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[dkightley]

Whilst I'm at a stall point with work on the Tamar Bridge part of The Bridges at Saltash, I've been starting some investigation work into building DCC and automated train control into the layout.

There has been a couple of threads mentioning the new miniature DCC controller from CT Elektroniks...the DCX65. Their website links to a YouTube video that shows a T gauge unit running nice and slowly:
[youtube]BbPmpL-Rhpo&t=133s[/youtube]

I had looked at doing some experimentation a few months ago....but the gentleman on the trade stand who are listed as an importer of CT products was not at all helpful. The best I could gather was that I needed to spend in the order of £200 on hardware over and above the cost of the decoders. I was somewhat disappointed in the way I was treated once I mentioned T gauge!!

Putting this set back on one side, at the Loughborough show, I spoke to someone on the MERG stand who was more than helpful! MERG....the Model Electronics Railway Group....sell a range of kits to members that are of great interest. Having joined, I was able to browse through the excellent Wiki and other technical resources....and with access to their forum to supplement the information, I have hatched a plan to firstly get my test track DCC controlled.....but ultimately to get the Saltash layout fully DCC and computer controlled. Or at least that's the plan.

And that plan is to end up with using a laptop to control all the trains running in both directions over the Royal Albert Bridge...and on the branch line that runs under it. There will be the one point between the bridge and Saltash station, and what I call a "flexible traverser" controlled by servos from the laptop....and train sensors littered all over the place so that trains can be automatically run. I also plan to have an App on a spare iPhone I have that can be used to control trains and points using wifi.

As I'm diving into several different things here, I'm going to get things going in stages. The first stage will be to get a DMU DCC chipped and running on my test track under manual control via the laptop. The second stage will be to get servos under computer control.....then signals....and then get track sensors fitted and working. The fifth stage will be to get wifi control from a phone....and the final stage is to get trains running safely using automation to create scenarios, etc.

I've started getting phase one under way. I have placed an order for a couple of DCC decoders....and over the next few days will order some of the electronics kits needed from MERG.

And the cost......decoders will be around £35 each....and the basic electronics to get phase one up and running...approx. £45. I'll document things as I go....and welcome any comments, etc as I go.

[dkightley]

Having done further reading I've started the process off by purchasing the following kits from MERG:

DCC Command Station with CBUS interface
USB Interface
8 channel Relay/Accessory Driver
8 channel Layout Feedback Interface
Servo4 - servo driver interface
LDR Train detectors

I already have a 15v 3A DC power supply (ex-laptop) which will be sufficient to power the whole system.

For anyone who has not had any exposure to DCC, here's a run through what I've bought.

The Command station is the heart of an installation and provides the power supply to the track for a small layout (as a T layout is!). It also provides a 5v DC supply for accessories and provides a control bus for the CBUS control system...to which input and output devices are connected.

The USB interface will be the first accessory I will be attaching to the CBUS. This will allow me to connect a laptop so I can use software that emulates a DCC hand controller to actually control the DCC decoders in the trains.

The two 8 channel input/output accessories will allow trains to be detected and points and signals to be controlled over the CBUS system. The software that emulates the train controller (JMRI...I'l cover that later) also has the ability to handle this two-way communication to pass to a control panel emulator...where signals and points can be controlled and trains detected to indicate their location on the panel. The remaining two items on the list are what's needed to connect the I/o devices with the bits on the layout.

The JMRI software....which I'm just really starting to get to look at.....looks as if its quite a clever piece of software engineering that from what I have seen so far, does three basic things.

Firstly, it will emulate a DCC hand controller and communicates via the computer's USB and the USB interface unit to the CBUS system so commands can be sent to DCC controllers fitted to locos. Secondly, it has a Control Panel emulator....which allows panels to be set up to mimic your track layout, and allows points and signals to be operated and their state indicated on the panel. It will also receive via the same connection route, signals from train detection circuits so that your trains' locations can be indicated as well on the panel.

