IN CONTROL
Lighting and Control Panels in Models
Bob Schneider – Whirlpool Corporation
OF WHAT?
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Most of the displays I do are backlit or try to simulate production control panels.
Because of typical fast approaching deadlines I have tried to simplify the
components needed to accomplish a variety of looks.
Keeping a supply of light parts and powers supplies handy takes away one less
thing to worry about.
I try to use simpler plug and play items so I don’t have to worry too much about
amps, resistors and volts. I dropped out of electronics circuits class but I do like to
solder though. More elegant.
I have had to repair some models from our vendors in the field that were black box
kind of affairs. Open it up and there is a rats nest of wires, bad connections, or
shorts. Sure it looked great on the outside, but if it won’t turn on in San Antonio
Texas, I get to fly down and fix it. And it was glued together. And it was headed to
San Diego in a day
Always leave a way in to fix this stuff because it will go wrong.
PLANNING
FIND OUT EARLY IN THE PLANNING STAGES:
• What will be on the display
• What text or graphic will be backlit
• Where will the graphics be, front (A) or back (B) surface or both
• Overlay, in-mold decorated (IMD), underlay, dead-fronted
• Slideshow, video or special features using a LCD screen, smart-phone, TV
• Back lighting, colors, filters, half-mirrored or RGB LEDS
• Access needed for wiring, connectors, switches!
• How will it be attached
• Power requirements
• Travel requirements (high or low temps, g forces, gorillas)
COLOR TEMPERATURE
4500K to 5600K range for Neutral or Natural
LEDs as specified by some manufacturers.
Cool Blue LEDs are 7500K to 9900K.
ACRYLIC:
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MATERIALS
Sheet stock- go for quality: impurities, crazing from solvents and paints can be an issue with
cheaper grades. Less than 3/16” may warp or sag
Tinted: some grays or bronzes may look murky in thicker pieces. Shine a flashlight through it
to check. Again, select quality, higher $ material.
Milled or thermo-formed shapes: keep it cool when machining and polishing to minimize
crazing. Cold air and water help. Keep solvents to a minimum. Allow time for evaporation or
flash-off of paints.
Evonik/Acrylite makes acrylic specifically for the sign industry and back lit signs. I use the LED
type for diffusing. About 25% better than white acrylic.
http://www.acrylite-shop.com/US/us/us/sheet/acrylite-led-3rb9eum8heh.html
PLASTIC OVERLAYS:
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Thinner Mylar or other plastics need a backer or nest to support it
Limit 2-sided tape to perimeter if possible for easier removal later. Thin (1/8” to ½”) strips
work better
Clear layers should be separated by about 0.012” (0.3mm) to prevent contact and sticking
that may show a moiré like effect
We typically have our vendors make these for us
GLASS:
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Thickness
Color, low-iron (water clear) or soda-lime glass (green tint)
Surface prep and hardness of whatever coating is key. Etch with a cream.
Silkscreen or mask and paint
LIGHT TYPES
CCFL: COLD CATHODE FLUORESCENTS LIGHTS
An 1/8” diameter glass fluorescent light tube more often used to light up computer
screens, just like LEDs. Re-purposed by gamers to light up their computer
hardware and sold by companies that appeal to gaming industry. They have been
re-packaged into a ½” acrylic tube/diffuser to protect the thin high-voltage wire
running from end-to-end. They typically piggyback into a 12V computer wire
harness
CCFLs provide a nice neon-like glow in white
and other colors. Limited by pre-made
lengths 4”, 6” 8” 12”. You can use the
CCFL tube by itself to get light into some
tight spaces. Just remember to insulate
the wire.
This web site is who I use for most of my
CCFL lighting needs.
http://www.coolerguys.com/4inccfl.html
LIGHT TYPES
• LEDs (LIGHT EMITTING DIODES)
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Select a voltage level: 9 volts can use a 9V battery. Better selection of products with 12V
because it’s a common car voltage (?) 24V used more in architectural lighting.
Color: Generally we use “neutral” or “natural” white and tint as needed. Earlier we used
cooler LEDs because that’s what the customers were used to seeing in the marketplace,
because that’s what was available and affordable for manufacturing.
LEDs produce a narrower range of light color than most lights. Higher quality ones are
more consistent, batch to batch.
3528SMD (3.5mmx2.8mm) normal size, 5050SMD larger and brighter. Both available on
8mm wide PC board and self sticking flexible tape (my favorite)
http://www.superbrightleds.com/ Has been my go to source although there are many
suppliers out there.
