This page is part of my Model Remodel series of articles.

DISCLAIMER: If you choose to attempt any of these modifications, you assume all risks thereof. I just wanted to share my experiences here. Neither Fanhome, nor myself, are responsible for any damages that may occur.

In Battle Section Part 1, we designed and printed up a mount to hold all of the electronic components needed to control the Battle Section of the Model Remodel version of our 1:900 scale U.S.S. Enterprise NCC-1701-D. Now, it is time to actually wire everything up. This took quite a bit of time and I was not able to take pictures of every single connection, but I will provide a connection list and other details to hopefully explain how it all went together.

Preparing the Battle Section

This work took place once we reached Stage 90 in our build. As the second (starboard) nacelle does not being to arrive until a much later stage, I pre-ran a length of my 4-wire 26 AWG cable through the pylon uprights. It is not seen here, but I did leave about 6″ of wire sticking out the top of the pylon:

Next, we ran the wires of a 5.5mm Male Barrel Plug Connector down through the square display base opening and into the interior of the Battle Section. We only need a couple inches of the wire inside the ship, but I wanted to show how it can be installed through a gap between the Upper Bracket and the top outer panels. This will be the main power feed for the entire ship:

While entirely optional, I also ran the wires of a pre-connected 4-pin JST 2.0 plug through the same gap on the other side of the display base opening and into the Battle Section. One of these wires (I chose the yellow one) will be used for the signal of the IR Receiver I plan to install into the custom base. The other three wires of this cable will be spares in case I need them for anything else:


Building Up the Electronics Mount


Just like with the Saucer Wiring, I prepared three MOSFET boards by soldering Trigger/PWM (red) and Ground (black) wires to them using a length of 26AWG 2-wire cable:

These MOSFETs were then attached to the Custom Mount I created in Battle Section Pt. 1 using small 2×4 mm screws, as shown:

In case you did not notice, I also de-soldered the large screw terminals from each of these MOSFET Boards. They took up a lot of room and space is limited inside the Battle Section:

Voltage Dividers

Next, I began working on the connectors for the HC-05 and HM-10 Bluetooth Transceivers.

NOTE: If you have not configured these BT modules yet, check out my Bluetooth page for details!

Both modules are limited to a 3.3V input signal on their RX pins. As I have mentioned before, we can lower the 5V output of the Arduino IO pins to 3.3V using a voltage divider. To begin, I cut a small 4-pin section of female 2.54 mm Female Pin Header and soldered a 2KΩ ¼ watt resistor between these pins.

For the other leg of the voltage divider, I first soldered a short 1KΩ ¼ watt resistor to a length of yellow wire. I also used heat shrink tubing along the way to protect the connections when I can:

The opposite end of this resistor was soldered to the pin that will connect to the RXD pin of the Bluetooth Transceiver. You can see how this will work: the 5VDC output of the Arduino will pass through the yellow wire and 1KΩ resistor, but because the next point it soldered to ground via the 2KΩ resistor, only two-thirds of the voltage is available at that point. And, two-thirds of 5V is 3.3V – which is exactly what the RXD pin needs:

I soldered an orange wire to the pin that will connect to the TXD output of the Bluetooth Transceiver. No resistor is required:

As I test fit this connection to one of the Bluetooth Transceivers, I realized we could better protect the 2KΩ resistor if I resoldered the resistor to the other side of the Pin Header, seen here:

Finally, I added a red and black wire for the VCC (+5VDC) and GND (-) pins:

The heat-shrink tubing was then slid up into place and heated until snug:

We need two of these harnesses, so I made an exact copy of the first one:

When connected to the Bluetooth Transceiver, you can see how the yellow wire of this harness provides signal input to the RXD pin via a voltage divider to ground. I found this to be a space-saving solution and still operate as we expect:

Installing the Other Components

We can now slide the HC-05 (top) and HM-10 (bottom) Bluetooth Transceivers into the Mount. I also took some small 1.6x4mm screws and mounted the Arduino Nano, as shown:

