Discussion in 'Members Personal Layouts' started by paul_l, Dec 5, 2015.
Welcome to Victoria Road, a 60's based Scottish layout
Victoria Road is an end to end layout, with a traverser at one end and a terminus at the other.
Probably, I should go back to the beginning..........
Returning to the hobby after a 20 year break, my meagre stock was P4 Pre-group Highland with a converted Lima Cl 20 for testing and some American H0 stock.
The P4 test plank was dug out from the loft, and was showing its age - dont suppose 20 years use as a shelf helped. The electrics - single hand held controller powered from a H&M Duette, were flackey. The boss - bless her cotton socks suggested as Christmas was fast approaching why dont I upgrade my controller, cutting a long storey short I am now the proud owner of a NCE PowerCab system. The Cl 20 was converted to DCC with a TCS decoder and ran smoothly - well impressed. Still had the problem of a simple tatty plank (S bend with a pair of B8's forming a crossover) Highland Railway Pre-Grouped wagons and a BR loco, with no sight of an HR loco appearing for some time, and wanting to get something running the seed was sown to build a small 00 gauge layout.
While visiting the local Model Railway show on the Saturday, a couple of Bachmann Jinty's took my fancy at a bargain price, along with a couple of Hornby Railroad wagon packs. The boss decided to pay the show a visit on the Sunday to see what the fuss was all about - a decision she will always regret, noticed a layout with sound (American 0 gauge, also using NCE DCC), commented that the controller was the same as mine and my loco's didnt make any sounds ...... well....... Santa came home armed with a Hornby Cl 08 sound equiped loco... its a long time from October to Christmas day to wait for Santa to complete his delivery round, I'd have been quicker using the post office - maybe not. So the pressure was on I had from mid October to December to get something running. A trip to the local model shop got points and flex - Code 100 Peco, I now remember why I started to model in P4 20 years ago... and the following track plan was built.
The bit with the ? - I have lifted and relaid this bit 3 times now, I just cant decide single or double track. Single track everything enters and leaves via the lower track, double track - trains enter from the lower track, but can only depart from Platforms 3 & 4, giving rise to empty coaching stock movements. Without a run round a station pilot is required.
I like seeing elevated railways cutting across roads glimpsing views between buildings, so I made the decision to build the layout elevated. Also cluster of points straddle the base board joints, so I made the whole unit removable.
Yes, what next??
The final decision was made to use the layout as a single track, by the purchase of a couple of DMU's - dont see many empty stock movements of DMU's from one platform to the next.
Now that I had this DCC thingy, I decided that all points etc should be controlled by the system. Looking at accy decoders, all around Â£40 each (to operate 4 point motors), and I needed to control 6 motors, this wasn't going to happen. Browsing around I came accross the MERG site. (Model Electronics Railway Group).
They produced kits which are sold to members, 1 years membership, plus 2 dcc accy decoders (with inbuilt CDU) came to Â£37, less than the cost of a single ready made unit, so game on.
These units also took power from a separate 16V AC supply, a great advantage for me as I use a NCE PowerCab, which only outputs 1.5A, so being able to power devices away from the track bus is a bonus.
I only have 4 points on the layout, 1 x 3way, 1 x dbl slip & 2 x standard points using 6 point motors, I could easily remember which point was which, but visitors had nae chance, fortunately I had stumbled across JMRI and DecoderPro to help set up and backup my DCC loco decoders, part of the JMRI system is PanelPro, which is designed to operate the layout.
Now were cooking, a track plan with clickable points, route selection to provide route setting via a single mouse click or tablet button press, simples........ well there was a steep learning curve, but it was worth it, and will be covered in upcoming posts.
The fiddle yard is now a traverser, originally a sector plate, then a traverser using bales catches for alignment, ok but not good, so I decided to motorise it using stepper motors, initially controlled by a Raspberry Pi, but the motor and controller took over 30 seconds to move between tracks, so a potential 5 min to move from track 1 to 6. So this was replaced with an arduino based system, and it worked
This was my first attempt at using arduino, so took best part of a year to complete and a lot of asprin .
But was still a manualy controlled system from its own panel, I wanted to be abel to control the traverser via DCC, lots more head banging later and we have.... drum roll please maestro
I will try and produce separate write ups in the appropriate sections later.
Victoria Road is approx 11ft long by 2ft wide, but is at least indoors - Dundee in the winter is wet and cold, actually its the same in summer as well.