The third basic function of the software....which I've not explored very far yet....is that trains can be controlled in a semi or fully automatic way, including appropriate control of signals and points, etc. This function is the one that I am aiming for....but of course, the other two functions will need to be mastered first!

This is all very exciting stuff.....and is now only possible due to the one new DCC decoder that was launched earlier this year. The only problem I have.....is that I have nothing other than a power supply, so will have to be patient and wait!

[dkightley]

Well.....the kits have arrived!

IMG_3251_red.JPG (115.15 KiB) Viewed 11226 times

Each kit is nicely packed in its own plastic bag with instructions (extracted & unfolded in the picture), a component checklist, and all the bits needed to assemble. The only thing they could add to make the kits perfect is some solder.....but no worries as I have plenty!

The pcbs are superb quality....and everything should go together very easily........checklist: iron, solder, tools, kits, coffee. All present......lets get busy!

[dkightley]

Here's a few more details of the system as I hope to have working....soon!

The main DCC control system.....

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On the left is the main DDC control board. This...as its name implies...is the main pcb for the DCC system. It powered by a 15v AC or DC supply (in my case an ex-Toshiba power supply) and provides the DCC track supply and control....two wires that connect direct to the track....which I have set at approx. 12v. The board also controls the CBUS, the input/output bus for controllers and input and output devices. This bus is whet a DCC hand controller would be connected to....but in my case, I'm not using a hand controller, I'm connecting the CBUS to a PC.

Which brings me neatly to the smaller board on the right....which is a USB interface. This board connects to the controller board via four wires....a 12v supply and 0v, and two CBUS lines, CMDH and CMDL. ANd of course there's a USB connector to connect to the PC...in my case my Sony Vaio laptop running a freeware software control package called JMRI.

Both of these boards have been function tested and are ready for connecting up to some track and my laptop, which still needs JRMI installing. I have one big problem, though. I need some DCC chipped locos....which I haven't got yet. I have a couple of DCX65 controllers on their way from Austria....and when they arrive, I need to shoehorn one into a power unit....and then I can test all three things out,,,the software, the above pcs, and the chipped loco!

[dkightley]

Once I get the DCC system running a train, I can start concentrating on interfacing things to the control system. Starting with outputs.....here's the output interface main boards:

IMG_3260_red.JPG (108.72 KiB) Viewed 11182 times

The board on the left is an eight channel output device...less it's chips as it's not tested yet. This board takes its power from the main 15v AC or DC supply and connects to the CBUS. Under control of the CBUS, it can receive up to eight different on/off commands from the JMRI controlling software.....for controlling signal lights and points. I will be connecting direct to these outputs for any signals I have, and to the board on the right of the picture....a servo control board....for controlling points.

The servo control board operates up to four radio control servos, the throw of which can be programmed by connecting to a PC and using a small software package to set the positions and throws. The board is powered from the main 15v AC or DC supply to power the servos. The control circuit is powered from the controlling pcb.

Currently, I don't think I'll need more than one of these output boards.....but as many as required can be connected to the CBUS.

[dkightley]

To complement the outputs, there is an input interface....and as per the previous post, the board is devoid of its chips:

IMG_3262_red.JPG (111.53 KiB) Viewed 11182 times

The board on the left is an input interface board that connects to the CBUS....from which it gets its power. The board has eight inputs which can be sensed as being either high or low...and each has an address to identify it. I'll be using a few of these boards to pick up signals from an array of sensors....including LDR train sensors, track section occupancy detectors, and for point position switches.

The board on the right is one of the first sensors...in fact it is three LDR track sensors. The wiring is not yet complete, but there's basically three LDRs, each with a sensitivity adjustor and a repeat LED to indicate its sensing correctly.