5050SMD
3528SMD
LIGHT TYPES
• ELECTROLUMINESCENT PANELS AND WIRE: I haven’t had recent experience
with EL lighting. Had problems with shorts and the noise or hum. I expect they
have improved in 15 years. Hopefully someone in the audience would like to share
their experiences?
• NEON: Yes, neon. Hard to get now but still a great source of intense light that
stands up to daylight. Use it to create background glow. Still an option.
• Fiber Optic: Uses a bright LED to pump light through clear plastic fibers. Sideemitting fiber diffuses the light outward as opposed to the end like most fiber
optics. Not as bright as neon
FILMS-TINTS
We use tinted films to match LCD number displays or when certain graphics
are called out as a different color than the rest, like cycle-dependent items
on a washer panel. Besides the suppliers below, it is possible to spray
tinted clear-coat onto a plastic substrate and use that as a filter. Handy
when you are matching the tint across several items.
• Roscolux films: filters and equipment available from this theatrical
supply company, including LED panels and diffusers
http://www.rosco.comn
• 3M Automotive and Architectural window films:
Mostly greys and ambers, mirrored films.
http://solutions.3m.com/wps/portal/3M/en_US/Window_Film/Solutions/
• Solar Graphics films: architectural film supplier with full spectrum
of colors. Nice samples. http://www.solargraphicshome.com/
TECHNIQUES
BACK LIGHTING
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Diffused light shining through clear graphics (dropped out) surrounded by
opaque field
Set lights 1” back to help spread it out, minimize hot spots
Use white material when creating the light box that surrounds the source. Or
paint it white. Diffuses the light better. Chrome or polished metal may create a
hot spot or shadow
EDGE LIT:
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Like on an LCD computer screen, fluorescent tubes or LEDs on the edges light up
the entire panel with an even glow
Requires a white back surface, several diffuser layers, and image layer. Dust
specks between layers may cause moiré effect
Harder to set up on the fly but gives a low profile-high quality image
PROJECTED:
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Using a small presentation projector to show an image on a back projection
screen
Images must be flipped to read right from the front
Heat from the light-source should be vented
TECHNIQUES
BACK SPRAYING
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Spraying a solid opaque paint layer onto the back surface of a clear or tinted
material
Graphic elements (words, arrows, dots) may be silkscreened, engraved, or use
rub-downs as a mask that will be removed with solvents, sanding or by picking
them out
Front surface can be left clear or also receive more paint detail
IN-MOLD-DECORATED OR BURIED GRAPHIC INSERT:
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Like a overlay but inserted into the injection mold when the production part is
made
We simulate this by spraying the front surface with the graphic with 2-4 coats of
catalyzed clear until the graphics recesses are filled in. Usually polished in
between each coat to 600 grit until the final one is polished
DEAD-FRONTED:
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Looks like a solid surface on the A surface until the lights are turned on behind it
We spray a light coat of paint just enough to cover but still transparent to let the
graphics shine through
Or the background color is close enough to the material tint that it seems like
the graphics are just a shadow.
CONSTRUCTION
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Design for disassembly, access, repairs
Back loaded displays with screw mounting as opposed to floating displays with the
panel stuck in place with 2-sided tape. Front loaded into a recess is 2nd best option
2-sided tape is attached to whatever is on the surface. Paint peels off of acrylic and
glass unless it is bonded or the surface abraded somehow. A layer of vinyl on the B
side will also eventually give way
Try to use a hidden ledge or some physical fastener to at least support the piece
vertically. Gravity is not our friend
Remember to create space and access for all the connectors, power switches, USB
and charger cables when working with smart-phones or LCD displays
Always have a back-up unit ready to swap in before show time
Work with the actual image when positioning whatever digital display screen you
are using. Suggest using a smaller image than full-screen so it can be adjusted to fit
the target viewing area
Place the display as close as possible to the “A” surface to reduce parallax effect
View the final construction in a low light condition to pinpoint light leaks or bleed
thru
CONSTRUCTION
When working with LEDs and wiring in general you
might need:
1. A good soldering iron with a fine tip. Temperature controlled is
best.
2. 60-40 blend of solder(more lead)
3. Fine wire cutters and wire strippers. Sharp teeth work, too
4. Plastic terminal blocks work well to keep the clutter down.
McMaster-Carr has some good ones.
5. If you want to go solderless most of the companies that sell LEDs
also sell connectors that clamp onto the LED strips, and plug type
connectors to the power supply
6. Good eyes because these things keep getting smaller.
7. Stick to low voltage for safety. 120 volts is unnecessary.
8. We use standard 6 plug power strips to plug all the power supplies
into. Power strips are fastened in place and the cord zip - tied as a
strain relef.
PRODUCTION EXAMPLES