Just to give a rough idea of the layout, here's another short vid.
Great story so far Paul, looking forward to the next update
As its late this'll be quick .....
Back to the Traverser
The final version is shown above.
The dog leg on the rear 3 tracks is to allow the traverser fit into the window opening, as the traverser extends beyond the rear of the layout.
The drive mechanisim is a separate sled arrangement, with two lengths of 6mm screwed rod, passing through T nuts attached to the traverser to provide drive. They effectively act as a worm & wheel, which prevents movement when not being driven.
Why 6mm screwed rod, well the thread pitch of 6mm is 1mm per rev. making the maths simpler...... nah it didn't. If I were to start again I would use 8mm screwed rod, as it would be a little more sturdy.
I had a refurb kit for a roller blade - not mine the kids, but that contained as set of 22x8 bearings (8mm raises its head again), so I used a piece of 8mm OD, 6mm ID ally tube as a spacer, and held captive by a pair of nuts ( affectionately known as Matt and Tom)
The woodern frame had blind holes drilled with a forstner bit to hold the bearing.
Giving the drive assembly.
Tune in same place tomorrow for the next installment
Great video Paul. The view through the buildings with the trains running past is very effective. A different take on the usual scenes where everything is in view all the time.
Like it ...... Like it ........ Like it.
You're easily pleased then, only issue is I need more buildings to shoot between.Time to sharpen the knives as well as the pencil.
Ah well, time for work
Got to agree with Tom on this one, good work Paul
Looking good Paul. ...and a great introduction to Victoria Road.
I do like the video where the loco and coaches are passing behind the buildings, very effective indeed.
For once I can claim the between houses view as a deliberate design feature, and its also at the viewing height for me sitting in my computer seat - non of this armchair modelling, I'd only see the underside of the base board
Ok where were we
The base was made, the traverser is supported on computer desk keyboard linear slides - doing this again I would use drawer slides, screwed onto woodern supports.
Next the motors
Mk1 Raspberry Pi + stepper motor shield + 2 x geared stepper motors
Cost R/Pi Â£28, stepper motor shield + 2 motors Â£12 total Â£40
plus a pair of 6mm / 5mm universal couplings Â£5 the pair)
It worked but took 5 min to move between tracks, so take upto 30 min to move from track 1 to 6.
A change of tack was needed, so I changed to an arduino + sparkfun Big Easy Driver stepper controller and a nema17 stepper motor.
It worked , speeds was considerably faster, I just had to learn how to program it.
Mk2 had an LCD display plus rotary switch to select the track and a push button to activate the move.
Built initially on a bread board.
This was extensively tested - read I played trains a lot
But there were issues, by driving only one the screwed rods the traverser tended to go squint towards then ends of the stroke, and would stall. So I looked at running two motors, built the circuit, and was writing the program, when Morag was admitted into hospital to change her medication, what was supposed to be a week to 2 weeks ended up being 8 weeks. However this forced break gave me time to rethink the drive, and I modified it to being a single motor with a GT2 drive belt linking both screwed rods.
5mm bore 20T pulleys were tapped M6
and threaded on to the screwed rod
hooked up to the bread board and tested
I found I also had to increase the input voltage, I was using 16V, but could still stall if the traverser was full, increased to 20V but still happened occationally, eventually I used an old HP printer power supply 32V and result
The big easy driver can handle input voltages from 9V to 35V, and will also provide a 5V out for the arduino.
Now that the circuit was stable, the final step was needed, I wanted to be able to control the traverser from the NCE handset, or via the JMRI software, so a DCC interface had to be built......
Da Da Daaarrrrr - tune in for the next installment.
Keep it coming Paul........ This'll get me to sleep,
That`s a nice piece of engineering there Paul. I like the tensioner set up for the belt.....well executed.
Of course, if I wasn't so tight I would have bought a belt the correct size, at approx Â£18 each, instead I got a pack of 10 from China for Â£17 inc. Delivery.
And I now have 9 spares
Looking great Paul, I love the look of the gubbins ( is that OK as a technical term ?)
of the traverser
I ran the traverser in the manual mode for around 6 months, but found I had to keep going back to the fiddle yard to set the traverser for the next required track - I know its only 11 ft max, but I had always wanted to operate the traverser via DCC.
