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Here are a couple of ideas: (1) Supposing your traverser only stops at a road (and not at a gap between them), add a reed switch for each road, operated by a magnet attached to the mating surface. When you power-up the system, have the Arduino examine these switches to work out where the traverser is. (2) Use a wafer switch with three positions as the 'power' switch for the system. The positions being "run", "park" and "off". So when you switch off, you let the traverser drive itself to a known parking position, and the system will have a known position next time you power up. - Richard.

I think some marked-up photos could work well. My computer is in the office, the layout is in my hobby room, so a manual method would be best for me. If I desaturated them and printed them out on A4 paper, I could mark them up by hand and put them into a ring binder. Ten or twelve photos would cover the underside of the layout. What I need to do, is stop altering the wiring. The Magnorail system is going through multiple iterations at the moment. - Richard.

I am cheating :-) The wiring is neat and tidy at its ends, but the excess is doubled back inside the plastic trunking. If I mess up making off the end of a wire, I use up a bit of the surplus and no-one is any the wiser. - Richard.

- Richard.

I have started my second box of cable clips (100 in a box). With the layout tipped up and resting on its rear backscene, horizontal cable runs are in trunking and vertical runs are clipped into cableforms. It will all look ok when the trunking lids go on. So far, I haven't written down anything to do with the wiring (gulp!). I am working on the basis, the cableforms are small bundles. I never put more than three wires of the same colour together, and it is fairly easy to see where they are going, "so I don't need a schematic". After all, the wiring is pretty simple - there are a lot of circuits but they are nearly all the same sort of thing e.g. a servo, a light or a track feed. There are very few one-offs like the connection to a display or a switch. This may well be a flawed approach, but a previous layout had a smaller quantity of much more bulky cableforms, white wire throughout (no colours) with numbered ident sleeves on every wire, and a 400-row spreadsheet to explain each wire. I had to have a printout in my hand to solve any problem or indeed alter anything. And the spreadsheet was a pain to keep up to date. I need to find a happy medium. It might be a series of A4 pages, each page showing a sketch of a pcb or module and its connected wiring? This would cover everything except the individual track feeds. - Richard.

I have installed my "scenics processor" under the baseboard: For some reason it looks neater in the flesh than it does here. The board is finally running from layout power and not its USB port. I still ended up phoning a friend for help with one of the functions. I don't know why I struggle so much with software; all I know is that sometimes, the ideas and the code seem to come naturally enough, and at other times I am completely stuck. I will hardly ever want to alter the configuration, so I have tucked the two buttons "yes" and "no" away out of sight. With a bit of luck, I will still be able to reach them if the layout is resting on its trestle table, or on its wall brackets, or on whatever trestles I use at a show. I am running out of spare real estate under the baseboard, hence the note about a "signal actuat(or). I want to put a signal with a servo here one day, and I very nearly screwed the Arduino in its place. I want to move back to my Magnorail system now. - Richard.

Sometimes you can spot these drivers pretty quickly - like this one? - Richard.

- Richard.

A friend has sent me a series of these entitled "the lost art of driving", I will post the ones I think we are allowed within the forum rules. - Richard.

If you are really keen, you can drill a small hole through the middles of the buffer heads, cut off the heads and their shanks, and put the heads back in their retracted positions. A piece of styrene rod through the hole to hold the assembly together. Somehow, seeing a retracted buffer where it ought to be extended looks better than the other way round. - Richard.

I am saddened to see, Model Car World aren't offering shipping to the UK. http://www.modelcarworld.de I do hope this is a short-term measure. I had added some Brekina RHD models to my cart, and had to give up. - Richard.

I have finished the code for my "scenics processor". This has ended up just like building a layout; I keep on thinking of new details, and eventually decide to simply stop. My "scenics processor" is one Arduino Nano, and it is currently driving three servos, an LED replicating a rotating strobe lamp, and a narrative display. All of these are running at the same time and are working to their own schedules: The white lump on the harness to the left of this arrangement is a temperature and humidity sensor, so the display can include a "weather report" based on the local conditions and, arguably, the whole shebang can be seen to be doing something useful. (The breadboard is holding a switch, the Arduino behind the breadboard is doing nothing). The success of this is entirely due to my being able to construct a couple of C++ classes, one to drive a servo object and one to drive an LED object, and get them to compile and indeed work! Without these, I think I would have split the display, servos and LEDs across several individual Arduinos. The source code is just over a thousand lines; about a quarter of this is comments and white space, and another chunk is text strings for the display, but its size has pretty much reached the limit of what I can cope with in one file. The project is using about two-thirds of the flash memory in the Arduino (I'm happy to use most all of this) and one-third of the RAM (so I am happy the code isn't going to run out of space when it runs). I have a PIR sensor built into the layout, and I need to integrate this into the software. When this is working, the software side of the "scenics processor" should be done for the time being and I can put in the wiring for the various animations. I feel I have somewhat blackened my nose with Arduino software. I began with my Magnorail project, this was too ambitious at the time so I tried this scenics processor and then a model barrier. I am now working my way back up this chain, so I can return to the Magnorail with a bit more knowledge and confidence. - Richard.

- Richard.

Alan, A while ago I had a go at making a Mk1 brake composite using some laser-cut sides I drew up and had made by York Modelmaking. I had a lot of trouble getting the sides to hold themselves to the right shape (the constant curve of a Mk1 side) and even more trouble getting the very narrow strips above the windows to stay in a continuous straight line. Possibly, a strip of small L section brass would help along the tops of the sides. I suppose, much depends on how much of the Lima carcass you keep - I seemed to cut so much of it away, there wasn't enough left to build on. If I was doing it again, I would think about cutting some full-width bulkheads to the correct profile, and discarding most all of the Lima body except the ends and roof. If I was able to cut the sides myself, I would look into cutting an additional "inner" side, and building a sandwich with a gap inside to hold the glazing. If the first layer went onto the model with the correct curve, the subsequent layers ought to build up to make a robust model. Hope this helps, - Richard

It's solid die-cast. Best kept as a paperweight. - Richard.

