Welcome to my page on how to add LEDs underneath the
dark catapult plastic on my Medieval Madness.
This page will show you my mod to illuminate the normally dark
catapult plastic. Using just a few components,
I was able to
put together a couple of LEDs to successfully illuminate this area
powered by the G.I. circuit in the game.
Please read on!
First I took two superbrite
"white" LED's. The negative side is typically indicated by a shorter leg
or a flattened section
on the LED itself, or both. I marked the negative
side with a sharpie. I am going to use two LED's to get enough
dispersed light to look like there is a lamp under the plastic. The LEDs
are pictured below.
Next, as pictured below, I soldered the positive
lead of the left LED to the negative lead of the right LED together and
added a resistor to that leg. I jumpered the negative lead of the left
LED all the way over to the positive lead of the right
LED. Power will
eventually be tied to the lead with the resistor and the far right lead.
This is a great configuration because in an A/C
circuit, power goes positive and negative 60 times a second. LED's are
really diodes that emit light. Therefore, as the positive portion of the
A/C cycle starts to go up, one of the LED's will go on.
Once it reaches
it's peak and starts to go down, the opposite LED will now be biased on
and light. Therefore, we have
a lamp on for every cycle of the A/C
waveform. Our eyes cannot detect the off/on state due to it going so
Therefore the LEDs look as if they are both on.
|Pictured below is a close-up of the
resistor, the jumper wire and the LED's. Please note, I did change from
resistor to a 110ohm resistor later in the building of the
circuit. I wanted to dim the output a bit and adding a little more
resistance did the trick. The resistor color you will look for will be brown-brown-brown for a 110ohm
In the picture below, I have pictures a
quick test of the LED's. I connected 5v DC to one side of the LED
circuit as a
test. Notice that
only one side will work at a time due to the way we have the LED's
connected. You have to reverse
the polarity of the power leads to get the
other portion of the circuit to light.
|The next step was to figure out how to mount the
LEDs to the playfield and get them powered from the G.I circuit.
This was a tough dilemma due to the tight space under the catapult
plastic. I also did not want to drill a hole in the playfield.
I came up with the idea of
using the tab off of a light socket. Below is a picture of the pieces
before I modified them. Also
that I added some heat-shrink tubing to the resistor area to ensure
I did not get a short circuit.
In the next illustration, you will see that I
started off by cutting
the metal tab off of the lamp. What I wanted was the
flat piece of metal
for my circuit to attach to, and the hole through the metal to use as an
attachment point to
an existing hole in the catapult area on the playfield.
|The next picture below illustrates how I insulated the portion of the
tab that will hold my circuit. I simply used electrical
tape. Also a
quick note that I have wires attached now. These wires came from a flat
computer ribbon cable that I had
|The next picture illustrates how I was able to use
my daughter's hot glue
gun to secure the circuit to the lamp tab.
|Below you will see a picture of the
existing hole I used in the catapult area. You can see the catapult
the circuit and paper. There is a long metal rail that
runs along the length of the left side of the playfield. There is a
screw here that holds a portion of that rail
down. I am going to use this screw and my lamp tab to achieve the
mounting of the LED circuit.
|Next I have included a couple of pictures showing the circuit
attached. The wires are run through the back portion of the hole
used by the catapult. There is plenty of room for the catapult to work
and the wires to fit. I will secure the
wires under the
playfield in the next few steps.
|Once again I grabbed the hot
glue gun from my daughter and secured the wires to the playfield. This
method is great
because if you want, you can easily remove the hot glue
from the playfield without
any damage or residue. However,
the hot glue is strong enough to
hold these wires in place even when tugged on. See pictures below for a
The picture on the left is illustrating the wire coming
out of the catapult hole. The second illustrates the wire running
down the length of the playfield towards a G.I. light I used for
In the next picture, you will see how I attached the
above wires to an existing G.I. lamp. Look for the small wires
with the large white/red wires.
|The next picture illustrates the initial test of the
circuit in the game. The LED's give off quite a bit of light and with
two of them
working, and bent in different directions, it really covers a wide area.
The benefits of using LEDs instead
of a #44 or #47 lamps are that LED's give off
no heat and use a fraction of the power that a
lamp would use.