laminate is carefully glued to the back of the resin panel with
Formula 560 glue. Very strong, it dries clear, and if any seeps
into an instrument on the front, it can be cleaned with a damp Q-tip
easily. Once dried, we take a look at what it will look like
once backlit. The 20 white holes are for LED's that will be
The LED's are CA'd into the
panel, and again we use wire wrap techniques, this time to take
advantage of the small gauge wire. We need to run the wires from
the LED's to power and ground "in between" the cutouts for the
gauges. Otherwise, they will cast a "shadow" from the
panel's upcoming backlight. They Kynar insulation glues easily to
the epoxy laminate using CA.
Almost all off-the-shelf
LED's have a 15 or 30 degree pattern. That is, they shine a
"spotlight" pattern 15 or 30 degrees wide. To look at
these on-axis is almost painful. In addition, even careful preparation
has left the LED's at slightly different levels of protrusion. In
order to fix both of these issues, we simply mill off the dome of each
LED, leaving a consistent height. This fixes diffusion angle by
replacing the bubble top (which was essentially a lens) with a frosted,
flat surface. The end result is minimization of on-axis glare, and
maximization of off-axis visibility!
Below you can see the
result so far. The upper and lower panels are both running off a
standard BEC, and are terminated with standard servo plugs. The
back of each colored LED is painted with multiple layers of matte black,
so the white backlight (next step) does not wash out the colors.
Now we start moving
forward. First the upper Instrument panel is aligned, and affixed
to the main with CA and screws from the back side. Then, we build
a light bucket out of balsa. Small diameter wooden dowels
reinforce the long joins, as they are at an angle, as the box is
slightly asymmetrical, to match the instrument panel. The inside
is lined with shiny aluminum tape, and 8 Luxeon LED's are mounted
equally spaced. Affixed with servo mount tape for insulation from
the aluminum, they are fixed to the back of the unit with standard 15
minute epoxy. The outside of the light bucket is painted flat
The rat's nest of wires
from the 8 Luxeon lights gets cleaned up using an insulation
displacement connector (remember those 40 pin connectors from your hard
disks before SATA??) This one got cut down to 16 pins, and
connects all 8 lights simultaneously.
This is what we started
with, small keychain-sized photo frames. These were purchased from
Amazon.com for $14.95 each, and they have a 128 by 128 bit display, run
off 4.2V (a little teeny LiPo is inside), and most importantly,
automatically page from frame to frame sequentially...... Just
like an animated GIF!
So, the next step is to create an
animated GIF displaying what we want. I created this GIF
with 14 frames. We have a target come onto the screen, and
when it approaches, it is identified as a MIG 23 (a common
Airwolf aggressor at the time). It is then shown to actually be
TWO MIG's, separating as they come into range.
The animation shows two missiles
being fired at the approaching and diverging targets, with the
targets disappearing off the screen as each one is destroyed.
The tiny LiPo is replaced
with power leads, and the display is mounted inside the recess machined
inside the back of the panel.
Now, we attach the light
bucket to the back, apply power... and voila! Exactly the effect I
was looking for.