Electrical

Simple Structure Lighting

It’s been a REALLY long time since my last post, since I got caught up in several other things after I started this review. I also planned to do more real-world testing with the lighting system reviewed here. I haven’t found time for that either, but I kept procrastinating on posting hoping I’d find a spare weekend. I didn’t. So I’m going to post what I have, and I expect I’ll eventually do a follow-up when I’ve had a chance to light a couple of buildings.

Woodland Scenics came out with their Just Plug building lighting system a couple of years ago, and I’ve been meaning to take a look at it, and see how useful it would be ever since. On the surface, it appears to be a dead-simple plug-and-play method of lighting buildings that you can power off any low-voltage AC or DC supply, such as the AC accessory outputs on a DC power pack or a simple “wall wart” power adapter. And it is.

It’s not cheap. A pair of stick-on LED lights with wires sell for US$10, the basic hub goes for US$17 without lights, and the expansion unit for a similar cost, and they’ll happily sell you a 1 Amp power supply for US$20 (about three times what you’d pay from a good electronics shop). A large system, with two expansion hubs, eight light hubs, and 32 lights would cost about US$348, or US$10.88 per light (with power supply). You could build the same thing yourself for less than a tenth of the cost. Except for two things.
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Signals and Signaling with Arduino

I’m going to vary from my normal focus on modeling Japanese railroads today to talk about signals and modeling them in a more general sense. Heck, who am I kidding, there haven’t been many posts on modeling Japanese railroads of late. But I digress from my digression. Back to the subject: signals.

If you want to cut to the chase: I’ve written an Arduino library for controlling lineside LED-based signals. It’s only part of a complete signaling system that I’m working on, and at present you’d have to do more work to make practical use of it. But the code is public and can be used independently of anything else I’m eventually going to create; skip down to the end for details.
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More on Layout Lighting

I’ve been thinking about a number of things related to the layout this month, but mostly about lighting the layout itself. The current layout is lit by a mix of my original track lighting system (using compact fluorescent bulbs) and the newer fluorescent tube valences.

That experience convinced me of the merits of fluorescent tube lighting. It also convinced me of the need to build the lighting valence as part of the benchwork, rather than trying to suspend it from an irregular ceiling. As you can see above, the heating ducts caused some difficulty in attaching the lighting units in this part of the basement.
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Going Around the Wall

Benchwork is fundamental to a model railroad. It provides the structure that ties everything together, and over the long term dictates what can and cannot be done. While I created Sumida Crossing, I was intent on recreating the “tabletop” approach I’d used on the Kitchen Table Layout, but as a sectional layout with permanent scenery, something that would hold up well to moves.

That led to a number of decisions on how to build my benchwork. But now that I’m thinking of a different kind of layout, I need to re-think that, examine my past decisions, and decide on a new structure. Read on for the details.
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Tram Controller Status

I’m continuing to work on the Tram Controller project (main page, past musings), to the exclusion of all else layout-related, which doesn’t make for interesting posts here. But I’ve made a number of decisions in the past month, and it’s probably worth summarizing them and where that puts the project overall. Short answer: making good progress, but slower than anticipated (what else is new; all my projects run “slower than anticipated”).

I’ve also been thinking about the diorama-like layout I’m going to initially use this with. The current candidate plans for that are on the new One Point Five Meter Line page.
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Arduino Controls and a Simple Throttle

Having covered the motor control and the sensors, my next step in creating the automated two tram controller was to deal with the very small number of controls I need to have. In my original design, the plan was to have just three pushbuttons:

- Run: when pressed, the trains would start to move.
- Park: when pressed, the trains would return to their starting locations so the system could be turned off.
- Emergency Stop: when pressed, the trains would come to an immediate stop until run was pressed again.

And all three were to be “on when pressed, off when released” pushbutton switches. I was already thinking this needed to be changed, and when I started playing with switches I became even more convinced.