To power the Arduino Nano, I soldered up the +5VDC (red wire) and GND (black wire) pins to a length of 26AWG 2-wire cable:

Now is a good time to share the pinout diagram of the Arduino Nano, my Nacelle wiring guide, and what each pin should connect to. If using a Arduino Nano, Pins 3 and 6 are connected as shown below. I didn’t know it at the time, but my Nano was a ‘Every’ model and required reversing the wires of Pins 3 and 6 and changing the code:

To connect the HM-10 Bluetooth Transceiver to the Nano, I soldered the yellow RXD wire to Pin 13 and the orange TXD wire to Pin 12:

To connect the HC-05 Bluetooth Transceiver to the Nano, I soldered the yellow RXD wire to Pin 3 and the orange TXD wire to Pin 2. I also soldered the positive (+) trigger wire for the Window Lighting MOSFET to Pin 9.

NOTE: If you are using an ‘Nano EVERY’ model of the Nano with the ATmega4809 chip, do not solder Pin 3 just yet.

Next, I soldered the positive (+) trigger wire for the Bussard Collectors MOSFET (on the upper left in this picture) to Pin 5:

Then, I soldered the positive (+) trigger wire for the Warp Grilles MOSFET (on the upper right in this picture) to Pin 6:

I brought all of the negative (-) black leads from the three MOSFET boards together…

… and soldered these wires to the second GND pin on the Arduino Nano. I know I am not the world’s best ‘solderer’, but it works:

IMPORTANT: It was at this point where I powered up all of the electronics so far and tested them. I quickly found out that no voltage would come out of Pin 6. After a lot of research, I realized that my code was written for an Arduino Uno/Nano using the ATmega328 chip. I did not realize that my Nano was the newer ‘Nano Every’ model with the ATmega4809 chip. Without getting into the details, you cannot use Pin 6 for a PWM signal when using the IRRemote library and a ATmega4809 chip – there is a timer conflict. Therefore, it was necessary to swap Pin 3 and Pin 6 in both the code and the wiring.

During this troubleshooting process, I even swapped out my Nano for a second one. Therefore, I had to resolder all the connections, but this time the yellow RXD wire of the HC-05 Bluetooth Transmitter was soldered to Pin 6:

The trigger (+) wire for the Warp Grilles MOSFET was then soldered to Pin 3 instead. The rest of the pin connections are unaffected by this change and were connected as before:

Powering the MOSFETs

Moving on to providing main power to the MOSFETs, I soldered lengths of wire to the VIN- and VIN+ terminals. I wanted each MOSFET to have a direct power feed to prevent any power loss or excessive amperage anywhere else. First up is the MOSFET that will control the Window lighting. I tried to feed the wires down into the existing holes, but struggled so much, I just soldered them on top:

Next, I soldered separate lengths of wire to both the Bussard and Warp Grille MOSFET inputs. You may notice I marked each MOSFET with a Sharpie to indicate which is which: W – Warp Grilles, B – Bussard Collectors:

Finally, I brought all of the positive (+) and negative (-) power leads together (Arduino +5V/GND, VCC/GND of the two BT Transceivers, and all three MOSFET feeds). At this point, our Mount assembly is ready to be installed into the Battle Section of our ship:

Lighting the Battle Section

I used the same 5V DC USB LED Light Strips in Daylight White (6000K) as the Saucer to light my Battle Section. I cut four lengths of the LED Strip to accomplish this: one at 15.5 inches long, one at 8 inches, and two at 4.5 inches.

