Last update: Jan 24 1996

USS Enterprise LED Circuit Design

Caution: I've still got a few small corrections, additions, and/or deletions to make before I can safely say this will work. But it should be fine to start with...

Have fun. :-)

[ USS Enterprise model ]


Simply put, this document provides you with everything you should need in order to build two LED circuits for installation into the AMT/Ertl model of the USS Enterprise, registry NCC-1701-A (as pictured above). If done properly, you will have flashing anti-collision, saucer illumination, and flashing navigational lights (as pictured below).

Comments which appear in italics like these are both recommendations and observations as I came across them in building this model for the second time. To distinguish between the two model and circuit building attempts, I will refer to the first as the '89-model and the second as the '96-model.

[ USS Enterprise model (lit) ]


I first built the circuitry for lighting the AMT/Ertl model kit of the USS Enterprise NCC-1701-A back in 1989. Six years later, I am now in the process of rebuilding that kit and its lighting circuits to replace the original model which was recently damaged beyond repair.

There was no written record of the original circuitry. However, I was able to recreate the circuit and the wiring layout from the now "exploded" '89-model. With my crude diagram in tow, I set out to purchase the supplies necessary to reverse engineer it. After rebuilding the circuit on a test board, I was convinced that I had correctly duplicated enough of the original work to begin the '96-model.

For the '96-model, I decided to forgo the two most difficult aspects of this process: I would not include the square red LEDs for the torpedo tube launchers nor the square yellow LEDs for the saucer's planetary sensor dome, since my modelling skills have waned quite a bit since I first did the '89-model. This fact should be noted, since I make changes to the circuit itself later.


The placement of these lights was modelled after scenes from the feature film Star Trek II: The Wrath of Khan, specifically those which took place within the Mutara Nebula. When built correctly, it should come very close -- given the limitations of resistor tolerances -- to the timing of the lights seen in those scenes.

During some timing tests, it seemed that the original circuit was far too fast to be considered an accurate representaiton of the lights in the scenes mentioned. It may be because of the number of lights involved increasing the power demands and thus slowing the capacitor's output, but I'm no electrician and I didn't have the spare parts to waste on putting them all into a test run.

Since I reduced the number of LEDs in the '96-model, resistor values used in this new model and those lights which were not used will be noted within curly braces. For me, this modified circuit matches the requisite scenes quite nicely.

Essentially, there are two circuits involved:

  1. Circuit One [ ASCII ] for illumination and anti-collision lights:

  2. Circuit Two [ ASCII ] for navigational lights:

You will also need lots of insulated wire. I haven't a clue as to the gauge used in the first model, but it was fairly light. The important thing is to ensure that two wires laying side by side will fit going into, through, and then out of the channels made in the nacelle strut. They should fit fine everywhere else.

Each circit runs off a 9 volt battery. You can get by with just one power source if you know how to connect the two circuits, but be forewarned: the combination of anti-collision lights and running lights make a noticable impact on the output of the torpedo tube and hull illuminating lights.

LEDs were chosen since - short of improperly wiring them - they should last nearly forever. Bulbs would eventually break and their replacement would prove to be difficult, if not impossible. However, this results in the use of yellow LEDs in place of some preferred white-lighted areas. A small sacrifice, in my opinion.

There was no lighted version when I built the '89-model, hence any discussion about fibre optics is moot.

The circuit boards and the batteries will reside in the secondary hull of the ship. In order to gain access, the primary deflector array (the front end to the Engineering section) should not be glued into place.

If you feel adventurous, you can play with the size and type of resistors to get a different duty cycle for the lights. Here are some relavent details for that task:

Pin diagram [ ASCII ]
Waveform diagram [ ASCII ]
Equations [ ASCII ]

Circuit Construction

Just follow the diagrams -- and, if you want, my notations on how things were modified -- to create the circuits. If it wasn't already obvious, I would strongly advise that you solder everything to the chip mount without the chip in place. Heat extremes can damage chips easily.

You'll probably want to add a length of wire from the point where your 9 volt clips make contact with the circuit board so that you can easily attach the circuit to the rest of the model by twisting each lead into their respective positive and negative "bundles" from the ship. Once wired, you'll have to carefully pack everything back into the secondary hull. The '89-model had a "circuit board first - wires after" approach and the 9 volt clips would dangle out of the opening nicely.

Also, ensure that you either have long 9 volt clip leads or you extend the existing ones. My '96-model has more of an "any way you can" approach to packing the circuits, since I did not leave enough leader on the 9 volt clips to allow them to hang out of the front of the secondary hull while the circuit rested snugly in the back.

LED Pre-Installation

After looking at my newly purchased '96-model of the NCC-1701-A (labelled as being from the movie Star Trek VI: The Undiscovered Country), I've found that many of the lighting holes have already been pre-drilled. As well, each nacelle strut is already channeled and can accomodate wiring. This was, no doubt, to facilitate the lighted model that now exists (but didn't when I built the '89-model). For most of you, half of your work is already done. However, some of the more difficult cuts have yet to be made.

In each case, you'll want to take care and test-fit often. Also, because of the triangular blade shape of the knife (unless a drill is used), you should come in from below the finished surface. If you didn't, the tapered hole on the outside surface of the model would not fit flush against the LED.