Tinternet being a very handy resource, I went searching for hints, solutions for DCC on an arduino, I needed to get DCC signals into the arduino, then be able to decode them into something I could use / understand.
Fortunately, several DCC libraries have already been written, I just needed to find the one which best suited my needs, and several circuit diagrams were available to interface to the DCC track bus.
The circuit shown below
The DCC in is from the DCC Track Bus - so common to all DCC systems, if your system can controll accessories then it will work with this.
The DCC signal goes to the optoisolator OK1 (a 6N137) and is passed through and outputs to pin 6. By using an optoisolator the arduino is isolated from the DCC track power.
Pin 6 is connected to Pin 2 on the arduino which is set to receive.
Now we have the signals into the system, how do we decode them.
Well the library I used was the arduino DCCdecoder library.
The first tests were carried out with an Arduino uno and just the above circuit plus a couple of LEDs to prove it works.The sketch (arduino program) and DCCdecoder library define the following structure
int address; // Address to respond to
byte output; // State of output 1=on, 0=off
int outputPin; // Arduino output pin to drive
boolean isDigital; // true=digital, false=analog. If analog must also set analogValue field
boolean isFlasher; // true=flash output, false=no time, no flash.
byte analogValue; // Value to use with analog type.
int durationMilli; // Milliseconds to leave output on for. 0 means don't auto off
unsigned long onMilli; // Used internally for timing
unsigned long offMilli; //
The decoder addresses to be controlled each need there own entry, and the total number of addresses have to be declared that the arduino will respond to.
So for the traverser I have two entry roads (main - A & runround - and 6 traverser tracks - 1 to 6, but only 1 to 5 can physically reach entry road B.
That give a total of 11 addresses needed.
The address range I have used is 100 to 110 (100 = A + Track 1, 101 = A + Track 2..... 105 = A + Track 6, 106 = B + Track 1............ 110 = B + Track 5)
A decoder entry look like
gAddresses.address = 100;
gAddresses.output = 0;
gAddresses.outputPin = 7;
gAddresses.isDigital = true;
gAddresses.isFlasher = false;
gAddresses.analogValue = 0;
gAddresses.durationMilli = 500;
So when accy decoder 100 is turned on Pin 7 (an LED) on the arduino comes on for 500 milliseconds (half a sec). This is long enough for the traverser side of the program to see the change. Now in theory, it should go off after 0.5 sec, however the tracverser side of the sketch takes over and hogs all the processing untill the move has completed, then the LED goes off.
I set the sketch to send diagnostics to the serial port of the PC (via the usb port)
Each address was set up and tested
The Traverser / stepper motor controll was then added to the sketch.
From the pic below, ignore the 1st line as is a remnant from the last move to take place.
So for each entry the DCCdecoder library detects an address its looking for, in the first case Basic Addr 101, and sets it active.
The sketch calculates the value of New position = Basic addr - 100. then if New Position is not equal to current position, sends the new position the stepper motor has to move to. Finally sending the message Moving to track A - 2
And just to show it works
The circuit was now moved from the breadboard to a more permanent stripboard.
The Processor changed from an Arduino Uno to a Cloned Arduino Nano (job lot from China £17 for 10 inc p&p)
The circuit was drawn / designed using the open source software Fritzing
The left hand Strips are for the Big Easy Driver (which also supplies the 5V for the Arduino), the right pair of strips are for the arduino. This makes both easily removable.
The parts for the decoder / controller
The board assembled without main chips
And with chips
And the video
Overall this has probably taken 2 years to get to this stage where I'm happy with it and now have each route selectable via the hand controller or JMRI Panel Pro.
Well that was a long post, so how do I use the thing.
With the entry tracks labelled as A - Main line, and B - Run round
and the traverser track labelled 0 to 5
The following Accy Addresses were allocated
Route Accy Addr
A 0 100
A 1 101
A 2 102
A 3 103
A 4 104
A 5 105
B 0 200
B 1 201
B 2 202
B 3 203
B 4 204
I now have 2 ways
1. Using my NCE PowerCab hand set
Step 1 Press Select Accy button and enter accy address for the required route
Step 2 Press 1 = N(ON) to authourise the move.
2. Use JMRI Route table set up from my Layout panel for Victoria Road.
Just click on set for the route required
As can be seen from this one route table I can set any route for the layout, and is my primary method.
How I made the route tables will be the subject of another post in the DCC section, but not quite yet.