I soldered a long length of 2-wire 26AWG cable to the 8 inch section first:

The free end of this LED Strip was connected to the 15.5 inch piece with about 1 inch of wire. The free end of the 15.5 inch piece was soldered to a 4.5 inch piece with another inch of wire. Finally, the free end of the 4.5 inch piece was soldered to the second 4.5 inch piece with about 3 inches of wire. So, it should be one long chain circuit like this:

I wrapped the starting 8″ section so it would start and end at the two front Rod Supports of the Upper Bracket, as shown:

To insulate the exposed contacts of the LED Strip, I used Black Tulip Fabric Paint to cover any exposed contacts of the LED Strip anywhere it might contact the metal skeleton, such as this post:

This first section of LED Strip needed to be installed now so it can light the nearby windows underneath the Mount platform. We can now use FM screws to secure the custom Mount into place:

The main leads of the LED Strip chain can be trimmed down and soldered to the OUT pins of the Windows MOSFET. Here, I used green wire for positive (+) and black for negative (-):

Connecting the Neck Wiring

I fed all the wires coming from out of the bottom of my Neck assembly through the two holes I drilled in the Battle Section Front Panel and into the space behind the Deflector Dish. Then, I fed the tabs of Neck assembly into the Battle Section and slid it towards the rear to lock it in place. I then gathered up all the negative leads from the following (circled below):

  • Neck-to-Saucer Barrel Plug Connector (Main Power)
  • Neck Lighting LED Strip
  • Neck Beacon Light
  • Neck Formation Lights (red/green)
  • Neck Photon Torpedo Launcher

These wires were soldered to the negative wires of the Mount components and the Barrel Plug Connector going out the bottom of the ship (arrows below):

In the same way, the positive wire of the Neck Window Lights and Saucer Separation Magnetic Switch were joined to the positive wire of the Neck-to-Saucer Barrel Plug Connector and these wires were soldered to the positive wires of the Mount components and the Barrel Plug Connector going out the bottom of the ship. The negative wire of the Neck Window Lights was soldered to the negative OUT of the Windows MOSFET (alongside the Battle Section windows).

Next, we can move on to connecting the remaining wires to the Arduino Nano, as shown:

Then, we can solder the wires from the nacelles to the PWM MOSFETS, as shown:

The Ventral Battle Section Beacon

I actually assembled the rest of the Battle Section before I realized we need to wire up a light for the beacon on the bottom of the Battle Section – whoops! This flashing warm white beacon will need to be connected to the same circuit as the one I added under the Neck. For this, I used the same pre-wired warm white 0402 micro LED as before (also colored with my Yellow Brush Sharpie):

As this LED needs a resistor, I cut the leads of a 100Ω resistor short and soldered one end into the same Arduino connector hole as the Neck beacon (DIGITAL 7).

NOTE: I later realized that I have been using a 470Ω resistor on these beacon lights elsewhere, so I changed this resistor after the picture was taken:

To the free end of this resistor, I soldered the positive wire of the LED. A piece of heat-shrink tubing was added as well:

The extra lead of the resistor was snipped off and the tubing heated into place. Then, the negative lead of the LED was soldered to the great glob that is my main negative junction. Like I said, I am no soldering jedi!

UPDATE March 7, 2024: After I closed up my battle section, I realized I forgot to add the pull-down resistor for my magnetic reed switch in the ‘cobra head’ – see my NECK page for details. This is a 10KΩ (10,000 ohm) ¼ watt resistor meant to keep the switch from floating between the on and off state and causing a noisy signal. It was simply soldered between Nano’s pin A0 and Ground, as shown here:

With the ventral beacon now connected (and tested), I could finish up the steps of Stage 90 and install the Lower Bracket skeleton. The main power line and 4-wire plug were routed out through the display stand hole. The ventral beacon LED was routed out this opening of the Skeleton:

This completes the majority of the wiring of our Model Remodel Enterprise D. I gave the entire system a functional test and everything worked as expected. I have to admit, I am happy this work is behind me as I am not the best electrician in the world!

Next Section

 SAUCER ENGINES – Upgrading the lighting (and light-blocking) of the saucer’s Impulse Engines

2 thoughts on “BATTLE SECTION PT. 2”

  1. Question: Where does the positive wire of the Neck Lighting LED Strip go, as this was not mentioned

    1. It connects to the mains positive (+) junction inside the battle section. The negative goes to the Windows MOSFET output.

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