Let There Be Light
Donal V. Buckley
addition of light to a model can go a long way to customising a kit in a
way that is unique and doesnt require masterclass painting or sculpting skills.
With some basic information, care and patience, ( of which we all have plenty,
right? ) and minimal cost, you can light any suitable kit. Granted in the kit
area you may not find a huge amount of use but some types, robots and
spacecraft lend themselves to enhancement by lighting.
Before starting to light any model, there are some basic questions that must
- What are the areas to be lit?
- What colour is required for the desired effect?
- What will be the light source?
- What will the power source be?
Question one is obvious but probably no less than not starting to paint until
youve decided the desired effect.
Question two should be decided before continuing. There are many differences in
the set-up between a coloured light source and a white light source.
Question three is important for a couple of reasons; depending on the colour
required, you may have problems with heat dissipation, or hiding the light
source. If its white you have to use lamps with different heat output and power
setup whereas if its coloured it may require more circuitry.
Question four could be the determining factor; battery, DC or AC. This will be
answered by considering the light source you have in mind, where youll have the
model and will it be permanent or movable?
If you intend regularly making electronic lighting sets, there are certain
- Soldering Iron, ( electric or Gas portable )
- Good pliers.
- Good electronics type wire snips
- Resin-cored solder
- De-soldering tool or Solder Wick.
To explain each of these
The soldering iron is used to solder wire / components together, components
into circuits etc. My own choice is electric iron. However Butane powered
portable irons are also very useful. Word of caution when buying either, make
sure the iron has an easily changed tip and that you can find replacement tips
easily. Weller Irons and tips are the most widely used.
For both the pliers and snips; buy a decent pair. Many of you will already
Multimeters are available in both Digital and Moving Coil/Analogue types. You
can pick up a very basic one of either from about STG7.00 ( US$12? ). Prices
go up and up as functions/reliability increases. You should be able to measure
resistance and voltage ranges with these. A diode testing function is also
useful, but not necessary. These are necessary to verify the integrity of a
circuit or component, impossible to do without it in a complex circuit.
The resin-cored solder ( this is the normal type, but check when purchasing
as you dont want un-cored solder ) is easily available. I prefer a thinner
gauge to thick gauge, but its not very important.
The de-soldering tool or wick is important for when you screw up. Wick is a
lot cheaper and works fairly well with a tiny bit of practice. De-Soldering
tools take more practice but are a lot more effective in removing all solder,
however for home use starting off Id recommend the solder wick.
How to Solder/Remove solder in a few sentences
Soldering works by heating the components/wire/printed circuit board ( PCB )
involved and applying the solder to the heated area for a very short time ( 1/2
secs ). The solder melts and flows over the components, the soldering iron is
removed, the solder on the components, which should not be moved at this stage,
solidifies and creates a permanent bond, which because its metal,, allows
electricity to flow. The metal items to be soldered should be of a
copper/tin/lead/nickel type substance, they should be clean, i.e. this means
shiny for electronic components. The resin in the solder allows the solder to
bond easier without oxidation . The soldered connection is called the joint.
Note: It takes specialist equipment to solder/weld aluminium ( European spel
ling ) or steel. If you use a Soldering Iron to melt or engrave plastic you
will ruin the tip. After use coat the tip with solder and turn off. Allow the
solder to cool on the tip.
To remove solder, heat the joint and place a length of solder wick on it,
holding it in place with the soldering iron. The soldering will be removes from
the joint by capillary action in the wick, (absorbed).
Obligatory Caution: Heated Soldering Iron Tips are damn hot. Be careful. Solder
is a lead alloy. Dont eat it. Wash hands after use.
I don't intend to get into all the different component types and variations,
just some basics. All these should be easily available from an electronics
- Plenty of small gauge wire, preferably in both black and red colours.
- Selection of resistors. Preferably ¬ or « watt. See later in text for more
details of sizes and resistor colour-codes.
- L.E.D.s. Available in Red, Green, Amber and much more expensive Blue.
Flashing L.E.D.s can also be useful.
- Light conducting source if necessary, fiber-optic cable or clear acrylic rod.
- Power source. Either a voltage adjustable DC transformer or a battery pack.
Since I dont want to be responsible for anyone frying themselves Im not going
to deal with AC
- Veroboard. This is a Brand name of circuit board which is pre-drilled, bare
on one side with copper strips on the other side which can be cut as necessary,
making it easier to assemble a circuit. Usually fairly cheap. Dont know what
the US equivalent is, it may be Veroboard there as well.
- Black Heat Shrink tubing wide enough for the L.E.D.s or Fiber-Optic cable,
also useful for insulating wires.
- White light source. Halogen bulbs, bicycle lamp bulbs, grain-of-wheat
A Basic example: Lighting the Halcyon ABC Warriors Eyes
This one is pretty basic but soon as I opened the kit I thought it could
benefit from a pair of red L.E.D.s as the eyes.
You will need: two Red L.E.D.s, narrow gauge insulated wire, soldering iron
and solder,, drill and cutter/small bit to take out the vinyl eyes, scalpel,
no 11 blade, power source, ( a single 9V PP3 type battery is good for this),
resistors, and battery clip or holder.
- First remove the excess vinyl from the front and rear head sections.
- Next, cut a hole in the rear head section to allow the cable access.