Round LEDs

With each of the pre-drilled holes, you'll want to ensure that the LED you will be putting there fits snugly. Slight trimming may be required.

You'll need to cut two more holes in the topsite of the saucer. To each side of the impulse engine cowl there should be two recessed "lights". Simply grab your knife and start drilling from below. Once you punch through the plastic, you'll want to do finer trimmings and test-fit the LED more often. Also, you may need to enlarge the pre-drilled holes slightly to fit those LEDs which will sit there.

The next hole to drill is in the bridge dome. A raised bubble of plastic just behind the bridge proper indicates the anti-collision light. As before, start from below and take your time. And watch that you don't open up the back edge of this piece while drilling! As part of this, you'll need a hole for the LED's wires to come down through (if it's not already open). I simply opened up the thin plastic beneath the dome piece.

The final hole is below the main shuttle bay. This might be a bit tricky since it is across the seam of two pieces. If memory serves, I had first drilled in from the outside, coming close to the final size I would need. Then, with each part in hand, I carved out the remaining plastic to ensure a snug fit for the exterior surface. You may also want to try a small drill bit. If smaller than the LED to go in, you can still manually trim back each piece (or use a slightly larger bit).

Yes, memory did serve. I first bored in from the outside, holding the two pieces firmly together, then fine tuned it from the inside, each piece in hand.

Square LEDs

With the first set of square LEDs, comes a step up in difficulty. The piece labelled as the planetary sensor dome, located on the bottom side of the saucer, must have four areas cut out to accomodate the four yellow LEDs which will be mounted flush with the saucer's hull.

The most difficult cutting will be for the torpedo tube launchers. The piece is small and fairly thick to cut into so if you're not comfortable with doing this, you may want to skip this option entirely. However, the final effect (as pictured previously) will look quite good, in my opinion.

For the torpedo tube launchers, you'll be removing the raised portion of this part and then some, in order to accomodate two square LEDs. I suggest using a new X-acto blade, heated by soldering iron, candle, whatever. If the heat is uniform across the blade and not too high, the blade should ease nicely into the plastic. If this kind of kit bashing is new to you, be sure to experiment a bit with scrap parts or with the plastic tree the parts came on. By removing a small square first, you'll find it easier to expand the hole by finer degrees and ensure a better fit, than if you were to cut a large hole which may turn out to be too large.

Or, you can do as I've done for this second attempt: skip it altogether

Wiring the LEDs

These diagrams illustrate the placement of each light in the model.

For the saucer section, you may wish to run wire between the LEDs along the exterior edge of each half. This will require some kind of back masking to the windowed portions of the saucer so the wires will not be so visible (unless you're like me and you don't care if people peek in and see them), but it will reduce any problems you might enounter with the limited space between the two halves of the saucer.

All LEDs will should be fitted and wired together before glueing them into place (in case this wasn't obvious to begin with). For each LED, I would suggest doing the following:

  1. with the model part(s) necessary, place the LED in its position and note the space and angles available.
  2. place the model parts aside.
  3. using a pair of needle nose pliers (or a similar tool), bend the LED's leads at a point 1mm to 2mm from it's base to a 90 degree angle so it points to the interior of the model, or in a direction which offers more space.
  4. widen the separation between the leads by 10 to 90 degrees, depending on space available. For the saucer section, one disk could use a narrow angle while the other a wide angle so that when the two halves are placed together, the LED's leads will not interfere with each other.
  5. using an appropriate length of wire to connect to either a neighbouring LED (in the case of the saucer section) or to reach the circuit board (in the case of each nacelle), plus a lot of slack for comfort, twist the wire and LED lead together. Ideally, you'll be wrapping the wire around the LED's lead.
  6. repeat the above step for the other LED's lead.
  7. solder these two connections.
Almost every LED is wired into the circuit individually. Only the navigational lights around the upper and lower outer edges of the saucer will need to be done in series (unless preferred otherwise).

Final Construction

It's a simple matter to drop in the round LEDs and glue them in place. A small amount used after they are in place but not fully seated should be good. The square yellow LEDs will require more glue along the entire surface area which rests against plastic, unless your fit into the planetary sensor dome is snug.

For all LEDs, you may wish to seriously consider painting the portions which are exposed to the interior of the model black (or silver, if you think it will reflect enough) to prevent the model from glowing or lighting up from within.

Personally, I used black for both models.

While building the model proper, there are two options: either

I used the first method for the first model.

And again, for the '96-model. I had started laying out pieces of wire to see if the second method would work, and found myself dealing with too many "spider legs" all over the place.

Because of the exposed leads on the LEDs in the saucer, I used small portions of electrical tape to both "tie-down" each pair of exposed wires and to insulate them from the wires from the other half of the saucer. Granted, you will see this taping if the model is held up to the light, but I don't usually hold mine up to such scrutiny.

A suggestion might be to cut out a piece of light cardboard from a cereal box to shape and use that to block light from passing through. If large enough, it would also serve to insulate the top/bottom wire pairs from each other. But be sure to test fit! The curvature of the hulls leaves very little space to play with in between, especially if your wiring is there.


Well, I hope this all makes sense to you. If you've built your kit well, and the wiring didn't break in the process, you should now have a nicely lit up model of the USS Enterprise NCC-1701-A.


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D. Joseph Creighton <Joe_Creighton@UManitoba.CA>