Getting Real - 2
season, I noticed the "Holiday Projectors" designed to project
Rudolph on your garage door. These units projected an image
that was bright enough and did not require a cooling fan. It was
a simple matter to insert a portion of a 35mm slide with the
image of the moon into the projector where the holiday image
would normally be placed. I used black masking tape to mask
out the entire slide except for the image of the moon. The pro-
jector was mounted on the ceiling and produced a very believ-
able image of the moon
over downtown Kansas
City.
Okay, it's true; I can
never leave well enough
alone! Should I aim the
moon low on the hori-
zon, high, or somewhere
in between? Then I
thought, why should I
be forced to make that
choice? Why shouldn't
the moon move up and
down in the sky so that's
it’s not always in the
same place?
To make a long story
short, I accomplished
this with a slow speed
display motor and three
stage gear reduction
drive. A bolt protruding
from the large gear runs
2: The moon in its mid position.
2
3: The projector for the moon.
3
in a slotted bracket
screwed to the back
of the projector,
moving it up and
down as the gear
rotates. It cycles
over about 20 min-
utes. The speed is
slow enough that
the movement is
not noticeable.
Lastly, it makes no sense for the mechanism to be running dur-
ing the daytime. I installed a relay interface to the blue night
lights, so that the moon projector and drive mechanism are
only on during the night time cycle.
Thunder and Lightning
Those who have spent time in the Midwest know that thunder-
storms are a common occurrence on humid summer evenings.
I wondered how I could effectively create thunder and lightning
in the layout room. The thunder is not a problem. The sound
could be produced with digital sounds you record yourself and
an MP3 player, or any of a number of commercial sound mod-
ules available such as those from Innovative Train Technologies.
The real challenge was creating lightning. The board I pur-
chased came with a "super-bright" LED. Unfortunately the light
from the LED would be wholly inadequate for my 30' x 40' lay-
out room. In addition, I did not want just a bright flash to fill
the room. What I wanted was an actual lightning bolt projected
onto the sky. How could I accomplish this?
4: The drive system for the moon
4
MRH-Aug 2013