There are two benefits to using toggles versus “on while held” button switches: first, I eliminate a switch, since I need two toggles rather than three pushbuttons. Second, I avoid using those pushbuttons, which have proven to be problematic in my testing. They tend to “bounce” for a long time, and they may remain “on” only for a fairly brief time, making it hard to avoid all bounces and still reliably tell that they were pressed in the first place.

The other control I wanted to add was a way to customize the top speed of a train (or trains, really), so the different models could be made to run at similar (and prototypical) speeds. I don’t want one train rocketing down the tracks while the other creeps along, even if they have very different motors and gear-trains. So I’m going to add a pair of potentiometers, used as “tram #1 max speed” and “tram #2 max speed” controls. And note that these are for the trains, not the motor shield A/B outputs. At various times each tram will be controlled by one or the other.

My first step was to create a simple throttle that used one pot, three switches, and one motor control to run a train on a simple test track. This gives me a proof-of-concept example that ensures I really understand what I think I understand (always a concern with me and electronics).
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Detecting Trains with IR Sensors, Part II

This is going to be a short post: it’s working! I have my IR LED phototransistor sensor program detecting things (not trains just yet), and I’ve posted the example code, see the bottom of the Tram Controller page for a links to that, and the earlier motor control code. Both example programs are public domain, feel free to use them however you see fit. I’ve benefited from a lot of public domain programs, and I think it’s only fair to give something back. When the tram controller program is a bit more polished, I plan to publish it in the same way, although it may be months before I get to that point.
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Detecting Trains with IR Sensors, Part I

In my continuing work on the Arduino-based Tram Controller, I’m now playing around with the part I really wanted to work with, the Infra-red optical sensors themselves. This turned out to be rather more complex than I’d anticipated, but I’m most of the way there, even if I don’t quite have the system working yet. This is a post about what I’ve done so far, and what I’ve learned, with a bit about what remains to be done.
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Arduino CPUs and Motor Shields

I’m still playing with Arduinos this week, but the little beasties are multiplying. That’s partly because I want to be able to test with the various CPU architectures, but also because each has unique strengths and weaknesses, and I’m still evaluating which of them is going to be the right choice for my tram controller. At the same time, it turns out that there are a number of options for motor shields, as I mentioned last time, and they too have strengths and weaknesses.
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Revisiting Arduino

Two years ago I wrote about my plans to use an Arduino to control a pair of trams on a double-track line sharing single-track stations at each end, replicating the design of the Tōkyū Setagaya line. That’s briefly written up in that earlier post, and I also have a full page about the project that goes into more detail, with a sub-page about the current testing work.

Back then I bought an Arduino Mega 2560 and a bunch of other parts including a “shield” used to drive DC motors, loaded the basic test program that blinks a LED into it just to convince myself I could do it and the hardware worked, and then put it on a shelf for “later”. And forgot all about it while I worked on other things, only infrequently looking at the empty tram tracks and thinking “I really should figure out how to make that work.” It’s not like I dislike the work: I enjoy both programming and soldering simple circuits together. I just never could work myself up to starting what I expected to be a fairly major project. It was always: “I’ll work on that after I finish project ‘X’”, but there was always another “X” to occupy me.
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Wire

I went off on a tangent this past week. It all started when I asked myself: what gauge wire should I use on my decoders? And the root of that question was thinking that the wire I’d used on my first install, two weeks ago, was too thick. The answer turned out to be less obvious than I thought it would be, and consumed (and is still consuming; I’m not done) a lot of time.
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Bus Wiring and November 2011 Status

DCC is often said to simplify a model railroad because it requires “only two wires”. While that’s true to an extent, most real model railroads will require quite a bit more. Or maybe I just like to over-complicate things.
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DCC Power II

The DCC Power work continues, but it’s still not done, as I have to do the power panels for the urban scene and the unsceniced return loops, but with the panel I built and tested back in September/October finally installed under the tables of the River Crossing scene, I’m at the halfway mark (having done the Riverside Station scene back in March).

