Thursday, November 2, 2017

Market Street: Electronics and DCC

From the start, I knew I wanted the Market Street layout to have multiple operators working in parallel: switch crews making up and breaking up trains at the station, road engineers coming from the roundhouse, and taking a train out, and freight crews switching the cannery and packing house on the layout. That meant I needed to choose a DCC system for controlling the trains, and I needed to decide what kinds of throttles to use. There were two obvious choices: I could go with Digitrax, the standard for Free-Mo modules, or I could use the same system I had at home - EasyDCC. Neither was attractive. I’m not fond of the Digitrax system; I’ve always had trouble understanding how to use their controls, and have seen too many cases where an errant button press disabled a throttle. EasyDCC would allow me to reuse my existing throttles, but I’d still need to buy a new command station and booster, find an enclosure for both, and then wire all the modules with coax to allow wired throttles to be plugged in around the layout.

Another engineer running a train on the Silicon Valley Freemo-N layout with a phone

Luckily, I was reminded of the local Silicon Valley Freemo-N group. They’d set up their dozen modules (most based on Bay Area scenes) at the 2011 NMRA convention up in Sacramento. When I stopped by to check out the layout, Dave asked if I wanted to run a train. “Sure, but I don’t have a throttle.” “Doesn’t matter,” he replied. “You’ve got a phone - just install WiThrottle.” They were using the iPhone-based WiThrottle, all talking to some random command station connected to a computer. I downloaded the app, and within a few minutes was running a streamliner across their layout.

Fast forward to last year. At the Bakersfield NMRA convention, one of the vendors had the SPROG 3 - a tiny DCC booster and command station that can power smaller layouts. It could be driven by the dirt cheap Raspberry Pi computers and the JMRI software, making for a full DCC system in less space than a cigar box. This seemed like the perfect choice - wireless throttles for the layout meant no wires for a throttle bus. Operators came with their own throttles, so I didn’t need to shell out hundreds for throttles. It could all fit in some tiny box.

Back: Electronics

Front: Monitor

The Sprog / Raspberry Pi plan won. The Raspberry Pi is a full Linux computer; with a keyboard, mouse, and monitor, it could do anything a big computer could (though a bit slower). I wandered over to Fry’s to pick up the Pi ($50). At the same time, I picked up a cheap flat panel monitor with an HDMI plug; the cheapest, at $99, was a 22 inch display - bigger than I expected. It turns out smaller monitors are speciality items now. That monitor set a minimum size for the electronics box.

With the monitor and electronics, I made a plywood box to hold them all in - the monitor set just inside, facing one way, and electronics the other. The box also contains the power strip, extension cables to reach the modules, and power for switch machines - all nice and compact, and easy to transport. Once it’s plugged in, I can use the monitor to start up JMRI and the command station; with some quick clicks on my phone, I’m running a train. All I need to do now is get some additional plywood to make lids for both halves of the box, and I’ll be all set.

Interesting aside: my nephew came over a couple weeks back and wanted to see my trains. The big layout was a mess, so I laid the Market Street modules on the floor, plugged things in, and we ran trains. When we went back inside, he beamed. "Mommy, we ran trains with a phone!"

Now, that 22 inch monitor is too large to use just for starting up JMRI; check out our next episode to hear what else I can do on that screen.

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