[dkightley]

I've completed my first serious test session.....with no issues whatsoever. I connected the control board to the USB interface board and the 8-channel output board:

IMG_3263_red.jpg (117.4 KiB) Viewed 11099 times

Green lights all round...indicating each board is powered up...and USB cable connected to my PC, which was running JMRI PanelPro. When I took the photo, I'd "taught" the output board the CBUS address ids for outputs one and two....and the red LED is illuminated and under control of one of the output controls in the software. A very complex way of turning a single LED on and off!!

This board will be controlling the three servos on my Bridges at Saltash layout; one at each end of the flexi-traverser, and one point on the layout. And here's a glimpse of the track layout schematic I'm creating for the layout:

IMG_3264._redJPG.jpg (152.34 KiB) Viewed 11099 times

Most of the layout is behind the scenes. The screen view is looking from the North....the single line across the top is the line over the Royal Albert bridge with the line splitting into two tracks at Saltash station on the right. The branch line on the left is the Tamar Valley line which appears briefly on the layout.....and my flexi-traverser is at the bottom, represented by three sidings joined by points to the main line..and the branch.

I've broken the layout into 12 track blocks. Each will have occupancy indication which will show as the track changing colour from blue to red, which is mainly to show on the schematic....and there will be 13 LDR driven sensors for exact train location so the automation knows where things are!

[dkightley]

I've made some progress....but as I'm severely restricted over what I can do with no loco decoders, I'm restricted to casing up the basic electronics. I have had a couple of DCX65 decoders on order from DCC Components for around five weeks, and I'm finding I'm having to lean on them to chase the decoders from the suppliers in Austria.

Anyway.....progress so far: I've just finished wiring up the first case:

IMG_3289_red.JPG (206.91 KiB) Viewed 10876 times

On the LH side, top to bottom....the incoming power socket on a small pcb (connected to a fuse holder in the case side), followed by five pc power connector sockets that are the connections to the layout and the rest of the electronics.....two raw 15vAC/DC outputs, a 12vDC output, the command bus (CBUS), and the track power. In the middle is the main control pcb...the heart of the system...and to the right, top pcb holds a socket to plug in a hand controller for DCC engine control, and below it is the USB interface for connecting to a PC/laptop for loco and layout control.

I have a second box part made that will hold the pcbs that drive the servos that operate the one point on my layout, and the flexi-traverser. There is capacity in this box to power any signals there may be. I'll also be printing four other boxes that will contain the pcbs, etc for all of the track section occupancy sensors and their interface boards, which will also be fed by LDR train detectors.

[dkightley]

Box number two.....the component controller box. This box holds the pcbs that drive the servos that operate the points, and has capacity to operate any signals I may need to power:

IMG_3297_red.JPG (112.92 KiB) Viewed 10822 times

Only two pcbs here...LHS is the servo control board and RHS is the CBus interface board. The yellow wires at the top are the three signal wires for the points....notice the spare ways on the green terminal block....they're the spare outputs. Bottom LHS are two matching connectors for the board wiring....15v AC/DC in and the CBus connection. The servo leads will exit out a slot in the lid.

[dkightley]

There's been some progress since my last post.....

I've obtained and assembled a few more PCBs. A couple of 5v power supply mini-boards which are needed to supply the 8-way input boards I've already assembled. And half a dozen (superbly named) Twin TOTI boards. TOTI = Train On Track Indicator.....the circuit detects if a loco is in a section of track powered by the track supply the sensor is connected to.

I've temporarily connected these boards up with a triple LDR train sensor board...and have done a some testing....I can switch an indicator on the software track panel using one of the LDRs!!

Here's a photo of the boards ready for casing up:

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Left to right.... a Twin TOTI, a mini-5v supply board, the 8-way input interface board, and a PCB that will be mounted underneath the track board...a triple train detector.

I've created the CAD design for the first of four boxes that will hold the input circuitry. Hope to have a couple printed in the next few days. I now need to modify the box design for the final case...which has one extra connector, and an extra PCB inside.