Starting from the basics: Since the voltage of all LEDs is below 6V and
4.8V, which are Mini-Z car's voltages (batteries/rechargeable B), you need
to solder a resistor for each WHITE LED. However, red and yellow (also
green) LEDs can be used 2pcs with one resistor, I'll explain it and the
voltage thingies a bit later.
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The chassis modifications
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First you need to take the power to LEDs out of somewhere. I did this
by opening the top of the chassis (the top between battery holders) and
soldered wires of a 9V battery clip inside. The idea is: you attach one
std.9V battery clip to the car and another one to the body. This way you
have a simple and a small switch for taking the body and chassis totally
apart from each other. (Damn this is complicated to explain without pics:)
Back to wires: another is put somewhere where ALL batteries give their
plus-side and the other wire is put on minus side. Picture your car's
front facing up: My car has the FIRST wire on a AAA-battery connector at
the left side on the bottom. This is the last battery connector on the
other end (I forgot already if it was minus or plus..). However, the
SECOND wire is soldered to the car's own power switch, so the lights go
on/off the same time that you turn the car power on/off. It is quite safe
to solder wires to these places since there are no sensitive parts near
but you shouldn't take too much time heating any parts because there might
come up some unpleasant surprizes (plastic starts to melt etc.).
NOTE: you need to put some extra attention to this stage since the
power switch has 3 pins for wires and you need to solder the wire to the
correct one. The original wires go to two pins: middle and one side. I
believe the correct pin was that where the cars original wire goes but not
the one in the middle, got it? If it goes wrong, your car's lights are on
when the car is off or they are always on, nothing more serious than that.
HINT: You might want to bring the wires out from the holes which are
used for engine's power connectors.. There is just enough space to bring
the wires outside the "case" without making any extra holes..
You don't have to worry about the 9V battery clip's plus'es or minus'es
YET, since you can change that when you are connecting the SECOND battery
clip to the body-end.
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Voltages, LEDs, Resistors..
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I mentioned about the voltages in the beginning. When you are purchasing
the parts, the salesman usually knows how to calculate correct resistor
values (Ohms) for LEDs, if you can tell him how much is the original
voltage that you need to connect them to. And if you can do this youreself
you can just go and buy everything you need.
In this case, if you even consider ever using normal alkaline batteries,
you need to calculate voltages with 6V (Volts). If you are SURE you will
never ever use nothing but rechargeable AAA-cells you can calculate
voltages with 4.8V which is about the voltage of four AAA rechargeables.
The voltage of a red/green/yellow LED is about 1.7V. Above this, the LEDs
may burn out or even explode (which is, however, not so common :). And
then there are blue and white LEDs. Blue LEDs have a voltage of about 3.2V
if I remember correctly and white was a bit more, perhaps even 4.2V. If
you are planning white or blue ones you need to find out the exact
voltages of them since I don't remember..
When you place white/blue LEDs to Mini-Z you need a resistor for each
and every blue or white LED, since you can't connect two or more
white/blue LEDs serially (the voltage would be too low: 2*4.2V=8.4V etc.).
You can connect, however, up to three red/green/yellow LED serially
together and add a smaller resistor to these: 3*1.7V=5.1V. This way you
need to lower the 6V voltage with a resistor by only 0.9V since
6V-(3x1.7V)=0.9V. It might be easier to figure things when working with
the body if you use only two LEDs with one resistor, when you need to
lower voltage with a resistor by 6V-(2*1.7V)=2.6V.
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Mounting the LED etc.
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Since everybody doesn't neccessarily know that much about the normal
mounting excluding electrical details I thought to give some advice on
it, too. Since I don't know what bodies people have in their cars I'll
just say that you might want to finalize the holes (for the LEDs) mainly
from the inside. This because the LED is shaped to be more narrow in the
end than in the bottom. If you shape the final holes from the inside you
have more chances to make it look better outside because it's not
cool-looking if your LEDs come out from the body all-the-way.
I used instant glue and plastic model glue when attaching my lights but
my BMW body has it's white LED a bit loose since i've bumped them to
something a few times. It seems that the glue attaches well to the body,
but I haven't got an idea which glue takes good grip of the LEDs.
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Perhaps the easiest way
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I thought in which order would it be easiest to add lights to MZ (it IS
worth it, especially with white LEDs!) and came up with a list like this:
1. Buy what you need (LEDs, resistors, 9V battery clips, some el.cord
[soldering iron, tin solder, cord cutters, hobby knife..])
2. Mount the battery clip to the chassis.
3. Make holes to the body (drill, sold.iron, knife..) and attach all LEDs.
4. Solder and glue the resistors and cord for connecting everything in the
body. (Excluding second battery clip)
5. Turn the power on and test before you solder, the right way to connect
the 2nd battery clip. If you solder it "upside down" the LEDs won't
work. When right, all LEDs should shine.
Oh yeah, you Must solder all LEDs the same way so that they all shine: A
LED has a shorter and a longer "leg". A good way to work is to connect for
example all long legs to the same cord and then solder the resistors
etc to the remaining, shorter legs. so that all LEDs come right.
NOTE: If you connect some red/green/yellow LEDs serially, you connect the
legs like -long-short-long-short- and a resistor somewhere on the way (of
course..).
Hope this gets you on the way with your lights, if something was left
blurry, I can try to give some more advice and update these pages..
-Juha