I wonder why Brekina have made the model at all, and the only reason I can think of is for customers who have visited London and fancy a Routemaster. This would explain the choice of route on the model. I don't know, but perhaps there are Routemasters running as tour buses in Germany? The model is expensive by British standards, but I think this is reflecting the higher cost of plastic moulding production over die-cast. The result looks very good and I would hope most of us would get away with only one for a layout. - Richard.

A week on, my Arduino display now has a selection of pages to describe the layout, the loco roster and, when a sensor arrives in the post, the weather. This is the latest prototype - nothing to it really: It has dawned on me (eventually), if I have a display I can have a user interface. So the system now has two buttons labelled “YES” and “NO” and some suitably user-hostile prompts to get inputs to change the roster: I have endured plenty of software like this during my life, so it seems only natural to create some of my own. And, only two Arduino inputs used to change whatever settings I can dream up. The layout has a PIR sensor embedded into one of its ‘wings’. I put this in to trigger the animations, but maybe it would be neater to fire off a “please do not touch” message on the display? In the meantime, I have added a get-out screen for occasions when I remove all of the locos from the roster :-) - Richard.

The last time I travelled on a 'service' RM I fell asleep , quite a deep sleep really and I had to be woken by the clippy. The route had terminated mid-way and I had to blearily make my way onto another bus. The next time I went to London all the RMs had gone except for the heritage ones, but it was a nice way to say goodbye to them. - Richard.

I am so sorry I missed the auto corruption. Some of them are very good. A while ago I built the Peco turntable for manual operation and added a neodymium magnet at each end of the deck. One of these meets up with a mating magnet on the bottom of the well to act as a sort of a latch. It's still working nearly five years on. If you could get the magnets the right size, so they hold the deck in position but pull away when the motor moves, this might give you the final alignment you need. https://www.rmweb.co.uk/community/index.php?/topic/94323-compact-fiddle-yard-for-165-mm-gauge/&do=findComment&comment=1751052 (Sorry I can't find the link to the turntable thread you mention) - Richard.

I had a look at battery power for a control panel, but I decided if I was going to run three wires for the serial control data, I might as well add a fourth wire for a supply of power. It was as though batteries are best when the item wants to be wireless. I wonder if a solar panel would be enough here? After all, you run quite short trains, and they go quite slowly. This might need a bit of fiddling around to get enough volts. A solar charger for a car battery? - Richard.

Yes. Just: pinMode(A0, INPUT_PULLUP); Then put a switch between the analogue pin and the 0V line. This seems to work fine for A0 to A5, but I don't know about the extra two analogue pins on the Nano. I found myself having to do this because I bought one of the old-fashioned motor driver shields, and this consumed most of the digital pins. - Richard.

When I find myself using low-value resistors I always end up doing many iterations. I'm not too sure what you are doing here but if you are wanting to lose a volt or two, regardless of the load, a few silicon diodes in series might work. Each diode drops about 0.6V. If you want the circuit to be reversible, put a matching chain of diodes facing the other way in parallel with the first. Those 9V batteries don't contain very much electricity so to speak. If you don't need portability, you could try a DC-DC convertor like this: https://ebay.us/72bDAx driven from a spare wall wart plug you have lying around. Let me know how you get on. I may have to stay away from the keyboard for the rest of today, because of the date, to avoid getting shot, but I'll be back. - Richard.

I bought an LCD for the Arduino as a Christmas present for myself, but the charity shop where I work has been forced to close (. third time this year .) so I have been learning about the LCD instead. My ancient Panasonic laptop is running fine with its new operating system, and the Arduino development environment uses the correct serial port every time: I have written a very simple program to display a series of pages to describe the layout. So far I have managed six drawings of engines in "ASCII Art" style and 10 pages of narrative explanations. Examples: This lot is consuming only about a fifth of the Arduino's flash memory, so I could add many more pages. I could describe the layout and explain a bit about what is going on. The title page at least is reasonably finished now, and proudly states the scale and subject! Incidentally, the display contrast is just right for normal viewing, but I could tweak it for photos. So ... the plan is to use this Arduino as a sort of "ancillary scenics processor" to handle most of the animations on the layout and this display. Possibly add a real-time clock module or a temperature sensor, to try out something new. This is very much a learning exercise for me with no pressure (I don't care if I have to give up), to work myself up to writing some better code for the separate Arduino connected to the Magnorail system. I am thinking of building the display into the side of a building or maybe an advertising hoarding, in much the place it is here on the layout. This will make it visible regardless of whether the layout has its lighting rig in place. As far as I can make out, this topic gets about a hundred views with each new post. I am putting very little scale-specific material here and I do hope people can pick up on anything useful, regardless of the scale they are using. It all seems like a monologue sometimes, but the project is growing nicely and I am happy with it. Wishing everyone a pleasant if low-key Christmas, in these rather trying if not downright tragic circumstances. - Richard.

Ian, A trick with stranded wire I was taught many years ago. Put one end in the vise, unwind as much as you can from the reel in a straight line. Grasp the far end with pliers and pull it until the wire "gives". Cut off and discard the ends. You will then have a manageable length of wire, able to lie neatly into a harness. - Richard.

Happy Christmas to everyone (my favourite engine) - Richard. HappyChristmas.ino