Lighting the roundhouse

Lighting on the layout has always given a great impression, especially with dimmed room lighting. Many plastic kits come prepared for interior lights, with mounting holes in the base plate for lamp socket and miniature bulb. One disadvantage is that the bulb can be difficult to hide if one has an open building or a detailed interior one wants to show off, so for the Wolf Creek roundhouse, we opted for a slightly different solution than the traditional light bulbs.

Early in our dialogue with Tom Andersen regarding the design of the roundhouse, it was decided that we should have lighting, and we wanted lamps that matched the building while also having the entire interior visible. Tom mentioned that the company Ngineering had developed LED lights that matched, and that they were working together to create a complete set just for this model. We decided to order this kit, containing everything we needed to make 16 ceiling lamps and four wall lamps, plus an 18V power supply and distributor board. We also got some extra LEDs free of charge for training, and because we had never worked with LEDs before we decided to buy some special tools to facilitate the work. All the components are also available individually.

We opted for Micro LEDs (1.6 mm x 0.8 mm), yellow-white in color to impose older lighting. Other colors are also available, as well as so-called Nano LEDs which is even smaller, but we thought these were more than small enough to start with!

Tiny!

The wire is only 0.11 mm in diameter including insulation, and the insulation is of a special kind that burns away when the wire is tinned. When soldering the wires to the LEDs, we used this little tool to keep everything in place and ease the soldering process. The LED is held in the right clamp and the wire in the left, the wire is then passed over the LED and soldered to the right side, then the LED is turned around and the process repeated for the other wire. Finally, the protruding ends are cut off and the wires bent 90 degrees.

A handy tool

The gooseneck wall lamps were made of 0.45 mm tubing cut to the proper length and bent into shape. To prevent the tube from being flattened when bent, Ngineering recommended having a 0.3 mm guitar string or similar inside the tube before cutting and bending, but this proved very difficult to implement in practice without deforming the lamp when pulling out the string again. Instead, we removed the string immediately after cutting, and pulled the wires through before the tube was bent. To ensure that all lamps would be identical, we bought a jig for bending.

Bending the gooseneck lamps 1

Bending the gooseneck lamps 2

Bending the gooseneck lamps 3

The lamp shade came in two different sizes (7mm diameter for the hanging lamps and 5mm for the wall lamps) and was punched out, but without a center hole. This hole was made with a 0.5 mm drill before the tube was pushed through and fixed with glue, the tube has a small flange on the end that the lamp shade lies on. We also put on a small cap that was glued to the wall after the lamp was mounted and adjusted in length.

Mounting the lamp shade 1

Mounting the lamp shade 2

On the ceiling lamp shades we drilled a 0.3 mm center hole for the wires to be pulled through, before the lamp shade was glued to the LED assembly. Then the wires were twisted together and painted black. However, it was difficult to get the lamps to hang straight using only the wires, so the lamps will be re-made using the same tubing as the wall lamps. Then they will also tolerate a bit more handling without being destroyed.

An exciting moment when the first test lamp was finished and ready for testing! Here we used one of the cheap LEDs that were included for training, hence the yellow glow, the final LEDs have a different color temperature. The lamp is wired to a conventional 9V battery via a small LED tester that we purchased along with the lighting kit. The LED tester makes additional resistors unnecessary, and works on up to two LEDs connected in series.

The moment of truth!

For the wiring inside the roundhouse to be minimally visible, all the wires were laid on top of the stringers. Each of the three inner divider walls has four ceiling lamps, which are connected in series with the positive along one stringer through all the LEDs, and the negative back along the other stringer. Similarly, the four gooseneck lamps in front are connected in series with the positive forward along one side wall and the negative back along the other, the picture below shows the wires barely visible inside the front wall behind the lamps.

Internal wiring

All the wires come together at the back of the roundhouse where they are connected to another set of larger gauge wires, and carried further to the distributor board on the underside of the layout. Because the roundhouse is to be removable, the wiring must go through a multi-pin connector that unplugs, which will be located in a small shed directly behind the roundhouse.

The distributor board is basically a two-sided circuit board that offers many opportunities for a flexible setup and connection of multiple LED circuits. Side A (3) that we have used is laid up with 4 20ma circuits for up to four series LEDs in each circuit (4, indicating circuit and LED), without the need for additional resistors. If one wants to reduce the brightness, the board is already prepared for this, with solder pads for resistors (7) so that each LED (5 and 6, anode and cathode) can be adjusted individually. Side B is even more flexibly organized, with the possibility of free choice of series or parallel LEDs, with appropriate resistors. The board also has solder pads for power connection at both ends (1 and 2) so that multiple boards can be connected together.

Distributor board (picture courtesy of Ngineering)

 

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