electronics

Fiddle yard wired up

A few more ticks on the list this weekend with the tracks all wired up now.

Power comes in through the RJ45 connector at the bottom, through the flexible black cable to the two copper strips. The solid coloured wires are wired to the common track, while the striped wires go through the micro switches to the other track.

Testing with a multimeter showed that the wiring in the above photo was wrong; that has since been corrected. Haven't done a live test yet.

Also cut out the wood and cardboard for the two smaller outside tracks, though I mis-calculated on the cardboard and ended up making twice as many platform edges as I needed.

Funicular mechanicals

Part two of my funicular building series...

Track

Funiculars need something to roll along on, i.e. some track. I didn't want to use regular N scale track though as this would look a bit over-sized for my tiny funicular. Instead I quickly (read: crudely) soldered up some code 40 track to 6mm gauge. To help with traction, I added a sheet of metal under the sleepers, the thinking being that if I magnetised the funicular, it would stay stuck to the track.

With the aid of some hot glue I attached the track to the scene and built up the surrounding landscape with some plaster. Some ballast was added, and then the whole thing toned down with some dirt-coloured watery plaster. This does a nice job of making the track look a bit worn out.

Cable

What I really wanted was a moving funicular. I decided fairly early on that a DC gear motor underneath the baseboard would be the way to go, driving a continuous loop of "cable...

Adding lights to buildings

Three weeks since my last update, however all is not quiet in Utrainia. Over Christmas lots of new items were acquired, among them a pair of rail-busses, a land rover, many dozens of people, and some buildings and building supplies. I look forward to adding these to the railway.

Before Christmas however, I spent some time adding lights to Raparapa. I wanted the buildings to be illuminated, but I wanted the buildings to still be removable. To achieve this I came up with a cunning scheme using little L brackets made from metal, and tiny wee disc magnets that attach onto plates. The brackets and plates look like this:

The L brackets attach onto the walls of the buildings a small distance off the floor level. The plates are on the ground, and the magnets go in between, making ...

Keepalive for the Kato TGV

My Kato "sud est" TGV runs well considering its age, however since then N scale mechanisms have come on a bit, and the orange TGV is lacking in a few areas. Chief would be the lack of flywheels, causing very abrupt stops when the wheels loose contact with the rails. Since two of the eight wheels have traction tires, it doesn't take a whole lot of movement to cause this to happen.

So I decided to have a go at fixing this today. I decided that a small keep-alive circuit might do the trick. The theory is that by adding some capacitors to decoder, they provide a small amount of storage capacity, capable of powering the decoder for a fraction of a second until the engine moves a little further and regains power.

That's the theory. In my parts drawer I have a bunch of capacitors, so I pulled out a bunch and measured them up. The TGV motor car doesn't have a whole lot of free space, so most of my capacitors wouldn't fit. In the end only some 10V tantalums were small enough. ...

ArduinoCMRI and RS485

A fun little side project of mine is Arduino C/MRI, a library that lets you easily connect your Arduino projects up to the JMRI layout control software, by pretending to be a piece of C/MRI hardware. Hence the name.

In previous episodes, we've looked at various methods of expanding the capabilities of Arduino C/MRI; be it by using shift registers, or emulating larger boards. But at some point you're going to need more than just one board, and that's where things get confusing.

The logical answer, you would think, is to connect multiple Arduino's to your computer. Simple. One USB cable for each one. The problem is, JMRI is not designed to address more than one C/MRI system at once. Trust me, I've done everything including hacking the XML config f...

DCC decoder installation for the Kato Glacier Express

The Kato Glacier Express is a beautiful model of a very iconic railway. It's also the first European train that I've purchased. There is one glaring problem with it though: it's difficult to put a decoder into. I believe Digitrax now makes a drop-in decoder, but I don't have the luxury of such things, so instead I've spent the past few days hard wiring an NCE Z14SR decoder into it.

Dismantling the shell

The first step is to completely dismantle the loco. Start by gently prising the sides apart so that the top pops off the chasis.