Oct 2013

Occupancy Detection Yet Again

About fifteen months ago work on adding occupancy detection to Sumida Crossing stalled. That was in part because I’d planned to use the BDL168 detectors to also do transponding, and a few months earlier had abandoned that plan since I was unable to get that aspect to work reliably, even on a simple test track. The number of solder joints on the BDL was also a nuisance that caused me to put off further work.

Recently I’ve been rethinking my approach. The BDL168 is an amazingly cost-effective solution. Ignoring the transponding part, you get 16 detectors on a board that includes a LocoNet bus interface for US$120 (street price). That’s $7.50 per detector (if you can use all 16). That’s really hard to beat for a bus-connected detector. I’d originally planned to install one per table on the layout, and my cost would have worked out to around $10 to $15 per detector on average.

On the other hand, I’m thinking that I might want to move to either a OpenLCB/NMRAnet bus (if I want a feature-rich bus for the future) or a really dumb serial bus (like S88 or C/MRI). The latter is attractive since I can potentially interface to it with an Arduino, opening up some room for home-brew devices. Of course I could do that with NMRAnet, but today that requires a US$45 shield to add to the Arduino (or one with it built in), which kind of takes away from the appeal of using $10 Arduinos to do things like drive signal masts.

While thinking about this, I went off and started researching what was available commercially or as home-brew circuitry and software libraries for these busses and for doing occupancy detection with them, as the latter would be a good way to get my feet wet and solve my “don’t want to solder those #$@! BDL168s any more” problem.

But in the past week I’ve been sidetracked into looking at homebrew inductive-coil detection circuits.


Tram Platforms

Kato recently introduced a couple of low-level platforms suitable for trams. There isn’t much info available on these, aside from machine-translated Japanese summaries, which don’t really explain much. And I thought they were interesting as possible candidates for my One Point Five Meter Line layout, even though that’s using Tomix FineTrack and they’re designed to be used with Unitrack. So I ordered a couple, and now that I’ve had a chance to play with them, I can provide my impressions.

Central Station I - Design

After initially thinking I’d build my own viaduct for the One Point Five Meter Line’s urban station, I’ve decided instead to use Kato’s Viaduct Station Entrance building (I had a spare one), possibly supplemented by one of the Station Shops buildings, as seen above. This will be fine even though I’m using Tomix track and station platforms, since the viaduct station simply creates a flat base for track, and isn’t specific to Kato’s track. The height would be, but I’m not connecting it to Tomix viaduct track, so that doesn’t matter.

September 2013 Monthly Status

September was an eventful month: work began in earnest on the “One Point Five Meter Line”, my short layout for displaying building models and showing off my Tram Controller. Additionally I made significant progress on the tram controller program, continuing the work I’d begun in August on driving multiplexed LEDs and, although I didn’t write about it, refining the sensor code to allow it to run faster.

The tram controller program itself is beginning to come together. It’s still a ways from actually running a train, but I’ve assembled the pieces and made a start on the actual logic that will know where the trains are and perform actions on them, based on the use of sensors and timers. After about six months of sporadic work, I can almost see the end in sight.

As usual I have more projects running through my head than I have time to do. There are a half-dozen buildings disassembled on my workbench (where they’ve been since May) waiting to be painted, lit, decorated, and reassembled. I’m hoping to make a start on those soon, with the completion of the benchwork for the One Point Five Meter line serving as a spur. Once I have a place I can put them, and wiring I can use to light them up and see how they look, I’ll be more interested in getting them done.

But despite the things not done, this month has a definite sense of accomplishment and progress, something I can’t say about the layout(s) every month. Read More...