To recap, the board contains a PM42 DCC circuit breaker that provides four separate circuit breakers and a BDL168 occupancy detector that can provide up to sixteen occupancy detectors and eight transponding sensors (see my pages on occupancy detection and the BDL168 for more details). This board provides occupancy detection for six electrical blocks, two each on the commuter tracks and one on each subway track where it loops below the expressway. Although I’m also wiring up the transponding sensors, as mentioned previously I’m having doubts about them due to problems in testing and the anticipated low power draw of my trains being borderline to register on them.
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Wiring Without Solder

Well, I’m not moving the site just yet. Conversion of pages is going more slowly than expected, and there are more pages that I consider necessary than I first thought there would be. So I’ll probably have a few more posts over the next couple of weeks before switching over to the new software and hosting provider. However, for the curious I’ve included some jpegs of the new main page and one of the subordinate pages showing the new layout and navigation links in the Diagrams album (these are reduced somewhat by iWeb; the type used for text on the page is about the same or slightly larger than the type used today).
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How I learned to stop worrying and love the BDL168

Well, perhaps that’s a bit strong, but I’m coming to terms with its design flaws and the poor state of the documentation surrounding it and the PM42. I now have the first set of PM42 circuit breakers and BDL168 occupancy detectors (with two sets of RX4 “transponding receivers”) installed, and have done a bit more reading over the weekend. I’ve discovered a few things and come to a few conclusions as a result of that work, and that’s making me feel that I have a handle on this now. But I had to work through a number of issues to get to this point.
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February 2011 Status - Occupancy Detection Revisited

Work has progressed slowly this month, partly from distractions, and partly because I’ve been reluctant to finish up the block occupancy detector wiring. I finally realized that the reason for this was that I wasn’t happy with my hybrid approach to occupancy detection and transponding.

To recap, my Subway and Commuter loop tracks were to be divided into blocks, with Digitrax BDL168 occupancy detectors and PM42 circuit breakers (circuit breakers are typically one per track per table, whereas there may be two, three or even four detectable track sections on a single track on one table, and more in a couple of cases). The PM42 provides for four circuit breakers, which is a nice fit for the four tracks, and the BDL168 is divided into four independent quadrants (so each can be wired to a separate circuit breaker), each with four block detectors. I’d originally planned one PM42/BDL168 per scene, meaning that wires would have to cross a table boundary in the Urban and Riverside Station scenes.

And that was a problem, for several reasons. First, running wires between tables violates my “keep all wires except bus wires local” design goal (it makes the layout harder to disassemble), second while the BDL168 can support 16 occupancy detectors, in some places I needed more than four on one track, which broke the association of the PM42 circuit breaker element to a single track, meaning a short would shut down a second line. And finally, I wanted to do Transponding, and the BDL168 only supports 8 transponding sensors (using a pair of RX4 sets), meaning some blocks would be able to report which train was in them, and some would only be able to report that some train was present, but not which. None of these were fatal flaws, but they were eating at me. And I finally realized that I only needed two more sets (seven instead of five) to fix these problems.
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Almost There - January 2011 Status

January went primarily to the backdrops and the risers/inclines of the Riverside Station scene commuter loop, and now the Riverside Station scene begins to come together. The tables themselves are not yet connected to each other or anything else, as I’m taking the opportunity to work on the wiring with them stood on edge, which is much easier than working on it from below.

