

No decient videos yet. Although you can build and run DCC++ on ESP module based boards, it is far from the almost plug-and-play of running DCC++ on an Arduino Uno / Mega based system. At this point it can be like starting another hobby of Electrical and Software Engineering. Your best guidance at the moment is to carefully read the README.md file. To wire-up the EZSBC ESP32 you will have to work from the code (software) where the I/O pins are defined to the EZSBC pin diagram to the motor board pins.

The ESP32 is actually only the module on these boards, ao you can purchase an ESP32 board in the Arduino Uno form factor which will - following the README and DCC++ guidance - may allow you to wire-up an Arduino or Pololu motor board. Warning ESP32's run at 3.3 VDC where most Arduinos run at 5 VDC, so any motor driver will have to deal with the 3.3 V I/O pins.

ArduCAM ESP32 UNO System Board

Banana Pi BPI-ESP32 Board

You will still have a lot of configuration to do before compiling and downloading the software to the ESP32, but it will be a great adventure. I would recommend installing the PlatformIO IDE and trying to build the software package before buying much more hardware. 

ps. Headers - Many boards come without headers, but the boards use 0.1" (2.54 mm) spacing, so headers can be purchased from many suppliers like 40 Pin (40 X 1) Header Connector. These headers are designed to be cut into shorter lengths. If you want to stack or build a base board you can get Header Connector, Long Pin 10 Position (four for each board).

@Michael re: Where do you want to spend your time?

Hi Michael,

Have fun! 

Having been an electronics

Having been an electronics hobbyist most of my life, hard wiring things isn't a big issue for me. As I'm fond of saying and it's the truth, "I've been wielding a soldering iron since I was 6 years old." I prefer circuit diagrams but examining the coding definitions is fine too. I'm much more comfortable in the hardware world than the software one and I know what a header is, I just wasn't sure that's what they were called on an Arduino! This whole wonderful world of Arduino's is new to me. My last foray into any sort of programmable micro controller was a BASIC STAMP.

I agree that plug and play can be a great time saver, I just want to be sure I'm not limiting myself in some way. With my current pike, I can't imagine that I need anything beyond what a Digitrax Zephyr has, basically 128 speed steps and the normal range of function switches for sound locos, so you guys tell me how much computing power I need. if the Uno or Mega gives me that in a base unit then so be it. I know that I will be ordering at least one ESP32 because I'm very much interested in constructing the WIFI throttle, hopefully some sort of steam version of it. I have a relatively miniscule budget so I have to buy what I can when I can. The two ESP32's or  one ESP32 and an UNO or Mega are my Valentines day present from my wife! Right now  they will sit for probably about a month because the motor shield for the base unit and the other components for the throttle have to wait. Of course, depending on where I order from, they may take a month to get here. As I said, we do have Amazon Prime, my lovely wife is a movie junkie, but ordering from Amazon is just one option.

So having read all this what do I get  folks?

Backend options =/= Functionality change

Dear Michael,

Short answer :
- 1x 16u2-equipped UNO R3
- 1x L289P Motor Shield (2A capable)
- 1x 15VDC 2A Plugpack PSU
- Some form of JMRI Host system

Longer Answer:

Irrespective of what "hardware backend" you choose (UNO or ESP),
the DCC++ system (and it's functionality/featureset) does not change.
(same core code, same RS232 Serial<> DCC-Track conversion task, same result). 

I mean, darn, change the "computer" you use to run JMRI to instruct the DCC++ system,
(DCC++ is _NOT_ "standalone", it still needs _some_form_ of JMRI, 
running on some computing device _other_ than the "DCC++ hardware",
to act as the "brains"),

and there's still no real change in capability. This is why a PC or MAC running JMRI and using a DCC++ "backend" is functionally no-different (and easily understood/compared) to a RasBerry Pi 3B + DCC++ rig....
(arguably the RPi solution is "easier", as it _includes_ a WiFi access point built-in to the RPi,
whereas a PC or MAC JMRI host will need some other "WiFi accesspoint" device to form a "complete system"...

...the more "seperate boxes" one has to wire-and-make-continuously-work-together to form a "ready to use" system, the less modeller-friendly it is, and the less -likelyhood there is for popular uptake,
no matter how "technically cool" it may be...).

AFAICS, the only tangible difference is _maybe_ the Current Handling (Amps) capability of the typically-reccomended L298P motor shield (UNO compatible) VS whatever "standard"/reccomended motor-shield the ESP option requires...

...and in either case, if the layout/loco-roster-in-question requires more than 2Amps, 
you'll be looking for some form of "distributed-power/booster farm" solution which scales with the layout anyway...
(IE either UNO or ESP option does not change the layout's current-demands...)

Personally, it's not even a question. Until the ESP solution is fully-feased and properly-documented,
(DCC++ is not "properly documented" to "RTR Commercial Product" level at this time by any means,
but there is enough validated-config and "walk-thru" step-by-step info available to make it "typical-modeller capable"),

 reach for a 16u2-equipped UNO R3 + L298P motor shield + 15VDC 2A plugpack PSU,
(Plus a suitable JMRI host "computer" of your choice),
plug-it-in, turn-it-on, and enjoy...

