Alisdair, Alastair, Alistair, Jim, James, Stuart, Nigel, Steve, Andy and Graham convened at the Edinburgh Society of Model Engineers' spacious Almondell clubrooms for our August meeting.
Members worked away quietly (for the most part) at their personal projects. Stuart is installing lighting in his mill building using Woodland Scenics' "Just Plug" system. This includes a diffusion film which is applied to windows to disguise non-detailed interiors - apparently Stuart does not propose to spend the next few years modelling textile looms.
Alasdair was making up Electra couplings using Tamiya long-nosed photo etch pliers. He prefers to work without a jig, instead using a detailed drawing he rustled up in SolidWorks, which shows the relationship of the coupling to the mounting he includes in his 3D wagon prints.
Alisdair was working on detailing an EFE Austerity tank, adding finer handrails and the smokebox "star" added by many Scottish drivers to their locomotives in pre-grouping days. The tradition has been followed at the Bo'ness and Kinneil railway, where Alisdair blows his whistle and wields a fishbolt spanner, on their No 19. Here he is explaining the matter to James.
The main business of the day, apart from the usual conversation and discussion, was a short presentation from Nigel and James on "doing DCC properly and cheaply", prompted by recent interest from group members. This focused on the options for inexpensive control systems, rather than on DCC technology itself or its installation in models. The notes below are via the imperfect filters of my brain and notepad, so any errors or misunderstandings are mine, and not due to to Nigel or James.
We learned about four potential routes to a low-budget but effective DCC control for a typical 2mm modeller: these are MERG CBUS, DCC-EX, SPROG, and JMRI.
MERG's system at its most basic has four elements: a command station, one or more handsets, a plug-in point for the handset, and a DC power supply. The first three come as kits from MERG which the modeller assembles. A minimal setup costs about £90 currently (plus £29 to join MERG for a year) with additional handsets at about £40 each. A module can be added for connection to a computer's USB port, or to boost power above one amp (for larger scales). Its main attraction is the excellent, highly ergonomic handset; its high success and satisfaction rate; the good documentation and community support from MERG; and assembly using normal 2mm soldering skill levels with through-hole technology components rather than surface mount devices. Points against are the lack of a "recall stack" to select quickly between a small pool of models; and (depending on your point of view) the effort required to cut through MERG's enthusiastic explanation of all the other things they do to focus on basic DCC. The modeller is left to make their own choice of enclosure for the elements, which can be as compact or spacious as desired. Here is Nigel's, which uses a diecast metal enclosure principally because he had one available. Unfortunately I forgot to take a photo of James' version, which uses a plastic enclosure.
DCC-EX is based on the Arduino microcontroller. Elements for a basic system are an Arduino Mega; Arduino Motor and WiFi shields; and (depending on various factors) a voltage regulator and/or power supply. A mobile phone or tablet is used as a low-cost user interface. It is possible to make a basic system for £40; a kit of parts (without case) costs around £90. Its advantages are minimal soldering and simple access to automation functions. Disadvantages are the lack of a low-priced physical controller; support requiring use of the Discord social media platform; and the need to invest time in understanding the software architecture. Here is Nigel's DCC-EX implementation:
A third possibility is the SPROG, a commercially-manufactured family of DCC controllers. At its simplest, this offers a single-board solution with a USB connector at one end and connections for power supply and track feed at the other end for £80 including a power supply. Unlike the MERG and DCC-EX solutions, a computer must be constantly connected for the system to work, and physical throttles are restricted to relatively expensive devices such as the Train Control Systems UWT-50. It excels as a simple and portable test-track controller using a laptop.
Also mentioned was JMRI, an open-source, very capable, very elaborate software suite for model railways, compatible with almost all DCC systems. Decoder Pro provides a visual interface for programming DCC CV values: it is compatible with most decoders and keeps an audit trail of changes as they are made. The user interface for layout control is from a computer screen or from a mobile phone.
In conclusion, choice between these four is driven by personal preference for the various user interface options, and (for the choices requiring it) whether a computer is available. As for most things in life, there is a simplicity-flexibility payoff to understand and factor in to a decision as well.
The talk was very illuminating - thanks Nigel and James for generously sharing your knowledge and experience.
The rest of the afternoon passed in gentle contemplation of these and other matters, and by 5 p.m. everyone had gone home peacefully.