- Next is probably the most difficult bit. Using a small drill bit (1/32 )
cut a hole directly through the centre of each eyeball. Next I used a 1/64
drill bit ( really small ) to extend the cut-out of the eyeball. Next from the
back of the head section, use a cutter to cut very slowly down to the eyeball
without taking out the lids. A round cutter is best for this. You can them
finish off with the No. 11 scalpel blade to align to the eyelids. You will
need to cut a channel in each side of the inside of the head to allow room for
the L.E.D.s and wire. If you cut too far forward youll take off the eyelids
and need to re-model these slightly with milliput.
- Next you need to check the fit of the LEDs. What I found was that the
eyeball doesnt take the LED precisely. There were some slight gaps at either
side. I molded this up from the inside with milliput, (my first attempt was to
use glue to fill the gaps but the glue made a mess of the LEDs, so I went back
to Milliput. I used one spare LED and Superfine Milliput to make the correct
Another suggestion from Stewart in Liverpool is heat thin Plasticard and put
the LED into it while its hot, thus giving a good fit. (Thanks Stu !)
- Assuming your test fit is O.K. next paint the inside of the head black,
otherwise youll get some of the light shining through the vinyl, especially as
you will have had to cut out some of the vinyl inside the head.
- Next TEST assemble your circuit and ensure its working. The longer leg of a
LED (say it quickly! ) is the positive. Wrap this to the short leg of the other
and then connect the positive on one and the negative on the other to the
appropriate side of the battery. Both LEDs should light. If you mixed up the
sides reverse it on the battery, both LEDs should light. However, only hold
this for a few secs to ensure the circuit works.
- In order to properly build the circuit you must solder all connections
together. For those familiar with it, I recommend shrink-wrapping all soldered
IMPORTANT: Because each battery type is different and the chemical make-up of
the battery determines the current ( Amps ) you MUST add a resistor to limit
the current, to prevent the LED shorting out and blowing/burning out.
Especially in this case, as once its added theres no going back. However with
a current limiting resistor in place and dont change your power source, you
should have unlimited lifespan from the LED.
For wiring the Halcyon I used a PP3 Battery. Current is quite low from these
batteries, I calculated a 375W Resistor.
To make it easy, without calculations, try a « or ¬ Watt 1 KiloOhm resistor,
connected to the positive LED leg. If you need greater brightness, halve or
quarter either of these values if you are using an Alkaline or Ni-Cad 1.5V
Note on Resistors, LEDs
If you are interested, this will be helpful for other circuits;
Resistors are measured in Ohms and come in different resistance, symbol W and
power usage symbol W, ranges and also different manufactured types. The types
dont matter here.
Note: the values of resistors can be determined from the colour bands on them,
their colour code. See The Resistor
Color Code Chart for details on
how to read it.
Resistor values are not quite straightforward. The typical values are; 1.1,
2.2, 3.3, 4.3, , 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, 9.1, 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27,
.100, 110, 120, ., 200, 220, 240, 300, 330, 360, 430, 470, 520, , 560, 620, 680, 750, 820, 910,
1000, (1k), 1.2K, 1.5K, 2.2K, ..etc. As you can see its not a straight increase
of values. There are intermediate values available, but for modeling purposes
you dont nee this accuracy.
The main ranges of Power Consumption for our purposes are; «, ¬ and 1 Watt
Also for our purposes, they can be wired in two different ways: series and
- leg of one connected to the leg of the next (daisy-chained);
Series. Values of R1 and R2 are added.
- Parallel resistors are connected beside each other;
- Parallel: Values are given by; R1 x R2
R1 + R2
However this formula is only used for two resistors in parallel. There is
a different one for more than two: ( 1 = 1 + 1 + 1 .)
R R1 + R2 + R
Series is useful for adding up smaller values to give a larger, e.g. 1 K W + 1
K W = 2 K W
Parallel is useful for splitting larger values to give smaller, e.g. 2 K W x 2
K W = 1 K W
2 K W + 2 K W
Light Emitting Diodes (LEDs)
These are semiconductor devices, which emit light when correct current and
voltage are applied. For red LEDs voltage is 1.5V and current (I) of 18mA. For
green diodes voltage rises to 2.2V. LEDs are connected Forward Bias i.e. the
anode (positive terminal) is connected to positive with respect to the cathode
(negative terminal). For most model circuits which are operated by battery or
DC transformers, this means positive leg to positive connection and negative
leg to negative connection.
They are available in Red, Green, Amber, and Blue, although the Blue is rare
and more much more expensive. There are also flashing LEDs, however they do not
flash in synchronous time so they should not be used in array as a light
sequence; however they can be useful as simple timing devices in a circuit,
although only as a control for normal LEDs, e.g.: using a flashing LED to
switch on a transistor driver circuit for other LEDs, or even a simple current
feeder to (maybe) two LEDs in series, although I havent tried this.
There are a lot of potential uses for electronics in kits, running and
navigation lights, search- and identification lights, sirens, speakers and of
course, eyes, screens, dials, etc. There are books available for electronics in
models. As with all else, some practice and some care, along with the right
tools, will go a long way, regardless of electronics knowledge or background.
If I ever get time Ill try to add some circuits with diodes, transistors and
555 timers, but don't hold me to it, o.k.?
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