Happy Modelling,
Aim to Improve,
Prof Klyzlr

PS Want "More Power" (Orgh Orgh Orgh) from your DCC++ rig, 
without doing a "multiple-booster power-distribution" rig?
Then check out another stonking tutorial from Dr Geoff Bunza
https://model-railroad-hobbyist.com/node/35753 

@ Michael

PM sent.

what's the architecture?

it's not clear to me what controls the loco when using a WiFi throttle?   Is it a DCC decoder using DCC++ as the command station controlled by JMRI  using the WIfi Throttle to communicate with the PC/JMRI?

while electronic experience is good, integration with software is another battle that involves a different set of debugging techniques.   You can't see what software is doing using a voltmeter or scope and there'sf the difference between PC software and Arduino/esp32 firmware

Follow the signal path

Dear Greg,

As my colleague in Pro Audio was want to say: "...Follow the signal path..."

To begin, we're all familiar with the Conventional "DCC System" components/requirements, Yes?

- Throttle
(provides "human command input User-Interface",
how we as-humans enter "loco 1234, move forward at 10% speed" commands to the system)

---> via ??? "throttle buss"/wireless-connection --->

to the - Command Station
(the "Brains" of the system, defines what "function and features" the system has,
EG how many Consists can the Command Station handle?
Can the system do Simple or Advanced consists?
etc etc etc)

---> (usually some form of proprietary "logic level" link) --->

to the - Booster
(the "Brawn", boosts the "logic level" DCC command-stream from the Command Station into "Track level" DCC signal)

---> via Track-buss/feeders/track/wheel-pickups --->

to one/many - Decoder(s) 
(listens to the Booster Output signal,
takes approx 14V from the signal to use as "raw power",
and responds to overlaid DCC commands addressed specifically for it)

Now, pls keep in mind that _every_ DCC system must have _all_ of these "logical" components to be a "complete" DCC system.

Each of the logical components may be physically combined/separated/mounted in various ways,

(EG a NCE PowerCab has the human-user "Throttle", 
the "Command Station" brains software+processing-unit,
and small 2A "Booster" circuit,
all physically mounted in the one single/common "hammerhead throttle" enclosure.

Whereas a NCE PROCab system has physically separate Hammerhead "Throttle(s)",
a CS02 "Command Station" box,
and separate PB110a "Booster" box...)

but _all_ of the logical components _must_ be present.

SO, translating this "basic DCC-system schematic/terminology" to the "DCC++ equivalents"

Throttle = SmartDevice
(typically an Android or iWhatever, running "EngineDriver" or "WiiThrottle" app respectively... ),

---> via WiFi/LAN network --->

Command Station = JMRI software running on (some form of computer, Raspberry Pi, etc)
+ Arduino running "DCC++" code
(NB the DCC++ Arduino has no "Brain" of it's own,
it simply converts the "Smart noises" output that the JMRI software+PC "brain" makes,
into "DCC protocol" packets of info at "Logic level".

Said another way, the Arduino is simply the "RS232-over-USB < --> DCC output" hardware buffer the typical PC does _not_ have built-in.

NB that the "JMRI PC" and "Arduino" are typically physically connected via a USB cable)

Booster = Arduino-compatible Motor Shield
(Yes, the Motor-shield is physically piggyback-connected directly to the Arduino,
but _schematically_/_electrically_, the Motor Shield's only real job is to take the logic-level DCC-signal on the Arduino Output pins, and Up-Volt them to "Track Level" DCC signal)

--> via Track-buss/feeders/track/wheel-pickups -->

...the decoder in the loco, as you're already familiar with...

Does this help?

Happy Modelling,
Aim to Improve,
Prof Klyzlr

wifi link

in this case, isn't the wifi link not just to the PC/Pi but to jmri another fly in the ointment that needs to be sorted out?

My current pike has two locos

My current pike has two locos that don't even run at the same time. The maximum will probably be three. I don't mind the tinkering and the figuring out, even trial and error as long as I don't let too much of the smoke out. I enjoy that part of it. It's part of the attraction.

@ Gregc

When Gregg Berman made the DCC++ software available it had two parts named "Controller" and "Base Station".  The Controller is computer software that ran on his PC and created all the throttle commands.  The Base Station "Sketch" (software)  is downloaded to an Arduino physically connected to a motor shield.  The Controller computer and Base Station Arduino are physically connected via a USB cable.

Four months later one of the JMRI developers added the necessary coding to JMRI to allow it to act as the controller.  JMRI software runs on a computer (PC/Mac?Linux/RasperryPi) and provides the same throttle commands as Gregg's Controller software.

JMRI includes a WiThrottle Server that allows smartphones and tablets to create throttle commands which are then forwarded to the Base Station.  The WiFi connection is between the phone/tablet and the JMRI computer.  It is identical whether you are using DCC++, Digitrax LNWI, or any other WiThrottle compatible device.  That "fly in the ointment" was sorted out a decade ago.

wifi throttle connection

is the Wifi throttle connection to JMRI nothing more than an IP address and socket number specified on the wifi throttle configuration screen?