The Old Mill, Part 3

For such a modest structure, the old mill certainly has been the focus of considerable attention. This chapter covers the installation of the little porch light, electronics for the water wheel mechanism, internal lighting, and completion of the flume. This may not look or sound like a lot, but believe me it wasn't trivial to accomplish.

The porch light—I have no idea what else to call it—is a modified Märklin streetlight (above), which ordinarily is almost twice as tall as what's needed. First, I removed the base by slicing it lengthwise with a sharp knife and prying it off. Then I clipped off the pole above the light bracket. After drilling a hole in the stone patio (no idea what else to call that, either) and carving a recess slot underneath, I inserted the light pole and lowered it to the desired height. With the height established, I lowered it further, then bent the pole 90 degrees. Finally, I pushed the bent pole up into the recess, and secured it in place with CA (below). The reason for these drastic measures is that the pole cannot be shortened from the bottom, and if left straight the pole would stick out the bottom of the layout!

The Märklin light is an SMD LED that has its own driver circuit; because it's meant to be powered by a higher voltage than I'd be delivering to it, I adjusted the load resistor by piggybacking another resistor on it (visible below, to the left). Meanwhile, the water wheel motor runs on 1.5VDC, whereas the layout power supply is 6VDC. To deliver the proper voltage to the motor, I connected two diodes in series with a load resistor; this creates a voltage drop across the diodes of 1.5 volts. It's the same principal behind the old constant lighting trick for locomotives, back when 1.5 volt grain-of-rice lamps were sometimes used for headlights.

The main mill structure is internally illuminated with a single 3mm warm white LED (below). To diffuse the light, I painted it with white acrylic paint. I soldered the LED leads to 24 gauge solid wire, which holds the LED upright in position. The wires are bonded to the structure base and pass under the stone wall parts to join the rest of the wiring (above).

The last accomplishment of the day was scratchbuilding the flume and associated woodwork (below). Just as John Allen most likely had done, I cobbled it together from scraps of stripwood cut to fit, although the specific design differs from John's. After painting it with thinned Railroad Tie Brown, I simulated water and wetness with gloss acrylic medium, then bonded it in place on the dam stonework.

Still to come is the roof, which is turning into a little project of its own: because the structure is illuminated, extra measures must be taken to prevent light leaks from under the eaves where the roof meets the walls. But once the roof is at last done, the mill will be installed on the layout—the first structure to have the honor!

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