one LED to one rod relationship around the perimeter.
With this arrangement, I would have light from the display
patterns moving in both the X and Y directions across the
LED matrix, and I would have light moving up and down
in the Z direction as well, because of the varying lengths
of acrylic rods. In addition, I would have three different
sizes of rod ends, like little glowing discs that would be lit
from the LEDs below.
When I finally visualized how this thing might look
and how it could be built, I immediately flashed back to a
Superman movie and his crystal palace hide-away. Thus,
the Crystal Palace is the name I gave to this device. So, off
I went to Delvie’s Plastics (
ordered 1/8”, 1/4”, and 1-1/2” acrylic rods. Delvie’s has
the best prices for plastic I have seen.
However, because you have to buy the rods in
quantity, this can be a kind of expensive purchase. The
upside it that I have enough material to build many
projects that require acrylic rods.
Next up, I had to figure out how to position the acrylic
rods accurately over the LED matrix and support them well
enough that they stood vertically. Being a wood worker, I
decided to mill a piece of 3/4” hardwood with holes for
each rod. This worked out well.
Finally, I built an enclosure for my breadboard out of
1/4” MDF and glued the drilled hard wood support on
top, after carefully measuring so that the rods would be
positioned accurately over their respective LEDs in the
matrix. I also cut a square hole in the side of this
enclosure for the USB power cable which connects to the
Teensy 3.1 microcontroller to pass through. After gluing
up the enclosure and doing some finish sanding to round
over edges and remove any traces of glue, I painted the
enclosure with black sparkle paint. This turned out to be a
crude but effective enclosure (Figure 4).
You can watch the finished Crystal Palace in operation
mtjrkF2MqbM. If I were to build
another one of these, I would do
some things differently.
First, I would have made the
breadboard square and not
rectangular by mounting components
on both sides of the board. I might
even make a PCB (printed circuit
board) instead of using point to point
wiring next time.
Second, I would probably design
the rod support and enclosure in a
CAD system and 3D print it for much
better positional accuracy.
Finally, I am thinking about
making a bigger, better Crystal Palace
by using a 32x32 RGB LED matrix
like the one I used in my Light
Appliance project (see N&V’s
October 2014 issue).
Bigger is always better, right?
46 June 2015