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Freight Trains, Electronics and October 2010 Status

Not much got done on the layout itself in October, mostly I’ve been running trains (as documented in an earlier post with a video) and doing a bit of electrical work (mostly the previously noted update to the power panel). I’ve spent a good bit of time on a couple of other things though.
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Adding a DCC Meter, And Related Topics

Although I wrote about the power panel previously, there were a couple of things left undone. I was missing one of the ammeters for the lighting power (the store I get them from had run out), and I’d misplaced one of my LNRP LocoNet Repeater panels, so I’d substituted a UP5 panel I took off the old HO layout. Also, I’d realized that my portable RRampMeter DCC volt/amp meter was useful, but wiring it into the system when I wanted to check something was a real nuisance. Over the summer I bought or found the missing bits, and finally decided to order a new RRampMeter (the version without the nice case) to mount as a permanent part of the circuitry (I’m keeping my other meter--the one with the case--for workbench and other testing uses). So it’s a good time to summarize what the panel does, and talk about the new meter a bit.
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Myths The Internet Told Me and August 2010 Status

The Internet is a wonderful invention. Without it, I wouldn’t be able to order trains from halfway around the globe and have them delivered in under a week, nor would I have any idea of the difference between an E233-1000 and an E233-2000 (both are commuter trains, but the 2000 is a narrow-bodied variant with a end door for emergency exits; this model runs through onto the Chiyoda subway and nobody makes a model of it yet, but I want one). I hear that some people have more serious uses for the Internet, as well.
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July 2010 Status - Behind the Scenes

Much of July went to more electrical work, partly planning, but mostly just crimping spade lugs to wires. Around 200 of them this month. There are now a total of six bus wire pairs beneath the tables: two for DCC (command station and future booster), two for the two tracks of the outer (Rapid/Shinkansen) loop, which will be switchable from DC to DCC, and one each for DCC accessory power and the Occupancy Detector & Signaling systems. I also wired up the control panel for the power.

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Scotty I Need More Power!

DCC doesn’t need to be complicated. At the simplest, it’s a pair of bus wires from the command station running under the track, with feeders connecting the track to it at intervals. I can, however, make anything complicated. Probably more complicated than it needs to be. It’s a talent.

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More Electrical Work

Rather than turning my attention immediately to the Riverside Station scene, I decided to get the electrical systems ready for the eventual use of the two “ground level” loops, which will require DCC. And that meant I needed to finalize my plans. And although most of them had been worked out last year, and revised (in my head if nowhere else) over the winter, there was still a bit of planning needed before I was ready to start cutting wire. This had to encompass the DCC systems (both power and the LocoNet control bus) as well as the various power strips to supply them, and some additional power supplies for eventual LED lighting. I’d started thinking more intensely about this while I was working on the wiring recently, but needed to bring that to conclusion and write down the results.
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Subway Track Cleanup, Etc.

This weekend went largely to the beginning of the final (I hope) laying of the subway track, which has been in place, in whole or in part, through more than six months of construction. As a result, it has gotten a bit dirty. All track was pulled up, cleaned with isopropyl alcohol on a cotton pad, and relaid. At the same time, insulated unijoiners (black, in the photo above) were inserted to divide the track into electrical blocks (for power feeds and future occupancy detectors) and power feeds were wired up to terminal strips under the table. I didn’t get it all done, perhaps a bit more than half, but I should be able to finish it during the week and run trains by next weekend.
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May 2010 Status - Carving Foam

Time marches on, but it seems to be crawling on the banks of the Sumida. The hillside covering the subway has made little apparent progress over the last month, going from squarish blocks of pink foam to carved, but still pink, sections, which only just received a first coat of primer (and have yet to be glued in place).
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December 2009 Status - Subway Track in Place

The subway level track is nearly complete, with the underlying foam and cork glued down, and the Unitrack in place. Read More...

It’s Alive! - November 2009 Status

Work has been progressing more slowly than I’d like, and the first level of foam has yet to be glued down, or the subway track installed. The backdrops were taken down and repainted in a lighter shade of blue, and I’m much happier with them now. Read More...

September 2009 Status

The tables (phase 1, excluding the end section with the helix) are all assembled and mounted to the legs, with scenery backdrops and paint. That’s taken more than a month (after a couple of months of planning, mostly deciding on a track plan). I’m still in the design phase for the electrical systems. After some experiments with foam height and bridges, the design of the subway (and its implications for how many foam layers I will use) is done (I hope). Read More...